Slope DEM extraction and accuracy analysis based on multi-source reference data

Reference DEM is indispensable and important data in the accuracy analysis of InSAR DEM extraction. Considering the abundance of available DEM data, how to choose reliable reference DEMs to meet the accuracy requirements of DEM extraction for different terrains is an urgent problem in DEM extraction.In this article, ALOS DEM of 12.5 m, STRM DEM of 30 m, and STRM DEM of 90 m were selected as reference DEMs. Based on two Sentinel-1A images from 2020, DEM data on slopes in some areas of Dexing City was extracted. InSAR technology was used to extract S1A DEM data from the experimental area, and ASTGTM DEM data as a reference. About 300 detection points were randomly selected using the detection point method, the corresponding evaluation indicators were selected, and accuracy checks on S1A DEMs extracted from different reference DEMs were performed. The research results show that the extracted S1A DEM has a higher accuracy when ALOS DEM with a resolution of 12.5 m is used as the external DEM, with its RMSE in experimental area A of 9.412 m. The extracted S1A DEM has a relatively lower accuracy when ALOS DEM with a resolution of 90 m is used as the external DEM, with its RMSE in experimental area A of 10.293 m. This experiment guides extracting DEM from different terrains and can help scholars better choose reference DEM when conducting InSAR experiments. The research results can provide important technical support for slope disasters and early warning.