New encrypted transform method for digital image based on dissymmetrical discrete fractional Fourier transform
HE Jun-fa · Optical Technique · 2005
By using the two parameters of dissymmetrical discrete fractional Fourier transform as secret keys, a new encrypted transform method of digital image was presented. The fractional Fourier transform of the input image was performed by two one_dimensional FRT with different orders in the x and y directions in cascade. The two orders are considered to keys, only when the transform order in each direction is respectively matched with that of the asymmetry fractional Fourier transform, the encoded image can be reconstructed exactly. Because of its particularity of image reconstruction, it is regarded as a new optical security system and can be used in anti_counterfeiting. The digital computation experiment validated the correctness and feasibility of the method.