| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve the problems that pixel values outside an extraction part are substantially changed and quality at the time of decoding declines in the case that a difference between the pixel value around the extraction part of resolution information and the substituting pixel value of the extraction part is large, and the effect of smoothing an edge is reduced and it is difficult to improve the encoding efficiency of irreversible encoding when the change of the pixel values outside the extraction part is reduced by a conventional technique. <P>SOLUTION: The generation of a substituting value after resolution information extraction is performed so as to smooth an edge by using an interpolation function. At the time, the correlation of the pixel values within a block is calculated for main scanning and sub scanning directions, interpolation by the interpolation function is performed for the direction of the low correlation, and the edge is smoothed by using a linear LPF for the direction of the high correlation. Thus, the encoding efficiency of the irreversible encoding to gradation information is improved while keeping the quality at the time of decoding. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
