| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance a compression rate in no-loss sub-band conversion compression. SOLUTION: In a no-loss optimum sub-band converter 100, a pixel correlation evaluation means 110 evaluates respective correlations of prescribed reference possible pixels around a prediction target pixel, and an optimum value calculation means 120 obtains selected sets of pixels or a proper optimum function maximizing the correlation among the pixels to calculate an optimum value. A sub-band conversion means 130 generates a sub-band conversion coded signal resulting from dividing the digital image signal into prescribed bands, on the basis of the optimum value. An entropy coding compressor 200 applies entropy coding to a sub-band conversion coding signal which is an output of the no-loss optimum sub-band converter 100 to generate a no-loss compression image signal.</p> |
