Video-rate calculation of depth from defocus on a FPGA

Abstract

Depth from defocus is a ranging method that provides depth estimation at every pixel in an image. It uses a pair of defocused images from a conventional monocular camera. To enable video-rate processing, which is important for industrial applications, an established algorithm was implemented on a field programmable gate array (FPGA). A bifurcating pipeline of 2-D filters provided the depth calculation. Multiplier and SRAM facilities on the FPGA were utilised efficiently by exploiting the filter symmetry. The coefficient and data bit-widths were limited to improve efficiency. The results compared favourably with the full width calculation. Range images were processed within 14 ms.