Wavelet-based coding of time-varying vector fields of ocean-surface winds

Geoscience applications often produce sizable datasets that are vector-valued and increasingly in need of compression algorithms to reduce storage and transmission burdens, particularly when the data are time-varying. In this paper, several advanced interframe-compression techniques are extended from the traditional realm of natural video to the coding of time-varying vector fields. Although similar to natural video in some respects, time-varying vector-field sequences often possess complex temporal evolution of vector-valued features that are important to the analytic quality of the data yet defy the simple motion models widely employed for natural video. To improve coding performance, motion compensation with reduced resolution is proposed such that motion compensation is applied only at low spatial resolution, while high-resolution information, for which the motion model fails, is intraframe coded with no temporal decorrelation. In empirical results on datasets of ocean-surface winds, this reduced-resolution motion-compensation technique results in significant performance improvement and greater feature preservation.