All in focus camera vision system for robot navigation and manipulation based on the DFF criteria

A method to improve the resolution in depth by applying the depth from focus (DFF) criteria is proposed. The depth from focus is a criteria used to get simultaneously both the all-in-focus image and three-dimensional information with a single camera. But in these criteria there is a well-known drawback; the resolution is good only at short distances. Here, the optical characteristic that describes the limitation of the measurement range is analyzed. Then, a better criterion to improve the resolution in the depth is proposed by considering the "best focal distance". In order to use this new method, it is necessary to modify the focal distance (zoom) in the camera. Then, an accurate control of the camera should be done to acquire a good view of the desired target and later by, applying the depth from focus criteria together with the best focal distance, being able to obtain good depth (three-dimensional) information