Browsing by Author "Yang, Shih-Wei"

Now showing 1 - 11 of 11

3D surface profile measurement of unsymmetrical microstructure using Fizeau interferometric microscope
(2013-04-01)
Yang, Shih-Wei
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Lin, Chern-Sheng
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Lin, Shir-Kuan
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電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper, an automatic optical inspection system for the 3D surface profile of an unsymmetrical microstructure using Fizeau interferometer was proposed. This non-contact optical inspection system is suitable for measuring the lens sag and 3D surface profile of symmetrical and unsymmetrical microlenses. Referring to the unsymmetrical microlenses as an example, the distribution of the interference fringes is partly dense and partly rare, and is completely different from the equally dense distribution of symmetrical microlenses. Thus, a novel algorithm is proposed to solve the above mentioned problem in this paper, namely, individually determining the darkest points of the dark fringes and the brightest points of the bright fringes, and fitting these discrete points as close curves through the Bezier curve theory. As the contour lines of an unsymmetrical microlens are obtained, the 3D surface profile of the unsymmetrical microlens can be plotted correspondingly. Furthermore, the proposed system has the following advantages due to its non-contact structure. This system is specifically designed for in-line measurements according to the rapid inspection speed; it has no need to coat a reflective layer on the inspected microstructure, thus avoiding damaging the surface structure of the sample. (C) 2012 Elsevier Ltd. All rights reserved.
An automatic optical inspection system for measuring a microlens array with an optical interferometric microscope and genetic algorithm
(2013)
Yang, Shih-Wei
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Lin, Chern-Sheng
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Lin, Shir-Kuan
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Fu, Shu-Hsien
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Yeh, Mau-Shiun
Purpose - The purpose of this paper is to propose an automatic optical inspection system for measuring the surface profile of a microlens array. Design/methodology/approach - The system set-up was constructed according to the principle of the Fizeau interferometer. After capturing the ring interference fringe images of the microlens with a camera, the diameter, profile information and optical properties were analyzed through a microlens surface profile algorithm using innovative image pre-processing with a precision of less than 0.09 micron. Findings - By integrating with the genetic algorithm, the XY-Table shortest moving path of the system is calculated to achieve the purpose of highspeed inspection and automatic microlens array surface profile measurement. Originality/value - The measurement results of this system were also compared with other systems, including the atomic force microscope and stylus profiler, to verify the measurement precision and accuracy of this system.
Automatic defect recognition of TFT array process using gray level co-occurrence matrix
(2014)
Yang, Shih-Wei
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Lin, Chern-Sheng
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Lin, Shir-Kuan
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Chiang, Hsien-Te
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電控工程研究所
This study proposed an automatic optical inspection (AOI) system for detection of thin-film transistor (TFT) array defects. gray level co-occurrence matrix (GLCM) and MATLAB regionprops function were used to calculate 53 TFT array defect features, which were inputted into the neural network to train the defect classifier. The images to be inspected were compared with a standard image first, in order to judge whether the TFT array samples have defects. For defective images of a TFT array, the proposed defect classifier can successfully recognize five kinds of defects in the process. According to the experimental results, the defect recognition rate of proposed system is verified to be 83.3%, which can replace manual inspection and reduce the risks of false inspections due to long duration manual work. Moreover, the proposed AOI system can improve testing efficiency and reduce manufacturing costs. (C) 2014 Elsevier GmbH. All rights reserved.
AUTOMATIC INSPECTION SYSTEM FOR DEFECTS OF PRINTED ART TILE BASED ON TEXTURE FEATURE ANALYSIS
(2014-01-02)
Yang, Shih-Wei
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Lin, Chern-Sheng
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Lin, Shir-Kuan
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Tseng, Yung-Chin
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電控工程研究所
An automatic inspection system of printed art tile defects is reported in this artucke. After calculating eight defect features of art tile using the gray level co-occurrence matrix and the average R, G, B values of a defective area, the results were input into a backward propagation neural network for training the defect classifier. During inspection, the proposed system compared the inspected image with a standard image and removed noise by an erosion operation in order to preliminarily determine whether the art tile had defects. For the defective art tile images, the proposed classifier successfully identified four types of common printing defects. The proposed algorithm had an average recognition rate of 90%, suggesting that the recognition accuracy is good, and only requires 1-2s to inspect an art tile with the size of 15x15cm(2). The inspection speed is faster than the conventional manual inspection, and recognition results are more stable. The proposed system can reduce the risk of error caused by the long duration of manual inspection, and thus, can reduce manufacturing costs.
Automatic optical inspection system for 3D surface profile measurement of multi-microlenses using the optimal inspection path
(2014-07-01)
Yang, Shih-Wei
;
Lin, Shir-Kuan
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper, an automatic optical inspection system is proposed for measuring the three-dimensional surface profile of multi-microlenses according to the optimal inspection path. The proposed system is applicable for full and sampling inspection of microlens arrays, and has the following contributions: (1) the optimal inspection path of sampling inspection is derived by a Genetic Algorithm considering the acceleration characteristic of the XY-table. (2) The incomplete microlens fringe is removed, and the center of each microlens can be automatically positioned. (3) The phase difference of each neighboring pixel is calculated through the concept of sign reversal in order to rebuild the surface profile. According to the experimental results, the lens sag of microlenses in different sizes can be correctly measured by the proposed system, and a relative error of 3.4% (max) can be achieved. Compared with other methods, the positioning time of the proposed method is shortened by 10% to 30%, validating the practicability of this system.
