Generating and authenticating method of self-embedded digital watermark of JPEG (Joint Photographic Experts Group) image

Abstract

The invention relates to the technical field of image security certification and discloses a generating and authenticating method of a self-embedded digital watermark of a JPEG (Joint Photographic Experts Group) image. The method comprises the following steps of: reducing a protected JPEG image by 1 / 4; coding the image by applying a fixed length block encoding method; and embedding a code as a watermark onto a DCT (Digital Component Technology) coefficient low frequency component of the protected image. If hostile attacks such as tampering, replacing, and the like are carried out on the JPEG image containing the watermark, a tampered area can be precisely determined by comparing an extracted watermark with the image containing the watermark, the tampered area can be approximately restored, and the restored image is 1 / 4 of the original image. The invention achieves a better coding effect on the basis of analyzing the JPEG parametric statistic characteristics, a limited bitmap matrix is not needed, and any quality factor can be used for quantization.

Description

technical field [0001] The invention belongs to the technical field of image security authentication, in particular to a method for generating and authenticating a JPEG image self-embedded digital watermark. Background technique [0002] With the rapid development of computer network technology and the digitalization of information media, the content protection of digital products is particularly important, and the fragile watermark technology developed in recent years provides technical guarantee for the content protection of digital products. Fragile watermarking belongs to a branch of digital watermarking. In addition to the basic characteristics of watermarking, such as imperceptibility, security, etc., it also has the ability to detect tampering, and the extraction of watermarking does not require the original image. The current research in this field mainly includes several levels such as fragile watermarking, semi-fragile watermarking, and self-embedding watermarking....

AI Technical Summary

Problems solved by technology

Since such a watermark scheme uses a bitmap matrix, when the number of bits of the DCT coefficient value is greater than the corresponding bit in the bitmap matrix, the restored image will cause distortion, so it can only be used for some specific images. operate while being restricted to quantizing DCT coefficients with quality factors less than or equal to 50%

Therefore, there are certain limitations in practical applications.

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