An object tracking method tracks a target object between successively generated infrared video images using a grey-scale hat filter to extract the target object from the background. The filtered image is binarized, and candidate binary blobs are extracted. The binary blob that minimizes the Euclidian spatial distance to the previous position of the object and satisfies a specified appearance model is selected, and its center of mass is taken as the current position of the object. Where the object is a person's eye, the eye state and decision confidence are determined by analyzing the shape and appearance of the binary blob along with changes in its size and the previous eye state, and applying corresponding parameters to an eye state decision matrix.