The experiments show that compared with other recently proposed algorithms , our algorithm has following advantages : ( 1 ) high security ; ( 2 ) high robustness ; ( 3 ) good watermark detection capability ; and ( 4 ) capability to detect changes of images in localized spatial and frequency regions 实验结果表明,与目前国外流行的脆弱水印算法相比,该算法具有以下优点: ( 1 )安全性高; ( 2 )容忍度强; ( 3 )检测能力强; ( 4 )能从空间与频率两方面分析图像的变化,从而能初步判断图像操作的属性。
Thirdly , this dissertation analyses the echo simulation of chirp - subpulse stepped frequency signal and chirp signal . and the detection capability of chirp - subpulse stepped frequency signal and chirp signal in low altitude moving target is compared . the results show that chirp - subpulse stepped frequency is better 再次,本文分析了chirp子脉冲频率步进信号和chirp信号的回波模拟问题,在此基础上,对chirp子脉冲频率步进信号和chirp信号对低空动目标检测的性能进行了比较,结果显示chirp子脉冲频率步进信号具有较好的性能。