Papers by Chern-Sheng Lin
Distributed and Multiplexed Fiber Optic Sensors V, 1995
The real advantage of an optical fiber displacement sensor lies in solving vibration testing prob... more The real advantage of an optical fiber displacement sensor lies in solving vibration testing problems for which the measured system need precise and various frequency response. Here we present a description of the experimental setup, test procedure, and data-processing method for measuring the vibration isolated effect of an air cushion table. The nonlinear vibrations of a table are discussed and investigated by optical fiber and Michelson set-up. From the experimental results we proved this measuring device is economical and feasible.
Journal of Nondestructive Evaluation, 1996
A digital image processing method to analyze the fringes of a modified caustic is described. The ... more A digital image processing method to analyze the fringes of a modified caustic is described. The experiment is easy to perform and simple, and the image processing technique and detecting system can operate automatically, precisely, and quickly. Recording with two video cameras two sets of caustic images during crack growth, the computers process data with a specified fringe counting algorithm. We obtained two complete sets of data, one providing a full field view of the distribution of stress and the other providing the stress intensity factor.
Indian Journal of Pure & Applied Physics, Nov 1, 2002
Yun-Long l Lay' & !'C h c rn !Shc n g I Lin~ /. ,-. IL Depa rtment o i' UeClJ'On ic Engincc rihg.... more Yun-Long l Lay' & !'C h c rn !Shc n g I Lin~ /. ,-. IL Depa rtment o i' UeClJ'On ic Engincc rihg. N,l tiq'nal IChin-Yi Ins itut e (iTecl; no logy. Ta ichu ng. Taiwan. ROC \
Optik, 2000
An automatic system for computerizing visual measurement the laser diode module has been develope... more An automatic system for computerizing visual measurement the laser diode module has been developed. A polarization filter plate is used to aid in segmentation of the laser light images from the background. Measurements are derived from a combination of least squares approximation to discrete data and error evaluation of a light field. The system provides the laser module assembly lines with desired functions, such as distribution of the intensity, the full width at half maximum (FWHM), and divergent angle and stability analysis. Experiments were conducted that illustrate the comparisons between this image-based system and a typical sensor device.
Purpose-The purpose of this research is to develop an automatic optical inspection system for thi... more Purpose-The purpose of this research is to develop an automatic optical inspection system for thin film transistor (TFT) liquid crystal display (LCD). Design/methodology/approach-A new algorithm that accounts for the closing, opening, etching, dilating, and genetic method is used. It helps to calculate the location and rotation angle for transistor patterns precisely and quickly. The system can adjust inspection platform parameters according to viewed performance. The parameter adaptation occurs in parallel with running the genetic algorithm and imaging processing methods. The proposed method is compared with the algorithms that use artificial parameter sets. Findings-This system ensures high quality in an LCD production line. This multipurpose image-based measurement method uses unsophisticated and economical equipment, and it also detects defects in the micro-fabrication process. Originality/value-The experiment's results show that the proposed method offers advantages over other competing methods.
An optical inspection system has been developed to study laser speckle technology which analyzes ... more An optical inspection system has been developed to study laser speckle technology which analyzes the solar wafer roughness. It can, accurately measure the surface roughness, without contacting with the surface of the solar cells and increase the speed of measurement. The incident laser light on the surface of a solar wafer generates a reflected light, then, the variations in roughness of the speckle pattern can be observed for further analysis and judgement. According to the randomly-distributed bright spots, statistical methods are adopted to analyze the diffraction efficiency of computersimulated surface relief gratings and calculate the surface roughness of solar wafers. The surface roughness of a solar wafer is determined by a CCD camera and the conveyor while using independently-developed software for rapid and continuous imaging as well as analysis through the image processing toolkit. In the future, this inspection technology can be utilized in industries related to solar waf...
Optik, 2018
This study aims to inspect the common defects of the edge of the mirror elements, including scrat... more This study aims to inspect the common defects of the edge of the mirror elements, including scratches, impurities, and edge serration, which occur in the production of mirror elements, where a mirror surface was illuminated in different directions in the experiment. The imaging system was used to inspect the defect position, enhance image contrast, and judge whether the defect exceeds the permissible range. With a novel algorithm, the image contour was analyzed by edge detection, and combined with edge evaluating parameters to improve the quality of the coating edge. According to the experimental results, the proposed algorithm has an average recognition rate of 96% and the recognition speed on a mirror element sized 10 × 7 cm is only 0.1 s.
