This paper describes a variational approach for estimating a discontinuous
optical flow from a sequence of images. Defined as the apparent motion of t
he image brightness pattern, the optical flow is very important in the comp
uter vision community, where its accurate estimation is strongly needed. Af
ter a short overview of existing methods, we present a new variational meth
od that we study in the space of bounded variations. We first present an in
tegral representation of the optical flow problem which appears to be not l
ower semicontinuous. The relaxed functional is then calculated. We conclude
by challenging questions about the possible numerical analysis of the abst
ract results.