Robust Multi-watermarking Algorithm for Medical Images Using Patchwork-DCT

Abstract

The fast development of digital information technology has made great improvement on medical imaging digital information technology. The medical images can not avoid the defect of suffering being attacked or tampered maliciously when they are transmitted, and medical image watermarking algorithms can solve the impact of these attacks or malicious tampering, watermarking algorithms techniques are required in the field of image processing. However, the effectiveness of most proposed watermarking algorithms under geometric attacks for medical images are not promise, such that have poor ability to ensure the safety of the medical images. This paper proposes a robust encrypted multiple watermarking algorithm for medical images based on Patchwork-DCT. First, the Patchwork shearing transform and Discrete Cosine Transform (DCT) are combined to extract robust feature vectors against geometric attacks on medical images. Second, considering with the relatively small capacity of medical images and comparatively high requirements for privacy, zero watermark technology is used to embed and extract the watermark. Finally, the Logistic Map encryption algorithm is implied to enhance the security of the watermark information. The experimental results show that the proposed algorithm can effectively embed and extract watermark information, producing relatively good effect on traditional attacks and geometric attacks. The proposed algorithm can be applied in many fields.