Blind Digital Image Watermarking Resistant to Printing and Reshooting

Abstract

The invention provides a blind digital image watermarking method resistant to printing and reshooting. The method comprises the following steps of: a watermark pattern of a centrally symmetrical graphis designed; the watermark pattern is embedded into lab color space of the carrier image to obtain the watermark image. a color printer is used to print the watermark image to obtain a printed image.a camera is used to take photographs of printed images, captured image is obtained, the captured image is converted into lab color space and inverse geometric transformation is carried out to obtaina watermark estimated image, the image block with the same size as the watermark pattern is located and clipped from the watermark estimated image, the normalized phase relation value between the image block and the watermark pattern is calculated, and whether the watermark pattern is included in the captured image is judged according to the normalized phase relation value. By embedding watermarksinto two color channels in Lab color space at the same time, the method of the invention originally proposes a watermark synchronization method of inverse geometrical transformation by using periodicimage self-convolution, which can extract watermarks from printed rephotographed images.

Description

technical field [0001] The invention relates to the technical field of digital image watermarking, in particular to a blind digital image watermarking method resistant to printing and reshooting. Background technique [0002] The rapid popularization of Internet technology has provided great convenience for the dissemination of digital media such as audio, image and video, and the acquisition of digital media has become almost costless. At the same time, the illegal acquisition, misappropriation and tampering of digital media are also intensifying, which not only brings troubles to the authors of media works and media, but sometimes even affects the credibility and security of the country. Digital watermarking technology emerges at the historic moment and plays a huge role in digital media authentication and copyright protection. [0003] Digital image watermarking technology refers to embedding a small amount of watermark information into digital images, while the original...

AI Technical Summary

Problems solved by technology

Since the electronic original version of the printed image is often not available, the watermark extraction process can only use the printed image itself, so the watermarking requirement for anti-printing retakes must apply a blind watermarking scheme

[0006] At present, there is no effective blind digital image watermarking scheme that resists printing and retaking in the prior art

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