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Block Truncation Coding Using Pattern Fitting. Source: Pattern Recognition, vol.37, 2004, pp.2131-2139 Authors: Bibhas Chandra Dhara, Bhabatosh Chanda Speaker: Shu-Fen Chiou( 邱淑芬 ) Date: 2004/09/08. Outline. Introduction BTC (Block Truncation Coding) Purposed method
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Block Truncation Coding Using Pattern Fitting Source: Pattern Recognition, vol.37, 2004, pp.2131-2139 Authors: Bibhas Chandra Dhara, Bhabatosh Chanda Speaker: Shu-Fen Chiou(邱淑芬) Date: 2004/09/08
Outline • Introduction • BTC (Block Truncation Coding) • Purposed method • Experimental results • Conclusions • Comments
Introduction • Since 1970s the block truncation coding (BTC) has been studied a lot. • High PSNR but low compression ration. • A modified scheme of BTC is proposed to achieve high compression ration and keeping PSNR as high as possible.
BTC (2/3) 44 block + Bit pattern
BTC (3/3) (a) Original image (b) Reconstructed image with conventional BTC(PSNR=32.89 and bpp=2)
Purposed method 編碼端 Pattern fitting Encoding the block 將影像分成 Entropy coding and send 不重疊的 n n方塊 原影像 解碼端 receive 重建影像方塊 組成重建影像
Pattern fitting (1/4) Pattern book Set of two-level patterns
Pattern fitting (2/4) 44 block
Pattern fitting (3/4) 44 block
Pattern fitting (4/4) Output image after pattern fitting
Encoding the block (1/2) Considering entropy coding for and 8-bits for A
Experimental results Original image Reconstructed image
Experimental results Original image Reconstructed image
Experimental results Conventional BTC (PSNR=32.89 and bpp=2) Purposed method (PSNR=31.59 and bpp=0.64)
Experimental results Experimental result of proposed method and others
Conclusions • Instead of determining bit-pattern for a block, an optimum bit-pattern is selected from a pattern-book. • Our method is presented to achieve higher compression ration and keeping PSNR as high as possible.
Comments • 如何決定wi? • 計算壓縮率時, 是否也應考慮Pattern book?