Electronic Measurements and Signal Processing Group, Technische Universität Ilmenau, 98693 Ilmenau, Germany.
Biosignal Processing Group, Technische Universität Ilmenau, 98693 Ilmenau, Germany.
Sensors (Basel). 2018 Jul 3;18(7):2136. doi: 10.3390/s18072136.
Wideband microwave imaging is of interest wherever optical opaque scenarios need to be analyzed, as these waves can penetrate biological tissues, many building materials, or industrial materials. One of the challenges of microwave imaging is the computation of the image from the measurement data because of the need to solve extensive inverse scattering problems due to the sometimes complicated wave propagation. The inversion problem simplifies if only spatially limited objects—point objects, in the simplest case—with temporally variable scattering properties are of interest. Differential imaging uses this time variance by observing the scenario under test over a certain time interval. Such problems exist in medical diagnostics, in the search for surviving earthquake victims, monitoring of the vitality of persons, detection of wood pests, control of industrial processes, and much more. This paper gives an overview of imaging methods for point-like targets and discusses the impact of target variations onto the radar data. Because the target variations are very weak in many applications, a major issue of differential imaging concerns the suppression of random effects by appropriate data processing and concepts of radar hardware. The paper introduces related methods and approaches, and some applications illustrate their performance.
宽带微波成像是在需要分析光不透明场景的地方都感兴趣的，因为这些波可以穿透生物组织、许多建筑材料或工业材料。微波成像是一个具有挑战性的问题，因为需要解决由于有时复杂的波传播而导致的广泛的逆散射问题，因此需要从测量数据中计算图像。如果只对具有随时间变化的散射特性的空间有限的物体（最简单的情况下是点物体）感兴趣，则反转问题会简化。差分成像是通过在一定时间间隔内观察测试场景来利用这种时间变化。在医学诊断、寻找幸存的地震灾民、监测人员的活力、探测木材害虫、控制工业过程等方面都存在这样的问题。本文概述了点状目标的成像方法，并讨论了目标变化对雷达数据的影响。由于在许多应用中目标变化非常微弱，因此差分成像是一个主要问题，涉及到通过适当的数据处理和雷达硬件的概念来抑制随机效应。本文介绍了相关的方法和方法，并举例说明了它们的性能。
