Watermark embedding method and device based on wavelet-domain enhanced image masks

Abstract

The invention discloses a watermark embedding method based on wavelet-domain enhanced image masks, and the method is mainly used for solving the defects that just distortion thresholds of wavelet coefficients calculated by the existing method are inaccurate and nonadjustable. The method comprises the following steps: firstly performing wavelet decomposition on an input image; calculating brightness masks for the wavelet coefficients through the maximum weighted averages of background brightness and brightness variation of low-frequency sub-bands, calculating texture masks for the wavelet coefficients through local standard deviation of the compressed input image and edge masks of high-frequency sub-bands, and determining directional masks for the wavelet coefficients according to the direction of the sub-bands; and finally performing weighed synthesis on the brightness masks, the texture masks and the directional masks so as to obtain the just distortion thresholds of the wavelet coefficients. The method has the advantages that the accuracy and adjustability of the just distortion thresholds of the wavelet coefficients are improved, the watermark embedding strength is better estimated, and the visual quality of the watermark-containing image is improved; and the method can be used for evaluating the perception characteristics of eyes on a digital image so as to adaptively control the watermark embedding strength in the field of digital image watermarking.

Description

technical field [0001] The invention belongs to the technical field of image processing, and relates to a watermark embedding method and device based on a wavelet domain enhanced image mask, which can be used in the field of digital image watermarking to measure the perceptual characteristics of digital images by human eyes and adaptively control the watermark embedding strength. Background technique [0002] With the continuous progress of human society and the rapid development of computer technology, digital images have become an important way for people to receive information and perceive the objective world in the era of digital vision due to their advantages of intuition, vividness, large amount of information and cross-language. Various fields of the national economy such as industry, medical care, military affairs, education, communications and aerospace. As an important way for humans to obtain visual information, the perceptual characteristics of the human visual s...

AI Technical Summary

Problems solved by technology

However, this method only considers the distribution characteristics of pixels in the low-frequency sub-band when modeling brightness sensitivity, and ignores the influence of background brightness and brightness changes on brightness sensitivity modeling, which reduces the wavelet decomposition coefficient and can be distorted. The accuracy of the threshold affects the visual quality of the watermarked image

At the same time, the above methods do not consider the influence of the brightness sensitivity and texture sensitivity of the human eye in characterizing the characteristics of the image mask, so that the wavelet decomposition coefficient can not be adjusted flexibly, and the distortion threshold cannot be adjusted flexibly, which affects the visual quality of the watermarked image.

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