REDUCTION OF SIDELOBE AND SPECKLE ARTIFACTS IN MICROWAVE IMAGING - THE CLEAN TECHNIQUE
REDUCTION OF SIDELOBE AND SPECKLE ARTIFACTS IN MICROWAVE IMAGING - THE CLEAN TECHNIQUE
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DOI：
10.1109/8.1144
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发表时间：
1988-04-01
影响因子：
5.7
通讯作者：
STEINBERG, BD
中科院分区：
文献类型：
--
作者：
TSAO, J;STEINBERG, BD
大型随机细阵列提供了高角分辨率的微波图像，但受到高旁瓣电平引起的伪影（假目标和目标分裂或斑点）的困扰。CLEAN算法减少旁瓣引起的伪影扩展到相干辐射场和理论放置在定量的基础上。CLEAN技术通过迭代消除发现的最大目标来分解相干多目标场景的接收回波，在每一步中，消除信息用于创建目标图像。图像包括目标强度、相位和方向。该过程是为由随机稀疏阵列组成的成像仪器而设计的。导出的条件，当满足时，保证所有正确的目标将被保留在清洁的图像和所有假目标丢弃。提出了一种基于移动阈值的目标坐标提取算法。结果表明，远弱于旁瓣电平的目标可以被检测和显示，而没有伪影的危险。目标动态范围和图像对比度可以增加高达两倍的信噪比每个元素。<>
Large random thin arrays provide a high angular resolution microwave images but are plagued with artifacts (false targets and target breakup or speckle) caused by high sidelobe levels. The CLEAN algorithm for reducing the sidelobe-induced artifacts is extended to the coherent radiation field and the theory placed on a quantitative basis. The CLEAN technique decomposes the received echoes of a coherent multiple-target scene by iterative cancellation of the largest target found. At each step, cancellation information is used to create a target image. The image includes target intensities, phases, and directions. The process is designed for an imaging instrument consisting of a random thinned array. A condition is derived which, when satisfied, guarantees that all proper targets will be preserved in the cleaned image and all false targets discarded. An algorithm involving moving thresholds is derived to extract the target coordinates. It is shown that targets much weaker than the sidelobe level can be detected and displayed without the hazard of artifacts. The target dynamic range and the image contrast can be increased by up to twice the signal-to-noise ratio per element.<>