Automatic optical inspection system for 3D surface profile measurement of multi-microlenses using the optimal inspection path
(2014-07-01)
Yang, Shih-Wei
;
Lin, Shir-Kuan
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper, an automatic optical inspection system is proposed for measuring the three-dimensional surface profile of multi-microlenses according to the optimal inspection path. The proposed system is applicable for full and sampling inspection of microlens arrays, and has the following contributions: (1) the optimal inspection path of sampling inspection is derived by a Genetic Algorithm considering the acceleration characteristic of the XY-table. (2) The incomplete microlens fringe is removed, and the center of each microlens can be automatically positioned. (3) The phase difference of each neighboring pixel is calculated through the concept of sign reversal in order to rebuild the surface profile. According to the experimental results, the lens sag of microlenses in different sizes can be correctly measured by the proposed system, and a relative error of 3.4% (max) can be achieved. Compared with other methods, the positioning time of the proposed method is shortened by 10% to 30%, validating the practicability of this system.
Design of an automatic shift control system with self-learning ability for a bicycle
(2015-07-01)
Lin, Shir-Kuan
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Yang, Shih-Wei
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Cheng, Chi-Chang
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電控工程研究所
;
Institute of Electrical and Control Engineering
An automatic shift control system with self-learning ability, for a bicycle is proposed in this paper. The concept of pseudo pedaling speed is used as the shifting basis, and the pseudo pedaling speed is derived from the wheel speed read through a microcontroller. According to the pseudo pedaling speed histograms, all riders\' pseudo pedaling speed histograms approach normal distribution. Hence, a straight forward algorithm of shifting using the mean and standard deviation of the riders\' pseudo pedaling speed is developed. The microcontroller commands the actuators to shift up or shift down a gear with the proposed algorithm. According to the experimental results, the proposed system has been shown to function well, thus, enhancing the convenience and comfort of cycling.
Design of virtual keyboard using blink control method for the severely disabled
(2013-08-01)
Yang, Shih-Wei
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Lin, Chern-Sheng
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Lin, Shir-Kuan
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Lee, Chi-Hung
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電控工程研究所
In this paper, a human-machine interface with the concept of "blink control" is proposed. The human-machine interface is applied to an assistive device, namely "blink scanning keyboard", which is designed specifically for the severely physical disabled and people suffering from motor neuron diseases or severe cerebral palsy. The pseudo electromyography (EMG) signal of blinking eyes could be acquired by wearing a Bluetooth headset with one sensor on the forehead and the other three on the left ear of the user. Through a conscious blink, a clear and immediate variation will be formed in the pseudo EMG signal from the users' forehead. The occurrence of this variation in pseudo EMG signal could be detected and filtered by the algorithms proposed in this paper, acting like a trigger to activate the functions integrated in the scanning keyboard. The severely physical and visual disabled then can operate the proposed design by simply blinking their eyes, thus communicating with outside world. (C) 2013 Elsevier Ireland Ltd. All rights reserved.
Fall detection for multiple pedestrians using depth image processing technique
(2014-04-01)
Yang, Shih-Wei
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Lin, Shir-Kuan
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電控工程研究所
;
Institute of Electrical and Control Engineering
A fall detection method based on depth image analysis is proposed in this paper. As different from the conventional methods, if the pedestrians are partially overlapped or partially occluded, the proposed method is still able to detect fall events and has the following advantages: (1) single or multiple pedestrian detection; (2) recognition of human and non-human objects; (3) compensation for illumination, which is applicable in scenarios using indoor light sources of different colors; (4) using the central line of a human silhouette to obtain the pedestrian tilt angle; and (5) avoiding misrecognition of a squat or stoop as a fall. According to the experimental results, the precision of the proposed fall detection method is 94.31% and the recall is 85.57%. The proposed method is verified to be robust and specifically suitable for applying in family homes, corridors and other public places. (C) 2014 Elsevier Ireland Ltd. All rights reserved.
Lens sag and diameter measurement of large-size microlenses using sub-pixel algorithm and optical interferometry
(2014-04-01)
Lin, Shir-Kuan
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Yang, Shih-Wei
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper, an automatic optical inspection system is designed specifically to measure the diameter and lens sag of large-size microlenses: 1. The proposed algorithm of measuring lens diameter locates the lens center through the Euclidean distance array, and determines the lens edge along an initiated ray using linear interpolation with sub-pixel accuracy. 2. The lens sag is calculated from a single fringe pattern of large-size microlens, in combination with the measured lens diameter. 3. According to the experiment results, the proposed system has advantages of high applicability, rapid processing speed, and good accuracy with the RMS error <=% of measuring a large-size microlens, but without the requirement of prior training. The system architecture of non-contact measurement would not cause scratches on the lens surface and is inexpensive, this, which is particularly suitable for the in-line inspection of industry field. (C) 2013 Elsevier Ltd. All rights reserved.
THE CHEMICAL STAIN INSPECTION OF POLYSILICON SOLAR CELL WAFER BY THE FUZZY THEORY METHOD
(2013-08-01)
Lin, Chern-Sheng
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Lin, Chih-Wei
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Yang, Shih-Wei
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Lin, Shir-Kuan
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Chiu, Chuang-Chien
This study proposed an automatic optical inspection (AOI) technique to improve the inspection of chemical stains on solar wafers. Poly-silicon solar cell wafers were inspected for chemical stains, and the inspection was rapid and stable. The system used a laser-reflection-point-based AOI method for solar wafer chemical stain inspection. Based on the fuzzy theory, the image binarization algorithm could efficiently filter irrelevant image information, and the back-propagation method was also utilized to determine if the image was stained. The inspection algorithm integrated fuzzy theory and the back-propagation method in order to shorten the comparison time and quickly find the target. The experiment proved that the validity of the proposed method could achieve a recognition rate of 98% from among 1000 images.