| 摘要 |
A wavelet transform coding technique is provided, which may be part of TROBIC or may be used independently in a wide variety of compression applications. The wavelet coding technique is carried out by a simple block codec with wavelets (SBCW) that uses wavelet filters to transform 32x2 image blocks into subband coefficients organized in a tree structure. These coefficients are then encoded using a novel entropy coding technique with precise rate control. The Two Row Buffer Image Compression (TROBIC) technique operates on 32x2 blocks of pixels and uses a block-based coding scheme to provide alternative coding modes for image blocks containing different types of image data. The TROBIC algorithm automatically evaluates the image presented to determine regions containing text, graphics, synthetic images and natural images along with determining the most effective combination of global-index coding, local-index coding, lossless coding and wavelet coding to use to guarantee the desired compression ratio and high quality.
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