中文摘要：

为了实现含水印图像的篡改定位及无失真提取水印，在小波变换、数字水印和篡改定位技术的基础上，提出了基于改进小波系数调整的可逆水印算法。对载体图像进行小波变换，通过循环取模编码对水印图像进行加密以保证其安全性，通过均匀嵌入算法将加密后水印嵌入到调整后的小波系数中。该水印算法能够鉴别图像的真伪，能够发现载体图像所遭受的恶意篡改区域，并在载体上显示出来。仿真结果表明，与传统水印算法相比，算法能够无失真地提取水印（NC=1），还能通过定位水印找到载体图像发生篡改的位置。

英文摘要：

To achieve the watermarked image tampering localization and lossless watermark extraction, based on the wavelet transform, digital watermarking technology and tampering localization principle, the watermarking algorithm is proposed. Firstly, the carrier image is through wavelet transform; then through the cycle modulo coding to encrypt the watermarking image in order to their safety. Finally, encrypted watermark is embeded in adjusted wavelet coefficients through uniform embedding algorithm. The watermarking algorithm can identify the authenticity of the image, and the tampering suffered area can be found in the carrier image and display on the carrier image. Simulation results show that comparing with the conventional watermarking algorithm, the algorithm is the watermark without distortion （NC= 1）, but also by positioning the carrier image watermarking to find the position of tampering occurred.