METHOD AND DEVICE FOR EMBEDDING ELECTRONIC WATERMARK FOR DETECTING FALSIFICATION AND PROGRAM, AND FALSIFICATION DETECTION AND DEVICE USING ELECTRONIC WATERMARK AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide a technique detecting a falsification while suppressing the deterioration of an image quality.

SOLUTION: A process up to the quantization of the DCT coefficient of a normal JPEG encoding is carried out to a photographed image (S22 to S25). An error-detecting encoding making the number of the bits of electronic-watermark data redundant is obtained (S27), and error-detecting encoding data are enciphered (S28). A DCT block is divided into the same number of groups as the number of the bits of enciphered code data (S29). Quantized coefficients in each DCT block are modulated, and enciphered code data are embedded (S30). The normal JPEG encoding is shaped to an entropy compression-JFIF form (S31, S32).

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