128 Motion

Scene segmentation is best put as breaking down the scene you are looking at to see the different parts of it. Motion plays a crucial role in scene segmentation, encompassing motion parallax as a depth cue, motion for disrupting camouflage, and motion for capturing attention. Motion helps us pick out things in a scene that otherwise would blend in if it were still. Similarly, someone sitting across a room full of people would most likely blend in with everyone else in the room, but if they were the only ones waving at you, they would stand out.

The aperture problem refers to when the direction of motion of straight lines is ambiguous because you can’t see the ends or corners; in other words, if something (the aperture) is in the way of what we are viewing, it can distort the movement we are seeing by making it appear to be stagnant. Optic flow is motion that is coordinated across the entire scene and has a heading, or a point of convergence much like a car driving towards the horizon and looking increasingly smaller as it goes. Check out this cool site with moving examples of optic flow!

Visual area MT responds to local motion which is closest to us. MST is responsive to optic flow.