PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.
This PDF file contains the front matter associated with SPIE Proceedings Volume 8133, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
For an ordinary laser with two cavity mirrors, if the length of laser cavity changes half wavelength the laser frequency
changes one longitudinal mode separation. For a laser with three cavity mirrors, in which a feedback mirror is used to
feed part of the laser output beam back into the laser cavity, the external cavity length changes half wavelength the laser
intensity fluctuates one period. This presentation gives some research results in measurement field based on changing
(tuning) the length of laser internal/external cavity, including 1) HeNe laser cavity-tuning nanometer displacement
measurement instruments (laser nanometer rulers), 2) HeNe laser feedback displacement measurement, 3) Nd:YAG laser
feedback nanometer displacement measurement, 4) benchmark of waveplate phase retardation measurement based on
laser frequency splitting, 5) in-site waveplate phase retardation measurement instruments based on laser feedback and
polarization hopping, 6) quasi-common-path microchip Nd:YAG laser feedback interferometer, 7) non-contact Nd:YAG
laser feedback surface profile measurement. Some of these instruments have been put into application and display some
irreplaceable advantages.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This paper describes a compact, imaging Twyman-Green interferometer to measure small features such as corrosion pits,
scratches and digs on hard to access objects such as assembled parts. The shoebox size interferometer was designed to
guarantee proper orientation and working distance relative to the inspected section. The system also provides an
extended acceptance angle to permit the collection at selected view points on a subject. We will describe the various
image shifting techniques investigated as part of the prototype. All the components with the exception of power supplies
were integrated into an enclosure. The interferometer has been demonstrated to provide sub-micron depth resolution and
diffraction limited spatial resolution (a few microns). This paper will present the final performance achieved with the
system and provide examples of applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Three-dimensional shape metrology using fringe projection technique and fringe reflection technique are
effective ways to reconstruct three-dimensional shape for surfaces with different reflectance properties. Fringe projection
technique is used for measuring objects with diffuse surfaces and relies on the principle of triangulation, while fringe
reflectometry is used for specular reflective specimens based on principle of reflection. While fringe projection directly
provides the profile, fringe reflectometry measures the slope of the surface from which the profile is integrated. In this
study, the performance of these two fringe based techniques are investigated in relation to sensitivity and accuracy.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Automatically adapting the camera exposure time is crucial for industrial applications where minimum human intervention
is usually desirable. However, it is very challenging to realize such a capability for a conventional fringe projection system
where only a finite increment of the exposure time is allowed due to its digital fringe generation nature. Our recent study
on generating sinusoidal fringe patterns by properly defocusing binary ones permits the use of an arbitrary exposure time.
This provides the potential to adapt the exposure time automatically. This paper will present the principle of an automatic
exposure technique and show some experimental results.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A phase reconstruction method using frequency-shifting is proposed. The frequency-shifting method is
developed based on the properties of trigonometric functions. The computer simulation and the
experimental result are also presented to demonstrate the feasibility and validity of the proposed
approach in phase reconstruction.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Solid state light sources are replacing a tungsten filament based bulbs in Scanning White Light Interferometers. White
LEDs generate little heat, feature short switching times, and have long lifetimes. Phosphor-based white LEDs produce a
wide spectrum but have two separate peaks which cause interferogram ringing. This makes measuring multi layered
structures difficult and may degrade measurement precision even when measuring a single reflecting surface. Most non
phosphor white LEDs exhibit a non Gaussian spectrum, but multi-LED based white LEDs can achieve switching times
and stability similar to those of single color LEDs. By combining several LEDs and by controlling their input current
independently it is possible to create almost an arbitrary spectrum.
