支持预览的版权图像共享

针对数字水印技术均不考虑版权图像共享场景中用户的预览需求，以及软件控制方法和附加信息方法的局限性，该文提出一个支持直接从加密图像预览原图像部分视觉内容的版权图像共享方案。为此，将缩略图保持加密的思想引入到用户端嵌入的水印方案中，通过像素调整在加密图像上呈现原图像内容的模糊版本。用于调整的像素位被事先以信息隐藏的方法嵌入隐藏区域中，以保证解密的正确性。此外，用户水印被在解密的同时嵌入到图像中，用于实现对未授权重分发行为的追踪。这样一来，不仅满足了共享过程中用户的预览需求还同时保护了图像的版权。理论分析和实验测试的结果展现了所提方案的安全性、可行性、高效性和鲁棒性。

Preview-supported Copyright Image Sharing

In view of the fact that digital watermarking technology does not consider the preview needs of users in copyright image sharing scenarios, as well as the limitations of software control method and additional information method, a copyright image sharing scheme that supports previewing part of the visual content of the original image directly from the encrypted image is proposed. To this end, the idea of thumbnail preserving encryption is introduced into the user-side embedded watermarking scheme, and a blurred version of the original image content is presented on the encrypted image through pixel adjustment. The pixel bits to be adjusted are embedded into the hidden area by means of information hiding in advance to ensure the correctness of decryption. Moreover, the user watermark is embedded into the image at the same time of decryption, which is used to track the unauthorized redistribution behavior. In this way, not only the preview needs of the user during the sharing process is met, but also the copyright of the image is protected. The results of theoretical analysis and experimental tests demonstrate the security, feasibility, efficiency, and robustness of the proposed scheme.