| 摘要 |
PROBLEM TO BE SOLVED: To appropriately perform quantization processing using quantization matrix in an image coding device even when performing coding where processing performing orthogonal transformation in a block unit and processing not performing the orthogonal transformation are switched.SOLUTION: An image coding device 100 according to the present invention determines, in a character area presence/absence determination part 111, whether or not an input image to be a coding target picture includes character and line areas; when determining that the input image does not include character and line areas, creates a quantization matrix corresponding to all block sizes with a coefficient value having a gradient across a low frequency component to a high frequency component; and when determining that the input image includes character and line areas, creates only a quantization matrix corresponding to a 4×4 pixel block size with a coefficient value not having a gradient across a low frequency component to a high frequency component and performs quantization processing by using the created quantization matrix.SELECTED DRAWING: Figure 1 |
