Tracking colliding cells

The motion of leukocytes is significant in studying the inflammation response of the immune system. In inflammation conditions, some leukocytes slow down and eventually adhere to vessel walls. With many cells moving at a variety of speeds, collisions occur. These collisions result in abrupt changes in the motion and appearance of leukocytes. In this paper, we propose a novel method of tracking multiple cells undergoing collision by modeling the collision states of cells and testing multiple hypotheses of their motion and appearance. We demonstrate the results on in vivo intravital microscopy image sequences. The proposed method results in 20% more accurate cell position and 82% longer tracks than a previous approach.