Thin Cloud Correction for Single Optical Satellite Image Using Complementary Dark Objects on Multiple Visible Bands

Abstract

Optical satellite images frequently suffer from thin clouds, degrading the data quality. A thin cloud correction method is developed based on complementary dark objects on multiple visible bands to address this problem. First, thin cloud images are divided into irregular subareas using the superpixel segmentation algorithm, enabling the proper identification of dark objects in the spatial domain across different visible bands. A criterion is then established to classify the dark objects into two types, namely, absolute dark objects (ADOs) and relative dark objects (RDOs). Subsequently, the quantitative correlation of thin clouds between visible bands is estimated by adopting the ADOs. Dark objects present complementarity in visible bands; thus, the RDOs on one band are spatially densified by referencing the RDOs on the other visible bands. Thereby, a thin cloud map with fine spatial details is interpolated by using all the ADOs and RDOs on a band, and the correction procedure is performed through subtraction. Eight visible data captured by Landsat platforms are collected for simulated and real experiments to evaluate the method's performance. Three representative thin cloud correction approaches are selected for visual and quantitative comparisons. The proposed method can correct thin clouds effectively and restore various scenes accurately. The interpolated thin cloud maps show enhanced texture details and finer representation compared with the benchmarks. In addition, the advantages of dark-object densification for thin cloud map generation and the limitations of the proposed method are investigated.

Keywords

• Band correlation
• complementary dark object
• optical satellite image
• spatial interpolation
• thin cloud correction