Div. of Eng., Texas Univ., San Antonio, TX.
IEEE Trans Image Process. 1997;6(10):1400-11. doi: 10.1109/83.624959.
This paper examines the feasibility of extracting three-dimensional (3-D) or topographic information in spotlight mode stereo synthetic aperture radar (SAR). A display of a SAR (intensity) image has two axes: range and cross-range. Elevated scatterers appear closer in range; this phenomenon is called radar image layover. How the height of each scatterer can be computed from the difference in its layover between two images is investigated. This is analogous to computing height from disparity distance (triangulation) in optical stereo. The same procedure can be applied on pixel by pixel basis for terrain elevation mapping. A general expression is derived for the accuracy of the height estimate as a function of the range resolution and the angular difference between the image planes. Accuracy increases as the angle between the image planes increases, but the bright scatterers in one image tend to fade in the other image. This limited angular persistence of radar scatterers is also discussed. Trajectories for data collection are examined that provide near-optimal height estimates while eliminating the scatterer persistency problem.
本文探讨了在聚束式立体合成孔径雷达 (SAR) 中提取三维 (3-D) 或地形信息的可行性。SAR（强度）图像的显示有两个轴：距离向和方位向。凸起的散射体在距离向上显得更近；这种现象称为雷达图像叠掩。通过比较两幅图像中每个散射体的叠掩差异，研究了如何计算每个散射体的高度。这类似于光学立体视差距离（三角测量）中计算高度。可以逐像素地应用相同的程序进行地形高程测绘。推导出了高度估计精度的一般表达式，作为距离分辨率和图像平面之间的角度差的函数。精度随图像平面之间的角度增加而增加，但一个图像中的亮散射体在另一个图像中趋于消失。还讨论了雷达散射体的这种有限角度持久性。检查了数据采集轨迹，这些轨迹在消除散射体持久性问题的同时提供了近乎最佳的高度估计。
