Adaptive directional lifting wavelet-based lossless image coding with directional data hiding

This paper introduces a secure image coding method using adaptive directional lifting wavelet transform (ADLWT)-based lossless image coding with directional data hiding. ADLWT is an image dependent directional wavelet transform that provides high image compression performance. Since the lifting directions of ADLWT can be utilized as encryption key for decoding a correct image, the image can be protected from the illegal use by hiding the direction data into wavelet domain. We embed the directional data with the subband replacement method and the spread spectrum method into suitable regions so that the resulting bit rate is not increased. Experimental results show the proposed method can hide direction data with comparable bit rate of the conventional ADLWT-based image coding.