Depth from defocus by changing camera aperture: a spatial domain approach

The application of a new spatial-domain convolution/deconvolution transform (S transform) for determining the distance of objects using image defocus is described. The method, known as STMAP, involves simple local operations on only two images taken with different aperture diameters and can be easily implemented in parallel. Both images can be arbitrarily blurred, and neither of them needs to be a focused image taken with a pin-hole camera. STMAP is implemented on an actual camera system named the Stonybrook Passive Autofocusing and Ranging Camera System (SPARCS). Experimental results on real-world planar objects are presented. The results indicate that STMAP is useful in practical applications. The utility of the method is demonstrated for rapid autofocusing of electronic cameras. STMAP is computationally more efficient than other depth-from-focus methods. The results are comparable to a Fourier-transform-based approach