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GEOMETRICALLY INVARIANT WATERMARKING BASED ON RADON TRANSFORMATION 被引量:19
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作者 CaiLian DuSidan GaoDuntang 《Journal of Electronics(China)》 2005年第3期301-306,共6页
The weakness of classical watermarking methods is the vulnerability to geometrical distortions that widely occur during normal use of the media. In this letter, a new image- watermarking method is presented to resist ... The weakness of classical watermarking methods is the vulnerability to geometrical distortions that widely occur during normal use of the media. In this letter, a new image- watermarking method is presented to resist Rotation, Scale and Translation (RST) attacks. The watermark is embedded into a domain obtained by taking Radon transform of a circular area selected from the original image, and then extracting Two-Dimensional (2-D) Fourier magnitude of the Radon transformed image. Furthermore, to prevent the watermarked image from degrading due to inverse Radon transform, watermark signal is inversely Radon transformed individually. Experimental results demonstrate that the proposed scheme is able to withstand a variety of attacks including common geometric attacks. 展开更多
关键词 版权保护 鉴别 氡变换 几何攻击 不变量形心
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以特殊角度攻击地面固定目标的圆周导引律 被引量:1
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作者 胡正东 唐雪梅 王月平 《固体火箭技术》 EI CAS CSCD 北大核心 2015年第1期1-6,共6页
针对某些导弹以特殊角度攻击地面固定目标的任务要求,提出了一种仅利用视线角测量信息就能实现末速方向控制的圆周导引律。该导引律的基本思想在于控制导弹沿着一系列由导弹和目标的实时位置及要求的命中点角度所确定的圆弧飞行。利用... 针对某些导弹以特殊角度攻击地面固定目标的任务要求,提出了一种仅利用视线角测量信息就能实现末速方向控制的圆周导引律。该导引律的基本思想在于控制导弹沿着一系列由导弹和目标的实时位置及要求的命中点角度所确定的圆弧飞行。利用简单的几何原理即可快速解算出各时刻所需要的速度倾角,并将其转换成制导指令。仿真结果表明,与典型的最优导引律相比,圆周导引律更适合于过顶迂回攻击的情况,且受制导周期的影响较小,但受制导指令时延的影响较大。 展开更多
关键词 末速方向控制 圆周导引律 几何原理 最优导引律 过顶迂回攻击
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