Application of ant colony optimization for enhancement of visual cryptography images

Abstract

Visual Cryptography is a method that shows the idea of maintaining secrecy by concealing secrets in images. An image may be separated into k shares that can be stacked together to recover the first image approximately. This secret sharing scheme enables distribution of a secret amongst n persons, such that only predefined approved persons will be able to recreate the secret. In Visual Cryptography, the secret can be remade visually by superimposing shares. One of the fundamental disadvantage of conventional Visual Cryptography is the pixel expansion, where every pixel is substituted by m sub-pixels in each share that results in the loss of resolution. Thus enhancing the visual nature of Visual Cryptography is a generally researched area. The proposed technique improves the visual quality and resolution of Visual Cryptography utilizing the Ant Colony Optimization Algorithm and it takes into account a wide range of images, color and also gray. The proposed technique builds the quality and sharpness of the image. It is assessed subjectively regarding human visual perception and quantitatively utilizing standard measurements.