| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and system for encoding a signature into a digital image and auditing a digital subject image to judge whether it has been derived from the encoded image. SOLUTION: A signature is inseparably embedded within a visible image, and persists through image transforms, that include resizing as well as conversion to print or film and back to digital form. Signature points are selected from among the pixels of original image. The pixel values of the signature points and surrounding pixels are adjusted by an amount that is detectable with a digital scanner. The adjusted signature points form a digital signature, which is stored for future identification of subject images derived from the image. As a signature point to embed a signature, regarding the area in the size of M (5 to 10 pixels)×M matrices around a pixel of interest, an average value of luminance values in inside and outside areas is analyzed to determine whether the pixel of interest can be selected as a signature point. COPYRIGHT: (C)2007,JPO&INPIT
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