For 3D measurements, Vision computes error (ep) for a given pixel (p) according to the following equation:

e p = 1 2 f T x c x - c ' x - d - 1 - f T x c x - c ' x - d + 1

This equation computes and averages the interval between the depth achieved from the previous disparity and the depth achieved from the next disparity. Consequently, distant objects produce larger errors than near objects.