Abstract: In order to solve the problem of privacy disclosure in medical image's interest of region, a new reversible visible watermarking based privacy detection algorithm was proposed. The method embedded a binary watermark image into the interest of region of original medical image to protect privacy, and used visual masking of Human Visible System (HSV) and pixel's mapping mechanism to dynamically adjust the visibility and transparence of watermark. In addition, a shrinking projection technology was utilized to solve the problem of potential overflow and underflow during the embedding procedure. Finally, a random key was introduced to enhance the embedded watermark's robustness. The experimental results show that the proposed method achieves better performance in visibility and transparence of watermark, and the number of additional information produced by embedding is only 65608bits. In addition, the deletion of watermark is difficult without knowing the correct key, and the quality difference between the watermarked image and the recovered image is less than 1dB.

Key words: reversible watermarking, visible watermarking, medical image, privacy protection, Human Visible System (HSV)

摘要： 针对医学图像感兴趣区域隐私泄露问题,提出了一种新的基于可逆可见水印的隐私保护算法。算法将二值水印图像嵌入在医学图像感兴趣区域实施隐私保护,利用人类视觉系统(HSV)的掩蔽特性和自适应的像素映射机制,对水印可见性和透明性进行动态调整;采用收缩投影技术,有效解决了嵌入过程中可能出现的溢出问题;最后,随机数密钥的引入增强了可见水印的鲁棒性。实验结果表明,算法嵌入的水印具有较好的可见性和透明性,产生的水印附加信息数量仅为65608位;另外,在不知道密钥情况下,水印移去困难,恢复后图像与嵌入水印后图像质量相差不到1dB。

关键词: 可逆水印, 可见水印, 医学图像, 隐私保护, 人类视觉系统