<title>Point-constrained optical flow for LV motion detection</title>

Abstract

In this paper, we propose a new method for left ventricle (LV) motion estimation. The method is based on a point-constrained optical flow algorithm for heart motion estimation. The constrained points are the corresponding point pairs in subsequent images. The motion estimation of these characteristic points can be obtained using techniques such as shape-based tracking of perceptually salient points on the LV boundary. Knowing the motion of characteristic points the proposed algorithm is used to estimate motion at other image points. Using this approach the result of the optical flow algorithm is constrained by displacement of characteristic LV boundary points. The constraints are implemented by setting the values of the optical flow of characteristic points to certain fixed values. The spatial and temporal continuity functionals are specified so that the fixed values influence their neighborhoods and the optical flow field is interpolated between the constrained points. The experiments have been performed using ECG-gated MR images of the beating heart. The method has been applied to the image sequence and estimation of the motion field has been computed.