Holographic Watermarking Algorithm Based On Wavelet Transform And Its Application

With the rapid development of digital media technology,there are already a large number of piracy,copying and tampering problems,copyright protection has become today's digital media technology must solve one of the important problems.In view of this situation,a holographic watermarking algorithm based on wavelet transform is proposed,firstly,the watermark information is calculated by using Fresnel diffraction integral transform to calculate the field distribution of object and adding reference light.The image of carrier is decomposed by different wavelet transform,by choosing suitable embedding intensity,the watermark hologram is embedded into the wavelet component(middle and low frequency),then the small wave component is Ciscaopo inverse transformation,the watermark image is obtained,and the watermark information is embedded(the embedding method does not need to change the size and position of the original printing dot).It overcomes the difficulty of changing the position and size of the printing network at the same time based on the Roman holographic halftone coding method.The watermark hologram can be obtained by the inverse transformation of the whole watermark embedding process,and then the inverse transformation of the watermark hologram is used to extract the watermark information.In this paper,a four-step phase shift method is used to embed the holographic information into the wavelet coefficients by means of a single hologram and the residual error of the hologram,which realizes the embedding and extraction of the gray and color watermarking images in the color carrier image.The holographic watermarking algorithm based on wavelet transform is implemented,the numerical example shows that the image of gray-scale and color-carrier images can hardly be distinguished from the visual,so it has very good concealment,and the image of gray and color watermark is very clear,and good results are obtained.In the paper,the fingerprint watermark information is embedded into the wavelet coefficients by the singular value decomposition method,and the fingerprint watermark information is successfully put forward,and the example also obtains the ideal effect.The robustness of the method is studied by experiments,in this paper,the robustness test and the anti aggression experiment of the watermark carrier graph are carried out,and it is found that the image's shear strength is 50% and the watermark information isstill extracted,which shows that the method has strong robustness and can not be torn by the whole graph.