The degree of passivation of the grinding wheel is gradually increased during the machining process, the friction between the grinding wheel and the workpiece is increased which causing the vibration and noise of the machine are changed. Therefore, the vibration and noise values could be obtained by using the vibration sensor and microphone. We use the spectrum analyzer to analyze the trend of the variation of vibration and noise signals. As the wear of the grinding wheel increases, the sound acoustic pressure in the range of 4.3 kHz to 5.3 kHz decreases. As the friction between the grinding wheel and the workpiece increases, high-frequency noise greater than 6 kHz are excited and the acoustic pressure increases. According to the experimental results, it is known that the wear state of the grinding wheel and the noise spectrum in generating process has a significant correlation. The cutting force of the grinding wheel can be observed by the noise spectrum of the spectrum analyzer to identify whether there is an abnormality in the processing process to optimize the grinding parameter immediately for avoiding the damage of the lens.
In general, the manufacture of contact lenses is conventionally labor intensive, requiring manual handling and inspection of the cast lens during production. This paper is to build an AOI (automatic optical inspection) system, which include suitable light source, camera and image processing algorithms, for contact lenses defect inspection. The mainly defect type are missing lens and surface defect on the contact lenses. An illumination system with fixed focal lens and charge coupled device (CCD) is used to capture the images of contact lenses. After images are captured, an algorithm is employed to check if there are flaws showed on the images. Five kinds of defect can be detected by the designed algorithm. A prototype of the AOI system for contact lenses inspection is implemented. The experimental result shows that the proposed system is robust for in-line inspection.
The analysis of the diffractive phase elements (DPEs) that synthesizes pseudo-nondiffracting beams (PNDBs) in different axial regions are described. Those elements are designed by using conjugate-gradient method algorithm. To meet the requirement of lithography fabrication process, the obtained optimum continuous surface profile of DPEs must be quantized in the multilevel structure. In order to analyze the impact of different quantization levels, the axial-illuminance RMS variance of PNDBs for each quantized DPE is calculated and compared with each other. The compared results show that the axial illuminance of the PNDB of DPE with smaller-levels quantization fluctuates more rapidly than that of DPE with larger-levels quantization. Meanwhile, the analyses also show that the axial uniformity of the PNDB of DPE with a longer focal length is less sensitive to the quantization level.
In recent years, the glasses had gradually been personal accessory to human life, so the demand of various types of glasses has increased significantly, especially safe glasses and sunglasses. And the requirement of full-inspection of the lens of safe glasses and sunglasses are getting seriously. In the past, the fast lens optical quality inspection where performed by Ronchi test and the Ronchigram images were observed and judged by human eyes. However, the larger uncertainty of measurement will be induced while observing the Ronchi patterns using human eyes. Therefore, this study presents the development of an automatic lens Inspection Instrument based on Ronchi tester, which comprises of the machine vision, image analysis and processing technique without human operation involved. In addition, an optical quality index based on Ronchigram has been developed so as to classify the quality of test lens. In this paper, we propose a lens quality index (LQI) to evaluate the optical quality of lens to be inspected.
In order to develop a high accuracy optical alignment system for precision molding machine, a geometric matching method was developed in this paper. The alignment system includes 4 high magnification lenses, 4 CCD cameras and 4 LED light sources. In the precision molding machine, a bottom metal mold and a top glass mold are used to produce a micro lens. The two molds combination does not use any pin or alignment part. They only use the optical alignment system to alignment. In this optical alignment system, the off-axis alignment method was used. The alignment accuracy of the alignment system is about 0.5 μm. There are 2 cross marks on the top glass mold and 2 cross marks on the bottom metal mod. In this paper did not use edge detection to recognize the mask center because the mask easy wears when the combination times increased. Therefore, this paper develops a geometric matching method to recognize mask center.
Since the amount of data storage has kept growing, the transmitting rate of interface between data storages should be kept growing as well and the capacity of fiber-optic communication with single mode fiber become insufficient. Therefore, the multi-mode fiber which has much larger core diameter has been widely used in high data traffic application. The quality of end surface of fiber dominates the data transmitting efficiency. But the quality of cutting end surface which cut by the traditional mechanical fiber cleaving method was not good enough for the requirement of multimode fiber. In the recent year, the pulse CO2 laser was introduced to cleave the fibers. The optical system setup, laser pulse parameters, such as laser pulse energy, pulse width and number of laser pulse, will affect the quality of end surface of fiber. In this paper, the pulse CO2 laser fiber cleaving technology will be developed and the experimental setup will be introduced. And the relationships between the quality of cutting end surface and the cleaving parameters will be studied. The optimal laser control parameter set for fiber cleaving will be discussed as well.
The core of the power inductor is made by powder metallurgy. By its nature, the powder-formed part has inherent nonuniform porosity pattern and parallel tool marks on the metal surface. In the past, the surface inspection of core is usually performed by using human eyes. However, the larger uncertainty of inspection will be induced while observing the defect image using human eyes. In the automated optical inspection process, the feature of defect is not easily separated from the image background by using the simple binarization method. This study develops an image processing method and employs a uniform diffuse illumination to build up a surface defect inspection system. Experiment result shows the distinguish rate is 95.5%, therefore it is clear that this system can successfully detects a set defect of the core of inductor.
The fluorescent reaction is that an organism or dye, excited by UV light (200-405 nm), emits a specific frequency of
light; the light is usually a visible or near infrared light (405-900 nm). During the UV light irradiation, the photosensitive
agent will be induced to start the photochemical reaction. In addition, the fluorescence image can be used for
fluorescence diagnosis and then photodynamic therapy can be given to dental diseases and skin cancer, which has
become a useful tool to provide scientific evidence in many biomedical researches. However, most of the methods on
acquiring fluorescence biology traces are still stay in primitive stage, catching by naked eyes and researcher's subjective
judgment. This article presents a portable camera to obtain the fluorescence image and to make up a deficit from
observer competence and subjective judgment. Furthermore, the portable camera offers the 375nm UV-LED exciting
light source for user to record fluorescence image and makes the recorded image become persuasive scientific evidence.
In addition, when the raising the rate between signal and noise, the signal processing module will not only amplify the
fluorescence signal up to 70 %, but also decrease the noise significantly from environmental light on bill and nude mouse
In ultra-precision (distortion < 0.5 %) vision inspection system, the accuracy of measurement depends on sharpness and
distortion of image. The telecentric lens provides distortion-free and constant magnification (within depth of field)
image, so it has become an indispensable key module in the amount of visual measuring system. The article presents a
design and development of telecentric lens module for the wide range of vision inspection system (field-of-view > 100
mm). Based on the concept of equivalent design in optical tolerances, the lens module can be designed readily into a
telecentric system, which consists of five spherical lenses and a glass molded aspheric lens. In order to correct image
distortion, an aspheric lens would be added to the telecentric system. The experiment shows that the distortion can be
reduced from 1.5 % to 0.34 % and the depth of field (DOF) is also improved up to 28.3 mm.