A new scheme for coding both the shape and texture of arbitrarily shaped visual objects is presented. Based on set partitioning on hierarchical trees (SPIHT), the proposed shape and Texture SPIHT (ST-SPIHT) employs a ...
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A new scheme for coding both the shape and texture of arbitrarily shaped visual objects is presented. Based on set partitioning on hierarchical trees (SPIHT), the proposed shape and Texture SPIHT (ST-SPIHT) employs a novel implementation of the shape-adaptive discrete wavelet transform (SA-DWT) using in-place lifting, along with parallel coding of texture coefficients and shape mask pixels to create a single embedded code that allows for fine-grained rate-distortion scalability. The single output code simplifies the logistics of object storage and transmission compared to previously published schemes. An input parameter provides control over the relative progression between shape and texture coding in the embedded code, allowing for adjustment of the emphasis of shape versus texture quality in low bit rate reconstructions. The combination of features provided by ST-SPIHT, namely, explicit and progressive shapecoding in parallel with wavelet-based embedded coding of the object texture, is unique compared to previously published schemes. Computational complexity is minimized since the shapecoding takes advantage of the decomposition and spatial orientation trees used for texture coding. Objective and subjective simulation results show that the proposed ST-SPIHT scheme has rate-distortion performance comparable or superior to MPEG-4 Visual Texture coding for most bit rates.
This paper presents a fast motion estimator which can be used for real-time MPEG-4 encoding of arbitrarily shaped video objects. The approach is based on an existing algorithm which has already been applied successful...
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ISBN:
(纸本)9781581133110
This paper presents a fast motion estimator which can be used for real-time MPEG-4 encoding of arbitrarily shaped video objects. The approach is based on an existing algorithm which has already been applied successfully to format conversion. To exploit it for shape-adaptive coding, the algorithm has been adapted to the special properties of the MPEG-4 standard. With this new tool it becomes possible to encode arbitrarily shaped video objects (CIF, 25 Hz) in real-time with a MPEG-4 software encoder at a Pentium III 500 MHz. The real-time capability has to be paid by a slight loss of coding efficiency (about 0.2 dB in terms of rate-distortion measurements), compared to the MPEG-4 verification model.
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