We designed a new light source by combining a non phosphor white LED (American Opto Plus LED, L-513NPWC-
15D) and single color LEDs. This allowed us to fill the spectral gap between the blue and yellow peaks of the non
phosphor white LED. By controlling the input current of the LEDs individually a nearly Gaussian shaped spectrum was
achieved. This wide continuous spectrum creates short interferograms (FWHM ~1.4 μm) without side peaks. To
demonstrate the properties of this source we measured through a 5 μm thick polymer film. The well localized
interference created by the source allows measuring both surfaces of thin films simultaneously. We were able to pulse
the source at 5.4 MHz.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Three-dimensional measurement based on a pattern projection method has a lot of requirements such as inspections,
evaluations and designings in the fields of industry. We have proposed a projection technique using a single MEMS
mirror and a laser diode to realize a compact camera for three-dimensional measurement. This projection technique is
able to be transformed the mechanism of the projection from time domain to spatial domain. From this technique, we
achieved to develop a palm-top camera for three-dimensional profile measurement. In this paper, we propose recent
improvement of the principle and its applications. We have developed three-dimensional measurement method based on
a single MEMS mirror using three-color laser diodes and 3CCD camera. The measurement method has combined the
merits of pattern projection method with the merits of gray code technique.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Triangulation sensors have been in wide use for many years. Most point sensors use a laser spot, which is detected using
either a lateral effect photodiode or a linear detector array. The centroid of the spot is used to determine the range using
triangulation. On many engineered surfaces, this spot image may suffer from speckle, surface texture, or other issues that
limit the ability to repeatably measure the centroid. Many analysis means, such as fitting of the spot, zero crossing, and
averaging methods have been tried to make the sensor more robust to surface influenced noise. This paper will present a
system using a split image and phase detection to obtain the range. The speed of the sensor is gained by using simple
point photodiodes and a moire effect to obtain the phase measurement. The paper will discuss the pros and cons of this
approach, and show results on untreated metal parts.ear)
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A compact 3-D shape measurement system based on the combined stereovision and phase shifting method has been
developed, which consists of a miniature projector and two small cameras arranged as a stereo pair. The projector
projects sinusoidal phase shifted fringe patterns, which are captured by both cameras simultaneously. The two phase
maps calculated are used for stereo matching. The 3-D shape of the object is then reconstructed by the triangulation
method. This research focuses on improving the resolution and accuracy of the measurement system by using a sub-pixel
stereo matching method, a multi-image averaging method, and an error compensation method. Experimental results are
presented to show the effectiveness of the proposed methods in improving the resolution and accuracy of the system.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
It is one of the important necessities to precisely measure the inner diameter and/or the inner profile of pipes, tubes and
other objects similar in shape. Especially in mechanical engineering field, there are many requests from automobile
industry because the inner surface of engine blocks and other die casts are strongly required to be inspected and
measured by non-contact methods (not by the naked eyes inspection using a borescope). If the inner diameter is large
enough like water pipes or drain pipes, complicated and large equipment may be applicable. However, small pipes with a
diameter ranging from 10mm to 100mm are difficult to be inspected by such a large instrument as is used for sewers
inspection. And we have proposed an instrument which has no moving elements such as a rotating mirror or a prism for
scanning a beam. Our measurement method is based on optical sectioning using triangulation. This optically sectioned
profile of an inner wall of pipe-like objects is analyzed to produce numerical data of inner diameter or profile. Here, we
report recent development of the principle and applications of the optical instrument with a simple and compact
configuration. In addition to profile measurement, we found flaws and defects on the inner wall were also detected by
using the similar principle. Up to now, we have developed probes with the diameter of 8mm to 25mm for small size
objects and another probe (80 mm in diameter) for such a larger container with the dimensional size of 600mm.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
In this research, we propose to modify a traditional stereo microscope for quantitative 3-D surface profile measurement
based on the combined stereovision and phase shifting method. A simple optical system and a miniature projector are
used to project phase-shifted fringe patterns to the object surface. Two identical black-and-white cameras are used to
capture the fringe images of the object surface, one for each optical channel of the stereo microscope. The calculated
phase maps are used for stereo matching at the sub-pixel level. The 3-D surface profile is reconstructed using the
triangulation method. Experimental results are presented to demonstrate the feasibility of the proposed method.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Three dimensional, optical measurement systems are becoming more widely used in applications ranging from
aerospace to automotive. These systems offer the potential for high speed, good accuracy, and more complete
information than older contact based technology. However, the primary standards employed by many to evaluate
these systems were specifically designed around touch probe based coordinate measurement machines (CMMs).
