Browsing by Author "Chiang, Hou-Chi"

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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%.
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.
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.
Theoretical Deviation and Ray Tracing Analysis of Optical Rotary Encoder
(2016)
Chiang, Hou-Chi
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Su, Wei-Kai
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Huang, Ting-Wei
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Mang Ou-Yang
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電機學院
Servomotor system is widely used in industry for precise positioning system. In this paper, a method of numerical integration solution based on radiometry theory was proposed. The non-sequential ray tracing simulations analyzed the optical distribution of Optical Rotary Encoder. The numerical integration solution and ray tracing simulations had been verified. The method of numerical integration solution apply in the pattern design of Code Mask and Code Disk on both Incremental Encoder and Absolute Encoder.