A periodic optical flow model for cardiac gated images

For the purpose of motion-compensated processing we propose a temporal modeling approach for determining the image motion in a gated cardiac sequence, wherein the inherent image motion is periodic over time. To exploit the periodic nature of the cardiac motion, we use a Fourier harmonic representation to describe the motion field for the entire sequence. We then determine the motion field by estimating the parameters of this representation model. This joint estimation approach can take advantage of the statistics of all the available image data in the sequence. In the experiments, we applied the proposed approach to motioncompensated 4D reconstruction of gated cardiac SPECT images. Our results demonstrate that it could achieve robust estimation of the motion field and lead to improved image reconstruction despite the presence of strong imaging noise.