These standards were designed to work with the limitations of touch probes, and in many cases cannot measure the
types of features and errors associated with non-contact systems. This paper will discuss the deficiencies of
employing contact based characterization tests to non-contact systems, and suggest a new set of tests specifically to
cover the many aspects pertinent to non-contact, optical 3D measurement systems. Some of the performance
aspects addressed in this characterization method include: sensitivity to surface reflectivity and roughness, the
effect of angle of incidence of measurements, means to characterize volumetric variations that may fit complex
functions, and considerations of both spatial and depth resolutions. Specific application areas will be discussed as
well as the use of artifacts to provide practical functional data that can predict system performance on real world
parts.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A new instrument for measurements of thin transparent flats incorporates a novel in-line normal-incidence equal path
interferometer, and extended broad-band illumination to isolate the surface of interest while reducing coherent noise and
artifacts. Incorporating a 4Mpix camera, matching high resolution imaging system and vibration robust design; the
instrument satisfies the needs of current and future hard disk and pellicle metrology.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
3D Non-contact Inspection systems are becoming more capable and affordable, however successful application to
complex parts requires understanding the remaining system limitations. Turbine airfoils are key components used in
several important industries that present some unique challenges to any metrology application. Issues such as surface
finish, complicated shapes and unique geometries exercise many of the key capabilities of a non-contact 3D
measurement system. Therefore, many of the short comings of any 3D method become evident in addressing airfoil
measurement applications. This paper will address the key challenges posed by complicated shapes such as airfoils, and
what gaps still exist in the application of the technology.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
In a project to meet requirements for CBP Laboratory analysis of footwear under the Harmonized Tariff Schedule of the
United States (HTSUS), a hybrid metrology system comprising both optical and touch probe devices has been
assembled. A unique requirement must be met: To identify the interface-typically obscured in samples of concern-of
the "external surface area upper" (ESAU) and the sole without physically destroying the sample. The sample outer
surface is determined by discrete point cloud coordinates obtained using laser scanner optical measurements.
Measurements from the optically inaccessible insole region are obtained using a coordinate measuring machine (CMM).
That surface similarly is defined by point cloud data.
Mathematically, the individual CMM and scanner data sets are transformed into a single, common reference frame.
Custom software then fits a polynomial surface to the insole data and extends it to intersect the mesh fitted to the outer
surface point cloud. This line of intersection defines the required ESAU boundary, thus permitting further fractional
area calculations to determine the percentage of materials present.
With a draft method in place, and first-level method validation underway, we examine the transformation of the two
dissimilar data sets into the single, common reference frame. We also will consider the six previously-identified
potential error factors versus the method process. This paper reports our on-going work and discusses our findings to
date.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The anterior refracting surface of the eye when wearing a contact lens is the thin fluid layer that forms on the surface of
the contact lens. Under normal conditions, this fluid layer is less than 10 microns thick. The fluid layer thickness and
topography change over time and are affected by the material properties of the contact lens, and may affect vision
quality and comfort. An in vitro method of characterizing dynamic fluid layers applied to contact lenses mounted on
mechanical substrates has been developed using a phase-shifting Twyman-Green interferometer. This interferometer
continuously measures light reflected from the surface of the fluid layer, allowing precision analysis of the dynamic fluid
layer. Movies showing this fluid layer behavior can be generated. The fluid behavior on the contact lens surface is
measured, allowing quantitative analysis beyond what typical contact angle or visual inspection methods provide.
The interferometer system has measured the formation and break up of fluid layers. Different fluid and contact lens
material combinations have been used, and significant fluid layer properties have been observed in some cases. The
interferometer is capable of identifying features in the fluid layer less than a micron in depth with a spatial resolution of
about ten microns. An area on the contact lens approximately 6 mm wide can be measured with the system.