This study applied the Taguchi method to determine the optimal process parameters of the spinless... more This study applied the Taguchi method to determine the optimal process parameters of the spinless coating for touch panels, and used a fishbone diagram to determine the factors influencing quality characteristics. Factors were then selected according to prior experience, and an appropriate orthogonal array was created according to the selected factors before the experiment. The results indicated that photoresist is the critical material in the optical lithography imaging technology of the touch panel process, which is uniformly coated by a spinless coater onto a glass substrate according to the designed circuit pattern. It is formed after the exposure, development and etching processes. Finally, as coating parameters significantly influence film thickness quality, the experimental data record is analyzed to determine the optimal process parameters, and thus, reduce the probability of defective products and repairs. Improved coating parameters render photoresist film thickness unifor...
Journal of Sensors, 2020
This study focused on utilizing the Kinect depth sensor to track double-hand gestures and control... more This study focused on utilizing the Kinect depth sensor to track double-hand gestures and control a real-time robotic arm. The control system is mainly composed of the microprocessor, a color camera, the depth sensor, and the robotic arm. The Kinect depth sensor was used to take photos of the human body to analyze the skeleton of a human body and obtain the relevant information. Such information was used to identify the gestures of the left hand and the left palm of the user. The gesture of left hand was used as an input command device. The gesture of the right hand was used for imitation movement teaching of robotic arm. From the depth sensor, the real-time images of the human body and the deep information of each joint were collected and converted to the relative positions of the robotic arm. Combining forward kinematics and inverse kinematics and D-H link, the gesture information of the right hand was calculated, which was converted via coordinates into each angle of the motor of...
Metrology and Measurement Systems, 2017
This study proposes a surface profile and roughness measurement system for a fibre-optic intercon... more This study proposes a surface profile and roughness measurement system for a fibre-optic interconnect based on optical interferometry. On the principle of Fizeau interferometer, an interference fringe is formed on the fibre end-face of the fibre-optic interconnect, and the fringe pattern is analysed using the Fast Fourier transform method to reconstruct the surface profile. However, as the obtained surface profile contains some amount of tilt, a rule for estimating this tilt value is developed in this paper. The actual fibre end-face surface profile is obtained by subtracting the estimated tilt amount from the surface profile, as calculated by the Fast Fourier transform method, and the corresponding surface roughness can be determined. The proposed system is characterized by non-contact measurement, and the sample is not coated with a reflector during measurement. According to the experimental results, the difference between the roughness measurement result of an Atomic Force Micros...
Measurement Science and Technology, 2016
The data of a wafer with defects can provide engineers with very important information and clues ... more The data of a wafer with defects can provide engineers with very important information and clues to improve the yield rate and quality in manufacturing. This paper presents a microscope automatic positioning and wafer detection system with human-machine interface based on image processing and fuzzy inference algorithms. In the proposed system, a XY table is used to move the position of each die on 6 inch or 8 inch wafers. Then, a high-resolution CCD and one set of two-axis optical linear encoder are used to accurately measure the position on the wafer. Finally, the developed human-machine interface is used to display the current position of an actual wafer in order to complete automatic positioning, and a wafer map database can be created. In the process of defect detection, CCD is used for image processing, and during preprocessing, it is required to filter noise, acquire the defect characteristics, define the defective template, and then take the characteristic points of the defective template as the reference input for fuzzy inference. A high-accuracy optical automatic positioning and wafer defect detection system is thus constructed. This study focused on automatic detection of spots, scratches, and bruises, and attempted to reduce the time to detect defective die and improve the accuracy of determining the defects of semiconductor devices.
Sensor Review, 2014
Purpose – This study aimed to developed a defect detection system for a segment-type display modu... more Purpose – This study aimed to developed a defect detection system for a segment-type display module panel. Design/methodology/approach – The system included a data acquisition card, a video camera, a computer and a display module on a testing table. The video camera captured the display pattern of the display module and transferred it to the computer through the data acquisition card. The dynamic multi-thresholding method and analysis as well as back propagation neural network classification was used to classify the detected defects. Findings – The threshold values for the brightness at different positions in the display module image were obtained using the neural network and then stored in the look-up table, using two to six matrixes. Originality/value – The recognition speed was faster and the system was more flexible in comparison to the previous system. The proposed method, using unsophisticated and economical equipment, was also verified as providing highly accurate results wit...
Practical Holography VIII, 1994
A fuzzy control model in image formation qualities of holograms manufactured in dichromated gelat... more A fuzzy control model in image formation qualities of holograms manufactured in dichromated gelatin; Agfa 8E75 and other holographic recording material are described. A new model based on the fuzzy set theory is presented to control spectral shifting from the frequency of construction laser beam to the frequency of request. We are concerned with new simplified procedures inserted in ordinary hologram manufacturing process. From the modulation mechanism in these holograms we seize the intrinsic qualities and our model of fuzzy set analysis show to produce good general agreement with the experimentally measured image formation qualities.
