Frame recovery using multiple images in rolling shutter based systems

Abstract

An algorithm for recovering transmitted static identifiers (IDs) in rolling shutter based Optical Camera Communication systems is proposed by the authors, considering a system comprised of a camera and a circular light source. The goal is to allow the correct decoding when the ID frame is only partially detected in the image. A baseline algorithm as reference for the frame recovery success rate (FRSR) and a reconstruction algorithm based on the idea of capturing multiple frame fragments and reassembling them is proposed in order to recover the transmitted ID not entirely seen on a single image. It was proven, by simulation, that the maximum distance at which the IDs recovery can be guaranteed is increased by 2.5 fold with the proposed algorithm, for 6-bit, 8-bit and 10-bit codewords. An experimental validation algorithm was also proposed, using image processing techniques to extract the bitstreams and test the ID recovery process. The proposed algorithm improves the FRSR for a given distance, even in the presence of considerable bit errors in the bitstreams extracted from the images.