中文说明：在扩频空域系统，一个spreadwatermark信号隐藏在另一个扩频信号相同的频谱。水印是将一个小秘密throughmodulation与基于密钥的PRNS准备，而直接作为第二扩频信号的原始媒体。一个水印信号的引入到原来的媒体传播的许多信号样本，以便在每个样品watermarkenergy可以减少到一个不起眼的水平对人类感知系统。此外，由于该PRNS嘈杂的性质
English Description：
In Spread Spectrum basedwatermarking systems, a spreadwatermark signal is hidden within the same spectrum of another bandspread signal. The watermark is prepared by spreading a small secret throughmodulation with a key-based PRNS, while the original media isdirectly considered as the second band spread signal. A watermark signal introduced tothe original media is spread over many signal samples, so that the watermarkenergy in each individual sample can be diminished to an unnoticeable level tothe human perceptual system. Moreover, due to the noisy nature of the PRNS, theembedded watermark is also a noise-like signal and thus difficult to bedetected and manipulated by other people.