| 摘要 |
The present invention provides a system and method for finding exact area of forged or altered data in a watermarked image. A watermarked image is generated in such manner that each pixel value in the original image is adjusted to a predetermined level; first watermark keys to be embedded, said keys corresponding to each pixel, are generated based on predetermined user key data; a watermark is embedded by selectively adding or subtracting a predetermined value to or from each pixel value according to the first watermark key corresponding each pixel. The forged or altered data is found by such method that a second watermark key is generated based on the user key data; the first watermark key is extracted from the watermarked image; and the co-relation between the corresponding watermarks in these watermark keys is calculated. Corresponding watermark keys are compared in every pixel.
|
