Browsing by Author "Yan, Yung-Jhe"

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Adjustable panoramic inspection system for submillimeter fasteners
(2020-04-10)
Yan, Yung-Jhe
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Tsai, Ming-Shiou
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Chen, Wen-Bin
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Chen, You-Bo
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Sun, Ching-Cherng
Fasteners are critical and indispensable locking components in mechanical assembly. Submillimeter fasteners are massively and widely used in electronic devices. This study proposed an adjustable panoramic inspection system for M2 to M0.8 submillimeter fasteners. The system mainly consists of a panoramic imaging module, a back-light module, and an image grabbing and computing module. The panoramic imaging module would form four equal optical path lengths to keep the same imaging amplification between the different directions of the field of view. The back-light module was designed to provide uniform illumination and enhance the contrast of the pitch edge between the fasteners and the background. The image grabbing and computing module with a high-speed camera was designed to be adjustable for different sizes of submillimeter fasteners. The realized system can offer the function of four images in one shot to make a panoramic scene, independent illumination for recognizing, inspect screws from M0.8 to M2.0 screws, and short time consumption of image processing, such as 3.284 ms for M0.8 screws and 2.384 ms for M2.0 screws, to achieve examination of 6000 pieces in 1 min. (C) 2020 Optical Society of America.
Coding optimization for the absolute optical rotary encoder
(2018-01-01)
Wang, Ting-Feng
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Yan, Yung-Jhe
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Chiang, Hou-Chi
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Chen, Tsan Lin
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Ou-Yang, Mang
Precise positioning system is assuming increasing importance. One of Implementation is an optical rotary encoder system which is composed of a fixed light source, a group of photodetectors, and a coding disc. In fact, position resolution is affected with a permutation of coding on the disc. Unstable dc voltage was found from an analog signal transmitted by photoelectric detectors. Setting up a threshold voltage for digital binariz ation become difficult in this case. In this paper, the limitations, characteristics and operation mode of coding on the disc operation mode arrangement rules of coding on the disc was observed. After collecting the relevant literature, the mathematical sequence named De Bruijn sequence which matches to the arrangement of the above rules and restrictions was found. The desired requirements are summarized and used to filter out the best solution in all solution sets with the designed algorithm. Finally, the characteristics of new and old solutions are compared and discussed.
Design of light guide sleeve on hyperspectral imaging system for skin diagnosis
(2017-01-01)
Yan, Yung-Jhe
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Chang, Chao-Hsin
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Huang, Ting-Wei
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Chiang, Hou-Chi
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Wu Jeng-Fu
A hyperspectral imaging system is proposed for early study of skin diagnosis. A stable and high hyperspectral image quality is important for analysis. Therefore, a light guide sleeve (LGS) was designed for the embedded on a hyperspectral imaging system. It provides a uniform light source on the object plane with the determined distance. Furthermore, it can shield the ambient light from entering the system and increasing noise. For the purpose of producing a uniform light source, the LGS device was designed in the symmetrical double-layered structure. It has light cut structures to adjust distribution of rays between two layers and has the Lambertian surface in the front-end to promote output uniformity. In the simulation of the design, the uniformity of illuminance was about 91.7%. In the measurement of the actual light guide sleeve, the uniformity of illuminance was about 92.5%.
Design of synchronizing pupillometer for observing nerve conduction by pupillary responses
(2016)
Tsai, Yi-Chun
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Yan, Yung-Jhe
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Ko, Mei-Lan
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Huang, Ting-Wei
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Chiou, Jin-Chern
The pupil response to light can reflect various kinds of neural diseases, and different response for two eyes can be analyzed relative afferent pupillary defect. This study presents the novel wearable pupillometer for recording the pupil response and designs the experiment for verifying the synchronization of two cameras. Compared with other devices, the main feature of this study is proven reliable, portable, and wearable for obtaining the pupil response. In addition, our experimental result verify that the pupillometer successfully achieve the function of synchronization.
Development and verification of the coaxial heterogeneous hyperspectral system for the Wax Apple tree
(2019-01-01)
Li, Yi-Sheng
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Yan, Yung-Jhe
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Shih, Ruei-Siang
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Chang, Chao-Hsin
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Chen, Tzung-Cheng
This paper presents the design of the coaxial heterogeneous hyperspectral system, concurrently sensing for the visible (YES) light and short-wave infrared (SWIR) light wavelengths under the same space axis. By the designed mechanism, this hyperspectral system can provide more hands and broader wavelengths in every scan. The adequate spectral information of the target makes the analysis more comprehensive. For this hyperspectral system, the spatial correction and spectral correction are required. The spatial correction deals with the spatial match between the VIS and SWIR data. Moreover, the spectral correction is to eliminate the different response of the YES and SWIR sensor. The purpose of these corrections was to verify the design and provide the accurate reflection spectrum.
