A thin cloud removal method from remote sensing image for water body identification

Abstract

In this paper, a thin cloud removal method was put forward based on the linear relationships between the thin cloud reflectance in the channels from 0.4 μm to 1.0 μm and 1.38 μm. Channels of 0.66 μm, 0.86 μm and 1.38 μm were chosen to extract the water body information under the thin cloud. Two study cases were selected to validate the thin cloud removal method. One case was applied with the Earth Observation System Moderate Resolution Imaging Spectroradiometer (EOS/MODIS) data, and the other with the Medium Resolution Spectral Imager (MERSI) and Visible and Infrared Radiometer (VIRR) data from Fengyun-3A (FY-3A). The test results showed that thin cloud removal method did not change the reflectivity of the ground surface under the clear sky. To the area contaminated by the thin cloud, the reflectance decreased to be closer to the reference reflectance under the clear sky after the thin cloud removal. The spatial distribution of the water body area could not be extracted before the thin cloud removal, while water information could be easily identified by using proper near infrared channel threshold after removing the thin cloud. The thin cloud removal method could improve the image quality and water body extraction precision effectively.