Blind watermarking algorithm for 2D engineering graphics based on fractional Fourier transform
二维工程图中基于分数傅里叶变换的盲水印算法

A new method of digital watermarking for two-dimensional engineering graphics was proposed, In this method, the relative coordinate vectors of the lines were extracted from 2D engineering graphics for constructing a 1D complex signal. Watermark was embedded into the module of fractional Fourier transform coefficients of the complex signal based on the relationship between the values of watermark and transform coefficients. It is a blind watermarking algorithm due to the fact that watermark can be extracted without original engineering graphic. Experimental results show that the proposed algorithm is robust against the attacks such as moving, rotation, scaling, and is also safe towards illegal information extraction.