Patent ID: 7630564
Filing Date: 2009-12-08
Classification: H04N

Abstract:
1. A dequantizing apparatus for decoding lossy compressed original data, comprising: a dequantization-value estimating section that receives quantization index values and generates a plurality of dequantization values for each quantization index value; a distribution-information acquiring section that acquires distribution information of original data corresponding to each quantization index; a correcting section that corrects at least a portion of the dequantization values generated by the dequantization-value estimating section, based on the distribution information acquired by the distribution-information acquiring section; a distribution-information generating section that generates distribution information of the quantization indexes and applies a polygonal-line approximation to a frequency distribution of the quantization index values to generate a probability density function of the quantization indexes so that a polygonal line passes an internal division point according to a ratio of frequencies of adjacent quantization index values between the adjacent quantization index values in the frequency distribution of the quantization index values; and an output section that outputs a decoded image based on the dequantization values, wherein: the distribution-information acquiring section acquires the distribution information of the quantization indexes generated by the distribution-information generating section as the distribution information of the original data and acquires the probability density function generated by the distribution-information generating section as a probability density function of the original data.