Medium-resolution remote sensing image discrete point DEM (Digital Elevation Model) construction method based on medium value filtering

Abstract

The invention belongs to the field of a medium-resolution remote sensing image discrete point DEM (Digital Elevation Model) construction method, which discloses a medium-resolution remote sensing image discrete point DEM construction method based on medium value filtering. The medium-resolution remote sensing image discrete point DEM construction method comprises the following steps of: 1. calculating tidal height information at a satellite imaging moment; 2. dispersing a vector waterline extracted at the satellite imaging moment; 3. combining equidistant tidal level points dispersed in the above steps, building the reference grid of the median filtering according to a remote sensing image resolution ratio, labeling all dispersed equidistant tidal level points, and marking the ID (Identity) of the grid to which the equidistant tidal level points belong; 4. traversing all grids; and 5. on the basis of a median filtering result, building a final DEM result by linear interpolation. In the method disclosed by the invention, the method of median filtering effectively utilizes the elevation information of all discrete points falling in the grids to improve the elevation precision of the discrete point.

Description

technical field [0001] The invention relates to a method for constructing a discrete point DEM of a medium-resolution remote sensing image, more specifically, to a method for constructing a discrete point DEM of a medium-resolution remote sensing image based on a median filter. Background technique [0002] Surface elevation information is one of the basic data in geoscience research. Rapid acquisition and inversion of regional elevation information has always been a hot spot in remote sensing information inversion. On the one hand, for regions with rapid changes in surface morphology, analyzing the geomorphological elevation information in different time periods can obtain the evolution characteristics and laws of regional geomorphology, which can provide scientific decision-making basis for the coordinated development of economic society and natural environment; On the other hand, due to the muddy beach surface, dense tidal trenches, variable tidal flat erosion and silting...

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Problems solved by technology

[0003] At present, large-scale ground elevation information can be obtained through aviation and aerospace remote sensing, and many surface elevation inversion methods have been formed: ① Wehr A, Axelsson P, Du Guoqing et al. Respectively in "Airborne laser scanning: An introduction and overview. ISPRS Journal of Photogrammetry and Remote Sensing", "Airborne laser scanning: An introduction and overview. ISPRS Journal of Photogrammetry and Remote Sensing" and "LIDAR technology in Jiangsu coastal beach surveying and mapping" In the article "Application", LiDAR (Light Detection And Ranging, airborne laser detection and ranging system) was used to retrieve elevation information in different areas, but since the measurement accuracy of LiDAR data in shallow water areas is not high, it needs to be corrected later; ②Akira H , Stemphen G, Rabus B, Jin Yaqiu and others respectively in "Mapping from ASTER stereo image data: DEM validation and accuracy assessment", "Extraction of topography from side-looking satellite systems: A case study with SPOT simulation data", "The shuttle In articles such as "radar topography mission-a new class of digital elevation models acquired by spaceborne radar" and "Using Synthetic Aperture Radar (SAR) single-flight full-polarization image data for ground digital elevation (DEM) inversion", the use of stereo Inversion of the elevation information of space remote sensing images, but the data source is difficult to obtain and the cost is high; ③ Zhang Ying et al. proposed an elevation based on the water content of tidal flats in the article "Remote Sensing Measurement of Soil Moisture Content in Coastal Tidal Flats" The idea of ​​information inversion is to establish the correlation between the tidal flat elevation and the water content of the beach surface sediment, and invert the water content of the beach surface sediment to approximate the tidal flat elevation. Since this method requires the actual measurement of satellite-synchronized ground tidal flat soil information , it is not easy to realize commercial operation; ④Dang Fuxing in "Research on Shallow Sea Depth Retrieval Method Using Multi-band Satellite Data", Tian Qingjiu in "Jiangsu Coastal Water Depth Remote Sensing Research" In this method, the bottom terrain is retrieved from the perspectives of radiative transfer theory equation, semi-theoretical and semi-empirical water depth remote sensing model, and the correlation model between measured water depth and pixel radiation value. Due to the complex mechanism of satellite imaging, the inversion accuracy is not high.

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