We investigate an original method to compute the optical flow on image sequences. Instead of assuming invariance principles applied to individual pixels, this method considers objects as a whole, by constraining their total intensity during their motion. A variational implementation of this method has already been studied. We propose here a parametric implementation of this method using an affine prior model. A combined method between the variational method and the affine method is proposed in order to capture both affine components and non-affine components. Results on meteorological infrared data are presented.