Research on the adjacency effect for off-nadir optical remote sensing

With the application of the multi-angle remote sensing which obtain earth's surface data through several scan angles, the analysis of the adjacency effect in off-nadir optical remote sensing is significant. Monte Carlo method is used to simulate the atmospheric point spread function (PSF) that are appropriate for the off-nadir optical remote sensing. By the convolution of the atmospheric PSF and the surface-leaving radiance, the radiance caused by the adjacency effect could be calculated. The influence factor analysis shows that, in addition to the surface albedo and the meteorological range, the viewing direction will affect the adjacency effect dramatically. With the deviation of the viewing zenith angle from the nadir, adjacency effect becomes weak. Unlike the nadir remote sensing, the adjacency effect in off-nadir remote sensing is azimuthally dependent and the contribution of the background in the viewing direction is greater than others. Based on a three-dimensional scene and a whole chain optical imaging simulation software, the images before the optical system of the sensor with and without the adjacency effect are simulated. The calculation of the SNR, contrast and spatial resolution of the images reveals that the adjacency effect seriously degrades the image quality. These results could provide the basis for modeling the multi-angle optical remote sensing imaging system and exploring the correction algorithm of the adjacency effect.