Iterative self-adaptive reversible watermark embedding and extracting method

Abstract

The invention provides an iterative self-adaptive reversible watermark embedding and extracting method. The embedding method firstly adopts an iterative self-adaptive method to select an adjustment translation amount to achieve a balance of watermark embedding capacity and embedding carrier visual quality according to influence of the load data size and an integer vector on a peak signal to noise ratio; then a complete location map generation strategy is given according to a principle that neighboring pixel values are close so as to improve location map compression performance; and finally a layered orderly embedding strategy is adopted to embed load data in the lowest, the second lowest and the third lowest significance bits to avoid a circumstance that the capacity is sufficient but embedding cannot be realized. Compared with a conventional mean value adjustment integer transformation reversible watermark, the method provided by the invention can still maintain a large embedding capacity without setting a threshold value in advance, after a watermark is embedded, visual quality of a shelter is better, performance of the location map generation strategy is better than the conventional mean value adjustment integer transformation reversible watermark method and a compressed location map is smaller, thereby indirectly increasing the embedding capacity.

Description

technical field [0001] The invention belongs to the cross field of image information security and digital image signal processing, relates to a reversible watermark embedding and extraction method, in particular to an iterative self-adaptive reversible watermark embedding and extraction method. Background technique [0002] Reversible watermark refers to a special type of watermark that can be completely recovered after the watermark is extracted. Compared with traditional watermarking, reversible watermarking has strict requirements for lossless recovery of embedded carriers, and is generally used for distortion-free protection of important images, and has important application value in military images, medical images and remote sensing images. [0003] The difference-extended reversible watermarking method proposed by Tian et al. is a typical method of image reversible watermarking. This method performs Haar integer wavelet transform on adjacent pixel pairs, and expands th...

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Problems solved by technology

[0025] ① T is an artificial setting, not an adaptive choice. According to formula (5), T determines the integer transformation translation amount P of each small block mean value adjustment i , which further affects the embedding capacity in equations (8) and (9) and If T is too small, it will not be able to embed all the data, and if it is too large, it will easily lead to the lower visual quality of I′ relative to I, so it is not really adaptive

[0026] ②Generate L according to formula (6) 0 , L 1 and L 2 , ignoring P i In the case of <j, since τ is compressed data, the neglected value will have an impact on len(τ), which will also indirectly affect the maximum embedding capacity of the image and the visual quality of the embedded carrier

If S 2 There are no or only a small number of transformable integer vectors in , even though β can be directly embedded in S 1 , but since ζ cannot be embedded in S 2 , in which case the embedding strategy will fail

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