Development of Image Protection and Management Systems using Digital Watermarking Techniques

(1)图像和视频数字水印方法的研究：提出了一种新的基于小波变换的静止图像和视频数字水印方法。我们已经证实，该方法对常见的图像处理操作具有健壮性，例如有损压缩、添加噪声、降低灰度级和StirMark攻击。在频域数字水印方法的性能评价方面：重点研究了频域内基于量化和相关的数字水印方法，并提出了水印嵌入和提取系统的模型。其次，利用该模型对现有的数字水印方法进行了分析，并提出了如何评价其性能的建议。因此，我们可以知道可以嵌入多少比特，以及应该设置多大的嵌入强度。(3)图像数据保护与管理系统的开发：在上述研究成果的基础上，我们提出了以下几个图像数据保护与管理系统：(A)MPEG视频的回放与复制控制系统；(B)数字图像的检索与验证系统；(C)JPEG图像的认证与保护系统。此外，我们还通过实验的方式开发了一个适用于Windows PC的水印嵌入与提取软件。

(1) Development of digital watermarking method for images and video : We have proposed a new watermarking method for both still images and video using the wavelet transform. We have confirmed that this method is robust against common image processing operations like lossy compression as JPEG and MPEG, adding noise, reduction of grayscale level, and StirMark attacks. Furthermore, this method enables us to distinguish malicious changes such as modifying or forging a part of an image from non-malicious changes resulting from common image processing operations.(2) On the evaluation of performance of digital watermarking method in the frequency domain : We have focused on the quantization- and correlation-based watermarking methods in the frequency domain and suggested the model of watermark embedding and extraction system. Next, using this model, we have analyzed the watermarking methods and proposed how to evaluate its performance. As a result, we can know how many bits are able to be embedded and how large the embedded intensity should be set. Furthermore, we have discussed the improvement of the DWT- and DCT-based watermarking methods.(3) Development of image data protection and management system : Based on the above results, we have proposed several image data protection and management systems as follows :(a) Playback- and copy-control system for MPEG video.(b) Retrieval and verification system for digital images.(c) Authentication and protection system for JPEG images.Furthermore, we have produced a watermark embedding and extraction software for Windows PC by way of experiment.