This PDF file contains the front matter associated with SPIE Proceedings Volume 7544, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

Form error in-process optical measurement is to provide feedback during a machining process for precision control. Based on the method of water beam assisted form error in-process optical measurement, a new air beam approach was proposed to solve the problems of coolant dilution and optical transmittance through multiple media. In order to identify key parameters to reduce the workload of experimental tests, a factorial test was conducted on transparent window size A_t and stability est. Calibration and assessment of A_t and e_st were introduced. Factorial test design was also examined. Results of the study show that v_t, v_a, and d_a are the key parameters on A_t. Although all 6 main parameters are not significant, vt is relatively more important on est. When v_t increases, A_t will decrease. When v_a or d_a increases, A_t will increase. The findings agree with our understanding of the physical process of fluid flow. When v_t decreases, the transparent window size stability e_st will be better. Consider both stability e_st and air velocity v_a, Run 11 should be the best choice of conditions for A_t. A larger transparent window size At typically gives better transparent window size stability e_st. To achieve a balance between e_st and v_a, a suitable size of transparent window at A_t=~30 mm² should be a good choice. Further studies are necessary to confirm the findings.

Workspace Measurement Position System (wMPS) is a newly developed laser based measuring system for large scale metrology. Initially, theoretical definition of metrology process models of wMPS is described and uncertainties are propagated from internal parameters using Monte Carlo simulation in which uncertainty decreases with sampling duration. Angular uncertainty is affected by internal parameters pointed out by mathematical model and experiments are then carried out to determine the actual uncertainty in the azimuth and elevation in order to select appropriate parameters to design the measuring system. Experiment results reveal that wMPS has the ability of accurate measurement for large volume and the uncertainty is less affected by the working volume. Measuring results shows wMPS designed based on the parameters achieves relative high measuring precision.

An optical method is proposed for in-situ measurement of angles of space elements separated at a distance of several or several tens of meters. When it is necessary to measure large objects or geometrical elements within a large scale space, it is not always possible to bring these workpieces to conventional coordinate measuring machines (CMMs) which are widely used in industries. Mobile measuring systems provide ideal solutions for these applications. The basic idea of the presented research work is to set up the multiple common optical references through which the dimensional inspections of separation angles of bifacial lines in a large scale space can be fulfilled. The angles between the projection light and each element can be captured through a machine vision system, and thereafter the angles between those corresponding elements can be determined using the geometrical principles. The method and the calibration approach have been validated on our designed work station.

Using the house-made transmission grating (3300 l/mm) and IRDAXUV100G (USA) photodiode detector, higher order harmonics contributions have been measured in the spectral radiation standard and metrology beamline at NSRL and the contributions of the different orders have been analyzed. In order to accurately calibrate the performance of optical elements, higher order harmonics must be efficiently suppressed. Selecting the suitable filter in different wavelength, the higher order contributions can be efficiently suppressed. In wavelength region between 5 nm and 12 nm with proper Zr filters, the contributions of higher order intensity are less than 1.25%, after modified by quantum efficiency of the detector , the higher order contributions are restricted to less than 0.62 %. In wavelength region between 13 and 17 nm with Si filter, the higher order contributions are almost zero. In wavelength region between 18 nm and 34 nm with proper Al filter, the contributions of higher order intensity are less than 8.06%, after modified by quantum efficiency of the detector, the higher order contributions are restricted to less than 3.08 %.In wavelength region between 35 and 40nm with Al/Mg/Al filter, the higher order contributions are restricted to less than 10.00 % after modified by quantum efficiency of the detector.

In order to develop an on-line optical lens measurement system, a dual autofocusing algorithm consisting of coarse autofocusing and fine autofocusing is proposed to realize the accurate and automatic image grabbing. In the procedure of coarse autofocusing, variance function on the whole image is selected as sharpness evaluation function (SEF), and mean comparison method is applied to realize the hill-climbing algorithm for focal plane searching. A 3-point method is used to initialize the searching direction. In the procedure of fine autofocusing, a conditional dilation method based on mathematical morphology is used to extract the region of interest (ROI), namely, the target images, and a shape factor is employed to eliminate the disturbance regions. Brenner function within ROI is selected as SEF, and single-point comparison method is used to find the focal plane accurately. Compared to the traditional methods, this dual autofocusing algorithm not only can realize high precision focusing, but also has large autofocusing range. The experiment results show that the dual autofocusing technique can guarantee that the focusing position locates in the depth of field. The proposed algorithm is suitable for the on-line optical lens measurement.

The relationship between subjective ride comfort in a vehicle seat and human whole-body vibration can be modeled using frequency weightings and rms(root mean square) averaging as specified in ISO2631. However, recent studies indicate that, there are some flaws in the relationship between subjective response and objective vibration given by the ISO2631.This paper presents an alternative approach based on neural network model. Time-domain vibration acceleration signals are processed as neural network inputs, subjective evaluation results are quantified as outputs, and the weights of neural networks are used as frequency weighting coefficients to evaluate the vehicle ride comfort. The method has been used to evaluate the ride comfort on a number of conditions with good results achieved.

Symmetricom's Multi-channel Measurement System (TSC MMS) is a phase measurement device based on the measurement principle of dual mixer time difference method (DMTD). TSC MMS is purchased by Time and Frequency measurement laboratory in National Time Service Center of Chinese Academy of Sciences. In order to evaluate the measurement capability of DMTD and research the improved method of performance, in this paper, the TSC MMS performance test platform is set up. We ensure the test signals have better stability than system, and the invariant environment to reduce the effect of measurement produced by external environment as much as possible. Under the same condition, three-day data are collected to measure the noise floor of a system. Finally, we analyze the reasons attributing to the measurement results and proposed a improving method in detail. The measured results demonstrate that the Allan deviation stability will reach 3E-13 per second when the frequency of the input signals is 10MHz.

This paper presents two various methods of transmission delay measurement for converter. One is group delay measurement method for multi-lever converter by means of high performance vector network analyzer. The other is envelope method used to determine the absolute delay of a converter using fast sampling scope. A scheme and key technologies of group delay measurement are described. A good measurement example is given and measurement results and their uncertainty are analyzed. It can not represent the real delay when modulation signals pass though the converter, Because the group delay curve measurement is performed by a vector network analyzer which needs the input of sweep frequency stimulation signal. Therefore, the characterization of BPSK modulation signal is analyzed. Transmission delay measurement method of BPSK modulation signal which passes though the converter is researched. Finally, the two measurement results obtained using two methods mentioned above are compared.

In order to effectively detect and remove abnormal data during dynamic measurement of discontinuous surfaces, this paper presents an effective method based on the dynamic GM(1,1). The dynamic GM(1,1) is used to implement modeling for the primary measurement data. The model based on the dynamic GM(1,1) can be a good approximation to normal data, while insensitive to abnormal data. Through comparing the model with the primary measurement data, abnormal data can be effectively detected according to a certain criterion. An experiment is carried out to verify the proposed method for detecting and removing abnormal data. A gross error is artificially introduced into the mesh errors of a hob at the ninth cutting. For the ninth cutting edge, the residual error between the mesh error and the modeling value is 3.2077 and greater than 2.5S. The mesh error of the ninth cutting edge is abnormal and replaced by the corresponding modeling value. The experimental result shows that the proposed method can effectively detect and remove abnormal data during dynamic measurement of discontinuous surfaces.

According to the operation and operator theory in the new generation geometrical product specification (GPS), the verification operator of cylindricity errors is an ordered set of several feature operations, including partition, extraction, filtration, association, and so on. Each feature operation contains some uncertainty due to the variability of measurement process and the incompleteness of ISO specification, and the uncertainty in previous operation can be transferred to the subsequent operation, resulting in cylindricity errors with high uncertainty. To ensure accurate evaluation of cylindricity errors, a method is proposed for estimation of uncertainty propagation in verification operators of cylindricity errors based on the new generation GPS. By investigating the propagation model of the uncertainty of cylindricity errors, the calculation formulas for the uncertainty propagation of key feature operations in operator, such as association operation and filtration operation, are proposed. The uncertainty calculation expression is developed for the choice of verification operators of cylindricity errors. The effects of filtration operation and association operation on the uncertainty of cylindricity errors are further verified through a case study. Test results indicate that the proposed method can not only improve the veracity of evaluation, but also provide helpful guidance for the reasonable choice of verification operators of cylindricity errors.

In order to increase the speed of photoelectric conversion, a linear CCD is applied as the photoelectric converter instead of the traditional photodiode. A white LED is used as the light source of the system. The color information of the urine test strip is transferred into the CCD through a reflecting optical system. It is then converted to digital signals by an A/D converter. The test results of urine analysis are obtained by a data processing system. An ARM microprocessor is selected as the CPU of the system and a CPLD is employed to provide a driving timing for the CCD drive and the A/D converter. Active HDL7.2 and Verilog HDL are used to simulate the driving timing of the CPLD. Experimental results show that the correctness rate of the test results is better than 90%. The system satisfies the requirements of the color information collection of urine analyzer.

This paper presents a dual magnetic circuit magnetic bead method and corresponding system for testing human blood coagulation. The system is composed mainly of a dual magnetic circuit magnetic beads test assembly, a signal modulation and demodulation module, a digital filter as well as a waveform processor. Smart hardware design together with subsequent software algorithm is presented for the system to overcome the defects of traditional dual magnetic circuit magnetic bead method. Experiments for verifying the system are carried out in comparison with an ACL200 coagulometer from Coulter Co. USA. Experimental results indicate that the system features excellent precision, repeatability better than 2.10%, and show that the dual magnetic circuit magnetic bead system suppresses external interference factors effectively.

New generation Geometrical Product Specifications (GPS) consist of a series of standard drafted by ISO/TC 213, which relate to drawing indication, definition of tolerance and values of specifications, characteristic, parameters and definitions of actual features, comparing verification, measuring instrument, and calibration of size, distance, radius, angle, form and position of geometrical features, roughness profile, waviness profile, primary profile, surface imperfection and edges. The characteristics of the GPS, e.g. chain matrix model in each standard, a lot of new and mathematical terms, the size system, indications of dimensions other than linear sizes by using geometrical tolerances, uncertainty series and etc., are introduced in this paper. Based on the characteristics above, some challenges in the implementation of the GPS are analyzed. Therefore, a lot of in-depth adaptive studies of GPS in indications of the sizes and the dimensions other than linear sizes in the drawings, the evaluation models of uncertainties, the measuring techniques and instruments and etc. should be done, and the matching user manual should be provided to designers, manufactures, inspection personnel for the wide application of the GPS.

Stimulated emission depletion (STED) microscopy exploits nonlinear saturable optical transition of fluorescent molecules, allowed to overcome Abbe's diffraction-limit and provides diffraction-unlimited resolution in far-field optical microscopy. We elaborate the mechanism of STED and the conditions of depletion. The formula of STED microcopy resolution is deduced through effective point spread function (E-PSF). The STED system resolution is mainly dominated by the quality of the fluorescence depletion patterns in the focal plane. The depletion pattern is mainly affected by STED beam intensity, polarization, phase plate, primary aberrations, STED pulse shape, pulse duration and delay time. In this paper, we found related models and simulate the relationship between the depletion patterns and the parameters, and put forward effective approach to enhance the system resolution.

Molten salts (sodium and potassium nitrides) are going to be used in many different plants as heat transferring fluids, e.g. concentration solar plants, nuclear power plants, etc. In fact they present may important advantages: their absolute safety and non toxicity, availability and low cost. But their use, e.g. in the energy receiving pipe in the focus of the parabolic mirror concentrator of the solar thermodynamic plant, requires the accurate knowledge of the thermophysical properties, above all thermal conductivity, viscosity, specific heat and thermal linear expansion, in the temperature range 200°C÷600°C. In the new laboratory by ENEA Casaccia, SolTerm Department all these properties are going to be measured. Thermal conductivity is measured with the standard probe method (linear heat source inserted into the material) manufacturing a special probe suited to the foreseen temperature range (190-550°C). The probe is made of a ceramic quadrifilar pipe containing in different holes the heater (Ni wire) and the thermometer (type J thermocouple). The thermal linear expansion will be measured by a special system designed and built to this end, measuring the sample dilatation by the reflection of a laser beam by the bottom of the meniscus in the liquid solid interface. The viscosity will be evaluated detecting the start of the natural convection in the same experiment as to measure thermal conductivity. In the paper the construction of the devices, the results of preliminary tests and an evaluation of the obtainable accuracy are reported.

The paper describes the manufacturing and dimensional measurements of high precision work-pieces by PTB, which shall act as test masses (TM) for the satellite-based experiment MICROSCOPE. The manufacturing involves turning of Ti alloys and PtRh10. The measurements were made by in-process tactile probing, coordinate metrology, and form measurement. The high geometrical demands of the project could be fulfilled on both the manufacturing and the measurement sub-projects.

A high-precision optical scale called LDGI (Linear Diffraction Grating Interferometer) has been developed for long stroke measurement to nanometer accuracy. This study presents the principle of newly developed LDGI and its possible waveform errors of output signals. Mathematical methods for waveform error correction, pulse counting, signal subdivision and displacement calculation are proposed. All the digital processes are carried out by software. Experimental results show that the system has high tolerance to geometrical errors of the moving stage. The standard deviation of measured values is within 20nm even up to 18mm long stroke.

