水深数据约束下的声呐图像海底地形恢复方法

Recovering seabed topography from sonar image with constraint of sounding data

针对传统多波束系统和单波束系统在获得海底精细地形时的局限性,分析了高分辨率侧扫声呐图像与海底地形因素之间的关系,提出了一种利用高分辨率侧扫声呐图像恢复精细海底地形的新方法.根据侧扫声呐成像机理,构建模型获得声波在海底表面的入射强度和反射强度;基于Shape From Shading反演理论建立海底表面相对形状反演模型,并借助外部水深数据中分离出的地形高频项构建约束模型对反演结果进行约束;将外部水深数据提供的地形低频信息与约束后的反演结果叠加,实现绝对海底地形恢复.结果表明:该方法可获得相对中误差小于2%水深的海底地形恢复精度,并将测深数据分辨率提高近70倍.

To overcome the limitation of traditional multi-beam system and single beam system in obtaining the detailed seabed topography,the relationship between the high resolution side scan sonar image and the seabed topographic characteristics was studied,and a new method of recovering elaborate seabed topography from a side-scan sonar image was proposed.Firstly,the model for calculating both the incident intensity and backscatter intensity of acoustic wave on the seabed surface was given out according to side-scan sonar imaging mechanism.Secondly,an inversion model to get the relative shape of the seabed surface was built based on the Shape From Shading theory.And then the inversion result was forced into the actual corresponding seabed microtopography with the help of the high-frequency part of external sounding data.Finally,the low-frequency part of the external sounding data was merged into the constrained inversion shape,and the detailed seabed topography can be completely recovered.Experimental results show that the relative mean square error of recovered topography is less than2% and the resolution of recovered seabed topography is about 70 times higher than that of the topography produced by the external sounding data.