3D shape estimation and texture generation using texture foreshortening cues

The surfaces of 3D objects may be represented as a connected distribution of surface patches that point in various directions with respect to the observer. Viewpoint-normal patches are those whose tangent plane is perpendicular to the line of sight. Foreshortening of surface patches results from their obliquity, with a directional wavelength compression, and an accompanying 1-dimensional stretching of the spatial frequency distribution. This stretching of spatial frequency distributions was used to generate plausible depth illusions via local foreshortening of surface textures rendered from a stretched spatial frequency envelope. Texture foreshortening cues were exploited by a multi-stage image analysis method that revealed local dominant orientation, degree of orientation dominance, relative power in spatial frequencies at a given orientation, and a measure of local surface obliquity, which provides incomplete but useful information in a multi-cue depth estimation framework.