Focus Profile Modeling.

A focus profile depicts the image sharpness (or focus value) as the lens sweeps along the optical axis of a camera. Accurate modeling of the focus profile is important to many imaging tasks. In this paper, we present an approach to focus profile modeling that makes the search of in-focus lens position a mathematically tractable problem, and hereby improves the efficiency and accuracy of image acquisition. The proposed approach entails a transformation that converts the representation of a focus profile to quadratic form. An important feature of the approach is that no prior knowledge of the focus measurement technique is required. Experimental results are provided to demonstrate the effectiveness of the approach.