Automated Extraction for Water Bodies Using New Water Index from Landsat 8 OLI Images

The extraction of water bodies is essential for monitoring water resources, ecosystem services and the hydrological cycle, so analyzing water bodies from remote sensing images is necessary. The water index is designed to highlight water bodies in remote sensing images. We employ a new water index and digital image processing technology to extract water bodies automatically and accurately from Landsat 8 OLI images. Firstly, we preprocess Landsat 8 OLI images with radiometric calibration and atmospheric correction. Subsequently, we apply KT transformation, LBV transformation, AWEInsh, and HIS transformation to the preprocessed image to calculate a new water index. Then, we perform linear feature enhancement and improve the local adaptive threshold segmentation method to extract small water bodies accurately. Meanwhile, we employ morphological enhancement and improve the local adaptive threshold segmentation method to extract large water bodies. Finally, we combine small and large water bodies to get complete water bodies. Compared with other traditional methods, our method has apparent advantages in water extraction, particularly in the extraction of small water bodies.