Design and implementation of fuzzy controllers for auto focus, auto exposure and zoom tracking

This paper proposes the fuzzy implementation for the lens focus, aperture and zoom control of a video camera. The spectrums of grabbed images are used to design the focus membership functions for the focus control. The gray level mean and standard deviations are used to design the aperture membership functions for the exposure control. The object sizes, moving velocities and contour confidences are used to design the zoom membership functions for zoom control. The linguistic rules are described in the form of IF⋯THEN⋯ as the fuzzy implication to associate the membership functions and the consequences of the optical settings. The Max-Min composition rule is utilized to determine the output inferences. The weighted-average defuzzification is adopted to determine the lens motor control signal. The experimental results demonstrate that the proposed fuzzy controllers successfully achieve the auto focus, auto exposure, and zoom control of a video camera.