Computing and Using
Inspection-oriented VCRs

As an example, consider inspection of an object by a stereo head. We define the head position as the midpoint of the line connecting the optical centres of the cameras.

The stereo visibility algorithm takes as input a portion of the property sphere describing a visibility region (of a feature or set thereof), in which every viewpoint is weighted by an optimality coefficient encoding both visibility and reliability of inspection (notice that such a region may not be maximally connected).

The output of the algorithm is an ordered list of head positions ( c1 ,.....,ck ), ci = ( Vil , Vir ) , where ( Vil , Vir ) , are the viewpoints of the left and right cameras. The global complexity of the stereo positioning algorithm is R(O (F) + O(RC)) = O(RF) + O(R2 C), where R is the number of viewpoints in the visibility region, C is the number of viewpoints at a fixed distance from a given one (a function of the dome's resolution), and F is the number of viewpoints on the geodesic dome. If O(F) < O(RC), the complexity becomes O(R2 C). Figure 15, below, shows (shaded) the optimum position for a stereo head of baseline 400mm to inspect the planar face on the bottom side of the object, nearest the viewer, having the inverted `V' bounding contour. The focal length of the cameras was 20mm, the dome radius 1376mm. The stand is about 16cm tall. This solution was found in about two seconds.

Example of stereo head positioning
Figure 15: Example of stereo head positioning


[ Computing and using inspection-oriented VCRs | Path planning ]

Comments to: Sarah Price at ICBL.