Automated rotation rate tracking of pigmented cells by a customized block-matching algorithm

Abstract

This article describes an automated rotation rate tracking algorithm for pigmented cells that undergo rotation in a dielectrophoretic (DEP) force field. In a completely automated process, we preprocess each frame of a video sequence, then analyze the sequence frame by frame using a rotating-circle template with a block-matching algorithm, and finally estimate the rotation rate of the pigmented cells using a pixel-patch correlation. The algorithm has been demonstrated to accurately calculate the DEP-induced rotation rate of the cell up to 250 rpm. Cell rotation rates in various DEP force fields (i.e., by varying the applied voltages, frequencies, and waveforms to induce different force fields) were analyzed using this automated algorithm and reported in this article. Most importantly, the algorithm is accurate even when the cells have simultaneous translational and rotational motions across the video image sequence. Also, the algorithm is capable of tracking changes in rotation speed over a long period of time (90 s) by stably analyzing a massive data set of video image frames. © 2012 Society for Laboratory Automation and Screening.