Browsing by Author "Lee, Yu-Cheng"

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On Gaze Estimation Using Integral Projection of Eye Images
(2018-01-01)
Dung, Lan-Rong
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Lee, Yu-Cheng
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Wu, Yin-Yi
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交大名義發表
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National Chiao Tung University
This paper presents a gaze estimation algorithm using integral projection of eye images with advantage of low additional hardware requirement and low computational power. The algorithm needs only a webcam under nature light source and captured eye images in a non-intrusive way. Before integral projection, we used binarization process to eliminate the non-related image information to gaze position. Projected on binary eye images with projection adjustment method to avoid eye tilt makes projection error and defined the accurate integral range of eye ROI images to achieve robust gaze estimation. We analyzed the projection diagram with skewness to describe the variation of different gaze position. In skewness calculation, the pixel coordinate of eye ROI images has been normalized to avoid head moved back and forth makes the size of ROI changed. In horizontal direction, the error angle of our algorithm is 2.29 degrees, maximum error angle is 4.8 degrees and the resolution we defined is 7.5. Because our algorithm is inaccurate in vertical, we could only estimate gaze direction, but to estimate precise angle. The computational power of our algorithm is low, the average execution time of each frame is only 0.01652 s, only 24% of opponent.
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.