A unified account of three apparent motion illusions.

We discuss three motion illusions, the fluted square wave illusion, the reverse phi illusion and the Pantle illusion. In these illusions reversed apparent motion is either induced or eliminated by the introduction of a blank inter-frame-interval between the frames of the apparent motion sequence. In order to simulate these effects with the multi-channel gradient model we had to introduce low-pass spatial filters and second-order temporal differentiating filters. These illusions have been used as evidence of multiple motion mechanisms. Here we demonstrate that they can be considered as emergent properties of a single computational strategy.