A stationary (not moving) camera is viewing a white triangle translating vertically as shown on a stationary grey background. Six image patches have been marked and labeled. For each patch, match its letter label to one of the categories below describing properties of the motion field and computed optic flow within the patch. Assume the displacement due to motion is smaller than the patch size (that is, if a patch contains an edge, it will continue to contain the same edge after the shift occurs). Descriptions 1. Motion field is zero and computed optic flow is zero. 2. Motion field is nonzero but computed optic flow is zero. 3. Motion field is nonzero and computed optic flow is nonzero, but computed flow vector is incorrect. 4. Motion field is nonzero and computed optic flow is correct. List the description number that best describes each of the following patches