An interpolation-based lossless hiding scheme based on message recoding mechanism

Abstract

The secret message can be an image that encoded using a binary string. In a pure symbol such as the Japanese flag, there are many smooth areas. Such images degrade the quality of the stego image considerably because they contain many white-colored pixels in the secret image, most of which are encoded as “11111111.” Hiding schemes shift the cover pixel to conceal the secret bit 1. Hence, many pixels will be shifted for hiding a simple secret image such that the image quality of the stego image deteriorates. To solve this problem, we proposed a re-encoding mechanism to rearrange the value of the secret message. The proposed scheme re-encodes the secret message according to its occurrence probability. The frequently appearing patterns are encoded with the smallest distortion code to minimize image distortion.According to the results, the image quality of the proposed scheme is approximately 3dB higher than that of other methods. In particular, for very smooth secret messages such as logo images, the image quality of the proposed scheme is 12dB higher than those of the existing methods. Furthermore, the embedding capacity of the proposed method is 1 bpp higher than those of the existing methods.