Experiments in multiresolution motion estimation for multifrequency tagged cardiac MR images

In tagged magnetic resonance imaging of the human heart, different frequency patterns can be imposed and imaged as the heart moves. It is advantageous to use low-frequency patterns to improve both image acquisition time and the performance of gradient-based optical flow motion analysis methods. This paper explores the effects of three factors-image prefiltering, multiresolution optical flow, and multifrequency tag patterns through a serious of controlled simulation experiments. We show that use of image prefiltering in a multiresolution optical flow approach achieves significant performance gains, and permits a factor of four reduction in imaging time, without the need for multifrequency tag patterns.