• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7C
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• pp.658-665
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• 2005

Re-assignment scheme of index in index image is called reindexing. It has been well known that index image can be reindexed without losslessness. In this paper, we introduces an adaptive rank based reindexing scheme using co-occurrence frequency between neighboring pixels. Original index image can be converted into rank image by the proposed scheme. Using the proposed scheme, a better compression efficiency can be expected because most of the reindexed values(rank) get distributed with a smaller variance than the original index image. Experinental results show that the proposed scheme achieves a much better compression performance over GIF, arithmetic coding, Zeng's algorithm and RIAC scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12C
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• pp.1167-1174
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• 2005

In this paper, we propose a priority method on same co-occurrence count in adaptive rank-based reindexing scheme for lossless indexed image compression. The priority on same co-occurrence count in co-occurrence count matrix depends on a front count value on each raw of co-occurrence count matrix, a count value around diagonal line on each raw of the matrix, and a count value around large co-occurrence count on each raw of the matrix. Experimental results show that our proposed method can be reduced up to 1.71 bpp comparing with Zeng's and Pinho's method.