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几何绕射理论(Geometrical Theory of Diffraction,GTD)模型能够精确描述高频区雷达目标的电磁散射机理.该文在分析雷达回波稀疏特性的基础上,将参数估计问题转化为压缩感知理论中的稀疏信号重构问题,据此提出了一种基于压缩感知的2维GTD模型参数估计方法.该方法首先利用2维傅里叶变换成像确定目标散射中心的支撑区域,然后在支撑区域内对散射中心的GTD参数进行估计,最后利用聚类方法和最小二乘方法对估计结果进行修正.仿真和暗室测量数据实验结果表明,与现有方法相比,所提方法能有效改善模型参数的估计性能,且对提高散射中心类型参数的估计精度更为明显. 相似文献
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Non-rigid point matching has received more and more attention. Recently, many works have been developed to discover global relationships in the point set which is treated as an instance of a joint distribution. However, the local relationship among neighboring points is more effective under non-rigid transformations. Thus, a new algorithm taking advantage of shape context and relaxation labeling technique, called SC-RL, is proposed for non-rigid point matching. It is a strategy that joints estimation for correspondences as well as the transformation. In this work, correspondence assignment is treated as a soft-assign process in which the matching probability is updated by relaxation labeling technique with a newly defined compatibility coefficient. The compatibility coefficient is one or zero depending on whether neighboring points preserving their relative position in a local coordinate system. The comparative analysis has been performed against four state-of-the-art algorithms including SC, ICP, TPS-RPM and RPM-LNS, and the results denote that SC-RL performs better in the presence of deformations, outliers and noise. 相似文献
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用新溶剂法合成氯化石蜡-70的研究 总被引:1,自引:0,他引:1
用新溶剂法合成了氯化石蜡-70,重点讨论了原料的配比,氯化温度、氯化液循环流量,光照强度对反应的影响,发现氯蜡-42与溶剂的质量比为1:(2-2.5)、反应温度70-80℃、物料外循环流量400-600mL/min、光强为7W时氯化效果最好,并同原四氯化碳溶剂工艺进行了技术经济比较,表明新工艺合理可行,且简化了原工艺,提高了产品质量。 相似文献
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作为中国烹饪的一个重要组成部分,像生拼盘的制作技术以历史悠久、技巧独特、工艺精湛、别具风味依附中国烹饪而享誉世界。 相似文献