Multi-band filter design with less total film thickness for short-wave infrared
(2017-01-01)
Yan, Yung-Jhe
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Chien, I-Pen
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Chen, Po-Han
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Chen, Sheng-Hui
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Tsai, Yi-Chun
A multi-band pass filter array was proposed and designed for short wave infrared applications. The central wavelength of the multi-band pass filters are located about 905 nm, 950 nm, 1055 nm and 1550 nm. In the simulation of an optical interference band pass filter, high spectrum performance (high transmittance ratio between the pass band and stop band) relies on (1) the index gap between the selected high/low-index film materials, with a larger gap correlated to higher performance, and (2) sufficient repeated periods of high/low-index thin-film layers. When determining high and low refractive index materials, spectrum performance was improved by increasing repeated periods. Consequently, the total film thickness increases rapidly. In some cases, a thick total film thickness is difficult to process in practice, especially when incorporating photolithography liftoff. Actually the maximal thickness of the photoresist being able to liftoff will bound the total film thickness of the band pass filter. For the application of the short wave infrared with the wavelength range from 900nm to 1700nm, silicone was chosen as a high refractive index material. Different from other dielectric materials used in the visible range, silicone has a higher absorptance in the visible range opposite to higher transmission in the short wave infrared. In other words, designing band pass filters based on silicone as a high refractive index material film could not obtain a better spectrum performance than conventional high index materials like TiO2 or Ta2O5, but also its material cost would reduce about half compared to the total film thickness with the conventional material TiO2. Through the simulation and several experimental trials, the total film thickness below 4 um was practicable and reasonable. The fabrication of the filters was employed a dual electric gun deposition system with ion assisted deposition after the lithography process. Repeating four times of lithography and deposition process and black matrix coating, the optical device processes were completed.
Oil defect detection of Electrowetting Display
(2015-01-01)
Chiang, Hou-Chi
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Tsai, Yu-Hsiang
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Yan, Yung-Jhe
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Huang, Ting-Wei
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Ou-Yang, Mang
In recent years, transparent display is an emerging topic in display technologies. Apply in many fields just like mobile device, shopping or advertising window, and etc. Electrowetting Display (EWD) is one kind of potential transparent display technology advantages of high transmittance, fast response time, high contrast and rich color with pigment based oil system. In mass production process of Electrowetting Display, oil defects should be found by Automated Optical Inspection (AOI) detection system. It is useful in determination of panel defects for quality control. According to the research of our group, we proposed a mechanism of AOI detection system detecting the different kinds of oil defects. This mechanism can detect different kinds of oil defect caused by oil overflow or material deteriorated after oil coating or driving. We had experiment our mechanism with a 6-inch Electrowetting Display panel from ITRI, using an Epson V750 scanner with 1200 dpi resolution. Two AOI algorithms were developed, which were high speed method and high precision method. In high precision method, oil jumping or non-recovered can be detected successfully. This mechanism of AOI detection system can be used to evaluate the oil uniformity in EWD panel process. In the future, our AOI detection system can be used in quality control of panel manufacturing for mass production.
Portable LED-induced autofluorescence imager with a probe of L shape for oral cancer diagnosis
(2015-01-01)
Huang, Ting-Wei
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Lee, Yu-Cheng
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Cheng, Nai-Lun
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Yan, Yung-Jhe
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Chiang, Hou-Chi
The difference of spectral distribution between lesions of epithelial cells and normal cells after excited fluorescence is one of methods for the cancer diagnosis. In our previous work, we developed a portable LED Induced autofluorescence (LIAF) imager contained the multiple wavelength of LED excitation light and multiple filters to capture ex-vivo oral tissue autofluorescence images. Our portable system for detection of oral cancer has a probe in front of the lens for fixing the object distance. The shape of the probe is cone, and it is not convenient for doctor to capture the oral image under an appropriate view angle in front of the probe. Therefore, a probe of L shape containing a mirror is proposed for doctors to capture the images with the right angles, and the subjects do not need to open their mouse constrainedly. Besides, a glass plate is placed in probe to prevent the liquid entering in the body, but the light reflected from the glass plate directly causes the light spots inside the images. We set the glass plate in front of LED to avoiding the light spots. When the distance between the glasses plate and the LED model plane is less than the critical value, then we can prevent the light spots caused from the glasses plate. The experiments show that the image captured with the new probe that the glasses plate placed in the back-end of the probe has no light spots inside the image.
