IMAGE DATA PROCESSING METHOD AND IMAGE DATA PROCESSOR

摘要

PROBLEM TO BE SOLVED: To compress and expand the image data with high compression efficiency by eliminating the high frequency components of a low luminance area, according to its visual characteristics. SOLUTION: A DC component data under attention 501, i.e., the data on an arbitrary part of a layer 2DC wavelet space 1610, i.e., a DC space that is generated by the wavelet conversion is noted. If the data 501 has a low value, the insignificant decision threshold is increased for the corresponding area (layer 1HL estimation reference data 502) included in an HL space 1609 of a layer 2. In the same way, the insignificant decision threshold is increased for the corresponding areas (layer 1LH estimation reference data 507 and layer 1HH estimation reference data 508) in a layer 2LH space 1608 and a layer 2HH space 1607, in terms of both LH and HH spaces respectively. Thus, it is possible to reduce the quantity of data by eliminating the high frequency components of a low luminance area in accordance with its visual characteristics.