期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
Spread Spectrum Watermark Based on Wavelet Transform for Still Digital Image
1
作者 ShaoHai-mei MeiTian-can QinQian-qing 《Wuhan University Journal of Natural Sciences》 EI CAS 2004年第2期203-208,共6页
The proposed method inserts a watermark into the spectral components of the data using techniques analogous to spread spectrum communications, hiding a narrow band signal in a wideband channel. The watermark is diffic... The proposed method inserts a watermark into the spectral components of the data using techniques analogous to spread spectrum communications, hiding a narrow band signal in a wideband channel. The watermark is difficult for an attacker to remove. It is also robust to common signal and geometric distortion such as JPEG compression, cropping and scaling. In addition, the watermark can be extracted accurately without source host image at the receiver. Key words digital watermark - spread spectrum techniques - wavelet transform CLC number TN 911.73 - X 913. 2 Foundation item: Supported by Wuhan University Innovation Foundation (904270072)Biography: Shao Hai-mei (1975-), female, lecturer, research direction: wavelet application, image process, digital watermark. 展开更多
关键词 digital watermark spread spectrum techniques wavelet transform
下载PDF
Microwave and IF Cancellation of Leakage Signal for Spread Spectrum Radar
2
作者 Shen Yunchun & Shen Dongxu Harbin Engineering University, 150001, P. R. China 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1997年第4期50-55,共6页
This paper discusses the requirements for the cancellation of leakage signal, analyzes in detail the principals of cancelling leakage signal in microwave and IF band, and proposes the schemes to realize adaptive cance... This paper discusses the requirements for the cancellation of leakage signal, analyzes in detail the principals of cancelling leakage signal in microwave and IF band, and proposes the schemes to realize adaptive cancellation. Computer analog has shown that the proposed scheme has a very high convergence speed and can reach a high cancellation ratio. 展开更多
关键词 Adaptive cancellation RADAR Spread spectrum technique.
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部