Diffractive and Holographic Optics Technology II, 1995
A system of fabricating and evaluating a holographic plate in DCG or photoresist emulsion with ec... more A system of fabricating and evaluating a holographic plate in DCG or photoresist emulsion with economical manufacturing equipment is described. Here we insist on a new concept of DCG and photoresist holographic plate fabricating process and define five film quality characteristics to evaluate the quality of the film of a holographic plate with digital image processing technique.
Optics and Lasers in Engineering, 2002
This work presents an eye-tracking and pupil size-measuring device that interfaces with a compute... more This work presents an eye-tracking and pupil size-measuring device that interfaces with a computer for applications useful in psychometry, ophthalmology, physiology and virtual reality (VR) systems. This system utilizes a change-coupled device (CCD) camera, appropriate lenses, PC with frame grabber and a DSP unit with various types of VR equipment, i.e., HMD, simulator or LCD projection device. The digital signal processing unit is used to calculate the average brightness and contrast of the VR video image. A CCD camera with various attachments can be mounted on various VR systems to capture the human eye image for testing. An image capture card and a personal computer are used to analyze the test image. From the eye digital image, the computer obtains data on the pupil size and a trace of the tested eye. A pattern recognition computer program and five measurement parameters are used to distinguish the position of the pupil, calculate the pupil location coordinate and analyze the physical conditions of the user. These data can be plotted against the average brightness and contrast of the VR video image in real time. This information is shown on the screen of a personal computer and used for cross-link analysis. This eye-tracking interface can determine the position of a subject's pupil and map that position into a display point on a computer screen. The pupil size and location data versus the average brightness and contrast of a VR video image are computed in real time.
Optics & Laser Technology, 1994
In this paper a fuzzy model for fabricating planar-gratings is given. In the model, the diffracti... more In this paper a fuzzy model for fabricating planar-gratings is given. In the model, the diffraction efficiency of the holographic grating (predicted by computer simulation) has a reasonable match with the experimentally verified results. The method can be summarized in three steps: first, a choice of the grating characteristics, which are closely related to the diffraction efficiency factors, is made; secondly, according to our experience, we construct the fuzzy matrix from the grating manufacturing parameters and the grating characteristics; finally, we use the fuzzy matrix composition to obtain the diffraction efficiency factors. Then, coupled wave theory is used to predict the diffraction efficiency. The comparisons between the results of this fuzzy model and experiments are given. It is found that the application of fuzzy set theory in grating manufacturing reduces the cost of the process and improves the quality of the grating.
Microelectronics Reliability, 2001
An image, in-process inspection and accuracy positioning system has been developed as automated m... more An image, in-process inspection and accuracy positioning system has been developed as automated measurement machine to deal with ball grid array type printed circuit boards (PCB). A new technique is proposed to automate the boundary scan and circularity estimation. The attributes of a pixel at a pad or hole are calculated from the RGB color on PCB image. Here we introduce the idea of the least-square circle to ®nd the center of the holes and pads. The value of alignment shift can be obtained according to the four images in a special image capturing procedures. If the circle of the pad and hole can be determined correctly, the vision system can easily inspect the local deviation when positioning table locates the PCB on the image capturing point. The results of positioning and inspection are presented and evaluated including through hole locations, alignment calculation, system calibration, and statistical functions.
Applied Sciences, 2020
The human–machine interface with head control can be applied in many domains. This technology has... more The human–machine interface with head control can be applied in many domains. This technology has the valuable application of helping people who cannot use their hands, enabling them to use a computer or speak. This study combines several image processing and computer vision technologies, a digital camera, and software to develop the following system: image processing technologies are adopted to capture the features of head motion; the recognized head gestures include forward, upward, downward, leftward, rightward, right-upper, right-lower, left-upper, and left-lower; corresponding sound modules are used so that patients can communicate with others through a phonetic system and numeric tables. Innovative skin color recognition technology can obtain head features in images. The barycenter of pixels in the feature area is then quickly calculated, and the offset of the barycenter is observed to judge the direction of head motion. This architecture can substantially reduce the distracti...
Journal of Scientific & Industrial Research, 2010
This study presents fuzzy control to improve solar heat absorbance efficiency (SHAE) of a forced ... more This study presents fuzzy control to improve solar heat absorbance efficiency (SHAE) of a forced circulation solar water heater (FCSWH) system, and simplify user settings. FCSWH system controls startup and stopping of circulating pump based on temperature difference between outlet and inlet of collector. Fuzzy control adapts to uncertainty of sunshine duration and modulates temperature difference to maximize SHAE. According to results, water temperature in heat storage cylinder increased by 3~5°C under fuzzy control system, showing a clear advantage in SHAE over manual control system.
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Papers by Chern-Sheng Lin