Secured covert color image transmission using secret fragment visible mosaic image and reversible color transformation technique

In this paper a novel technique of fragment visible mosaic image is proposed. It is a unique and novel kind of computer art called Mosaic tile image steganography technique, which transforms a color secret image into a so called secret fragment visible mosaic image of the same size. Initially choose randomly any color cover image from the existing database, which looks similar to secret color image to be transmitted securely and which could be used as a disguise for the secret image. As a next step fragmented image is created by partitioning the payload and cover image information into tiles and sorting them in accordance with mean and standard deviation values of individual tiles. Later transforming the color characteristics of individual fragments of secret image in accordance with corresponding blocks of cover image. Such techniques play a major role in lossless retrieval of secret image information. The related data needed for retrieving the payload image like size of the tile, their corresponding mean and standard deviation values, color transformation values and the amount of degrees each tile is rotated to make it appear similar to target image is embedded into individual fragments of mosaic image for the lossless retrieval sensitive information in the form of payload image. To evaluate the effectiveness of proposed algorithm Root mean square error, Peak signal to noise ratio and correlation factors have been used as various parameters.