Effective autofocus decision using reciprocal focus profile

In this paper, we propose a new autofocus approach that transforms the focus profile to the reciprocal domain. A key feature of this approach is that it makes the autofocus process mathematically tractable in both in-focus and out-of- focus regions, thereby allowing a digital camera or camcorder to expedite the search of the best lens position for capturing the image that has the maximum focus value. Experimental results are provided to illustrate the advantage of the proposed approach.