Structure-from-motion by tracking occlusion boundaries

Active visual tracking of points on occlusion boundaries can simplify certain computations involved in determining scene structure and dynamics based on visual motion. The author describes two such simplifications, both involving the tracking of edge points corresponding to occlusion boundaries. The first technique determines local depth orderings by recognizing which side of a boundary corresponds to an occluding surface. The second technique is able to estimate the direction of observer motion in a simpler manner than most other, previously proposed approaches. The analysis is based on optical flow in the image near the tracked edge element