Fast depth from defocus from focal stacks

We present a new depth from defocus method based on the assumption that a per pixel blur estimate (related with the circle of confusion), while ambiguous for a single image, behaves in a consistent way when applied over a focal stack of two or more images. This allows us to fit a simple analytical description of the circle of confusion to the different per pixel measures to obtain approximate depth values up to a scale. Our results are comparable to previous work while offering a faster and flexible pipeline.