Single crystal diamond micro-cutting tools, which are used for fabrication of precision micro-parts, have very sharp tool edges with radii in the range of tens of nanometers or even nanometers. Although there are many types of tools, the tools with a rounded nose are treated in this paper. They can be used for fabrication of very smooth and accurate surface with 3D micro structures such as micro-lens arrays, diffractive optical elements and so on. The machined quality is highly depending on the tool edges' states and it is desired to manage them. This paper presents a measuring instrument based on atomic force microscope (AFM), which is designed and constructed for on-machine measurement of the cutting edge profile. It is a combination of an AFM probe unit for 3D edge profile measurement and an alignment system with an optical sensor for aligning the probe-tip with the tool's edge top so that the measurement can be carried out in a short time. Measurement experiments of micro-tools with (nominal) nose radii of 8 μm and 0.2 mm are summarized to show the performance of the instrument. And the nose radii were evaluated as 7.2 μm and 0.188 mm, respectively.

This study aims at the development of a less reflective electromagnetic pneumatic actuator often used in the anechoic chamber. Because a pneumatic actuator on the market is not appropriate for use in such a chamber and a metallic one has high dielectric constant which generates reflective electromagnetic waves to influence test parameters in the chamber. The newly developed pneumatic actuator is made from low dielectric constant plastics with less reflective of electromagnetic. A turbine-type air motor is used to develop the pneumatic actuator and a employ Prony tester is used to run the brake horsepower test for the performance test of pneumatic actuator. Test results indicate that the pneumatic actuator in the minimal starting flow is 17 l/min, and it generates a brake horsepower of 48 mW; in the maximum flow is 26 l/min, it generates a brake horsepower of 108 mW. Therefore, it works with a torque between 0.24 N-m and 0.55 N-m, and such a torque will be sufficient to drive the target button.

The Differential Interference Contrast approach (DIC) which is frequently used for image enhancement to increase the contrast between transparent object and its background is adopted for the dimensional measurement of a transparent structure. With the phase difference image retrieved using the DIC technique, the phase map of the examined object can be approximated by integrating the phase difference. Experimental results show the feasibility of using the transmitted DIC for transparent object measurement. The results show that the height of a transparent structure measured using the DIC method is quite close to those measured using AFM while those measured using the white light interference method results in much larger measurement than all others. However, when a structure is no longer a simple geometry, adopting this method directly might results in wrong results. In this paper, we would like to present the work had been done, discuss the challenge ahead, and possible approach can be adopted.

In-process form error measurement provides feedback for precision control. There many existing studies on in-process roughness and size measurement but few on in-process form error measurement. Water beam based in-process form error measurement is proposed to solve the opaque problem of the commonly used coolant in precision machining. Factorial test results show that the water flow rate Q_w is one of the five important parameters to give a reasonably acceptable transparent window size A_t for the in-process form error measurement. In this project, both experimental and computational studies were conducted and the results show that transparent window size A_t will increase with the water flow rate Q_w and will decrease with the height of medium hm, coolant concentration c_c, table velocity v_t, and water channel diameter Φ_w. Based on the results of A_t(Q_w,h_m) and the results of A_t(Q_w,v_t), the ranges of Q_w∈[0.65,0.75] ml/s, h_m∈[0.5,0.55] mm, and v_t∈[120,150] mm/s would give a transparent window size A_t∈[20,40] mm², which is reasonably acceptable for the laser measurement currently for the tests. The results will be useful for design of the in-process sensor.

This study presents a reflective-type optical encoder based on fractional Talbot self-image effect using a phase grating. An amplitude grating image is produced by the phase grating at a quarter or three quarters of Talbot distance. The encoder has the advantages of a large gap and more light efficiency. This work use a 850nm Light-Emitting Diode (LED) as light source, the light source will be collimated by a collimator ,and incident on a phase grating by 45° angle. The fractional Talbot self-image of phase grating is produced and projected on an amplitude index grating. The Moiré interference is occurred when the both gratings displaced from each other. The encoder includes a reflective-type phase-grating scale with period 20 μm and an index-amplitude grating. The gap between the phase index grating and mail scale was increased to three quarters of Talbot distance. The tolerance of gap between the index and main grating is 0.1 mm. The tolerance of yaw motion is ± 0.25°.

The conventional angular measurement method based on moiré fringe is only competent to measure one-dimensional angle. The grating is replaced by combined horizontal and vertical gratings, therefore the yaw and pitch angles can be measured at the same time by figuring out the displacement of the vertical and horizontal moiré fringe. Moreover, when the main grating is adhered to the mirror which is rigidly attached to the measurement target, the roll angle can be measured by obtaining the width change of the moiré fringe. To validate this improved method, an experimental verification system is set up. The moiré fringe images are captured by a CCD detector, and then the width change and displacement of moiré fringe are obtained using image processing technology. Experimental results indicate that in a view field of ±30' the yaw and pitch angles measurement precision reaches 0.5" and the roll angle measurement precision reaches 1.5".

This paper presents the measurement of the slide error of a large-scale ultra-precision lathe with an effective fabricating length of 2000 mm. A cylinder workpiece with a diameter of 320 mm and a length of 1500 mm was mounted on the spindle of the lathe with its rotational axis along the Z-direction. Two capacitive displacement probes with a measurement range of 100 μm were mounted on the slide of lathe with its moving axis along the Z-direction. The displacement probes were placed on the two sides of the cylinder workpiece over the horizontal plane (XZ-plane). The cylinder workpiece, which was rotated by the spindle, was scanned by the displacement probes moved by the slide. The X-directional horizontal slide error can be accurately evaluated from the probe outputs by using a proposed rotatingreversal method through separating the influences of the form error of the cylinder workpiece and the rotational error of the spindle. In addition to the out-of-straightness error component, the parallelism error component with respect to the spindle axis, can also be evaluated. The out-of-straightness error component and the parallelism error component of the slide error were measured to be 3.3 μm and 1.68 arc-seconds over a slide travel range of 1450.08 mm, respectively.

Rail track geometric parameters, such as gage, level, twist, longitudinal irregularity, and alignment irregularity, etc., have much influence on the operation safety of train vehicles. GJ-4 track inspection car is a large scale dynamic measurement equipment for measuring track geometric parameters precisely and efficiently. It is useful to find track defects, guide track maintenance, and eliminate potential safety problems of track. However the device of measuring gage and alignment irregularity of this track inspection car is installed on a hanging beam, which is not suitable for rapid inspection and has higher failure rate. Hence this sub-system is replaced by the laser-camera method. The rebuild car is named GJ-4G. It greatly eliminates the measurement errors caused by the existing subsystem and increases the measuring stability. The feasibility of this track inspection car has been proven by the practical experiments carried out by Beijing Railway Administration.

Predictive measurement method was proposed for the circular position of time grating CNC rotary table. To reduce the dynamic prediction error and achieve high precision position feedback, this paper analyzes the characteristics of the dynamic prediction error caused by multi-factors of space and time quantity, and then proposes a discrete standard quantity interpolation method for real-time error correction. A dynamic prediction error correction model is established for the circular position of time grating rotary table, and the measured values of time grating are adopted as the standard of predicted values. The last prediction error is corrected in real-time with the current measured values of time grating after current position predicting is conducted. An experimental positioning system is designed to confirm the validity of the proposed methods. The dynamic error of time grating CNC rotary table is ±2", which proves precise prediction is achieved.

An oblate solid cylinder damping material specimen is used to construct three damping systems with three different additional masses. The specimen is excited by an electromagnetic shaker in the vertical direction, and the specimen excites the additional mass vibrating. The damping properties of the damping material change as the additional mass and the exciting magnitude change. Not only the traditional damping properties, such as the damping ratio, the vibration transfer rate from excitation to additional mass, and resonant frequency, but also the nonlinear properties of the damping system with different masses are measured to evaluate the damping specimen. The magnitude-frequency characteristics of vibration transfer rate with different additional masses are measured under constant stable excitation and linear vibration state over a frequency range which includes the resonant frequency of the fundamental mode. The nonlinear vibration transfer properties with different additional masses are measured and investigated under higher vibration magnitude. Experiment results indicate that both linear and nonlinear damping properties of the damping system change as the exciting magnitude and the additional mass change.

A method to accurately measure landmarks of Hanjiangfish fossil based on computer vision is presented. Hanjiangfish is a deracinated vertebrate ever lived on the earth four million years ago. The geometric morphometry of the ichthyolite based on the landmark measurement is fundamental in the vertebrate palaeontology. The landmark measurement is based on digital model of the fossil. The Hanjiangfish fossil is measured fast and accurately by using the structured-light scanning method. The digital model of the fossil then is made from the cloudy data through the acquisition, align, merge, and edit processes. The local least-square method is used to fit two lines near the measured landmark. The landmark is the point of intersection of the two fitting lines, which is unique and accurate. The distance between all pairs of landmarks and interior angles from a triangulation of the landmarks can be measured fast and accurately by the digital model. Other important geometric parameters of the fossil, such as curvature and surface area can also be measured by the digital model. The Hanjiangfish fossil is also measured accurately by a universal tool microscope, which is used as a measuring standard with higher accuracy to validate the proposed method. The experiment shows that the measured errors of the distance and angle are less than 0.1 mm and 1' respectively, which are good enough for geometric morphometry of palaeontology.

An on-line monitoring system for controlling the thickness and the flatness of NdFeB (Neodymium Ferrite Boron) laminate components during the skiving process is reported. The on-line monitoring system mainly consists of a non-contact eddy-sensor, a preamplifier, an A/D conversion card and a computer. The detailed description of the system with respect to the connection between the probe and the grinder is provided. Practical on-line measurement and data acquisition experiments are carried out. Experimental results indicate that the system principle is feasible and the accuracy is up to μm order. The monitoring system can be used to improve conventional grinders that are widely employed currently in China.

This paper describes a computer vision method for reconstruction of three-dimensional object which is capable of reconstructing the profile of the object real time and achieving high accuracy. The approach makes use of the light-section projecting a line-laser beam on the surface of an object. This work is distinguished by three key contributions. The first is the introduction of the light-section method and laser triangulation method. The space coordinates of points in the bright stripe which are considered as the first bright stripe outlining the measured object can be figured out by way of the laser triangulation method. The second contribution is algorithms of coordinate restoration, involved camera calibration and calibration of the central axis of turntable, which restores the space coordinates of the original points in the original bright stripe from that of being considered as the first bright stripe. The third is the profile reconstruction method for plotting the profile of the measured object using the OpenGL. In this paper, an experiment on a small disposal paper cup has been carried out and the three-dimensional profile of the paper cup has been obtained. The results meet the requirement of high accuracy and simplicity of computation.

Rotary parts are used commonly in the field of precision machinery and their roundness error can affect installation accuracy greatly which determines the performance of machine. It is essential to establish a proper method for evaluating roundness error to ensure accurate assessment. However, various evaluation algorithms are time-consuming, complex and inaccuracy which can not meet the challenge of precision measurement. In this paper, an improved area hunting method which used minimum zone circle (MZC), minimum circumscribed circle (MCC) and maximum inscribed circle (MIC) as reference circle was proposed. According to specific area hunting rules of different reference circles, a new marked point which was closer to the real center of reference circle was located from grid cross points around previous marked point. Searched area was decreasing and the process of area hunting terminated when iteration accuracy was satisfied. This approach was realized in a precision form measurement instrument developed in NIM. The test results indicated that this improved method was efficient, accurate and can be easily implemented in precision roundness measurement.

Common profilometers cannot be used to measure the complex surfaces with large range. A cantilever profilometer with large range and high accuracy is presented in this paper. The profilometer is composed of inductive sensors, gratings and angle measurement structure, which are used to measure surface profile, movement displacement and angle of the cantilever beam separately. The angle measured by the invariant light-distance structure based on auto-collimation principle is used to compensate the Abbe error to ensure high measurement accuracy. For counting accurately, a method of resistance chain subdivision is designed to process the grating interference fringe signal. Experiment results show that the Abbe error can be compensate through the invariant light-distance structure based on auto-collimation principle. The designed profilometer can be used to measure complex morphology.

The shape and size of a pocket influences the pressure distribution on the working face of an aerostatic bearing and causes the vibration in normal direction of air gap. In order to analyze the pressure distribution on the working face of an aerostatic bearing caused by the shape of a pocket, an aerostatic bearing restrictor with multi-loop coupling pocket is proposed and double-loop and tricycle forms are taken as examples to illustrate the arrangements of a pocket and analyze the pressure-impedance relationship of a throttle system in different situations. Simulation is done using FLUENT, a computational fluid dynamics (CFD) software, to obtain the pressure distribution on the working face of an aerostatic bearing and the static performance curve with respect to the diameter of an orifice. The comparison between restrictors of aerostatic bearing with or without double-loop coupling pocket shows that the addition of a multi-loop pocket on the working face of an aerostatic bearing contributes to the improvement of surface pressure-averaging effect and static load carrying capability, and the reduction of air film vibration, thereby improving the measurement accuracy. These results are of practical significance for the design of key aerostatic bearing components.

Three kinds of TCC (transmission cross coefficient) calculation algorithms used for partially coherent imaging simulation, including the integration algorithm, the analytical algorithm, and the matrix-based fast algorithm, are reviewed for their rigorous formulations and numerical implementations. The accuracy and speed achievable using these algorithms are compared by simulations conducted on several mainstream illumination sources commonly used in current lithographic tools. Simulation results demonstrate that the integration algorithm is quite accurate but time consuming, while the matrix-based fast algorithm is efficient but its accuracy is heavily dependent on simulation resolution. The analytical algorithm is both efficient and accurate but not suitable for arbitrary optical systems. It is therefore concluded that each TCC calculation algorithm has its pros and cons with a compromise necessary to achieve a balance between accuracy and speed. The observations are useful in fast lithographic simulation for aerial image modeling, optical proximity correction (OPC), source mask optimization (SMO), and critical dimension (CD) prediction.

