Improving stego image quality in image interpolation based data hiding

Jung and Yoo proposed a new image interpolation method, neighbor mean interpolation, on which they first constructed image interpolation based data hiding (IIDH) scheme. However, the authors only adopted a simple method by adding the decimal value of secret into pixels in cover image. Therefore, even though neighbor mean interpolation method is very cost effective, Jung and Yoo's IIDH scheme does not have very high-resolution stego image. In this paper, we still use neighbor mean interpolation (NMI) to generate cover image, but adopt least significant (LSB) substitution and optimal pixel adjustment process (OPAP) instead of simple addition to improve visual quality of stego image. The main contribution of this paper is to prove theoretically that our IIDH schemes have the better stego image quality than Jung and Yoo's IIDH scheme.