Fast Multi-Focus Image Fusion Using Inner Channel Prior

In this paper, we propose a simple but effective sharpness prior—inner channel prior—to detect the focused area of multi-focus images. The inner channel prior is a kind of location feature of natural image sharpness. It is based on a key observation—the high-frequency information of the saturation channel is located inside the object. The inner channel prior indicates the focus degree inside objects, which can obtain better color fidelity and sharper object. Using the proposed prior combined with the multi-scale image fusion, we can directly obtain a sharp image with an extended depth of field focusing on all the objects. Results on a variety of defocused image sequences demonstrate the availability of the proposed prior. In addition, the proposed prior is insensitive to overexposure and can better maintain the color of multi-focus images.