Quality evaluation and enhancement of audiovisual signals based on digital watermarking

图像、视频、语音和音频的质量测量对于当今的音频和视频广播、电话网络、传输控制和电子商务至关重要，主要是因为质量既是客户满意度的关键决定因素，也是传输状况的关键指标。虽然主观质量评价一直是最可靠的视听质量评价方法，但它非常不适合在线监控和播出应用，而且非常昂贵和耗时。现有的客观质量评价指标需要原始信号来评价视听质量。原始信号不适用于某些重要应用。提出了基于数字水印的视听质量评价方法。所提出的研究的基础是，在视听信号中仔细嵌入的水印将经历与宿主视听信号相同的失真。通过参考真实检测率和包括人的主观评价的特定常用质量度量之间的理想映射曲线，可以基于提取的水印的退化来测量视听质量。基于水印的图像质量评价不需要原始信号，具有很高的准确度。为了通过互联网或无线网络实时、高质量地传输音频和视频数据，开发简单、健壮的错误隐藏和编码策略是很重要的。使用音频/视频水印包括额外的感知透明信息以帮助恢复分组或帧丢失的想法也可以带来几个优点。因此，所提出的研究的一个组成部分是调查用于视听信号的基于水印的分组丢失隐藏方案、视频传输中的压缩恢复以及语音信号在自组织无线网络上的自适应编码和传输的使用。

The quality measurement of image, video, speech and audio is of critical importance for today's audio and video broadcasting, telephony networks, transmission control, and e-commerce, mainly because quality is both a key determinant of customer satisfaction and a key indicator of transmission condition. Although subjective quality evaluation has been the most reliable method of audiovisual quality assessment, it is highly unsuitable for online monitoring and broadcasting applications, and is also very expensive and time consuming. The current existing objective quality evaluation metrics require original signal to evaluate audiovisual quality. Original signal is not available for some important applications. We propose to evaluate audiovisual quality based on digital watermarking. The basis of the proposed research is that the carefully embedded watermark in an audiovisual signal will undergo the same distortion as the host audiovisual signal does. The audiovisual quality can be measured based on the degradation of the extracted watermark, by referring to an ideal mapping curve between the true detection rate and a particular commonly used quality metric including human subjective evaluation. The watermarking based quality evaluation does not need the original signal and can be very accurate. To deliver audio and video data over the Internet or wireless networks in real time with high quality, it is important to develop simple, robust error-concealment and coding strategies. The idea of including additional perceptually transparent information using audio/video watermarking to help for the recovery of packet or frame losses can also lead to several advantages. A component of the proposed research is therefore to investigate the use of watermarking-based packet loss concealment schemes for audiovisual signals, compression restoration in transmission of video, and adaptive coding and transmission of speech signal over ad-hoc wireless networks.