Improved index coding algorithm using distance-based codebook sorting
码书距离排序对索引压缩算法的性能改进

The index map after vector quantization has a strong statistical correlation.That means the neighboring indices are the same or the offset between them is very small.Codebook sorting can,according to some criteria,enhance the correlation among neighboring indices.Based on the squared Euclidean distance between code words,a new codebook sorting method is proposed.Compared with the conventional mean-ordered codebook,the distance-ordered codebook has a much higher correlations between neighboring indices and the offset become even smaller.As a result,distance-ordered codebook can also significantly improve the compression efficiency of the AICS (adaptive index coding scheme) algorithm.