This paper will discuss the interferometer design and analysis methods used. Measurement results of different material
and fluid combinations are presented.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Conventional methods to measure the positions of the front and rear surfaces of thin films with multiplewavelength
interferometers are reviewed to make it clear how the method proposed here is novel and simple.
Characteristics of the linear wavenumber-scanning interferometry used in the proposed method are analyzed in
detail to make the measurement accuracy clearly. The positions of the front and rear surfaces of a silicon
dioxide film with 4μm thickness is measured by utilizing the phases of the sinusoidal waves forms
corresponding to each of the optical path differences contained in the interference signal. The experiments and
the theoretical analysis show that the measurement error is about 15 nm.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Optical metrology techniques have been widely used in geometric dimension and shape measurements due to many
features such as non-contact measurement, fast measurement speed, digital data format for computerized analysis
and visualization, superior resolution, and high accuracy, etc. Among these techniques, phase-shifting based surface
profilers have drawn more and more attention due to its full-field measurement and maturing wrapping/unwrapping
analysis characteristics. This paper analyzes the error sources in phase-shifting surface profilers, including phaseshifting
generation, non-linearity compensation, phase-shifting algorithms, surface contour extraction, modeling,
and calibration, etc. Some methods to improve the measurement accuracy through coordinate error compensation
are also proposed including transfer functions and look-up table (LUT) methods.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Our recent study showed that the phase error caused by improperly defocused binary structured patterns has a unique
relationship with the depth z. Based on this finding, the depth information can be extracted without the need of triangulation.
Because the measurement can be performed from the same viewing angle, this uniaxial measurement technique can
overcome some limitations of a triangulation-based technique, such as measuring a deep hole. This paper will present the
principle of the proposed technique and show some simulation and preliminary experimental results to verify its viability.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Two completely localized algorithms for deblurring shift-variant defocused images are presented. The algorithms exploit
limited support domain of 2D shift-variant point spread functions (PSFs) to localize the deblurring process. Focused
image at each pixel is modeled by a truncated Taylor-series polynomial and a localized equation is obtained which
expresses the blurred image as a function of the focused image and its derivatives. This localized equation forms the
basis of the two algorithms. The first algorithm iteratively improves the estimated focused image by directly evaluating
the localized equation for a given blurred image. The second algorithm uses the localized equation in a gradient descent
method to improve the focused image estimate. The algorithms use spatial derivatives of the estimate and hence exploit
smoothness to reduce computation. However, no assumptions about the blurring PSFs such as circular symmetry or
separability are required for computational efficiency. Due to complete localization, the algorithms are fully parallel, that
is, focused image estimates at each pixel can be computed independently. Performance of the algorithms is compared
quantitatively with other shift-variant image restoration techniques, both for computational efficiency and for robustness
against noise. The new algorithms are found to be faster and do not produce any blocking artifacts that are present in
sectioning methods for image restoration. Further, the algorithms are stable and work satisfactorily even in the presence
of large blur. Simulation results of the algorithms are presented for both Cylindrical and Gaussian PSFs. The
performance of the algorithms on real data is discussed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Laser triangulation sensors offer a simple, non-contact and fast solution to measure displacement, position, vibration and
thickness. However, these sensors are prone to target surface sensitivity since they rely heavily on a uniform back-scatter
of the laser spot. Here, sources of measurement noise including surface texture, speckle, beam deflection and asymmetry
are discussed. In addition, a few solutions using dithering as well as the beam shaping to reduce surface sensitivity are
explored. It is shown that a simple ditherer would induce additional error and a solution is suggested to compensate for
it.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
In this paper, the design and evaluation of a 3D stereo, near infrared (IR), defect mapping system for CZT inspection is
described. This system provides rapid acquisition and data analysis that result in detailed mapping of CZT crystal defects
across the area of wafers up to 100 millimeter diameter and through thicknesses of up to 20 millimeter. In this paper,
system characterization has been performed including a close evaluation of the bright field and dark field illumination
configurations for both wafer-scale and tile-scale inspection. A comparison of microscope image and IR image for the
same sample is performed. As a result, the IR inspection system has successfully demonstrated the capability of
