Bandpass optical flow for tagged MRI

MR tagging has shown gnat promise for detailed noninvasive cardiac motion i maging. Our research uses Low-frequency tags coupled with gradient-based op tical flow estimation to compute cardiac motion. We develop here a novel, f ast, fully automated optical flow method for tagged MRI by exploiting the F ourier content of the tagged images. This new method, called bandpass optic al Bowl works by extracting various subband images from tagged cardiac data , and then formulating multiple optical flow constraints for each subband. The resulting system is solved by least squares pseudo-inversion. The propo sed method is validated on simulated and real tagged data. (C) 2000 America n Institute of physics.