Local Image Features Resulting from 3-Dimensional Geometric Features, Illumination, and Movement: II

This is the second part of an investigation into the visual clues in illuminated scenes, in terms of the interactions between apparent contours, shade and cast shadow curves, boundary edges and markings, on smooth surfaces, pairs of surfaces meeting in a crease, and triples of surfaces meeting in a corner. We consider both ‘stable’ and ‘codimension 1’ cases, the latter meaning that we list events which occur in a generic ‘flypast’ of the scene. We assume there is a single principal source of light. The first part of this work is [DGH1]; in this second part we give details of the cases which involve creases and corners, and the ‘multilocal’ cases where two surfaces separated in space interact via occlusion or cast shadows. We also give some details of the mathematical background to our work; the full mathematical treatment will appear in [DGH].