提出一种SAR数据检测桥面高度的反演方法。用几何射线描述桥梁散射机制, 依据去取向理论和分类参数分析, 得到SAR成像中桥梁结构目标单次、二次、三次散射的成像规律。通过SAR图像分类参数的聚类与细化、滤波和Hough变换直线检测算法, 检测出单次、二次和三次散射回波所成位置线图像, 进一步构成桥面高度的反演算法。用机载Pi-SAR数据反演了日本鸣门大桥的桥面高度和桥面宽度, 并与实测数据对比。按照该方法, 进一步采用星载ALOS-PALSAR数据检测中国东海大桥的桥面高度。反演方法是可行的。

An inversion method of bridge height over water surface is developed. A geometric rays description is illustrated for scattering mechanism of bridge over water surface. Based on Mapping and Projecting Algorithm (MPA), polarimetric SAR images are simulated and the results show that the bridge in SAR image can be identified by three strips corresponding to single-, double- and triple-order scattering, respectively. A set of parameters based on de-orientation theory is applied to locate the imaging positions of single-, double- and triple-order scattering of the bridge body. The thinning, clustering algorithm, and Hough transform are employed to detect the lines indicating different orders of scattering. Then, these lines are used to invert the bridge height. Fully polarimetric data of airborne Pi-SAR at X-band is applied to inversion of the Naruto Bridge height and width. Based on the same principle, spaceborne ALOS PALSAR data of the Eastern Ocean Bridge is also applied to the bridge height inversion. The results show good feasibility of the bridge height inversion.