detecting and localizing inclusions within minutes for a whole CZT wafer. Important information is provided for
selecting defect free areas out of a wafer and thereby ensuring the quality of the tile. This system would support the CZT
wafer dicing and assembly techniques that enable the economical production of CZT detectors. This capability can
improve the yield and reduce the cost of the thick detector devices that are rarely produced today.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Optical shearography techniques were used for the first time to measure the surface resistivity/conductivity of different
organic-thin films. Different organic coatings i.e., ACE Premium- gray, white, and beige Enamels (spray
coatings), on a metallic alloy, i.e., a carbon steel, were investigated at a temperature range simulating the severe
weather temperatures in Kuwait, especially between the daylight and the night time temperatures, 20-60 °C. The
investigation focused on determining the in-plane displacement of the coatings, which amounts to the thermal
deformation (strain) with respect to the applied temperature range. Then, the alternating current (AC) impedance
(resistance) of the coated samples was determined by the technique of electrochemical impedance spectroscopy (EIS) in
3.5 % NaCl solution at room temperature. In addition, a mathematical model was derived in order to correlate between
the AC impedance (resistance) and to the surface (in-plane) displacement of the samples in solutions. In other words, a
proportionality constant (surface resistivity or conductivity=1/ surface resistivity) between the determined AC impedance
(by EIS technique) and the in-plane displacement (by the optical interferometry techniques) was obtained. Consequently
the surface resistivity (ρ) and conductivity (σ) of the coated samples in solutions were obtained. Also, electrical
resistivity values (ρ) from other source were used for comparison with the calculated values of this investigation. This
study revealed that the measured values of the resistivity for the ACE Premium - gray, white, and beige coatings
were carried out for the first time. No data on the values of (ρ) were found in literature for the same coatings, using
direct current (DC) methods. However, the value range of (ρ) of all investigated coatings, 0.25×108 - 0.27×1010 Ω-cm
was found in the insulator range.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Electronic speckle pattern interferometry is a useful deformation measurement method. In this paper, new method that can measure the deformation by limited information without using much higher speed cameras is proposed. The optical system that can record some spatial information into each speckle of speckle pattern is set up by using basic characteristics of speckle that has never been used before. In experimental results, it is confirmed that the out-of-plane deformation measurement by using only two speckle patterns before and after the deformation can be precisely performed by this method and that the resolution-power of new method is almost equivalent to that of ordinary method.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A novel measurement of laser coarse-fine coupling tracking is proposed for robot trajectory errors, which can not only
meet the requirements of large range, rapid response and dynamic tracking, but also achieve the high accuracy of
submicroradian magnitude. The mathematic model of robot parameters is deduced according to the motion definition. An
experiment platform together with the test system is built to complete the robot trajectory test. The circular and linear
trajectory, as well as the harmonious motion parameters, is tested respectively. Some error factors affecting the test
uncertainty are given to be considered according to the test experiment results.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We described a multi-probe system comprising three laser interferometers and one autocollimator to measure a flat bar
mirror profile with nanometer accuracy. The simulation and pre-experiment of multi-probe system have been conducted
on an X-Y linear stage which is composed of a ball bearing slider and a stepping motor. The two standard deviation of
the flat bar mirror profile is mainly fitting the range of simulation results (±20 nm). Comparison of our measured data
with the results measured by ZYGO white light interferometer system showed agreement to within approximately ±30
nm, excluding some points at the edge of the mirror. From the pre-experiment results, we conclude that the systematic
error caused by accuracy of the moving stage can't be ignored. To eliminate this systematic error, the multi-probe system
has been implemented on a high-precision micro-coordinate measuring machine (M-CMM) that has been built at the
Advanced Industrial Science and Technology (AIST).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
An improved arterial pulsation measurement (APM) system that uses three LED light sources and a CCD image sensor
to measure pulse waveforms of artery is presented. The relative variations of the pulses at three measurement points near
wrist joints can be determined by the APM system simultaneously. The height of the arterial pulsations measured by the
APM system achieves a resolution of better than 2 μm. These pulsations contain useful information that can be used as
diagnostic references in the traditional Chinese medicine (TCM) in the future.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A new apparatus for blind-guide is proposed in this paper. Optical triangulation method was used to realize the system.
