|
Sun glint, the specular reflection of light from water surfaces, is a serious confounding factor for remote sensing of bathymetric measurements and benthic habitat mapping. In remote sensing of water color and water temperature, image saturation is one of the main noises of water color satellite images due to the influence of solar reflection. Therefore, sun glint correction is an important part of marine satellite image preprocessing. The existing high resolution satellite image flare elimination algorithm exploit the high absorption of water at NIR wavelengths and the consequence that the water-leaving radiance for these bands can be assumed negligible. Since the Fresnel reflectance of water is only weakly dependent on wavelength the strengths of the glint signal at visible and NIR wavelengths will vary in the same way, so the NIR signal can be used to indicate the amount of glint at visible wavelengths. In this paper, the WorldView-2 satellite 8 band remote sensing image is selected as the research area in the South China Sea region. The effects and differences of four kinds of solar flare elimination algorithms are compared. The main research contents and conclusions are as follows: firstly, four kinds of lighting elimination algorithms are introduced, including the method of: (1) Hedley et al.; (2) Lyzenga et al. (3) fixed coefficient; (4) coordinate axis rotation. Then, the radiometric calibration of the satellite images in the study area is carried out, and different algorithms are used to correct the solar flare. Finally, the results of the algorithms are compared and analyzed. The results show that the four lighting elimination algorithms have good visual effects. The bright spots in the original image decrease with the wave fluctuation, and the texture features that are originally covered under water can be revealed. In addition, the radiance value curve before and after the solar flare correction is analyzed. It is found that the values of each wave band after correction are basically reduced, the overall fluctuation of the curve is reduced, and the high frequency change decreases. Compared with other methods, the method of coordinate axis rotation has the best correction effect.
|
