| 摘要 |
PROBLEM TO BE SOLVED: To conduct irreversible coding whose code amount is controlled while using a substantially reversible prediction coding. SOLUTION: The image coder encodes identification information to specify a corresponding picture element value predict section when a difference between a noticed picture element value and a prediction result of picture element value predict sections 20, 21 is within a threshold value and encodes a predicted error of a predict error calculation section 30 in other cases. The image decoder decodes the code into identification or the predict error and allows the picture element value predict section to provide an output of picture element data based on the identification information. When the threshold value is increased, the code amount is reduced, and when the threshold value is reduced, the code amount is increased but deterioration in the image quality is suppressed. |
