Ice lake contour automatic extraction method based on satellite images

Abstract

The invention discloses an ice lake contour automatic extraction method based on a satellite image, and relates to the technical field of satellite image processing. The method comprises the followingsteps: collecting satellite images and elevation data including ice lakes; performing radiation correction and atmospheric correction on the satellite image, and converting the pixel brightness valueof the original satellite image into surface reflectance to obtain surface reflectance data; fusing the satellite images by using a nearest neighbor diffusion algorithm to obtain an experimental satellite image which has a preset spatial resolution and comprises various spectral information; detecting and removing at least part of non-ice lake objects in the experimental satellite image; calculating a normalized water body index of the experimental satellite image, and extracting an initial distribution area of each ice lake from the experimental satellite image; constructing image block dataof each ice lake, and cutting the image blocks one by one; taking the boundary of the initial distribution area of each ice lake as an initial evolution contour, and extracting the target distribution area of each ice lake contour by using a non-local active contour method.

Description

technical field [0001] The present application relates to the technical field of satellite image processing, in particular, to a method for automatically extracting outlines of glacial lakes based on satellite images. Background technique [0002] Glacier lakes are lakes formed by glaciers or lakes whose main supply source is glacier meltwater, and are widely distributed in glacial areas. In the context of today's global warming, glaciers are generally retreating. The retreat of glaciers is closely related to the changes of glacial lakes, especially the rapid expansion of some lakes directly fed by glacial melt water, and some even burst, causing floods or debris flow disasters. Because glacial lakes are usually located in high-altitude and high-lying areas, they have the characteristics of suddenness, fast flow, large flow, and wide range of passages, which seriously endanger the lives and property safety of people downstream, and have destructive effects on the natural an...

AI Technical Summary

Problems solved by technology

Limited by the spatial resolution of Landsat, MODIS and other data, the extracted boundary of the glacial lake is inaccurate, which will lose the details of the edge of the lake, and it is impossible to obtain detailed information on the evolution of the glacial lake and the risk of collapse.

More importantly, it is impossible to obtain a large number of small-scale glacial lake data that are very sensitive to climate change, resulting in a large number of missing data in the glacial lake catalog database, wrong estimation of water resources in glacier areas, and insufficient evaluation and analysis of responses to climate change.

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