METHOD AND DEVICE FOR ENCODING/DECODING IMAGE DATA

摘要

PURPOSE:To provide an image data encoding method capable of reducing block distortion according to the increment of compressibility with a simple method and remarkably reducing computing quantity. CONSTITUTION:One-dimensional DCT transformation S11 in horizontally direction and one-dimensional DCT transformation S12 in vertically direction are applied to an nXn picture element block image segmented from an original image in two-dimensional DCT transformation process S1. A transformation coefficients of DC component out of the transformation coefficients of DC component and AC component obtained by the above stated transformation are corrected when color change occurs in DC component correction process S2, and after that, it is quantized in quantization process S3 with the transformation coefficients of AC component, and it is variable length-encoded in encoding process S4. At this time, the number of times of calculation can be reduced by encoding by selecting at least only (k) (k