Patent ID: 8805109

Claim:
A computerized method for generating a quantization matrix usable for independent disjoint block-level recompression of an image, the image generated by independent disjoint block level compression of a precursor image using at least one first quantization matrix, the method comprising: providing a second quantization matrix; updating, using a processor, the second quantization matrix to provide a monotonic relationship between a compression extent and a compression quality when performing independent disjoint block-level recompression of the image using the second quantization matrix, including, for at least one (row, column) position, performing the following, giving rise to the quantization matrix: calculating a ratio between values located at the position in the first quantization matrix and in the second quantization matrix; calculating a rounding of the ratio; calculating a rounding error, being a difference between the ratio and the rounding; and if the rounding error fulfills an unacceptability criterion, decreasing, using the processor, the value at the position in the second quantization matrix.