Stability of Phase Information

This paper concerns the robustness of local phase information for measuring image velocity and binoc ular disparity It addresses the dependence of phase behaviour on the initial lters as well as the image variations that exist between di erent views of a d scene We are particularly interested in the stabil ity of phase with respect to geometric deformations and its linearity as a function of spatial position These properties are important to the use of phase information and are shown to depend on the form of the lters as well as their frequency bandwidths Phase instabilities are also discussed using the model of phase singularities described by Jepson and Fleet In addition to phase based methods these results are directly relevant to di erential optical ow methods and zero crossing tracking