Simple least-significant-bit (LSB) substitution is the most straightforward way to embed the secret image in the host image. Based on the simple LSB substitution, the method using substitution table is proposed to improve the quality of the stego-image. In this paper, we shall bring up a new method that uses the un-embedded host pixel bits to partition the host pixel into different planes. This way, we can derive the optimal substitution table for each plane. By combining the optimal substitution tables, we can obtain the final result that we call the multi-bit-reference substitution table. After transforming the secret data according multi-bit-reference substitution table, we can embed the transformed secret data in the host image so that the host image will be degraded possibly less. The experimental results show that our method leads to good results.
