Patent ID: 9106823
Filing Date: 2015-08-11
Classification: G02B,H04N

Abstract:
1. An autofocus device comprising: a lens drive system for translating a lens; an imager for capturing an image through the lens; a contrast detector for detecting a contrast of an image captured by the imager; a first peak detector for detecting a first contrast peak of images captured at different lens positions as the lens is translated in a forward direction; a second peak detector for detecting a second contrast peak of images captured at different lens position as the lens is translated in a backward direction, the second peak detector operating after the first contrast peak is detected; and a backlash detector for detecting a backlash in the lens drive system according to the positions of the first contrast peak and the second contrast peak; wherein the lens is moved from an exceeding position to an in-focus position according to the previously detected backlash, the exceeding position is a position at which the first contrast peak is detected when the lens is translated in the forward direction.