Browsing by Author "Lu, JY"

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Fast full search in motion estimation by hierarchical use of Minkowski's inequality (humi)
(1998-07-01)
Lu, JY
;
Wu, KS
;
Lin, JC
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資訊工程學系
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Department of Computer Science
In this paper, we extend the idea of successive elimination algorithm (SEA) to obtain a fast full search (FS) algorithm accelerating the block matching procedure of motion estimation. Based on the monotonic relation between the accumulated absolution distortions (AAD) obtained for distinct layers of a pyramid structure; the proposed method successfully rejects many impossible candidates considered in the FS. The derivation of the monotonicity relation repeatedly uses in a four-dimensional vector space the l(1)-version of Minkowski's inequality, an inequality which is quite well-known in the field of mathematics. Simulation results show that the processing speed is faster than that of several well-known fast full search methods, including the SEA that uses just once the Minkowski's inequality (in a vector space of 256 dimension when the block size is 16 x 16). The processing speed of the proposed method is also competitive with that of the three-step search (TSS), which is often used for block matching in interframe video coding, although the visual quality performance of TSS is usually a little poorer than that of the FS. (C) 1998 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved.
Separated-transport-recombination p-i-n photodiode for high-speed and high-power performance
(2005-08-01)
Shi, JW
;
Hsu, HC
;
Huang, FH
;
Liu, WS
;
Chyi, JI
We demonstrate a novel p-i-n photodiode (PD) structure, the separated-transport-recombination PD, which can greatly relieve the tradeoffs among the resistance-capacitance bandwidth limitation, responsivity, and output saturation power performance. Incorporating a short carrier lifetime (less than 1 ps) epitaxial layer to serve as a recombination center, this device exhibits superior speed and power performance to a control PD that has a pure intrinsic photoabsorption layer. Our demonstrated structure can also eliminate the bandwidth degradation problem of the high-speed photodetector, whose active photoabsorption layer is fully composed of short lifetime (similar to 1 ps) materials, under high dc bias voltages.