Topography from Single Radar Images
Topography from Single Radar Images
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单雷达图像的地形
作者：
Robert L. Wildey
本文提出了一种从雷达图象产生数字地形的数学理论和相应的数值计算方法。因此，就像雷达测量之于摄影测量一样，雷达测斜之于摄影测斜。光测斜包括一个基本的不确定性原则，即使是地形，是均匀的正常的反射比强度，因为表面正常一致，是不是唯一的。这种法线方向的几何轨迹是隐含的，它生成一个表面。对于微波后向散射，在雷达倾斜测量的具体应用中，该表面是一个圆锥，其半角是入射角，其轴包含雷达，其顶点与地形点重合。虽然如果地面实况的正确定向的轮廓可用作约束，则可以去除不确定性，但情况很少如此。在没有照明线的情况下，需要一个辅助假设，例如走向线垂直于照明线。如果度量完整性是一个目标，那么这是一个荒谬的假设。在这里，“假设的局部圆柱”已被假定，一个前提，关于地形曲率的性质，似乎更现实，使生产的地形作为一组平行线积分。
A mathematical theory and a corresponding numerical procedure have been developed to produce digital topography from radar images as digital photometric arrays. Thus, as radargrammetry is to photogrammetry, so radarclinometry is to photoclinometry. Photoclinometry encompasses a fundamental indeterminacy principle even for terrain that is homogeneous in normal albedo, because the surface normal consistent with a given reflected specific intensity is not unique. A geometric locus of such normal directions is implied, which generates a surface. For microwave backscatter, in specific application to radarclinometry, this surface is a cone whose half-angle is the incidence angle, whose axis contains the radar, and whose apex coincides with the terrain point. Although the indeterminacy can be removed if a properly directed profile of ground truth is available as a constraint, such is seldom the case. In its absence, an auxiliary assumption, such as that the strike line runs perpendicular to the illumination line, is needed. If metric integrity is a goal, then this is an absurd assumption. Herein, "the hypothesis of local cylindricity" has been assumed, a premise regarding the nature of topographic curvature that seems more realistic and that makes possible the production of topography as a set of parallel line integrals.