| 摘要 |
PROBLEM TO BE SOLVED: To suppress deterioration in image quality and to enhance the immunity of imbedded information in the case of imbedding the information to image data by controlling a step width of re-quantization on the basis of a discrimination result of an image characteristic in the vicinity of a target pixel to which the information is going to be imbedded. SOLUTION: A block processing unit 1 divides image data to which information is imbedded into blocks each consisting of e.g. 3×3 pixels. An image characteristic discrimination unit 2 discriminates an image characteristic of the blocks on the basis of values of peripheral pixels. An information imbedding unit 3 decides a re-quantization step width on the basis of the discrimination result and imbeds information to a target pixel. The step width used for re- quantization of the blocks can be selected (decided) by discriminating the characteristic of the blocks with a similar method. The step width can be changed in multi-stages. |
