A novel extended secret image sharing scheme based on sharing matrix

Ensuring the safety of communicating parties while sharing secret information and concealing their communication behavior in everyday activities has become an increasingly important issue. One approach to address this challenge is through a secret image sharing (SIS) scheme that utilizes meaningful shares. However, existing SIS techniques face ongoing challenges in enhancing the visual quality of those shares while ensuring lossless recovery of the secret image. To overcome these challenges, we propose a novel extended secret image sharing scheme (ESIS) based on a sharing matrix. By locating the secret pixel value within a search window centered on the coordinate of the pixel value pair of the cover images, our method achieves lossless recovery of the secret image with resulting shares that are natural images of continuous tone indistinguishable from original cover images by human visual perception. Extensive experimental results demonstrate its effectiveness and advantages, supported by theoretical analysis.