Evaluation of Topographic Correction Effects for Landsat-5 Thematic Mapper Images with Complex Lighting Conditions

A number of methods are available for topographic correction of remote sensing data, and various approaches have been proposed for the evaluation of topographic correction effects. However, few studies have evaluated the topographic correction effects for images obtained under all possible sun elevation conditions. This study employed three correction methods, namely, Statistical-Empirical (SE), C-correction (C), and the Sun-Canopy-Sensor + C-correction (SCS + C) methods. These were used for topographic correction of 11 images obtained by the Landsat-5 Thematic Mapper sensor from June to December. An evaluation of the effectiveness of these three methods was carried out based on five evaluation indices, with the goal of investigating the variation in the topographic correction effect with changes in lighting conditions and the adaptability of topographic correction methods to those conditions. The results showed that the SE method effectively reduced the dependence of surface reflectance on the terrain when the solar elevation was greater than 46 degrees, yielding a very stable surface reflectance and a low proportion of outliers. At sun elevation below 46 degrees, the SCS + C method has good correction effect. After topographic correction using these three methods, the correction effect was compromised as the lighting conditions weakened. Within areas where the topographic and geographical conditions are similar to that of this study, the correction effect can be divided into three levels based on the solar elevation while obtaining the images, i.e., > 60 degrees, 50-60 degrees and < 50 degrees. Caution should be taken when conducting quantitative research on images obtained when the solar elevation is < 50 degrees.

Automated summary

This study evaluated the effectiveness of three different topographic correction methods for images obtained by Landsat-5 Thematic Mapper sensor. The results showed that the SE method was effective in reducing dependence on terrain when solar elevation was above 46 degrees, while the SCS + C method was effective when solar elevation was below 46 degrees. However, caution should be taken when conducting quantitative research on images obtained under low solar elevation conditions.