Fluid motion estimation method based on physical properties of waves

This paper presents a fluid flow estimation method for ocean/river waves, clouds, and smoke based on the physical properties of waves. Most of the previous optical flow methods based on fluid dynamics/mechanics estimate a smooth flow using a continuity equation and/or div-curl velocity constraint. However, abrupt or inhomogeneous image motion changes in such fluid-like images are not estimated well. In this paper, we assume that many fluid-like motion changes are due to wave phenomena that lead to a brightness change. Thus, a wave generation equation is applied with a two-step optimization. A novel constraint based on the velocity-frequency relationship equation and a wave statistical property are used. The results of experiments on synthetic and real image sequences show the validity of our method.