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
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
文摘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.
文摘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.
