Adaptive deformation correction of depth from defocus for object reconstruction

The accuracy of three-dimensional object reconstruction using depth from defocus (DfD) can be severely reduced by elliptical lens deformation. This paper presents two correction methods, correction by deformation cancellation (CDC) and correction by least squares fit (CLSF). CDC works by subtracting the current deformed depth value by a prestored deformed value, and CLSF by mapping the deformed values to the expected values. Each method is followed by a smoothing algorithm to address the low-texture problem of DfD. Experiments using four DfD methods on real images show that the proposed methods effectively and efficiently eliminate the deformation. (C) 2014 Optical Society of America