In some applications such as construction planning and land surveying, an accurate digital terrain model (DTM) is essential. However, in urban and sub-urban areas, the terrain may be covered by trees and man-made structures. Although digital surface model (DSM) obtained by radar or LiDAR can provide a general idea of the terrain, the presence of trees, buildings, etc. conceals the actual terrain elevation. Normally, the process of extracting DTM involves a land cover classification followed by a trimming step that removes the elevation due to trees and buildings. In this chapter, we assume the land cover types have been classified and we focus on the use of image inpainting algorithms for DTM generation. That is, for buildings and trees, we remove those pixels from the DSM and then apply inpainting techniques to reconstruct the terrain pixels in those areas. A dataset with DSM and hyperspectral data near the U. Houston area was used in our study. The DTM from United States Geological Survey (USGS) was used as the ground truth. Objective evaluation results indicate that some inpainting methods perform better than others.
Part of the book: Recent Advances in Image Restoration with Applications to Real World Problems