What does the Disparity Difference setting do in Semi-Global Matching? What is the effect of raising or lowering the Disparity Difference in Tridicon and XPro Semi-Global Matching (SGM)?
The Disparity Difference is a threshold for removing blunders when doing reverse matching. Left-Right matching is done first and then Right-Left matching is performed. The difference in pixels is the measure of disparity and this is given in pixels. The default value of 1 means a difference of 1 pixel is allowed. Increasing the disparity threshold to 2 or 3 means there will be more points but it also increases the likelihood of having suspect points. Decreasing the disparity threshold to 0 means no difference is allowed and it is harder to find matches (not recommended).