Adjacency effect correction of the GF-1 image in coastal waters of Hangzhou Bay and Taihu Lake, China

Abstract

For coastal waters, the radiation signals received by the sensor are affected by the high reflectance of the coastal land, inducing reduced image contrast and significant adjacency effect. Eliminate the atmospheric attenuation and adjacency effect, and obtain the accurate remote sensing reflectance above water surface is an important prerequisite for the quantitative water color remote sensing. Based on the in situ spectral data of the coastal Hangzhou Bay, China on July 23, 2017 and the Taihu Lake, China on April 29, 2016, as well as the synchronous Gaofen-1 wide field-of-view camera (GF-1/ WFV) images, the 6S model was used to eliminate the atmospheric attenuation, and a point spread kernel function was used to correct the adjacency effect. The experimental results show that the images after adjacency effect correction are clearer, with increased image contrast and more abundant information of the water body. Compared to the atmospheric correction results only after the 6S model, the average relative errors of three in situ synchronous samples in Hangzhou Bay after adjacency effect correction are reduced by 8.39%, 10.81% and 7.29%, and that in Taihu Lake after adjacency effect correction are reduced by 10.8%, 5.24% and 0.39%, respectively. The adjacency effect correction improves the radiation detection accuracy of the remote sensing reflectance above water surface and can be a reference for quantitative water color remote sensing in coastal waters.