JuanMotion Estimation using Ordinal
نویسندگان
چکیده
We present a method for motion estimation using ordinal measures. Ordinal measures are based on relative ordering of intensity values in a image region called rank permutation. While popular measures like the sum-of-squared-diierence (SSD) and normalized correlation (NCC) rely on linearity between corresponding intensity values, ordinal measures only require them to be monon-tonically related so that rank permutations between corresponding regions are preserved. This property turns out to be very useful for motion estimation in tagged Magnetic Resonance Images. We study the imaging equation involved in two methods of tagging and observe temporal monotonicity in intensity under certain conditions though the tags themselves fade. We compare our method to SSD and NCC in a simulated rotating ring phantom image sequence. We discuss computational issues and present an experiment on a real heart image sequence, which suggests the suitability of our method.
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تاریخ انتشار 1997