This paper discusses the influence of ambient temperature and relative air humidity on pepper blade thickness, and establishes theoretical model of these two ecological factors with the changes of pepper blade thickness, on the basis of experiment data of pepper blade thickness, ambient temperature and relative air humidity in 24 hours. The vivo measurement of plant blade thickness with high accuracy is realized using a self-developed precision plant blade monitor instrument. The correlation of the influence of ambient temperature and relative air humidity with the changes of pepper blade thickness is established, analyzed and modeled by controlling other ambient variables. Test results show that the changes of pepper blade thickness and ambient temperature vary inversely, and there is a significant negative correlation between them. However, the change of blade thickness and air humidity show the same trend, and there is a significant positive correlation between them. According to the correlation analysis, the influence model of ambient temperature and relative air humidity with pepper blade thickness is established using multiple linear regression method. Significant test results show that in the period of 0:00A.M.~7:00P.M., pepper blade thickness was significantly influenced by ambient temperature and relative air humidity, while during 7:00P.M.~0:00A.M., the influence was weaker, probably due to the inertia of environment factors and plant's physiological activities. The model of pepper blade thickness can be used to guide the establishment of water-saving irrigation system controlled by blade thickness monitoring.

Planar cross diffraction grating can be adopted to measure displacement as scale. In this paper, Planar grating interferometer configuration for precise displacement measurements is introduced, and the principle of interferometer based on polarization optics is deduced. According to 2-D grating interferometer structure, error sources are analyzed, and the pitch and yaw of 2-D grating guide caused by planar guide's non-linearity is the main factors to decrease the measurement system's accuracy. With grating interferometer error sources analysis, precise planar stage is proposed to integrate with the gating interferometer, the stage is compact and can minimize abbe error in structure. The methods of calibration and error compensation are employed to improve the position accuracy of the stage. As experiments show, the stage position repeatability is less than 0.1um.

In order to solve the contradiction between wide scope and high precision of coordinate measurement, a new coordinate measurement method based on coding target and vision measurement is proposed. According to the holographic characteristic of coding target, the position and orientation information of coding target can be obtained by any section of coding image on the target, then the position of the target probe can be obtained and coordinate measurement is realized. Two CCD cameras gather target coding image from two right-angled orientations and measurement model is established according to the spatial geometric relation. Special coding target is designed and the parameters acquisition method of coding target is studied. Experiments testify the coding target is designed rationally, and the coordinate measurement method based on coding target is established credibly. The system enlarges the measurement range with the measurement accuracy satisfied.

With the development of the machinery industry and the enhancement of the components precision, the large internal micrometer with three-point contact broadens its field of application. However, the calibration method for large internal micrometer with three-point contact has not been solved completely. In order to solve all the calibration problems for large internal micrometer with three-point contact of 100mm and above, this paper proposes a new calibration method. Different from that of the calibration criterion JJF1091-2002 in Micrometer for Measuring inside Dimension, this method mainly uses the high precision CMM to calibrate the internal micrometer with three-point contact. The procedures are as follows. First, use the CMM to scan and measure the internal micrometer with three-point contact. Next, make the evaluation of scanning point with the method of the maximum circumcircle to get the CMM measurements of the internal micrometer with three-point contact in different diameter positions. Second, use the internal micrometer with three-point contact to measure any standard ring gauges within its measuring range to get the indicating value which is also named as reference point indicating value. Third, analyze the diameter value got by using the CMM to measure the internal micrometer with three-point contact in different positions and the reference point indicating value. After data processing, the error of indication in different positions can be got. Last, analyze the uncertainty of measurement to test its feasibility.

In accordance with the principle of Three-Line, this paper analyze the correlation of every main parameter of internal screw thread, and then designed a device to measure the main parameters of internal screw thread. Internal thread parameters, such as the pitch diameter, thread angle and screw-pitch of common screw thread, terraced screw thread, zigzag screw thread were obtained through calculation and measurement. The practical applications have proved that this device is convenience to use, and the measurements have a high accuracy. Meanwhile, the application for the patent of invention has been accepted by the Patent Office (Filing number: 200710044081.5).

An image segmentation method is proposed to locate the position of laser spots reflected by corner-cube array during relative attitude determination between aircrafts. First, the laser spots image acquired by CCD camera is transformed to a grayscale gradient distribution image by the Roberts operator. Then the image is divided into several small pieces according to the distribution of both energy and grayscale gradient. Each piece is segmented based on watershed algorithm individually to detect the margin of laser spots. Seeds of watershed segmentation are selected by using prior knowledge of appearance and energy of laser spots predicted when the laser measure system is designed. A binary image which contains the edge information of the laser spots is acquired after all segmented pieces is merged together. Then expansion and erosion algorithm is used to reduce the effect of over segmentation. The method can effectively remove the system noise or the disturbance brought by the reflection of the other optical antenna near the corner-cube array on the client terminal. Experimental results indicate that location of laser spots calculated by centric method is exactly limited in the anticipated area. The uncertainty of the center location is no more than 1 pixel.

This paper presents a measurement method used to precisely measure the diameter of water jet. A He-Ne laser is coupled into the water jet as the light source, and the image of the water jet is captured by a CCD. The diameter of water jet can be thus measured from the captured images by such processing as sharpening, filtering, subpixel locating and fitting. Experimental results indicate that the proposed method can be used to make real-time measurement of the diameter of water jet with a simple and low-cost set-up. The method can also be used to measure the break-up length of water jet by introducing a microstage along the direction of water jet.

A novel micro-tribometry system has been developed specifically for investigating whether the limited dynamic response of conventional instruments might hide functionally important materials behaviour. It is based on a universal measuring head, suitable for use with a wide range of specimen stages, that incorporates a relatively stiff elastic sensing element and actively-controlled electromagnetic force actuation in both axes. This paper first reviews the rationale for the new design and then explains the critical design features. Characterization and calibration are discussed: the prototype unit is aimed primarily at use in the 10 - 50 mN, with a bandwidth of at least 100 Hz. The basic operation and capabilities of the micro-tribometer head are presented by means of demonstration experiments on smooth and relatively rough surfaces.

This paper discusses the aspects that influence the interaction between a probe tip and a work piece during tactile probing in a coordinate measuring machine (CMM). The trend of component miniaturization results in a need for 3- dimensional characterization of micrometer sized features to nanometer accuracy. As the scale of the measurement decreases, the problems associated with the surface-probe interactions become increasingly apparent. The aspects of the interaction that are discussed include contact forces, surface forces, tip rotations, finite stiffness effects and probe repeatability. These aspects are investigated using the Gannen XP 3D tactile probing system developed by Xpress Precision Engineering using modeling and experimental verification of the effects. The Gannen XP suspension consists of three slender rods with integrated piezo resistive strain gauges. The deformation of the slender rods is measured using the strain gauges and is a measure for the deflection of the probe tip. It is shown that the standard deviation in repeatability is 2 nm in any direction and over the whole measurement range of the probe. The probe has an isotropic stiffness of 480 N/m and a moving mass below 25 mg. Finally, the TriNano CMM will be discussed. This novel coordinate measuring machine is designed for measuring three dimensional micro features with nanometer uncertainty. The TriNano has a kinematic and highly symmetrical design based on three parallel axes and obeys to the Abbe principle in its entire measurement volume.

A novel method to observe pH distribution by dual wavelength fluorescent ratiometric pH measurement by scanning near-field optical microscopy (SNOM) is developed. In this method, in order to investigate not only the pH of mitochondrial membrane but also its distribution in the vicinity, a pH sensitive fluorescent reagent covers mitochondria instead of injecting it to mitochondria. This method utilizes a dual-emission pH sensitive dye and SNOM with a themally-pulled and metal-coated optical fiber to improve the spatial resolution. Time-dependence of Fluorescent intensity ratio (FIR) under acid addition is investigated. As the distances between the dropped point and the SNOM probe becomes closer, the time when FIR changes becomes earlier. The response of mitochondria under supplement of nutrition is studied by using this method. While the probe is near to mitochondria, the ratio quickly becomes to increase. In conclusion, it was confirmed that the temporal variation of pH can be detected by this method, and pH distribution in the vicinity of mitochondria is able to be measured by this method.

Micro cavities with high aspect ratio are widely used in different fields including aerospace and defense industries with the development of manufacturing technology. So how to measure the dimension of these cavities has become one of the major research subjects in the field of measurement and instrument. This paper describes some activities of the precision micro cavity measurement technique in Center of Ultra-precision Optoelectronic Instrument (UOI), Harbin Institute of Technology (HIT). The key issue of micro cavity measurement in UOI is called touch-trigger measurement method. The first scheme is double optical fiber coupling, in which light coming from the incident optical fiber is transmitted in the reversal direction via the optical fiber coupling into the effluent optical fiber, the lateral displacement of the touch-trigger sensor is transformed into the deflexion of light coming out from the effluent optical fiber, and the deflexion is transformed into an image signal by the object lens and CCD capturing system. And the second scheme is micro focal-length collimation, in which a fiber stem with a ball mounted on its end is used as a probe and a small segment of it is used as a cylindrical lens to collimate a point light source and image it to a camera, the deflection of the fiber stem can be inferred from the change in image acquired by the camera with ultrahigh displacement sensitivity. Experiments for these activities will be given with a focus on the measurement results and repeatability uncertainty.

In order to improve the small range and poor dynamic performance of a flexible tilting mirror system for rapid compensation of laser beam directional stability offset error, a direct adjustment method is constructed by means of a translational spectroscope, which fixed on a piezoelectric actuator, to steer the laser beam to the collimating state, and to compensate for the displacement offset and angular offset of laser bean respectively. This method reduces the flexible rotation link in-between, avoids the backlash and lags error of friction and elastic deformation, and simplifies their control modes for the compensation process, thereby improving the control accuracy and dynamic performance of adjustment system. Experimental results show that, the tilted reflecting plane of the spectroscope can be used to steer the laser beam to the valid positions within the adjustment range up to 100μm, to compensate the offset error of the laser beam, or to compensate the vibration of laser source and the tilt error of detector installation, its control bandwidth above 100Hz. These results suggest this method can provide an effective solution for rapid precision collimation and compensation.

Phase-locked frequency multiplying technology is utilized to amplify 10MHz signal to 640MHz. Pulse inhibition method is then exploited to make high-frequency signal have a phase shift of 2π. 20MHz signal with 2π / 32 phase shift is output after 5 times flip frequency division. In order to optimize electromagnetic compatibility, signal integrity and power integrity of a high-speed circuit, system simulation is performed using HyperLynx, a specially EDA simulation software. A whole printed circuit board (PCB) was made under the guide of optimized simulation results. Phase-shift experiments show that the output of high-frequency phase-shifting circuit system is two-way signals with a frequency of 20.0001 MHz with 1.8ns time difference, i.e. two signals with 12.96°phase difference are obtained.

We have been developing a new technique for measuring urine glucose concentration using near infrared spectroscopy (NIRS) in conjunction with the Partial Least Square (PLS) method. In the previous study, we reported some results of preliminary experiments for assessing feasibility of this method using a FT-IR spectrometer. In this study, considering practicability of the system, a flow-through cell with the optical path length of 10 mm was newly introduced. Accuracy of the system was verified by the preliminary experiments using urine samples. From the results obtained, it was clearly demonstrated that the present method had a capability of predicting individual urine glucose level with reasonable accuracy (the minimum value of standard error of prediction: SEP = 22.3 mg/dl) and appeared to be a useful means for long-term home health care. However, mean value of SEP obtained by the urine samples from ten subjects was not satisfactorily low (53.7 mg/dl). For improving the accuracy, (1) mechanical stability of the optical system should be improved, (2) the method for normalizing the spectrum should be reconsidered, and (3) the number of subject should be increased.

The design of optical and electronic parts of multimatrix measuring modules is presented. Four optical channels in optical scheme are used. Correction algorithms for sensitivity and mutual declination of matrix photo detectors are presented. The practical realization of multimatrix measuring module is presented.

According to the durability testing principle, an open, high intelligent and practical durability testing system was designed. In this system, various sensor signals and executive loads of the engine are provided to simulate the on-line environment of a real vehicle for ECU. Though the CAN based communication network, the monitor card sends the testing data to the management software, and the durability testing report is automatically generated for developers. This system greatly reduces the testing cost and shortens the development cycle.

Accurate calculation of the moment of inertia of an irregular body is made difficult by the large number of quantities. A popular method is to use a trifilar suspension system to measure the period of oscillation of the body in the horizontal plane. In this paper, an instrument for measuring the moment of inertia based on trifilar pendulum is designed; some sources of error are discussed; three metal disks with known moments of inertia are used to calibrate the instrument, the other metal disks with known moments of inertia are used to test the accuracy of the instrument. The results are consistent when compared with calculated moment of inertia of the metal disks. In addition, the instrument could be used to measure the moment of inertia of other irregular objects. The period of oscillation is acquired by the capture mode of MSP430 microprocessor, the mass is obtained by the Electronic Balance and the data is transferred to the MSP430 via serial port.

Magnetic-levitation (maglev) positioning stage is a system with complex nonlinear, strong coupling and low damping. This research focused on the control algorithm and the effect of eddy current damper applied to the system which consists of a moving table, four Halbach permanent magnetic arrays, four stators and displacement sensors. All of the magnetic arrays are fixed to the bottom of the moving table. To avoid the occurrence of oscillation while the stage is being positioned, a permanent magnet set which served as an eddy current damper was added to the system; and it is proved through theoretical analysis that the damping force generated by the eddy current damper is proportional to the movement speed of the table. A motion control mathematical model including the segment of an eddy current damper was built, and the nonlinear controller of the system was given based on the theory of differential geometry decoupling. Simulation results show that decoupling control of movement the moving parts can be realized in horizontal and vertical directions.

