A new auto-focus method based on focal window searching and tracking approach for digital camera

This paper presents a new method for auto-focus digital camera system. Our approach differs from other common auto-focus approaches, since a focal window will be searched and tracked before applying auto-focus algorithm to move the lens toward the proper position. The advantages are increasing the focus reliability and flexibility than common auto-focus approaches. Our approach consists of two major stages, motion detection and focal window searching and tracking. Motion detection firstly detects the region-of-interest (ROI) in image, then focal window searching and tracking stage selects a proper focal window among detected ROIs, and tracks this window through the consecutive image. The performance is tested by a high motion and a low motion sequences. Focus values derived from the selected focal window are shown to demonstrate that our algorithm can achieve auto-focus in both high motion and low motion conditions.