In contrast, we are inspired by the Eulerian perspective, where
properties of a voxel of fluid, such as pressure and velocity, evolve
over time. In our case, we study and amplify the variation of pixel
values over time, in a spatially-multiscale manner. In our Eulerian
approach to motion magnification, we do not explicitly estimate
motion, but rather exaggerate motion by amplifying temporal color
changes at fixed positions. We rely on the same differential approximations
that form the basis of optical flow algorithms [Lucas and
Kanade 1981; Horn and Schunck 1981]