The disparity dzx depends on the height to the object which
is of interest. Disparity dzy depends on camera alignment and
camera synchronization. In a calibrated system this disparity
should be zero, which means that the search area in the right
image can be limited. Disparity (dx,dy) is the measurement of
traveled distance.
Images with different heights in the same matching
window are expected in a field environment. Stereo matching
of a region will average the heights over that region. The
same region is then used for matching distance, as shown in
Fig. 4. This means that the height is the same for both
matches. Therefore is the distance traveled is height
independent.