This paper presents a novel piezodriven X-Y stage utilizing flexure hinges. Levers of high amplifying rate were adopted to magnify the output displacement of the piezoelectric actuator and a complex parallel four-bar mechanism was used to guide the mobile platform. In order to describe the static and dynamic behaviour of the stage, an analytical model was built and a series of formulae were deduced. Based on mathematical analysis, the configuration of the stage was optimized. Then Finite Element Analysis was applied to analyze travel ranges, natural frequencies and stress distribution. The simulation computation results demonstrate that the stage could reach a motion range of 200mby 200m and has a first order natural frequency of 265 Hertz, which is of good concordance with the theoretical estimate. Now a prototype is being fabricated.

To break through the limitations of static and dynamic characteristics of conventional step motor driven open-loop positioning devices, a two-dimensional precision positioning system with a travel range of 100mm×100mm has been developed. This paper presents its structure, control principle and performance experiments. This system, equipped with cross roller guides working as linear guiding elements, is driven by step motors through ball screw transmission. A threeaxis dual-frequency laser interferometric measurement system is established for real-time measurement and feedback of system's movements in three degrees of freedom (DOF) and an intelligent Fuzzy-PID controller is implemented for this system's motion control. In the controller, the PID module calculates the output from motor drivers and its initial parameters are tuned through expansion of critical proportioning method; the Fuzzy module optimizes PID parameters to fulfill specific requirements of different movement stages. A dead zone control mechanism is developed in this controller to minimize the oscillations around target position. Experimental results indicate that system with Fuzzy-PID controller shows faster response than that with ordinary PID controller. Moreover, with this controller implemented, the developed precision positioning system achieves better repeatability (±2μm) and accuracy (±2.5μm) within the full range than open-loop system using step motor.

This paper presents a DSP and FPGA based 4-axis motion controller, which use host PC as the platform. By adopting the strategy of two stage interpolation, the proposed motion controller supports 2-axis circular interpolation and 3-axis linear interpolation, and its maximum output pulse frequency of each axis can be up to 8 MHz. The controlling algorithms, such as improved coarse interpolation based on the time division principle, T-curve and S-curve velocity profile generation and the error compensation for the position loop, are implemented by DSP to ensure the high performance of the proposed motion controller. Meanwhile, the FPGA integrates PCI bus controller, dual port RAM, second-stage interpolation, encoder feedback logic circuit etc., which allows a flexible, compact, low-cost solution for various applications. Experimental results demonstrate that the presented motion controller features the merits such as the good real-time performance and high machining precision, and it can be used for a wide range of applications in numerical control system.

A precise translation stage is important for surface topography measurement based on scanning method, for it provides precise measurement datum and accurate positioning of scanning points. In this paper, a 2-D coplanar translation stage with synchronous XY position metrology is developed for surface scanning measurement. The mechanical structure of this stage is designed to translate along X and Y directions based on a common plane, which improves the movement flatness of the sample table. For higher precise 2-D positioning metrology, a novel double cross diffraction grating measurement system is proposed, by which the XY position of the sample table can be measured synchronously.

A multi-component Fourier Transform InfraRed (FTIR) gas analyzer with a low spectral resolution (8cm^-1) is described in this paper. The hardware of this analyzer is consisting of a rugged Fourier Transform Spectrometer (FTS), an uncooled pyroelectric Deuterated L-Alanine TriGlycine Sulfate (DLATGS) detector, a glass body long-path gas cell and relevant sampling devices. The transplantable software and algorithms include the building of spectral library from the free sources such as EPA, NIST, HITRAN etc, identification of spectrum components and a modified classical least square regression with automatic baseline compensation. In order to validate this system, we implemented a continuous on-line experiment using the 55 μmol·mol^-1 methane and 28 μmol·mol^-1 nitrous oxide standard mixtures. The experimental results show this low resolution analyzer has accuracy and robust analysis abilities. The description in this paper is helpful to facilitate the development of a FTIR multi-component gas analyzer.

An operational amplifier-based micro eddy current sensor circuit is developed for improvement of sensitivity, reduction of power consumption and application in small mounting space. An eddy current sensor is designed on the optimized parameters in this circuit. Meanwhile, an eddy current sensor static calibration system is built by comparing to the measurement unit of Switzerland TESA Inductance Sensor TT80 of high resolution. Simulation and experimental results show that the eddy current sensor has a high sensitivity, low power consumption and is capable of measuring a limited space. Also, the eddy current sensors are mounted in the honing head, and the feasibility of in-process inspection of parts being honed on the inner diameter have been verified in the Abrasive Machining (Honing).

A resonance frequency of 8.9MHz copper Interdigital Transducer (IDT) is fabricated on a 127.8°YX type LiNbO₃ substrate by lift-off process and the rapid droplet mixing is experimentally realized using the surface acoustic wave(SAW). The droplet mixing principle and the manufacturing process of the mixer are illustrated in detail. The droplet generates one swirl when only portion of the droplet is located on the saw propagating surface. The droplet generates two swirls when the whole of droplet is located on the saw propagating surface. The mixing between red particles with an average diameter of 1.5μm and a droplet with a volume of 3 μl is successfully implemented. No matter the droplet covers whole or just partly the saw propagating surface, the mixing process can be completed in one second when the applied driving power is 9W. The applications of SAW micro fluidics should be greatly enhanced using the rapid mixing process proposed in this paper.

In order to enlarge the measurement range of the monocular vision measurement system, enhance its measurement precision in depth direction, and realize the accurate measurement of large-scale equipement, a 3D mosaic method based on assistant target is proposed in this paper. By using the image of an assistant target in two adjacent measuring positions, on the basis of matching the images of feature points and epipolar constraint, it quickly computes the orientation and translation transform between the two adjacent measuring positions through linear algorithm and LM iteration method, and the scale factor of the translation is calculated from the distances between the feature points on the assistant target. At last, the measurement data in the local coordinate systems of different measuring positions can be transformed to the global measurement coordinate system with the transformation between the two adjacent measuring positions, and the three-dimensional mosaic of the measurement data is realized. This method overcomes the problem that the precision of the feature point three-dimensional coordinates in different coordinate systems seriously affects the mosaic accuracy. The experiment result proves that the proposed method is flexible and valid, and not only enlarges the measurement scope, but also raises the measurement precision for large-scale equipement.

A new technique is demonstrated for measurement of modulation transfer function (MTF) on image sensor arrays. Fourier analysis of a low frequency bar target pattern is used to extract MTF at odd harmonics of a target pattern frequency up to and beyond Nyquist. The technique is particularly useful for linear image arrays (either conventional linescan or time-delay- integration devices) where conventional slanted-edge technique is not always applicable. The technique is well suited to simple implementation and can provide live presentation of the MTF curve, which helps to ensure optimal alignment conditions are achieved. Detailed analysis of the technique and demonstration of experimental results are presented.

Electrical capacitance tomography (ECT) is a new technology for testing parameters of solid-air two-phase flow during the past decades. The key technique of ECT is the fast and accurate image reconstruction. In this paper, the principle and measuring process of ECT were elaborated, the reconstruction algorithm called generalized vector sampled pattern matching (GVSPM) method was used in two-phase flow particle concentration visualization. GVSPM method achieves accurate reconstruction by using an objective function that is calculated as the inner product calculation between the experimental capacitance and the reconstructed image capacitance. Mathematica simulation results showed that this method proved superior in the three parameters of capacitance residual, image error and image correlation, compared with the linear back projection (LBP) method. Using the GVSPM method, the "soft-field" effect and the ill-posed inverse problem in ECT technology can be effectively conquered, meanwhile, the reconstructed image has the advantages of high spatial resolution and low distortion.

A method based on white-light Michelson interferometer for measuring the retardation of multiple-order wave plates is presented. The linear polarized white-light splits into o-beam and e-beam by the test multiple-order wave plate which introduces retardation between the two beams, and then they are divided by a beam splitter and reflected by two plane mirrors in the Michelson interferometer respectively. Finally three white-light interference packets are formed. According to the optical path between the center packet and one of the side packets, the retardation can be obtained. The retardation of a multiple-order wave plate is measured in the experiment, whose result (2990.6nm) coincides with the one obtained by spectroscopic method (2992.8nm).

Start-stop torque is one of the key parameters of valve's capacity. In China, a torque spanner is used to measure the small-bore torque, but the accuracy is not very high. In the large-bore situation, the previous method can not be used to measure the torque, so the torque is determined by the design calculation result. Sometimes this result is far from the practical one, and the difference will impact the apolegamy of the actuating device of a valve. Some other methods, such as inductance type transducer valve torque sensor, strain gauge valve torque sensor, appeared. They both have the advantage of high accuracy, but their automatic level is low and their measuring equipments are complex. In this paper, a new style torque measuring device which is based on theory of mechanics of materials and measuring principle of strain gauge is designed. The maximal torque is 2000Nm. The measuring device is easy for installation, accurate on results, and is able to meet the actually online measuring demands.

The wavelength readout system reported in this paper is chiefly constructed of fiber Fabry-Perot tunable filter (FFP-TF), data acquisition card and a virtual instrument with programmable NI Labview. By combining the dynamic scanning of FFP-TF in C waveband (1520nm-1570nm) with 50nm free spectral range (FSR) and 4000 standard finesse value, the wavelength of a tested laser diode (LD) could be detected accurately, while the spectrum is displayed on line with the help of a virtual instrument to make the spectroscopy quick analysis possible. Furthermore, the scheme can also be applied for wavelength interrogation in fiber Bragg grating (FBG) sensing system. Considering the practibility and economical efficiency of such a system, it will be of great significance to adopt such a wavelength readout system in fiber sensors used for construction, mining, aerospace,etc.

Electro-magnetic acoustic detection technique has become a new development trend of nondestructive testing because of its high detection efficiency, accurate detection results, etc, so it now has been widely adopted in the railway department of our country. When the signal is detected using electro-magnetic acoustic detection technique, the influence of the poor condition of wheel surface, the existing electromagnetic interference and other factors will enable different levels of noise to exist in the detected signal, which will affect the signal quality, thereby reducing the detection accuracy. After introducing the structure and principle of electro-magnetic acoustic detection system, this paper has put forward two noise suppression algorithms for the noise problem of the detection signal, namely, phase difference algorithm and adaptive filtering algorithm. On the premise of reserving the necessary signal waveform of system, the algorithms can effectively suppress the noise of a detected signal, improve the quality of a data waveform, and obtain good detection results. The paper also compares two algorithms and points out that the better detection accuracy can be obtained if combining the two algorithms. This work has certain inspiration to raise the accuracy of electro-magnetic acoustic detection results.

The surface topography of automotive steel plate is decisive to its stamping, painting and image clarity performances. For measuring this kind of surface topography, an instrument has been developed based on the principle of vertical scanning white light microscopy interference principle. The microscopy interference system of this instrument is designed based on the structure of Linnik interference microscopy. The 1D worktable of Z direction is designed and introduced in details. The work principle of this instrument is analyzed. In measuring process, the interference microscopy is derived as a whole and the measured surface is scanned in vertical direction. The measurement accuracy and validity is verified by templates. Surface topography of textured steel plate is also measured by this instrument.

Low frequency time-code timing service is an important mode in the modern timing system, and it is actively commended by International Telecommunications Union (ITU). Low frequency time-code timing radio station (BPC) is built by National Time Service Center in China. The BPC broadcasts are used by millions of people to synchronize consumer electronic products like wall clocks, clock radios, and wristwatches. In addition, BPC is used for high level applications such as network time synchronization and frequency calibrations. Based on the modern signal characteristic of low frequency time-code of BPC, the additional spread spectrum modulation timing method in idle carrier wave is presented. A new structure of signal modulation is expatiated. The rationale of the additional spread spectrum modulation timing method in BPC is researched. The performance of a new system error is analyzed. The research results indicate that the anti-jamming performance can be improved by the additional spread spectrum modulation timing method in BPC, and low frequency time-code timing service can then be used broadly.

Electrical tomography (ET) aims at the study of the conductivity/permittivity distribution of the interested field non-intrusively via the boundary voltage/current. The sensor is usually regarded as an electric field, and finite element method (FEM) is commonly used to calculate the sensitivity matrix and to optimize the sensor architecture. However, only the lumped circuit parameters can be measured by the data acquisition electronics, it's very meaningful to treat the sensor as a multi terminal network. Two types of multi terminal network with common node and common loop topologies are introduced. Getting more independent measurements and making more uniform current distribution are the two main ways to minimize the inherent ill-posed effect. By exploring the relationships of network matrixes, a general formula is proposed for the first time to calculate the number of the independent measurements. Additionally, the sensitivity distribution is analyzed with FEM. As a result, quasi opposite mode, an optimal single source excitation mode, that has the advantages of more uniform sensitivity distribution and more independent measurements, is proposed.

with emphasis on the process of design and development method for the intelligent flexible structure distributed with orthogonal Fiber Bragg Grating sensor array, a fitting and reconstruction method based on orthogonal curvatures for three-dimensional curve and a method to make discrete curvatures continuous are analyzed with detailed algorithm processes and implementation steps in this paper. On the basis of the experimental calibration analysis with FBG model structures, a real-time apperception and reconstruction platform of intelligent flexible structures for analyzing and verifying the methodology and processes of the algorithm is developed with the technology of Visual C++ and OpenGL. The academic methodology and implementation technique are analyzed experimentally in the visualization platform. It reflects more accurately the real-time changes of intelligent flexible structures by employing an intelligent structure based on FBG as an experiment model. Experimental results prove the feasibility of the model design and the effectiveness of the three-dimensional reconstruction algorithm.

