A new reversible watermarking scheme based on Integer DCT for medical images

Abstract

Reversible watermarking algorithms make it possible that the original image can be totally restored after the watermark was extracted, so it is widely used in the protection of medicalimages. A new reversible watermarking scheme based on Integer Discrete Cosine Transform (IntDCT) and Difference Expansion (DE) is proposed in this paper. The IntDCT transformation not only avoids the distortion of truncation error, but also leads to a faster processing speed and an easily handled implementation in hardware. In our scheme, an image is firstly divided into some non-overlapping blocks, after which the difference expansion embedding and extracting algorithm is used on those blocks, whose energy is below some predefined thresholds. In order to satisfy the reversibility, overflow or underflow of data is also considered and prevented. Finally, experimental results show that the proposed algorithm may has potential applications in medical image processing.