Object tracking apparatus calculating tendency of color change in image data regions

An object tracking apparatus tracks an object on image data captured continuously. The object tracking apparatus includes an object color adjusting unit and a particle filter processing unit. The object color adjusting unit calculates tendency of color change in regions on image data and adjusts a color of the object set as an object color based on the tendency of color change to obtain a reference color. The particle filter processing unit estimates a region corresponding to the object on image data based on likelihood of each particle calculated by comparing a color around each particle with the reference color, using particles which move on image data according to a predefined rule.