Modification Method of Interferometric SAR Water Body Digital Elevation Model Based on Morphology Refinement

Abstract

A method for correcting an interferometric SAR water body digital elevation model based on morphological refinement, comprising the following steps: detecting a water body region in combination with an interferometric SAR amplitude image and a coherence coefficient map; extracting the skeleton of the water body region by using a morphological refinement method; With the skeleton pixel as the center, reference pixels are selected on the nearby land to preliminarily calculate the elevation value of the skeleton pixel; after the elevation value of the skeleton pixel is filtered, the elevation value of other pixels in the water body area is generated with the skeleton pixel as the seed point; for the water body The elevation value of the land area at the edge of the area is smoothed to complete the correction of the interferometric SAR water body digital elevation model. The invention uses the DEM of the interferometric SAR itself to correct the DEM of the water body area, and overcomes the problem of fuzzy number calculation in the correction in the interferometric phase domain and the inconsistency problem when using an external source DEM for correction in the DEM domain.

Description

technical field [0001] The invention relates to the technical field of interferometric synthetic aperture radar (Synthetic Aperture Radar, SAR) signal processing, in particular to a method for correcting an interferometric SAR water body digital elevation model (Digital ElevationModel, DEM) based on morphological refinement. Background technique [0002] Interferometric SAR is a technology that uses the interferometric phase information of two-channel SAR complex data to extract surface elevation information or change information. It expands SAR measurement to three-dimensional space and has the characteristics of all-time, all-weather, and high precision. Therefore, It is widely used in many fields such as topographic surveying, glacier research, marine surveying and mapping, and land subsidence monitoring. [0003] In topographic surveying and mapping applications, although interferometric SAR has high-precision surveying and mapping capabilities, due to some inherent char...

AI Technical Summary

Problems solved by technology

[0005] The main disadvantages of the above two types of correction methods are as follows: (1) The correction method in the interferometric phase domain can be performed before or after phase unwrapping when interpolating the interferometric phase. However, these two methods have certain limitations

Before the phase unwrapping, due to the periodicity of the trigonometric function, the interferometric phase is entangled between (-π, π], and the interferometric SAR system parameters need to be used to estimate the fuzzy periods of the interferometric phase on both sides of the water body before interpolation, and then Interpolation, when the system parameters are inaccurate, there will be errors in the estimation of fuzzy numbers, which will affect the correctness of interpolation; and interpolation after phase unwrapping, due to the noise characteristics of the interferometric phase in the water body area, the unwrapping will cause phase The propagation of the error makes the relative value of the interferometric phase on both sides of the water body incorrect, and the correct interpolation result cannot be obtained; (2) The correction method in the DEM domain is due to the collection method, time, elevation reference and resolution of the external data, etc. There are some differences from the actual interference SAR processing products, so when using these data to fill the water body area, it is difficult to completely match the two, and there will be systematic differences in local areas, which will affect the subsequent use of the product

Images