With the improvement of living standard, the incidence of diabetes increases year by year. Minimally invasive blood glucose monitoring is an effectively way to control diabetes, and it is achieved by measuring the glucose concentration of interstitial fluid in human body. This paper presents a portable minimally-invasive human glucose detection instrument which is based on a miniature integrated surface plasmon resonance (SPR) sensor. D-galactose/D-glucose Binding Protein (GGBP) which can specifically absorb glucose moleculars is used to modify the gold surface of SPR sensor for higher sensitivity and stability. The instrument includes an interstitial fluid extraction unit, a liquid flow unit, a SPR sensor unit and a circuit control unit. Interstitial fluid is extracted from human body using the interstitial fluid extraction unit, and it is then transported to the SPR sensor by the liquid flow unit, and the SPR sensor can detect the glucose concentration in the interstitial fluid. The acquisition and process of data is controlled by the circuit control unit, which controls the operation of the whole system as well. The glucose detection resolution could reach 6.25mg/L, and the experiment result has good linearity when the glucose concentration ranges from 6.25mg/L to 50mg/L.

The Long Trace Profiler (LTP) is a precision surface slope error measurement instrument used in synchrotron radiation optics for many years. By making some modifications to the LTP system, we developed a co-path scanning LTP (CSLTP) system to test the cylindrical aspherical surface which used in X-ray space optics. To reduce the mistake caused by air turbulence and manufacture faults of optical elements used, the CSLTP is designed with the least difference between the testing beam path and the reference beam path. Also, it uses multiple-beam interference but double beam interference to reduce the width of beam fringe. This improves the position precision of the beam fringe on the image plane.

To better understand the response and damage characteristics of structures under earthquakes, a great number of intelligent seismic sensors with high performance were needed to be installed distributed in the whole country. The intelligent seismic sensor was a cost-sensitive application because of its large number of usages. For this reason, a low cost intelligent seismic sensor was put forward in this paper. This kind of intelligent seismic sensor cut down the cost without sacrificing performance by introducing two three component MEMS accelerometers. It was composed by a microprocessor, two three component MEMS accelerometers, an A/D converter, a flash memory, etc. The MEMS accelerometer has better structure and frequency response characteristics than the conventional geophones'. But one MEMS accelerometer tended to be unreliable and have no enough dynamic range for precision measurement. Therefore two three component MEMS accelerometers were symmetrically mounted on both sides of the circuit board. And their measuring values were composed to describe the ground motion or structure response. The composed value was the in-phase stacking of the two accelerometers' measuring values, which enhanced the signal noise ratio of the sensor and broadened its dynamic range. Through the preliminary theory and experiment analysis, the low cost intelligent seismic sensor could measure the acceleration in accuracy.

A new kind of 3D measurement system has been developed to achieve the 3D profile of complex object. The principle of measurement system is based on the triangular measurement of digital fringe projection, and the fringes are fully generated from computer. Thus the computer-generated four fringes form the data source of phase-shifting 3D profilometry. The hardware of system includes the computer, video camera, projector, image grabber, and VGA board with two ports (one port links to the screen, another to the projector). The software of system consists of grating projection module, image grabbing module, phase reconstructing module and 3D display module. A software-based synchronizing method between grating projection and image capture is proposed. As for the nonlinear error of captured fringes, a compensating method is introduced based on the pixel-to-pixel gray correction. At the same time, a least square phase unwrapping is used to solve the problem of phase reconstruction by using the combination of Log Modulation Amplitude and Phase Derivative Variance (LMAPDV) as weight. The system adopts an algorithm from Matlab Tool Box for camera calibration. The 3D measurement system has an accuracy of 0.05mm. The execution time of system is 3~5s for one-time measurement.

An Offset Generator with low noise floor has been developed by Time & Frequency Measurement & Control Department, NTSC. The Offset Generator is designed with Phase Lock Loop, and the +100Hz offset is generated in the output stage. The Allan deviation noise floor of the Offset Generator is 1x10^-12 at 1 second. The Offset Generator has been installed in "Digital Multi-Channel Frequency Stability Analyzer" (DFSA), developed by Time & Frequency Measurement & Control Department, NTSC, too, and the Allan deviation noise floor of DFSA using current Offset Generator is about 4x10^-14 at 1 second and <1x10^-15 at 1000 second.

The rapid development of electronic products today, it is a very important part of that electric shock prevention remains the safety design of electronic products. When unplug the electrical equipment, the voltage in each pin of the plug is residual voltage. If residual voltage is too large, it may cause harm to human body, must attach importance to it and precisely measure it. Load of different electrical products lead to different transient voltage changes in sudden power-down, namely the changes in the residual voltage. In this paper, the load on the electrical equipment on the basis of type classification, focusing on the design of their corresponding capacitive load and peak power detection circuit link was simulated, thus arrive at the variation discipline of residual voltage, in order to better protect human safety.

A novel method for measurement and evaluation of cylindricity error is presented. The surface data of a workpiece can be measured from different views using digital fringe projection profilometry, and these data can be connected accurately using multi-aperture overlap-scanning connection technique. Thus all surface data of a workpiece can be obtained. The proposed method offers such advantages as non-contact, high efficiency and whole-field information. It can also be used to effectively overcome the axial undersampled problem with reference to the existing cylindricity measurement method. On the basis of new GPS, verification operators used for cylindricity error evaluation are constructed. The accuracy and reliability of cylindricity error evaluation can be ensured with the standard and optimal operation process. The validity and performances of cylindricity error measurement have been investigated through experiments.

With the increase of the number of IP cores integrated in SOC, the functions of SOC are becoming more complexed. Test time and test cost grow rapidly, therefore it becomes bottleneck of SOC test. Test scheduling is one of the efficient approaches to solve the forenamed question. Cross-entropy method, which is based on probability density function, has been used to solve the SOC test scheduling problem. Experimental results on ITC'02 benchmarks show that the proposed method provides better test time results compared to the Linear-Programming.

In order to analyze the resolution of variable fiber optic attenuator (VOA) instrument using digital micromirror device (DMD) precisely, the optical system of VOA is optimized and analyzed using Zemax to obtain the effective distributions of incident Gaussian beam (inside 1/e² Gaussian beam waist region) on the DMD. The beam is then divided into three power attenuation zones P₁, P₂ and P₃ using two cutoff normalized weight levels W₁ and W₂ for the DMD spatial samplers to arrive the desired high power attenuation resolution. C-Lens is also used as collimator to improve the working distance and decrease the insertion loss. Numerical simulation results indicate that the average power attenuation resolution is 5.072mdB, 3.811mdB and 0.674mdB respectively when the power attenuation percentage is 34.70%, 31.46% and 33.76% for P₁, P₂ and P₃ respectively. The study can be used to VOA test instrument applications.

In order to measure the attitude angles of our ultrasonic motor, a compact single stator multi-degree-of freedom (DOF) ultrasonic motor with a cylindrical stator and a spherical rotor is designed with one OEM encoder and 2D PSD (Position Sensitive Detector) sensor. The spherical rotor is rotated around three perpendicular axes by three natural vibrations excited on the stator. The OEM encoder disc is fixed on the rotor output shaft to measure the rotational angle of the output shaft. The PSD sensor is installed in loading sphere, and one LED is installed in the LED house, the line light emitted by the LED transmits along the output shaft axis and passes through the center of the spherical rotor, and then projects on the PSD surface, and the PSD and LED comprise the device to measure the pitch and roll of the rotor. The output current signals of the PSD sensor are changed into voltages, amplified by measuring circuits, converted into digital signals, and are transmitted to MCU. The attitude angles of the motor are calculated out using the proposed algorithm. The compact structure design of the motor makes the measurement of the attitude angles of the multi-DOF ultrasonic motor more practical and convenient.

A laser beam with an ideal wavefront passes through a random amplitude mask to produce speckle fields. The speckle fields then illuminate the measured lens and are modulated by its shape to further scatter the speckle fields. The shape of the lens can be measured from the sequential intensity measurements of volume speckle field and phase retrieval based on angular-spectrum propagation technique. The curvature radius of the lens is directly derived from the shape function. In comparison with the existing measurement methods, the method proposed has a simple set-up, a strong environmental anti-interference capability and a low cost. Experimental results indicate that the proposed method is an effective approach which can be used for the measurement of radius at low cost.

In this paper, a precision measuring device is developed for obtaining characteristic curve of tire profile and its geometric parameters. It consists of a laser displacement measurement unit, a closed-loop precision two-dimensional coordinate table, a step motor control system and a fast data acquisition and analysis system. Based on the laser trigonometry, a data map of tire profile and coordinate values of all points can be obtained through corresponding data transformation. This device has a compact structure, a convenient control, a simple hardware circuit design and a high measurement precision. Experimental results indicate that measurement precision can meet the customer accuracy requirement of ±0.02 mm.

This paper presents the absolute measurement of free form surface based on the use of interferometric technique to obtain the absolute height of surface, which utilizes the interference fringe obtained with an interferometric microscope to locate the points of surface and obtain the height information through a three-dimensional displacement stage. A theoretical model is established for this method based on the response of interference microscope to identify the main influence factors through analysis. A measurement system is developed based on a three-dimensional stage and a Linnik interference microscope. As the key operative part, the stage has two-grade positioning accomplished by a vertical scanning displacement function mechanism with a laser interference measuring system and driven by a servo-motor and a piezo-electronic transducer respectively. Performance tests show the stage meets the requirements for the measurement of large range surface according to the zero-order interference fringe tracing measurement method. Experimental results show that the measurement system has a vertical range of 8mm, vertical resolution of 0.002μm, and a repeatability error of less than 5%.

Double parallel-joints coordinate measuring machine (CMM) is a new type of coordinate measuring devices. In this paper, measuring principle and basic structure of double parallel-joints CMM are introduced at first and then total error sources that influence the measuring accuracy are analyzed. The possible accuracy of error sources correction is analyzed and the total error of the instrument is calculated. The error distribution is presented on the basis of accuracy design of the instrument. The error distribution is simulated and the error distribution law of the instrument is summarized. The accuracy analysis and the structure design of the instrument are guided by the research in the paper, and the solid theoretical basis is provided by the error correction to achieve the accuracy indicators of double parallel-joint CMM. The tasks accomplished in this thesis will be provided as a solid foundation for developing double parallel-joint CMM with our own intellectual properties and it will be accuracy higher and cost lower than the currently existing imported CMM.

In the article, an in-situ 3-D microscopic surface profilometer employing novel lateral confocal scanning principle, also called V-scan lateral confocal microscopy (VLCM), was developed to achieve in-field measurement with an effective vibration-resistance capability. The developed methodology combines digital structured fringe projection, lateral confocal scanning, shape from focus (SFF) and anti-vibration technique to perform lateral scanning for in-situ 3-D surface measurement. For microstructures having low reflectivity and high-slope surfaces to be measured within in-field process environment, it has been recognized as a great challenge for achieving accurate 3-D surface inspection. To overcome this, the presented method employing a new lateral confocal scanning strategy in combining a Z-axis vertical scanning with a horizontal X-axis scanning simultaneously, in which the scan pattern is similar to a V-shape. Meanwhile, to detect potential environmental vibration, a laser fiber interferometric positioning sensor based on heterodyne interferometry is employed to detect potential vibratory displacement between the optical probe and a tested surface for minimizing environment disturbance encountered in a real factory. A depth response curve is constructed by a series of images detected from successive depths during the V-scan lateral scanning. Potential vibration errors can be effectively detected by a fiber optic interometric positioning sensor and compensated simultaneously. A standard step-height target and several industrial V-groove microstructures have been measured to attest the measurement accuracy and feasibility of the developed approach. From the experimental results, it is confirmed that the depth resolution can reach 0.1 μm and the maximum measurement error can be controlled within 3% of the overall measuring height.

The axial beam scanning in confocal microscopy has been implemented using liquid crystal spatial light modulator (LC-SLM). A zoom illuminating lens is realized by introducing LC-SLM into the confocal illumination light path, and thus it shifts the focus of the objective lens axially. The axial optical sectioning in a conventional confocal microscope is hereby achieved by beam scanning rather than mechanically moving the objective lens. The axial focus shift of the objective lens is realized by changing the modulation phase bitmaps of LC-SLM. By electrically controlling LC-SLM, it has been demonstrated that the focus can shift in the axial direction continuously over a 100μm range, while the FWHM of the focal spot keeps the same as that without LC-SLM. Experimental results further show that the axial intensity curves shift axially in confocal microscopy and confocal axial beam scanning replacing mechanical scanning can therefore be implemented.

The resolution of the current length grating measuring system can reach micron level, sub-micron level and nanometer level. Researching and producing the high-resolution and high-preciseness length grating measuring system is the development tendency of measuring technology, while the high-preciseness length grating measuring system also has wide application prospects. In the practical application of the grating system, the error correction technology directly affects the measurement preciseness of the length grating measuring system. Therefore, launching the research on the error correction technology of the length grating measuring system is the important. The correction method of the length grating measuring system is discussed. In the method, the displacement length is traced back to the laser wavelength via the photoelectric microscope, line scale, laser Interferometer and data-fitting tool. The error correction method of the length grating measuring system mentioned in this article is simple in principle, more convenient to be implemented, provides high correction precision, and also can be implemented in real-time automatic correction. For some instruments, based on the length grating measuring such as three-coordinate measuring machine, length measuring machine and so on, the method is of important reference and consultation value.

Phase-shifting interference microscopy is a very important technique for precision surface topography measurement. In this paper, polarization phase-shifting interference microscopy is proposed for ultra-precision surface topography measurement. The principle of the microscopy is described and analyzed in details, a system based on the principle is constructed, and series of experimental testing are conducted on the system. The experimental results show that the measurement accuracy is better than 1.5nm, and high accuracy is verified.

