Improving Shape-from-Focus by Compensating for Image Magnification Shift

Images taken with different focus settings are used in shape-from-focus to reconstruct the depth map of a scene. A problem when acquiring images with different focus settings is the shift of image features due to changes in magnification. This paper shows that those changes affect the shape-from-focus performance and that the final reconstruction can be improved by compensating for that shift. The proposed scheme takes into account the effects due to magnification changes between near and far focused images and it is able to determine the depth of the scene points with higher accuracy than traditional techniques. Experimental results of the application of the proposed method are shown.