| 摘要 |
PROBLEM TO BE SOLVED: To achieve highly accurate prediction even if a signal value changes in a prediction direction and to improve image quality.SOLUTION: An image decoder includes intra-prediction means which performs intra-frame prediction processing for each block being a unit of prediction processing of an encoded block and generates a prediction image when an encoding mode on the encoded block is an intra-encoding mode. The intra-prediction means adds a value proportional to a luminance value change amount in a vertical direction of a pixel adjacent to the left of the block to a luminance value of a pixel adjacent to the upper part of the block and sets a value after addition to be a prediction value of the prediction image when an intra-prediction parameter shows vertical direction prediction processing. |