The main components comprise a notebook computer, a camera and two laser modules. One laser module emits a light
line beam on the vertical axis. Another laser module emits a light line beam on the tilt horizontal axis. The track of the
light line beam on the ground or on the object is captured by the camera, and the image is sent to the notebook computer
for calculation. The system can calculate the object width and the distance between the object and the blind in terms of
the light line positions on the image. Based on the experiment, the distance between the test object and the blind can be
measured with a standard deviation of less than 3% within the range of 60 to 150 cm. The test object width can be
measured with a standard deviation of less than 1% within the range of 60 to 150 cm. For saving the power consumption,
the laser modules are switched on/off with a trigger pulse. And for reducing the complex computation, the two laser
modules are switched on alternately. Besides this, a band pass filter is used to filter out the signal except the specific
laser light, which can increase the signal to noise ratio.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Recently, an automatic system for grading appearance retention in carpets using our own scanner and image
analysis techniques was proposed. A system for carpets with low pile construction and without color patterns
has been developed. Appearance changes in carpets with high pile construction were still not well detected.
We present an approach based on surface metrology that extract information given by the hairs on the carpet
surface. These features are complementary to the texture features previously explored. By combining both
features, we expand the use of the automatic grading system including some carpets types with high pile
construction.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Due to non-destructive optical techniques allows surface measurement with high accuracy, a Common Path
interferometer based on a Michelson configuration was implemented to analyze phase objects by using polarization
simultaneous phase-shifting interferometry. Each beam of the interferometer has a birefringent wave plate attached in
order to achieve nearly circular polarization of opposite rotations one respect to the other. The system is coupled to a 4-f
arrangement with Bi-Ronchi gratings collocated in the Fourier plane. The interference of the fields associated with
replicated beams, centered on each diffraction orders, is achieved varying the beams spacing with respect to the grating
period. The optical configuration allows obtaining n-interferograms simultaneously. The phase reconstruction is
performing by a three steps phase shifting algorithm. Experimental results are present for a phase object.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This paper presents an optical fiber Mach-Zehnder interferometer configured as an ultra-sensitive sound detector.
We used a 633nm, 0.5 mW, He-Ne laser, two 3dB couplers, a few meter of telecomm fiber, an U-bench mount to
increase the sensitivity of the device and an acquisition system composed by a photodiode and an amplifier
connected to a laptop and to an oscilloscope. The optoelectronic device enables us to record acoustic signals from
sources at distances longer than 4 meters, converting the interference patterns induced by the sound waves into a
digital signal. The ease of its applicability, thanks to its small size and low weight, and its ultra-sensitivity makes
this laser microphone a very attractive solution to issues such as monitoring, no-detectable sensing and perimeter
protection.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Chip sorter is one of packaging facilities in chip manufactory. Defects will occur for a few of chips during
manufacturing processes. If the size of chip defects is larger than a criterion of impacting chip quality, these flawed
chips have to be detected and removed. Defects inspection system is usually developed with frame CCD imagers.
There're some drawbacks for this system, such as mechanism of pause type for image acquisition, complicated
acquisition control, easy damage for moving components, etc. And acquired images per chip have to be processed in
radiometry and geometry and then pieced together before inspection. These processes impact the accuracy and
efficiency of defects inspection. So approaches of image acquisition system and its opto-mechanical module will be
critical for inspection system.