Portable LED-induced autofluorescence spectroscopy for oral cancer diagnosis
(2017-04-01)
Yan, Yung-Jhe
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Huang, Ting-Wei
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Cheng, Nai-Lun
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Hsieh, Yao-Fang
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Tsai, Ming-Hsui
Oral cancer is a serious and growing problem in many developing and developed countries. To improve the cancer screening procedure, we developed a portable light-emitting-diode (LED)-induced autofluorescence (LIAF) imager that contains two wavelength LED excitation light sources and multiple filters to capture ex vivo oral tissue autofluorescence images. Compared with conventional means of oral cancer diagnosis, the LIAF imager is a handier, faster, and more highly reliable solution. The compact design with a tiny probe allows clinicians to easily observe autofluorescence images of hidden areas located in concave deep oral cavities. The ex vivo trials conducted in Taiwan present the design and prototype of the portable LIAF imager used for analyzing 31 patients with 221 measurement points. Using the normalized factor of normal tissues under the excitation source with 365 nm of the central wavelength and without the bandpass filter, the results revealed that the sensitivity was larger than 84%, the specificity was not smaller than over 76%, the accuracy was about 80%, and the area under curve of the receiver operating characteristic (ROC) was achieved at about 87%, respectively. The fact shows the LIAF spectroscopy has the possibilities of ex vivo diagnosis and noninvasive examinations for oral cancer. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
QUALITY INSPECTION OF PHALAENOPSIS HYBRIDS USING HYPERSPECTRAL BAND SELECTION TECHNIQUES
(2019-01-01)
Ouyang, Yen-Chieh
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Chen, Bo-Han
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Lee, Meng-Chueh
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Liu, Tsang-Sen
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Ou-Yang, Mang
Fusarium wilt on Phalaenopsis is a disease that makes farmers suffer seriously. Although Phalaenopsis does not die immediately with Fusarium wilt, it seriously decreases the quality that buyers cannot accept. In this paper, we introduce an emerging method to detect Fusarium wilt at the base of Phalaenopsis stems. The detection model divides Phalaenopsis samples into two categories, healthy and infection. The band selection (BS) processing technique based on band prioritization (BP) is applied to extract significant bands and eliminate redundant bands. Subsequently, some algorithms which are constrained energy minimization (CEM), spectral information divergence(SID) and SeQuential N-FINDER to detect the Fusarium wilt, and we hope the research would help farmers decrease their losses.
The image registration of multi-band images by geometrical optics
(2015-01-01)
Yan, Yung-Jhe
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Chiang, Hou-Chi
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Tsa, Yu-Hsiang
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Huang, Ting-Wei
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Mang Ou-Yang
The image fusion is combination of two or more images into one image. The fusion of multi-band spectral images has been in many applications, such as thermal system, remote sensing, medical treatment, etc. Images are taken with the different imaging sensors. If the sensors take images through the different optical paths in the same time, it will be in the different positions. The task of the image registration will be more difficult. Because the images are in the different field of views (F.O.V.), the different resolutions and the different view angles. It is important to build the relationship of the viewpoints in one image to the other image. In this paper, we focus on the problem of image registration for two non-pinhole sensors. The affine transformation between the 2-D image and the 3-D real world can be derived from the geometrical optics of the sensors. In the other word, the geometrical affine transformation function of two images are derived from the intrinsic and extrinsic parameters of two sensors. According to the affine transformation function, the overlap of the F.O.V. in two images can be calculated and resample two images in the same resolution. Finally, we construct the image registration model by the mapping function. It merges images for different imaging sensors. And, imaging sensors absorb different wavebands of electromagnetic spectrum at the different position in the same time.
UAV 3D modeling with multi-spectral imaging: An example of wax apple tree
(2019-01-01)
Shih, Ruei-Siang
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Li, Yi-Sheng
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Yan, Yung-Jhe
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Yu, Chun
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Huang, Wei-Tsang
As the Unmanned aerial vehicle (UAV) become ubiquitous, many early studies utilizing the UAV for three-dimensional (3D) modeling system are successively proposed as well. The advantage of using UAV successfully advances efficiency and reduces the cost time for simplifying the process of collecting data. Moreover, the characteristics of the light sized and suspension of new designed UAV could allow the users to gather the precise data from the rugged terrain and through a crowd of trees and may build a detail 3D and hyperspectral images. By those high-resolution 3D model data, the texture and shape of observation can be seen and brings research into further analysis. However, there are some limits that the information of 3D modeling data in RGB wide bands is not adequate to investigate vegetation research. The hyper spectrum collects the information of tens of bands with the narrow bandwidth could analyze the detail difference between abnormal and normal situations when the plant is growing. Therefore, how to combine hyperspectral data into a 3D modeling system would be important when researches want to attain the location data and spectral image simultaneously. In this study, the UAV will be loaded with two kinds of systems, and try to build the model include 3D modeling information and spectral information. As a result, it can monitor the growth condition of plants, their environment, also the precise location at the same time so that it can make vegetation analysis more complete.