Browsing by Author "Chiang, Tsung-Han"

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A novel macroblock-layer rate-distortion model for rate control scheme of H.264/AVC
(2006)
Chiang, Tsung-Han
;
Wang, Sheng-Jyh
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The purpose of rate control is to adjust an encoder so that the amount of encoded bits can match the amount of desired bits. In this paper, we focus on the rate control of an H.264/AVC encoder. We first analyze the relation between the quantization parameter, MAD, and the coded bit number. We also analyze the encoding of header bits. Based on these analyses, we build up a new rate-distortion model. Moreover, we use motion vectors to predict the MAD value. Based on these modifications, we may better predict the quantization parameter and the amount of encoded bits. In experiments, our approach not only improves the stability of encoder buffer but also makes an obvious improvement of visual quality.
A reflective polarizer-free display using dye-doped polymer-stabilized blue-phase liquid crystals
(2012-06-01)
Lin, Yi-Hsin
;
Chen, Hung-Shan
;
Chiang, Tsung-Han
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光電工程學系
;
Department of Photonics
A reflective polarizer-free display using dye-doped polymer-stabilized blue-phase liquid crystal (DDPSBP-LC) has been demonstrated. The mechanism is a combination of electrically tunable light absorption and Bragg reflection. In this paper, the influence of light absorption in DDPSBP-LC by changing the dye concentration and absorption paths has been studied. Increased dye concentration can improve the contrast ratio of DDPSBP-LC; however, the response time is the tradeoff. Increasing the cell gap can improve the contrast ratio of DDPSBP-LC; however, the response time remains the same. The study of DDPSBP-LC can help in shutter-glass applications of 3-D displays and electronic paper.
A reflective polarizer-free electro-optical switch using dye-doped polymer-stabilized blue phase liquid crystals
(2011-01-31)
Lin, Yi-Hsin
;
Chen, Hung-Shan
;
Chiang, Tsung-Han
;
Wu, Chun-Hung
;
Hsu, Hsu-Kuan
We demonstrate a reflective polarizer-free electro-optical switch using dye-doped polymer-stabilized blue phase liquid crystals (DDPSBP-LC). At the voltage-off state, the dye molecules and liquid crystals form the structure of the double twist cylinders. As a result, the DDPSBP-LC is in dark state due to the combination of Bragg reflection and light absorption. At the voltage-on state, the blue phase structure is unwound locally. The DDPSBP-LC is then in bright state because of the small light absorption only. The applications of such a switch are shutter glass of 3D displays, and electronic papers. (C) 2011 Optical Society of America