In this article, design and characterization of a new image acquisition system and its opto-mechanical module are
presented. Defects with size of greater than 15μm have to be inspected. Inspection performance shall be greater than
0.6 m/sec. Thus image acquisition system shall have the characteristics of having (1) the resolution of 5μm and 10μm
for optical lens and linear CCD imager respectively; (2) the lens magnification of 2; (3) the line rate of greater than 120
kHz for imager output. The design of structure and outlines for new system and module are also described in this work.
Proposed system has advantages of such as transporting chips in constant speed to acquire images, using one image only
per chip for inspection, no image-mosaic process, simplifying the control of image acquisition. And the inspection
efficiency and accuracy will be substantially improved.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Quasi-monochromatic light reflected from an optically rough surface produces a complicated 3D speckle field. This
speckle field is often described using a correlation function from which the 3D speckle properties can be examined. The
derivation of the correlation function is based on a physical model where several critical assumptions about the input and
output fields in the model are made. However, experimental works verifying this correlation function are rare and
sometimes produce inconsistent results. In this paper, we examine some practical issues encountered when
experimentally measuring this correlation function, including: The realization of the ensemble average between speckle
fields at two point positions; and, The pixel integrating effect of the recording camera and the implications this has for
the statistics of the measured speckle field. Following verification of the correlation function and examining the speckle
decorrelation properties in 3D space, two practical applications are proposed, one is the aligning of the system optical
axis with the camera center and the other is the measurement of the out-of-plane displacement of an object surface.
Simulation and experimental results that support our analysis are presented.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Micro-thin wires are of significant importance to academia, research laboratories as well as industries engaged in
micro-fabrication of products related to diverse fields like micromechanics, bio-instrumentation, optoelectronics etc.
Critical dimension metrology of such wires often demands diameter estimation with tight tolerances. Amongst other
measurement techniques, Optical Diffractometry under Fraunhofer approximation has emerged over years as a nondestructive,
robust and precise technique for on-line diameter estimation of thin wires. However, it is observed that
existing Fraunhofer models invariably result in experimental overestimation of wire diameter, leading to
unacceptable error performances particularly for diameters below 50 μm. In this paper, a novel diffraction model
based on Geometric theory is proposed and demonstrated to theoretically quantify this diameter overestimation. The
proposed model utilizes hitherto unused paths-ways for the two lateral rays that contribute to the first diffraction
minimum. Based the 3-D geometry of the suggested model, a new 'diffraction formulation' is proposed. The
theoretical analysis reveals the following. For diffraction experiment, the Actual diameter of the diffracting wire is a
function of four parameters: source wavelength 'λ', axial distance 'z', diffraction angle corresponding to first
diffraction minimum 'θd' and a newly defined characteristic parameter 'm'. The analysis reveals further that the
proposed characteristic parameter 'm' varies non-linearly with diameter and presents a dependence only on the
experimentally measured diffraction angle 'θd'. Based on the proposed model, the communication reports for the
first time, a novel diameter-inversion procedure which, not only corrects for the overestimated but also facilitates
wire diameter-inversion with high resolution. Micro-thin metallic wires having diameters spanning the range 1-50
μm are examined. Experimental results are obtained that corroborate the theoretical approach.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Wavelength scanning interferometry based on a reflectometry model is proposed for measuring the absolute thickness
profile of a thin silicon wafer. A Fourier-based method of wavelength scanning interferometry is limited to thicker
wafers because of a tuning range limitation of the source. As an example, the minimum thickness measurable with the
conventional Fourier-based technique using a 4 nm-tunable (500 GHz) 1550 nm laser is approximately 170 μm. Our
proposed method enables an extension of thickness measurements with a reduction in systematic measurement error,
representing a significant advance. The so-called 'ripple-error' or 'fringe-bleed through' is much lower with a
reflectometry-based analysis compared to a Fourier-based analysis. Our method was verified by measuring and testing
several wafers with various thicknesses.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.