Real-time test is one of the important parts in digital holographic interferometry researches. In this paper, taking advantage of electrically addressed liquid crystal display(EALCD) features of real-timely writing in and reading out images, the digital holographic interferometry system for real-time measurement of displacement is designed. In order to raise the contrast of the holographic hologram, the image enhancement based on the Laplacian operator has been used to process holograms. Based many advantages of CCD and EALCD, the holographic interferogram with high contrast can be obtained quickly, which can realize the precise measurement of small deformation and displacement of objects. Moreover, the measurement efficiency and precision is raised greatly.

Based on Michelson interferometer principle and controlled via an elaborately designed computer program, the variation of interference order, which contains the information of refractive index and its variation, can be detected by an optical power meter and a CCD camera. According to the relation between the increment of interference order and the change in optical path difference, the refractive index of photopolymer samples can be calculated in an accurate way. Typical measurements of the refractive index of our photopolymer samples are 1.547 and 1.583 at wavelength 532nm and 457 nm, respectively.

Traditionally extensometer has been used to measure the tensile strain to determine mechanical properties such as elastic modulus, yield and tensile strength. But it can only measure the average strain within the gauge length and can not produces the information on the strain distribution inside two knife point. This paper presents a novel method which uses digital speckle correlation technique, and produces whole-field strain for a better understanding of material behavior. It offers a significant advantage over conventional techniques with an extensometer in tensile test. The measurement results are presented with a comparison of the traditional method, and the data evaluation method is discussed in detail. This paper demonstrates the capabilities of technique for both quantitative and qualitative strain measurement in a whole field environment, which is almost impossible with the traditional method.

In manufacturing of precise miniature devices, automatic assembly is the trend to replace manual work for better quality and higher yield. Precise measurement is a critical issue during assembly process because the parts are often complicated and quite different in size, shapes, surface condition, etc. The position and orientation error must be determined precisely before assembly. In the developed automatic assembly system, microscopic machine vision and precise linear stages were integrated in the measurement system for higher detection resolution and larger measurement range in working space. As to the extract of contour of parts with different surface condition, dynamic illumination control and different combination of feature detection algorithms were applied. The errors brought by non-perpendicularity among precision linear stages were compensated and the movement errors were reduced with effective measurement strategy. The measuring accuracy was validated with a special fabricated precise template. Assembly tests were done with the developed system and results indicate that the required position and orientation accuracy can be met successfully and consequently the assembly task can be fulfilled.

This paper puts forward a kind of measuring method, double right-angle prisms imaging technique and video graduation technology have been adopted in inspecting laser beam levelness, and realized the measurement and adjustment of laser level. In this article, optic inspection technology, video graduation technology as well as the measuring error analysis and the efficient way of designing regularizing calibrating inspection are discussed in detail. Compare with the traditional way that testing and measuring in an area of fifteen square meters, this instrument can inspect the laser beam levelness error in a smaller test position (500mm), it can be adjusted and assembled easily. Installing and adjusting can be more easy and convenient in this relative smaller space. The instrument accuracy of this paper excels 3', can fully satisfy the requirement of laser level for the levelness of ± 15'. This instrument has been applied in measuring tools enterprise of our country.

The paper introduces the white-light spectral scanning interferometry for surface measurement. This interferometry can be used to measure the roughness of both smooth surfaces and those with large step heights. This real-time surface measurement can be achieved using acousto-optic tuneable filtering (AOTF) technique without mechanical scanning. At first, the structure and principle of this interferometry is introduced. Then the algorithm of the surface roughness measurement is proposed. What's more, the experiment with standard test piece is conducted. Compared with the traditional laser-light interferometry, the data shows that the proposed method has a higher accuracy which is proved to be nano-scale. A conclusion is given at last in which the superiorities and the limitations of the proposed system were discussed.

We propose a dew condensation sensor which combines surface plasmon resonance (SPR) and quartz crystal microbalance (QCM) to measure both refractive index change and mass loading caused by dew condensation simultaneously. In order to excite SPR and enhance water vapor sorption, a periodic silver nanostructure is fabricated on an AT-cut quartz crystal oscillator by template deposition. A self-assembled membrane (SAM) which consists of polystyrene spheres with the diameter of 202 nm was used as the template, and silver thin film with the thickness of 45 nm was deposited on the SAM by vacuum evaporation. Sensitivities of the sensor for detection of dew condensation were evaluated as the shifts of the SPR extinction peak wavelength and the resonant frequency of quartz crystal. The sensor is cooled down with the chilling rate of -0.5°C/min in the environment-controlled chamber with relative humidity and the temperature of 43.2%RH and 25.0°C, respectively. The proposed hybrid sensor was able to measure both the wavelength shifts of SPR and the additional mass caused by dew condensation simultaneously. Furthermore, the QCM response of the sensor achieved the sensitivity higher than the under detection limit (3 μg/cm²) of conventional optical detection method such as chilled mirror surface dew point hygrometer.

There is a need of measuring distributed pressure on the aircraft engine inlet with high precision within a wide operating temperature range in the severe environment to improve the efficiency of aircraft engine control. The basic solutions and principles of designing high-temperature (to 523K) microelectromechanical pressure sensors based on a membrane-type SOI heterostructure with a monolithic integral tensoframe (MEMS-SOIMT) are proposed in accordance with the developed concept, which excludes the use of electric p-n junctions in semiconductor microelectromechanical sensors. The MEMS-SOIMT technology relies on the group processes of microelectronics and micromechanics for high-precision microprofiling of a three-dimension micromechanical structure, which exclude high-temperature silicon doping processes.

Launchers of digital television have already built in many cities of our country as one of fundamental establishments of metropolis. The sent signal from launchers is powerful in power, low in frequency and wide in bandwidth, and it also covers absolutely entire city including many building dense areas. In this paper the signal frame structure of digital television terrestrial broadcasting (DTMB) standard of our country named GB20600-2006 is analyzed. Then the scheme measuring the distance with the special discontinuous PN code in the DTMB signal is designed. At last the new method measuring pseudo-range with DTMB signal is approved considered with DTMB signal own characteristics and tested by the data gathered at many spots in Xi'an. It provides technique method and supplement on positioning and navigation in complex circumstance of city.

There are many relationships between ocean and human life, and it's vital for our survival and development. Ocean observation is of great importance because it enables the prediction of specific global atmospheric changes. And ocean buoy is the core of marine monitoring system. In this paper, we propose a new method based on principle of electromagnetic induction coupling to realize non-contact signal transmission and power feeding for underwater sensors through mooring cable. Sufficient power feeding and data transmission are confirmed by experiments. It can be expected that the proposed system allows easier attachment and detachment of sensors to mooring wires and finally leads to miniaturization of the whole sensor body due to battery-free sensor operation.

Magnetic stress sensor has been considered as the most suitable sensor for measurement of steel cable stress because of its simple structure, low cost and long service life. However, the theoretical foundation for sensor design has never been reported, so it is necessary to study the theory and method of sensor design. Following the magneto-mechanical principle, a theoretical model of magnetic stress sensor is developed. The model indicated that the output of sensor is the function of structural parameters, excitation parameters and stress applied, respectively. A sensor is designed for an engineering steel cable and experiments are done to verify the optimization. Experimental results are in good agreement with the theoretical predictions. Compared to the previous results, the sensor sensitivity is improved by about 4 times, which shows that this model is rational and feasible and the theoretical foundation for optimization is truly of great importance for optimizing the characteristic properties of a sensor.

Today aircraft attitude measurement technology plays an important role in an aircraft system because it can provide orientation for aircraft in action. Lately star sensor technology used in aircraft attitude measurement has become more and more popular because of its high accuracy, light weight, without attitude accumulation errors and other advantages. There are three main steps for star sensor to measure aircraft attitude, star image locating, star identification and attitude tracking. The latter two steps are based on the accuracy of star image locating. So it's critical to make efforts to advance the accuracy of star image locating. Some imaging errors, such as spherical aberration or coma aberration, also have negative effect on the accuracy of star image locating, of which the effect is necessarily reduced as well. At the beginning of this article, the structure of star sensor hardware is introduced. Secondly three methods for star image locating are described specifically, which are traditional centroid method, Gauss quadric fitting method and improved Gauss quadric fitting method. Subsequently an imaging calibration method is described for the purpose of reducing the effect of imaging errors. Finally the experiment shows that the accuracy of the star sensor is 2-arc-second.

The high-order even-modes of high-aspect-ratio rectangular diaphragms are further exploited in this paper to excite Lamb waves. Thus the capacitive Lamb wave transducer (CLWT) can be excited by not only the second-order mode but also higher order even-modes, so that we can obtain higher operation frequencies, and make the CLWTs operate at several different frequencies for different applications. An optimized design with a 3μm thick silicon plate and submicrometer thick conducting silicon diaphragms is given according to the characteristics of the lowest order Lamb wave (i.e. A₀ wave) and the TDK model for capacitive micromachined ultrasonic transducers (CMUT) with high-aspect-ratio rectangular diaphragms. Such a CLWT with multiple even-modes is significant and attractive for gas and liquid sensing in the field of biochemical measurements.

In this paper, an edge filter demodulation of fiber Bragg grating (FBG) displacement measuring scheme using long period grating (LPG) is reported and demonstrated. The system consists of a 3dB coupler, a sensing FBG, a LPG and a photo-detector. As the sensing element, FBG can convert the displacement information into the shift of the Bragg wavelength, and then the wavelength information is converted into power using edge filter demodulation. The experimental results show that there is good linear relation between the output power detected by the photo-detector and the displacement in the measurable ranges 0-3.6mm. The displacement sensitivity is 9.24pw/mm.

The adsorption technology is one key technology of wall-climbing robot. The research actuality of adsorption technology at home and abroad was introduced, and the characteristics of adsorption technology were analyzed. The magnetic absorption of underwater wall-climbing robot was used as an example, and the materials of magnetic circuit which included yoke iron, magnet, separated magnetic material and armature were chose, and the law that magnetic force changes with the magnetic gap was analyzed, and that the packaging rubber thickness of magnetic sucker impacts on the magnetic force was proved by experiment, and a magnetic adsorption device was developed, and a new magnetic adsorption body was provided for underwater wall-climbing robot .

This paper presents the development of piezoelectric energy harvesting from ultrasonic vibration in fluid environments. The ultrasonic is emitted by the transducer in the ultrasonic cleaner and propagated in fluid environments which causes the piezoelectric bimorph bending up and down, thus the PZT layer generates electrical charges. Some preliminary experiments including output voltages in different fluid environments and in draft angles of the piezoelectric device relative to the level surface have been investigated. The experimental result shows that the output voltages vary with the fluid environment, the maximum voltage is generated in clean water and then physiological saline and sea water. Additionally, different draft angle lead to various output voltages with the maximum voltage been present at 45°to 60°or 105°to 120°region and the minimum value at 90°in the same fluid environment. Some possible causes about this phenomenon are also analyzed.

This paper presents a method to study and design a fully pre-stressed double-layer six-component force/torque sensor. The structure characteristic of the fully pre-stressed sensor is analyzed. In order to achieve the best performance, the static mathematical model is built by using screw theory. Based on the task ellipsoid, the task model of the pre-stressed force sensor is built. The relationship between the sensor and the task is studied systematically. And the mathematic description of task-oriented performance evaluation of the fully pre-stressed sensor is proposed. The key parameters of the fully pre-stressed force sensor satisfying the purpose of the task are obtained. The research results of this paper are useful for the further research and practical application of the six-component force sensor.

A kind of sun sensor is designed based on the optical fiber. This project consists of three parts: optical head, photoelectric sensor and signal processing unit. The innovation of this design lies in the improvement of traditional sun sensor, where multi-fibers, used as a leader, are symmetrically distributed on the surface of a spacecraft. To determine the attitude of a spacecraft, the sun sensor should measure the direction of the sun. Because the fiber length can be adjusted according to the fact, photoelectric sensor can be placed deeply inside a spacecraft to protect the photoelectric sensor against the damage by the high-energy particles from outer space. The processing unit calculates the difference value of sun energy imported by each pair of opposite optical fiber so as to obtain the angle and the orientation between the spacecraft and the sun. This sun sensor can suit multi-field of view, both small and large. It improves the accuracy of small field of view and increases the precision of locating a spacecraft. This paper briefly introduces the design of processing unit. This sun sensor is applicable to detect the attitude of a spacecraft. In addition, it can also be used in solar tracking system of PV technology.

A hydraulic square pressure generator with a unique spool valve has been developed for use in a system to calibrate and evaluate the dynamic characteristics of pressure sensors. This hydraulic square pressure generator generates a hydraulic square pressure with a rapid transient response in the time domain and with abundant harmonics in the frequency domain at low fundamental frequencies, rather than square pressure with poor harmonics at high fundamental frequencies. Its rise time and fundamental frequency are around 32.0 μs and 5 Hz, respectively, supporting a wide range of dynamic calibration of hydraulic square pressure generators. The sensing cavity in the hydraulic square pressure generator constrains the pressure transient produced by the fluid in the valve and maintains the generated hydraulic square pressure for both tested and reference pressure sensors. Three pressure sensors are calibrated using the hydraulic square pressure produced by the system with an auto-regressive exogenous model. Their transfer functions are obtained by applying the common pole-zero principle to describe their dynamic characteristics in the frequency domain.

In order to solve the difficulties of the measurement of one-dimensional and bi-direction flow by a hot-wire probe, a test method and the model experiment are presented in this paper. Based on the exiting hot-wire sensor, another same sensor is added. The two sensors are installed in parallel whose distance is 6 times their diameters, and they are separately connected to the controller. If the flow goes around two circular cylinders in tandem with the low Reynolds number, an obvious velocity drop between free-stream and gap flow can be found. Consequently, the velocity detected by the upstream sensor is higher than that by the downstream one. Because the relatively fixed position of the pair of sensors has been determined beforehand, the direction of the one-dimensional flow can be deduced from the plus and minus of velocity drop detected by the two sensors.

