A method for generating all-in-focus images by integrating multiple differently focused images is described. First, based on the assumption that objects are defocused by a simple geometrical blurring model, we derive a formula between acquired images on certain imaging planes and spatial information of objects by using a convolution of a 3-D blur. Then, we analyze spatial frequency components of the blur kernel to obtain a 3-D filter that generates an all-in-focus image from the acquired images. Simulations of image generation are performed utilizing synthetic images to study how noise, object depths, and certain parameters of the blur and the filter affect the quality. We also introduce pre-processing that corrects the size of acquired images and a simple method for estimating the parameter of the 3-D blur. Finally, we show experimental results of all-in-focus image generation from real images.
