Capacity Controllable Location Map Free Reversible Watermarking

Reversible watermarking techniques enable the extraction of the embedding bits from a watermarked image in a lossless way. It exploits the high spatial correlation among neighboring pixels. Application in reversible watermarking includes military and medical images. Images occurs overflow or underflow problems during the imbedding process since pixels value may be out of range [0:255]. Most methods require a location map to solve such problems. A location map free reversible watermarking algorithm is proposed in this study. A prediction threshold value is computed, histogram shifting scheme based on the prediction threshold value to solve overflow and underflow problems. Another threshold value is adopted to achieve capacity control, image quality is better in different payload length with this control. The experimental results reveal that the performance of proposed method outperforms that proposed by FUJIYOSHI et al.