Patent ID: 8233075

Claim:
A method for adjusting a video imaging system that includes an auto-focus mechanism, the method comprising: receiving an invoking input from a user of the video imaging system and invoking an auto-focus procedure, which is a procedure of adjusting a focal distance by scanning the auto-focus mechanism; after receiving the invoking input, adjusting the focal distance from a first focal distance to a second focal distance by scanning the auto-focus mechanism in a first direction from a first position of the auto-focus mechanism corresponding to the first focal distance to a second position of the auto-focus mechanism corresponding to the second focal distance; capturing a first sequence of images while scanning the auto-focus mechanism in the first direction; processing the images in the first sequence so as to compute a measure of focal quality with respect to each of the images in the first sequence; setting an optical focusing threshold value based on the computed measures of focal quality; after scanning the auto-focus mechanism in the first direction, reversing the scanning direction and adjusting the focal distance from the second focal distance toward the first focal distance by scanning the auto-focus mechanism in a second direction; capturing a second sequence of images while scanning in the second direction; processing the images in the second sequence so as to compute a measure of focal quality with respect to each of the images in the second sequence; and when the measure of focal quality which is computed from the images in the second sequence surpasses the threshold, terminating scanning in the second direction and setting, as an optimal focus position, a point at which the measure surpasses the threshold, wherein the act of invoking the auto-focus procedure comprises sensing a manipulation of a user control, wherein the method further comprises sensing an end to the manipulation of the user control, and, afterward, deciding whether to change a direction of the scanning based at least in part on the act of sensing the end to the manipulation of the user control.