Multimodal Medical Image Protection Algorithm Based on Genetic Coding and Coupled Hyperchaotic Mapping

[Purposes] In order to ensure the security of multimodal medical images, a multimodal medical image protection algorithm based on genetic coding and coupled hyperchaotic mapping is proposed. [Methods] In the stage of chaotic sequence generation, the CMC-CTBCS coupling model was proposed, and the three-dimensional Sine-ICMIC cascade mapping (3D-SICM) was constructed with Sine mapping (Sine) and iterative chaotic map with infinite collapses (ICMIC) as seed mapping, which was applied for the design of multimodal medical image encryption. The stage of image encryption mainly included three parts: multimodal medical image fusion algorithm, zero watermarking authentication algorithm based on edge detection, and genetic coding selection encryption algorithm. First, a multimodal medical image fusion scheme in NSCT domain based on phase consistency and local Laplace energy was used to fuse magnetic resonance imaging and single photon emission computed tomography. Zero watermark information authentication based on edge detection was realized in the fusion process, and the fused mark images were generated. The tagged images were then encrypted by using a selective encryption scheme based on dynamic DNA coding and 6-bit RNA-S-box substitution. [Results] Theoretical analyses and numerical simulations show that the algorithm has good security.