Optic flow is processed in MST is used for navigation, orientation, and interaction with the physical world. It has been previously hypothesized that the human visual system would decompose optic flow into four independent motion types--translation, expansion, rotation, and deformation. Taking a parametric approach to optic flow to the problem we test to see how well humans can estimate the parameters of opt the motion types. Furthermore, we investigated whether humans can decompose the parameters when more than one motion type is present. Finally, we modeled the results for expansion rate estimation and parametric decomposition. Results and model simulations suggest that deformation isn't a principal motion type, however, there is evidence that shear is a principal component. |