This paper presents a shape-adaptive wavelet coding technique for codingarbitrarilyshaped still texture. This technique includes shape-adaptive discrete wavelet transforms (SA-DWT's) and extentions of zerotree e...
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This paper presents a shape-adaptive wavelet coding technique for codingarbitrarilyshaped still texture. This technique includes shape-adaptive discrete wavelet transforms (SA-DWT's) and extentions of zerotree entropy (ZTE) coding and embedded zerotree wavelet (EZW) coding. Shape-adaptive wavelet coding is needed for efficiently codingarbitrarilyshaped visual objects, which is essential for object-oriented multimedia applications. The challenge is to achieve high coding efficiency while satisfying the functionality of representing arbitrarilyshaped visual texture. One of the features of the SA-DWT's is that the number of coefficients after SA-DWT's is identical to the number of pixels in the original arbitrarilyshaped visual object, Another feature of the SA-DWT is that the spatial correlation, locality properties of wavelet transforms, and self-similarity across subbands are well preserved in the SA-DWT. Also, for a rectangular region, the SA-DWT becomes identical to the conventional wavelet transforms. For the same reason, the extentions of ZTE and EZW to codingarbitrarilyshaped visual objects carefully treat "don't care" nodes in the wavelet trees. Comparison of shape-adaptive wavelet coding with other coding schemes for arbitrarilyshaped visual objects shows that shape-adaptive wavelet coding always achieves better coding efficiency than other schemes. One implementation of the shape-adaptive wavelet coding technique has been included in the new multimedia coding standard MPEG-4 for codingarbitrarilyshaped still texture. Software implementation is also available.
This paper presents a shape adaptive discrete wavelet transform (SA-DWT) scheme for codingarbitrarilyshaped texture. The proposed SA-DWT can be used for object-oriented image coding. The number of coefficients after...
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ISBN:
(纸本)0819424358
This paper presents a shape adaptive discrete wavelet transform (SA-DWT) scheme for codingarbitrarilyshaped texture. The proposed SA-DWT can be used for object-oriented image coding. The number of coefficients after SA-DWT is identical to the number of pels contained in the arbitrarilyshaped image objects. The locality property of wavelet transform and self-similarity among subbands are well preserved throughout this process. For a rectangular region, the SA-DWT is identical to a standard wavelet transform. With SA-DWT1 conventional wavelet based coding schemes can be readily extended to the coding of arbitrarilyshapedobjects. The proposed shape adaptive wavelet transform is not unitary but the small energy increase is restricted at the boundary of objects in subbands. Two approaches of using the SA-DWT algorithm for object-oriented image and video coding are presented. One is to combine scalar SA-DWT with Embedded Zerotree Wavelet (EZW) coding technique (called SA-EZW), the other is an extension of the normal vector wavelet coding (VWC) technique (called SA-VWC) to arbitrarilyshapedobjects. Results of applying SA-VWC to real arbitrarilyshaped texture coding are also given at the end of this paper.
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