Multiple color image fusion, compression, and encryption using compressive sensing, chaotic-biometric keys, and optical fractional Fourier transform

A new multiple color image fusion, compression, and encryption using compressive sensing, chaotic-biometric keys, and optical fractional Fourier transform is proposed. In the proposed cryptosystem, the original four-color images are independently decomposed into four sub-bands by a 2-D discrete wavelet transform. The corresponding four LL sub-bands are fused to construct a single fused image, which is split into R, G, and B channels. Each channel is compressed by using compressive sensing (CS). The measurement matrix is constructed as a circulant matrix based on the random sequence generated with a logistic map, which is modulated by the compressed R and G channels of palmprint to produce the first chaotic- biometric phase mask (CBPM) and by the compressed B channel of palmprint to produce the second CBPM. The compressed R and G channels of fused image are encoded in a complex image, modulated by the first CBPM, and then fractional Fourier transformed. The transformed image is phase- and amplitude-truncated to obtain the first encrypted image and first decryption key, respectively. The first encrypted image and the compressed B channel are encoded in a complex image, modulated by the second CBPM, and then fractional Fourier transformed (FrFT). The resulting image is phase- and amplitude-truncated to obtain a final encrypted image and second decryption key, respectively. The proposed compressed single-channel cryptosystem has advantages of reduced date storage to be transmitted, uniqueness of biometric keys in CBPMs, very sensitive orders of the FrFT, and a single-channel hybrid optoelectronic setup. The proposed cryptosystem is highly secure against special attacks. Numerical simulation results validate the viability and security of the proposed system.