Humans view the world in three dimensions using their two eyes. Robots can do the same when they are equipped with two cameras. This is called stereovision. A stereo rig is a pair of cameras mounted on a device, looking at the same scene and separated by a fixed baseline (distance between the two cameras). This recipe will show you how a depth map can be computed from two stereo images by computing dense correspondence between the two views.
A stereovision system is generally made of two side-by-side cameras looking at the same direction. The following figure illustrates such a stereo system in a perfectly aligned configuration:
Under this ideal configuration the cameras are only separated by a horizontal translation and therefore all epipolar lines are horizontal. This means that corresponding points have the same y coordinates, which reduces the search for matches to a 1D line. The difference in their x coordinates depends on the depth of...