Browsing by Author "Kuo, Che-Wei"

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Intra Block Copy Hash Reduction for HEVC Screen Content Coding
(2016)
Kuo, Che-Wei
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Hang, Hsueh-Ming
;
Chien, Chun-Liang
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交大名義發表
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National Chiao Tung University
To meet a wide range of needs for video applications such as remote desktop, video conference, distance education, and cloud gaming, the ISO/ITU Joint Collaborative Team on Video Coding (JCT-VC) committee is recently specifying the Screen Content Coding (SCC) standard, as one of the extensions of High Efficiency Video Coding (HEVC). In this paper, the hash search method of the standard adopted Intra Block Copy (IBC) coding tool for SCC is investigated. We collect the coded data using the current hash table and examine their efficiency and explore possible ways for further improvement. A low complexity scheme of selecting effective hash nodes and a modified hash key generation method are presented. Experimental results show that the proposed method reduces on the average 37% or at most 70% hash table memory usage but it preserves the similar BD-rate savings and encoding complexity when integrated into the SCM-3.0 test model.
Intra Line Copy for HEVC Screen Content Coding
(2014)
Chang, Tsui-Shan
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Chen, Chun-Chi
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Liao, Ru-Ling
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Kuo, Che-Wei
;
Peng, Wen-Hsiao
This paper presents an intra line copy mode, which introduces a finer-granularity block partitioning structure for the intra copying technique, to further improve the coding efficiency for screen content. This mode first divides a prediction block horizontally or vertically into 1-pixel-wide lines and then operates intra copying line-by-line from the reconstructed pixels in the current frame. It shares some parallels with the notion of string matching widely used for lossless data compression. It, however, is more compliant to the current HEVC design and is parallel-friendly. This paper shall detail its various design issues, including the design of a fast algorithm based on hashing techniques and the impact of search window size on its performance and complexity trade-off Experimental results show that the proposed mode can offer 2.7-12.9% of BD-rate reductions, with 26% increase of encoding runtime while keeping the decoding runtime unchanged, when integrated into the SCM-1.0 test model.
Surface modification of commercial PtRu nanoparticles for methanol electro-oxidation
(2013-10-15)
Kuo, Che-Wei
;
Lu, I-Te
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Chang, Li-Chung
;
Hsieh, Yu-Chi
;
Tseng, Yuan-Chieh
The surfaces of commercially available PtRu nanoparticles (PtRu/C) have been successfully modified via a displacement reaction between the Ru atoms on the PtRu/C and the Pt ions in an aqueous hexachloroplatinic acid solution. The concentration of the hexachloroplatinic acid solution was deliberately formulated to allow for the formation of sub-monolayered Pt (Pt(1/16)) and monolayered Pt (Pt(1/8)) on the surface of PtRu/C. Material characterization, including X-ray diffraction patterns and transmission electron microscopy images, showed that the PtRu phases of the samples were identical but that the particle sizes increased slightly after the surface modification. Data from inductively coupled plasma mass spectrometry confirmed the deposition of Pt with negligible loss of Ru. X-ray absorption spectroscopy showed Pt-enriched surfaces, and the surface Pt content decreased in the order Pt(1/8) > Pt(1/16) > PtRu/C. Cyclic voltammetry and chronoamperometry were conducted for methanol electro-oxidation, and our results indicated impressive catalytic ability and carbon monoxide tolerance for Pt(1/16), followed by Pt(1/8) and PtRu/C. The mass activities of Pt(1/16) and Pt(118) increased 223% and 135% over that of PtRu/C. We attributed the observed improvements to the reduced amount of Ru on the PtRu surface, which resulted in an optimized PtRu ratio with enhanced catalytic ability. (C) 2013 Elsevier B.V. All rights reserved.