Automated Detection and Removal of Clouds and Their Shadows from Landsat TM Images

摘要

In this paper, a scheme to remove clouds and their shadows from remotely sensed images of Landsat TM over land has been proposed. The scheme uses the image fusion tech- nique to automatically recognize and remove contamination of clouds and their shadows, and integrate complementary informa- tion into the composite image from multitemporal images. The cloud regions can be detected on the basis of the reflectance dif- ferences with the other regions. Based on the fact that shadows smooth the brightness changes of the ground, the shadow regions can be detected successfully by means of wavelet transform. Fur- ther, an area-based detection rule is developed in this paper and the multispectral characteristics of Landsat TM images are used to alleviate the computational load. Because the wavelet trans- form is adopted for the image fusion, artifacts are invisible in the fused images. Finally, the performance of the proposed scheme is demonstrated experimentally.