A new approach to analysing texture-defined motion

It has been widely accepted that standard low-level computational approaches to motion processing cannot extract texture-defined motion without applying some pre-processing nonlinearity. This has motivated accounts of motion perception in which luminance- and texture-defined motion are processed by separate mechanisms. Here, we introduce a novel method of image description where motion sequences may be described in terms of their local spatial and temporal gradients. This allows us to assess the local velocity information available to standard low-level motion mechanisms. Our analysis of several texture - motion stimuli shows that the information indicating correct texture - motion velocity and/or direction is present in the raw luminance measures. This raises the possibility that luminance - motion and texture - motion may be processed by the same cortical mechanisms. Our analysis offers a way of looking at texture - motion processing that is, to our knowledge, new and original.