A K-Th Order Adaptive Transform Coding Algorithm For Image Data Compression

Chen, Cheng-Tie; Gall, D.J. Le

doi:10.1117/12.962304

Cited by 7 publications

(6 citation statements)

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“…The K-th order adaptive DCT [1] and variable block size strategy [7] are combined to further improve the coding performance. A relatively large block is segmented into variable block sizes according to a critenon involving means and variances.…”

Section: Discussionmentioning

confidence: 99%

“…By properly presetting the quantizer step sizes, a higher image quality can be achieved. A justification and detailed discussion on the adaptive thresholding and adaptive quantization strategy can be found in [1]. Note that different values of K may be used for different block sizes, i.e., different n 's.…”

Section: Adaptive Dct Algorithmmentioning

confidence: 99%

“…Let the mean and the standard deviation (SD) of the four adjacent subblocks be mk (i) and cTk(i), respectively, where i =1,2,3,4, and k ranged from 1 to L -1 is an index denoting the size of the current subblocks. The criterion for merging these four adjacent subblocks is (1) If ak < k (i) < bk for all i, merge;…”

Section: Adaptive Dct Algorithmmentioning

confidence: 99%

“…However, the block size considered is fixed for all the blocks and images. In [1], a scheme of K-th order a.aptive DCT algorithm has been studied, where threshold and quantizer stepsize are chosen adaptively by the K most significant DCT coefficients, and better results were reported. A variable block size DCT compression algorithm has been considered in [7].…”

Section: Introductionmentioning

confidence: 99%

“…Several DCT algorithms with quantizers adaptive to the image contents have been investigated (e.g., [1,10]). However, the block size considered is fixed for all the blocks and images.…”

Section: Introductionmentioning

confidence: 99%

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<title>Transform coding of digital images using variable block-size DCT with adaptive thresholding and quantization</title>

Chen

1990

Applications of Digital Image Processing XIII

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Discrete cosine transform (DCT) coding has been emerging as a key element for image data compression. Conventional DCT coding algorithms, which treat all the image areas indiscriminately, unfortunately give nonuniform image quality for various image contents. This motivates work on DCT schemes adaptive to the image contents so that a better tradeoff between bit rate and image quality can be achieved. In this paper, a DCT algorithm with adaptive thresholding and quantization is combined with variable block size segmentation to further improve the coding performance. A new segmentation criterion is proposed. Some simulation results are given to illustrate the superiority of this adaptive DCT algorithm with segmented blocks. It is also shown that this algorithm poses itself as a promising compression method to deal with the composite images consisting of text/graphics and natural scenes.

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Section: Discussionmentioning

confidence: 99%

Section: Adaptive Dct Algorithmmentioning

confidence: 99%

Section: Adaptive Dct Algorithmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Several DCT algorithms with quantizers adaptive to the image contents have been investigated (e.g., [1,10]). However, the block size considered is fixed for all the blocks and images.…”

Section: Introductionmentioning

confidence: 99%

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