Accurate Analysis of the Spatial Pattern of Reflected Light and Surface Orientations Based on Color Illumination

Abstract

3D recovery approaches require a variety of clues to obtain shape information. The shape from shading (SFS) method uses shading variations in images to estimate depth maps. Although shading contains detailed information, it causes some well-known ambiguities such as convex-concave ambiguity. In this study, a system installation using red, green, and blue illumination and an algorithm processing reflections on the surface were proposed to accurately analyze surface orientations and solve ambiguity problems. The algorithm evaluated combinations of light hitting the surface from different directions and detailed surface orientations to avoid erroneous predictions. The proposed system was tested with eight different methods in the literature developed from the earliest times to the present, and the initially erroneously predicted surface orientations were improved. Consequently, the correct orientation of the surface points was determined by removing the ambiguities in images taken without considering the location of illumination, and all the tested methods provided successful results using the proposed system.