Multiple bit digital watermark method capable of resisting printing, scanning and geometric transformation

Abstract

The invention discloses a multi-bit digital watermark method against the print scanning and the geometric transformation, which comprises the following steps: embedding the watermark in dispersion Fourier amplitude coefficient of the image; determining which Fourier amplitude coefficient every watermark bit embeds in according to the dispersion logarithmic polar coordinate of the Fourier amplitude coefficient; making the watermark detecting and extracting out-of-step when the image is carried out the geometric transformation of the pantographic rotating or the print scanning; synchronizing the information watermark according to the relation of the original mode and embedded mold when the watermark is detected and extracted because the pantograph and the rotating of the image corresponds with the translation of the Fourier logarithmic polar coordinate field at the radial and angel direction; extracting the meaning watermark information bit string; introducing the real interpolation and saving the time because the watermark embedding and detecting process doesn' t need the image interpolation arithmetic for the image and the Fourier amplitude coefficient; protecting the embedded mode. The invention can apply to the copyright protection of the digital image and video, false proof of the file and evidence, the monitoring of video broadcast.

Description

technical field

[0001] The invention belongs to the technical field of image authentication, in particular to a multi-bit digital watermarking method based on Fourier discrete logarithm and polar coordinate transformation, which is resistant to printing scanning and geometric transformation. Background technique

[0002] Digital watermarking technology is a kind of information hiding technology. Its basic idea is to embed secret information in digital products such as digital images, audio and video, in order to protect the copyright of digital products, prove the authenticity of products, track piracy or provide products additional information for . The secret information can be a copyright symbol, a user serial number, or product-related information. These meaningful secret information constitute a part of digital watermark, that is, information watermark. In order to extract and detect synchronous information watermark, a pseudo-random sequence for synchronization is al...

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