A high payload data hiding scheme based on modified AMBTC technique

In this paper, we propose a data hiding scheme which uses our modified AMBTC compression technique for embedding the secret data. Our modified AMBTC technique converts the one bit plane into two bit plane which helps in achieving better quality compressed image as well as high capacity. In this scheme, we first apply the original AMBTC technique on the given cover image then identify the smooth and complex blocks using a user defined threshold value. In case of the smooth blocks, it converts the one bit plane into two bit plane using mean value of the block and replaces all the bits of the bit plane with the secret data bits. It calculates four quantization levels in place of two old quantization levels. In case of complex blocks, it converts the one bit plane into two bit plane but here only the first LSBs of the newly constructed bit plane is replaced by the secret data bits. The four new quantization levels are calculated using the resultant bit plane. Thus, this scheme is able to embed 2 bits into each pixel of the smooth blocks and one bit in each pixel of complex blocks. It provides good quality stego image because the introduced error during the secret data embedding is reduced by having four quantization levels. Experimentally, our scheme is superior to the existing AMBTC based data hiding schemes in terms of both data hiding capacity and image quality. In fact, the proposed scheme hides approximately two times more secret data than the existing schemes with better image quality.