I have had some success using pairs of webcams for stereo vision. More recently, I have tried using consumer 3D cameras for the same application, and I am having trouble with them.
It appears that the lenses are not exactly parallel and that they are "cross-eyed" enough that more-distant features sometimes have less disparity than closer features. In other words, the two views converge something in the middle distance has zero disparity.
This would seem to be an insurmountable problem. Are there any known-good ways to deal with it?