Broadband wavelength converters based on difference frequency generation (DFG), single-pass and double-pass cascaded second harmonic generation and difference frequency generation (SHG+DFG), single-pass and double-pass cascaded sum and difference frequency generation (SFG+DFG) are fulfilled by utilizing segmented grating structure in lithium niobate waveguide. Under the small-signal approximation, the effects of the waveguide length and the response flatness on DFG-based wavelength conversion are investigated by use of matrix operator, and then a feasible scheme to enhance the bandwidth and stability of signal and pump wave is proposed. For single-pass/double-pass SHG+DFG wavelength conversion scheme and single-pass/double-pass SFG+DFG wavelength conversion scheme, the effect of segmented grating structure on conversion bandwidth is studied theoretically and numerically, the results show that the signal conversion bandwidth can be broadened by optimizing the aperiodic grating. Moreover, the influence of "balance condition" on double-pass SFG+DFG-based wavelength conversion is analyzed, one can achieve enhanced conversion efficiency and conversion bandwidth by adjusting the power and wavelengths of pump sources according to the "balance condition". In the end, a reasonable suggestion is presented to achieve broadband wavelength conversion under different requirements.

Precise low speed motion control is important for the industrial applications of both micro-milling machine tool feed drives and electro-optical tracking servo systems. It calls for precise position and instantaneous velocity measurement and disturbance, which involves direct drive motor force ripple, guide way friction and cutting force etc., estimation. This paper presents a comparison study on dynamic response and noise rejection performance of three existing disturbance estimation techniques, including the time-delayed estimators, the state augmented Kalman Filters and the conventional disturbance observers. The design technique essentials of these three disturbance estimators are introduced. For designing time-delayed estimators, it is proposed to substitute Kalman Filter for Luenberger state observer to improve noise suppression performance. The results show that the noise rejection performances of the state augmented Kalman Filters and the time-delayed estimators are much better than the conventional disturbance observers. These two estimators can give not only the estimation of the disturbance but also the low noise level estimations of position and instantaneous velocity. The bandwidth of the state augmented Kalman Filters is wider than the time-delayed estimators. In addition, the state augmented Kalman Filters can give unbiased estimations of the slow varying disturbance and the instantaneous velocity, while the time-delayed estimators can not. The simulation and experiment conducted on X axis of a 2.5-axis prototype micro milling machine are provided.

The technique of Phase Diversity (PD) is widely adopted to measure the wavefront error caused by atmosphere turbulence and system error. PD solves the Zernike coefficients of the wavefront by utilizing two images obtained with different defocus value. In this paper, we propose a method to restore the image and estimate the wavefront error of an imaging system. And we use present white noises to verify the robustness of the algorithm. We design an experiment system and implement it in our laboratory. The proposed algorithm is validated by computer simulations and experimental results. To use a broadband white object in experimental system a reasonable simplification for the system model is done. Our results show that the robustness against Gaussian white noises of the method is better then the case when the variance value is 0.03. The proposed method can be used as a wavefront sensor and restore the degradative images by photoelectric image system.

Joint Transform Correlator (JTC) is a more advanced optical pattern recognizer. Compared with computer correlation matched method, it has many advantages, such as parallel processing, high speed and more sampling points. The bottleneck technique of JTC is how to recognize the distorted targets in cluttered scene. The Maximum Average Correlation Height (MACH) algorithm applied in JTC is presented. The MACH algorithm has powerful capability of recognition for distorted targets (rotation and scale etc.). Through optimizing MACH frequency domain filter and projecting it to space domain, the MACH reference image can be obtained. This MACH reference image clearly records various distortions of a target. Based on the basic principle of JTC, the distorted targets in cluttered scene can be detected. Optical experiments with JTC show that the edge features of detected image should be extracted, the correlation calculation of MACH reference image and detected target can be performed accurately and the bright correlation peaks can be obtained. In the process of optical correlation recognition, the performance of MACH reference image is used sufficiently. The energy of correlation peaks is greatly enhanced, the cluttered scene can be suppressed effectively and the MACH reference image has high distortion tolerance. To demonstrate the feasibility of MACH reference image, the scale distorted car in cluttered scene is successfully detected.

This paper presents a unique two-stage image restoration framework especially for further application of a novel rectangular poor-pixels detector, which, with properties of miniature size, light weight and low power consumption, has great value in the micro vision system. To meet the demand of fast processing, only a few measured images shifted up to subpixel level are needed to join the fusion operation, fewer than those required in traditional approaches. By maximum likelihood estimation with a least squares method, a preliminary restored image is linearly interpolated. After noise removal via Canny operator based level set evolution, the final high-quality restored image is achieved. Experimental results demonstrate effectiveness of the proposed framework. It is a sensible step towards subsequent image understanding and object identification.

The noise interference and end effect is irritating in the HHT processing of strong noise signals. In view of this situation, an improved HHT method based on the wavelet denoising and wave characteristic matching is proposed. Firstly, according to the analysis of the noise interference in wave characteristic matching extension and HHT itself, the paper adopts the wavelet threshold denoising to make a pretreatment of strong noise signal that can wipe off noise interference effectively. Then, extends and reconstructs data at both ends of signal to restrain end effect during EMD and Hilbert transform with the wave characteristic matching. Lastly, obtains the early fault feature of four-way valve from HHT time-frequency spectrum accurately. Simulation and instances show that the improved HHT method is able to reduce the false components resulted from decomposing useless noise, restrain the end effect, enhance the accuracy and timeliness of HHT, and thus make HHT arithmetic more practical.

Moving object detection from moving camera sequences is an important subject in field of computer vision. This paper presents a new approach for moving object detection in sequences taken from moving camera, key idea of which is to compensate the camera motion by estimate affine transformation parameters of the background using a combined method of Scale Invariant Feature Transform (SIFT) algorithm and Random Sample Consensus (RANSAC) algorithm. Feature points are detected in consecutive frames by SIFT detector and matched according to Euclidean measure, which is the initial matching step. In order to eliminate incorrect feature correspondences and the correctly matched features in the image region of moving object, RANSAC algorithm is applied to rectify the initial matching results and the affine transformation parameters are estimated accurately. Followed by inter-frame difference and morphology operations, moving object is detected successfully. Tracking of features is robust by using SIFT and the computational complexity is significantly reduced by performing the RANSAC estimation algorithm. The effectiveness of the proposed method is demonstrated using real video sequences from moving cameras.

Due to high speed requirement of real-time online inspection, and disturbances in industrial scene such as illumination and vibration, the captured image of piston ring by CCD is not very distinct, interfering following image procedures greatly. Therefore, in this paper, two models of dimensional measurement and damage defect recognition for piston rings are both established and wavelet transform is added in the process to analysis the edge image to ensure the precision and accuracy of detection results. A series of detection algorithms are elaborated in detail. The first step in the algorithms is to make image-preprocess to original images of piston rings by extracting interested area, image-filtering, and image erosion, with the aim of obtaining precise edge of piston rings' images for defect recognition. In the next step, wavelet transform method is used to calculate accurate edge of piston rings, thus dimension parameters of piston rings could be calculated after calibration of pixel. Then the least squares method is applied to fit a relative datum curve of the edge of piston rings. Based on defect recognition algorithm model and the procedures above, the detection algorithm can distinguish the upper and lower surface of piston rings, recognize piston rings' breakages and justify whether piston rings are conforming or not. The application of detection algorithm has been used to actualize non-contact automatic online inspection system.

To achieve high location accuracy, a sub-pixel location method based on Zernike moment is proposed for the location of the center of target. Original images are preprocessed to weaken the effect of noise. Sub-pixel edge detection is implemented using Zernike moment. The center of target is located using an ellipse fitting algorithm. Some criterions such as grayscale, area and circular degree of the objects are used to recognize the target simultaneously. Experiments are carried out with synthetic image and real image to verify the accuracy and noise immunity of the proposed method. Experimental results show that the accuracy is better than 1/25 pixel. It can therefore be concluded that the method can be used to meet the requirement of high-accuracy measurement.

Measurement points are obtained using a CMM. Lyite rule is used to optimize the data. The algebra relationship between independent parameters and Cartesian coordinate system is built using parametric equations of Archimedes helicoid surface and the error equations about the parameters are constructed. The parameters are acquired use least square method. Experimental results show that the proposed method can be used to make the values of parameters close to the theoretical values, and so, it can be used to do other kinds of parameters fitting of helicoid surface.

For a projectile with slots at the base, the index of amplitude modulation in Doppler radar echo reflects the information of angular motion. According to our research, the procedure to obtain the index can be divided into two steps, i.e., 1) separating the envelope from radar echo and 2) estimating the index from the acquired envelope. Here we assume that the envelope has already been achieved. To obtain the index from the envelope so as to extract the motion information, we investigated first the signal model of the envelope. A constant envelope model of echo is modified as an amplitude modulation and frequency modulation signal to express the amplitude modulation. The envelope is simplified as the combination of DC, the component of spin rate, and the second harmonic of spin. To restrain long-range and short-range spectral leakages and improve the index estimation accuracy, an interpolated FFT method that iterates in frequency domain and time domain alternately is proposed to. It adopts the interpolation algorithm in frequency domain to alleviate short-range leakage effect, uses the time window and the iterative CLEAN technique to realize long-range leakage correction. The influences of such parameters, as modulation frequency, value of the index, and SNR are simulated. The results of simulation and experiment prove the rationality of the model and the validity of the proposed method.

In order to improve the precision of gravity matching aided navigation, a gravity correlation coefficient is selected to study the gravitational field intrinsic features using the method of normalized standard deviation firstly. Some statistics laws are identified from the random gravitational field through the statistical analysis of gravity correlation coefficient. So that series of gravity matching conclusions can be drawn. Secondly, a gravity intrinsic features threshold matching algorithm of gravitational field is proposed based on these findings. Finally, the simulation results obtained using the gravity matching algorithm in a gravity aided navigation system show that the threshold can be used to find the better gravity matching areas, enable the integrated navigation system to diverge effectively and increase the accuracy of gravity aided navigation system.

As the main objects, imagoes have been researched in quarantine pest recognition in these days. However, pests in their larval stage are latent, and the larvae spread abroad much easily with the circulation of agricultural and forest products. It is presented in this paper that, as the new research objects, larvae are recognized by means of machine vision, image processing and pattern recognition. More visional information is reserved and the recognition rate is improved as color image segmentation is applied to images of larvae. Along with the characteristics of affine invariance, perspective invariance and brightness invariance, scale invariant feature transform (SIFT) is adopted for the feature extraction. The neural network algorithm is utilized for pattern recognition, and the automatic identification of larvae images is successfully achieved with satisfactory results.

This paper presents a real-time navigation system in a behavior-based manner. We show that autonomous navigation is possible in different rooms with the use of a single camera and natural landmarks. Firstly the intelligent wheelchair is manually guided on a path passing through different rooms and a video sequence is recorded with a front-facing camera. A 3D structure map is then gotten from this learning sequence by calculating the natural landmarks. Finally, the intelligent wheelchair uses this map to compute its localization and it follows the learning path or a slightly different path to achieve the real-time navigation. Experimental results indicate that this method is effective even when the viewpoint and scale is changed.

Metal magnetic memory is a novel NDT method that can be used to detect residual stress distribution of ferromagnetic components.Wavelet decomposition and entropy theory are used and wavelet singular entropy is introduced to extract characteristic from abnormal signals of defect. Furthermore, RBF neural network is utilized to identify defect character. Experimental results showed that, compared to the traditional gradient value, the proposed new method can be used to effectively reflect defect character and it is immune to the effect of noises.

It is obvious character that the chopper must be used in Uncooled pyroelectric imaging system. At present, three mainly type chopper which are linear chopper, Archimedean spiral chopper and Fresnel zone plate array (FLA) chopper. The FLA has some advantages than the others, which used diffraction solution. The paper report pyroelectric focal plane binary optics chopper which was processed by laser direct writing etched Fresnel zone plate array shape, and draw the test results: the sub-beam ratio of 1.2 x 10³; diffraction efficiency more than 40%; non-uniformity: multi-point test better than 10% in the FLA chopper.

According to the deficiency of SIFT algorithm for matching multi-source remote sensing image feature points, this paper provides a multi-sensor image registration algorithm of window segmentation based on SIFT point and line feature vector. Firstly, we roughly matched the remote sensing images, and then we divided the remote sensing images into several separate temporary windows based on their characteristics. In the sub-window, we extracted SIFT feature point of remote sensing images and selected the eight directions points with the same name around the feature points to build line feature vectors. Finally, we ended up match point set by constraining the initial point of the SIFT algorithm. Tests show that this method achieved a high matching accuracy.

In order to improve the matching accuracy and the level of automation for image mosaic, a matching algorithm based on SIFT (Scale Invariant Feature Transform) features is proposed as detailed below. Firstly, according to the result of cursory comparison with the given basal matching threshold, the collection corresponding SIFT features which contains mismatch is obtained. Secondly, after calculating all the ratio of Euclidean distance from the closest neighbor to the distance of the second closest of corresponding features, we select the image coordinates of corresponding SIFT features with the first eight smallest ratios to solve the initial parameters of pin-hole camera model, and then calculate maximum error σ between transformation coordinates and original image coordinates of the eight corresponding features. Thirdly, calculating the scale of the largest original image coordinates of the eight corresponding features to the entire image size, the scale is regarded as control parameter k of matching error threshold. Finally, computing the difference of the transformation coordinates and the original image coordinates of all the features in the collection of features, deleting the corresponding features with difference larger than 3kσ. We can then obtain the exact collection of matching features to solve the parameters for pin-hole camera model. Experimental results indicate that the proposed method is stable and reliable in case of the image having some variation of view point, illumination, rotation and scale. This new method has been used to achieve an excellent matching accuracy on the experimental images. Moreover, the proposed method can be used to select the matching threshold of different images automatically without any manual intervention.

