High-capacity Reversible Watermarking Algorithm Based on the Region of Interest of Medical Images

A reversible watermarking algorithm based on the integer wavelet transform (IWT) is proposed for the parenchyma areas in the medical images of lung and brain. Firstly, we use the OTSU with the regional statistics method to segment the parenchyma areas of lung and brain images. Secondly, taking the parenchyma areas as region of interest (ROI) on which an IWT is performed. Finally, the multi-bits reversible watermarking is embedded in medium-high frequency sub-band based on histogram shifting. The experimental results show that the watermarking signals could be correctly extracted if the medical image were not tampered. Additionally, compared with the traditional method, the embedding capacity is improved by more than 10% using the proposed algorithm.