We propose a 2D microorganism tracking system using a parallel level set method and a column parallel vision system
(CPV). This system keeps a single microorganism in the middle of the visual field under a microscope by visual servoing
an automated stage. We propose a new energy function for the level set method. This function constrains an amount of
light intensity inside the detected object contour to control the number of the detected objects. This algorithm is
implemented in CPV system and computational time for each frame is 2 [ms], approximately. A tracking experiment for
about 25 s is demonstrated. Also we demonstrate a single paramecium can be kept tracking even if other paramecia
appear in the visual field and contact with the tracked paramecium.