In order to increase the efficiency of filling area, a novel declining scanning-line filling algorithm for filling area is proposed, in which the boundaries of image are traced through the adjacent connection, and their locations of the image edges are recorded at the same time. The direction of scanning-line is determined by the relative position between the seed point and the boundary point, and all the points in the adjacent field of scanning-line are filled only once. The vertical distance between the scanning-line is depended on the connected domain. The number of crossing points between the scanning-line and boundary is used to estimate the state of filling or ending. The algorithm can be used to fill the 4-adjacent or 8-adjacent fields, to settle the problem of deep recursion and iterative stack, and to solve the defect of repeated scanning and filling in traditional algorithm. By using the proposed algorithm, the filling result is accurate, the calculation of the algorithm is decreased, and the filling efficiency is enhanced.

The fabrication methods of binary and continuous-relief diffractive optical elements (DOE) by direct laser writing and lithography are analyzed. Laser metrology often requires the precision forming of a probe laser beam. This problem is solved optimally by application of DOEs. A number of scientific and practical applications require the fabrication of DOEs to create highly accurate aspherical wavefronts. This paper reviews the research directed toward the creation of equipment and technologies for DOEs with a binary, multilevel, and continuous profile. The results of the practical applications of DOEs (fabricated in Institute of Automation and Electrometry SB RAS) in optical measuring systems are presented.

According to the theory of self-mixing interference (SMI) in fiber ring lasers (FRLs), Fourier Transform method is adopted for vibration measurement. The harmonic components increase with the increase of the amplitude of vibration. According to the theory of self-mixing speckle effect (SMSE) in FRLs, the similarity to Gaussian form of probability density distribution increases as the velocity increases. A method based on the fractal boxes of a section of speckle waveform is adopted for demodulation. The relationship between the numbers of boxes and velocities of the object is linear. Dual-channel SMI is presented demonstrating the potential for multiplexing in FRLs. The dual wavelengths of the FRL are selected by two fiber Bragg gratings (FBGs). The output power in one channel is modulated by that in the other channel, which is resulted in the mode competition between the two channels. The experimental results show a good agreement with the simulation results, and indicate that SMI with parallel dual-channel is an efficient approach for multiple displacement measurement.

The researches in the millimetre wave range require the high accuracy for position of the mirror components. A mirror weight is the cause of the roll deformation of the elevation axle relatively the bearing. At result the elevation angle of a parabolic mirror axis orientation is not equal to the set values. For the measuring these roll angular deformations the new type of the anamorphic based system are used. The new method for roll angles measuring is developed. Optical scheme for the measurement system and anamorphic element is proposed. Equation for the static characteristic of the system and its graphical representation are shown.

In this research, an electron emission method which combines field emission and plasmon resonance is proposed and examined. Electron field emission properties of a sharp gold tip under continuous-wave laser irradiation at the plasmonresonant wavelength are investigated. Due to the application of plasmon resonance, the electric field in the vicinity of the emitter is strongly enhanced, resulting in the decrease of emission threshold voltage and the increase of emission current. The emission-area is strongly confined under illumination when the optical electric field is parallel to the emitter shank, and the optical modulation of the emission current is demonstrated.

The main mirror construction of the radiotelescope for the millimetre wave range requires to measure the line deformation of mirror's surface and shifts of the secondary mirror relatively main mirror. There is a necessity to construct the new radio-telescope RT-70 Suffa (Russia). The 3-D parabola main mirror of this radio telescope has a diameter 70 meters, and the elliptical secondary mirror with the diameter 3 meters are placed on the distance 21 meter relatively main mirror. Following issues dealing with this problem are described in this article: 1) the possibility of the design of deformation measurement system based on triangular method 2) the new scheme of optic-electronic measurement system. The great attention during the research was paid to the experimental approval of the theoretical results. The experimental setup of the described system had the following characteristics: infrared emission diode AL107B by power 15 mWt as sources of radiation; the objective by the focal length 450 mm as aperture of receiver video-camera, the CMOS matrix receiver by type OV05620 Color CMOS QSXGA with 2592*1944 pixels and one pixel size (2.2*2.2) μm² produced OmniVision as image analyzer . The computer simulation error and the experimental error measurement was 0.1 mm at the

We describe the use of Near Infrared Spectroscopy (NIRS) for the non-invasive investigation of changes in haemodynamics and oxygenation of human peripheral tissues. The goal was to measure spatial variations of tissue NIRS oxygenation variables, namely deoxy-haemoglobin (HHb), oxy-haemoglobin (HbO₂), total haemoglobin (HbT), and thereby to evaluate the responses of the peripheral circulation to imposed physiological challenges. We present a skinfat- muscle heterogeneous tissue model with varying fat thickness up to 15mm and a Monte Carlo simulation of photon transport within this model. The mean partial path length and the mean photon visit depth in the muscle layer were derived for different source-detector spacing. We constructed NIRS instrumentation comprising of light-emitting diodes (LED) as light sources at four wavelengths, 735nm, 760nm, 810nm and 850nm and sensitive photodiodes (PD) as the detectors. Source-detector spacing was varied to perform measurements at different depths within forearm tissue. Changes in chromophore concentration in response to venous and arterial occlusion were calculated using the modified Lambert-Beer Law. Studies in fat and thin volunteers indicated greater sensitivity in the thinner subjects for the tissue oxygenation measurement in the muscle layer. These results were consistent with those found using Monte Carlo simulation. Overall, the results of this investigation demonstrate the usefulness of the NIRS instrument for deriving spatial information from biological tissues.

To monitor the whole Shanghai Expo Park, a vehicle tethered aerostat optoelectronic monitoring platform with the characteristic of time-sensitive and all-weather monitoring is described in detail in this paper, which is hung beneath the tethered balloon and equipped with a variety of payloads, including visible light monitoring system, infrared monitoring system, hyperspectral monitoring system, GPS/INS system, monitoring and control system and so on. These equipments can be used for real-time monitoring, environmental monitoring, and ground target location of Shanghai Expo Park. The output High Definition (HD) image of Shanghai Expo Park from visible light monitoring system is clear and stable, and the stabilization accuracy of visual axis is 0.07°(3δ). The optoelectronic monitoring platform system uses the target location technology based on Global Position System/Inertial Navigation System (GPS/INS) system to output real-time location data compatible with Geographic Information System (GIS). Test results show that the maximum errors between the location results (latitude and longitude) solved by the target location program and the reference target are 0.2 0/00(latitude) and 2 0/00(longitude). Now the whole system has been used for surveillance the Shanghai Expo Park since April 2010.

A new approach of Fabry-Perot (F-P) filter, where the optical length of cavity is tuned by using linear electro-optic (EO) effect of crystals, is demonstrated with the numerical analysis. For achievement of polarization-independent tunability of this filter, directions of light propagation and the external field applied are illustrated by means of the index ellipsoid. An example of the F-P filter using LiNbO₃ crystal is discussed and its tunability is analyzed.

White cotton lint trash can not be effectively detected by white light imaging method. It becomes a serious problem in textile industry. Ultraviolet (UV)-induced fluorescence imaging method is based on the principle that different materials have different spectral excitation and emission characteristics. The fluorescence spectroscopy experiment gave reliable evidence that most white trash had much stronger fluorescent effect than that of lint. In order to simultaneously discriminate several kinds of white lint trash, an Optimal Wavelength Selected Model for describing cotton/trash discrimination was developed. It was determined that 342-388 nm was the optimal detection waveband for white trash detection. Imaging results and analysis clearly showed that for both uncovered and covered situation, the gray differences between white trash and lint were significantly improved when illuminated by a type of UV light. It was concluded that UV-induced fluorescence imaging method is a feasible way to detect most white trash. This method can also be used in white trash detection in seed cotton, wool, tealeaf, and tobacco leaf.

In this paper, based on the extended coupled nonlinear Schrödinger equations including exponential saturable nonlinearity (ESN) in optical fibers, the linearized coupled nonlinear Schrödinger equations are derived. Subsequently, the corresponding condition and gain spectra of cross-phase modulation induced modulation instability (MI) are deduced and calculated. And the variations of the critical perturbation frequency and the peak gain with the input powers are calculated and compared with the case of conventional saturable nonlinearity (CSN) in both the normal and anomalous dispersion regions. The results show that, the critical perturbation frequency and the peak gain increase with the input power, reach a maximum value, and then decrease. Moreover, in comparison, when the other parameters are the same, the varying rates will be faster than those of CSN. These features lead to a unique value of peak gain and critical frequency for two different input powers. This work may be beneficial to further study of new types of bistable or multistable optical solitons.

Polarization fluctuation caused by polarization coupling in polarization maintaining fiber (PMF) resonator is one of the major noise sources in resonant fiber optic gyroscope. Polarization axis 90-degree docking is an effective way to overcome the polarization fluctuation, but the 90-degree docking error has a major affect to the gyroscope noise suppression effect. In this paper, a fiber Michelson interferometer testing system of polarization coupling in doublecoupler polarization maintaining fiber resonator based on white-light interferometer is designed to realize 90-degree docking error control and obtain a good result of 0.37 degree experimental docking error. Then the detection method of sawtooth scanning is used to analyze the resonance characteristics and polarization characteristics of double-coupler polarization maintaining fiber resonator experimentally and obtains the response curve with 24 finesse and 179.65 degree phase interval of the two polarization eigenstates.

The analysis models of Zernike aberrations of precision conformal aspheric optical windows are built, and the influences on Zernike aberrations of different aspheric optical window shapes and the variation laws of Zernike aberrations of precision conformal optical windows at different gimbal angles are analyzed using the multi-configuration capability techniques of Zemax software. The results of analysis show that the astigmatism of conformal aspherical optical windows is the largest, coma is followed, and spherical aberration is smaller in the range of 45° gimbal angles, and the Zernike aberration coefficients of paraboloid and hyperboloid conformal optical windows are higher than that of ellipsoid conformal optical windows. Therefore the ellipsoid surface function is more suitable for the design of precision conformal aspheric optical windows from the point of view of optical system designs and aberration correction techniques.

Based on the appearance of infrared dual-band device and the technical parameters of infrared seeker, a new-type Cassegrain optical system is designed. The main advantages of the system are large field-of-view, infrared dual-band common path and compact structure. In the Cassegrain optical system, the working wavelengths are 3.7μm~4.8μm and 8μm~12μm, the field-of-view 4° and the aperture 240mm. The paraboloidal primary mirror and hyperboloidal secondary mirror are all replaced by spherical surfaces. So the problems of high machining accuracy and alignment become much easier. In order to balance the aberrations, two compensating lenses are used in the system. The amounts of compensating lenses are much less than other optical systems. So the new optical system becomes much more economy, light and compact. The total length of system is 170mm. The ratio of total length to focal length is 0.62. So it can meet the operating requirement of seeker in limited space. Moreover, the system has a good performance of athermalization between negative 40°c and positive 50°c. The design results of the system show that the MTF value of each field is greater than 0.7 when the cut-off frequency is 11 lp / mm. Wavefront aberration is less than 0.038λ.

Generally, the theoretical analysis of the fluorescent life time temperature measurement is based on the assumption of the exponential life time characteristic, but in practice, the actual curve of the fluorescence are different from exponential. This is the key-influence on the stability of the high precision fluorescent measurement system. The differences are analyzed base on the theoretical mechanism of fluorescent, and a cutting and normalized method is given to describe the degree of the non-exponent of the actual fluorescent curve defer from the exponential curve. Several kinds of typical fluorescence materials spectrum and its cutting and normalized experiment results verify this theoretical analysis. Some effective measures to improve the non-exponent of the system are taken and are applied to a temperature measurement system based on actual fluorescent curve analysis with resolution 0.1°C, precisions ±0.2°C, and real-time calibration is carried on. Based the theory base and the actuality of fluorescence optical fiber temperature sensor, two methods about fluorescence decay time constant are proposed. In the mean time, the mathematic model has been formed and analysis, so that the different schemes are selected in different situation.

Off-axis illumination (OAI) technology is widely used to enhance resolution for deep ultraviolet lithography. The realizing methods of OAI include geometrical optics method and physical optics method. However, the former has the disadvantage of weak intensity distribution controlling ability, and the latter introduces simulation errors evidently when dealing with near field diffraction propagation. A diffractive optical element (DOE) designing method using plane wave angular spectrum theory is presented in this paper. Several kinds of OAI modes at near field away from DOE can be realized, and simulation errors and the size of illuminator are also reduced. According to studying the relationships of the sampling point distance of DOE, light beam propagation distance, and the structure of the beam shaping unit, a method of determining the designing parameters is discussed. Using this method, several illumination modes are realized, and simulation results show that all diffraction efficiencies reach up to 84%. The method of DOE manufacturing is analyzed at last, and it is proven to be feasible.

To quickly measure the trace concentration of the single component toxic gas (e.g. sarin), a micro-array toxic gas detector is designed. A 3 x 3 gas sensor array with metalloporphyrins as sensitive materials is introduced. A micro-capsule that can be easy to be loaded and unloaded is designed for the gas reaction. A fiber-array optical path is designed, which is based on the principle that gas sensors will show different colors after reaction with the toxic gas. The tricolor information about the concentration of gas is collected by the color liner CCD. A control handling system with C8051F021 MCU as the core is implemented and embedded into the detector to perform the functions of gas sampling, data collection and analysis calculation. Data acquisition experimental results show that the proposed scheme can effectively collect the color information after gas reaction. Moreover, the system has many important advantages, such as small size, compact structure, high degree of automation, fast detection speed and high performance-cost ratio, etc.