BraTrack - A Low-Cost Marker-based Optical Stereo Tracking System
Motivated mainly by the capilarity of VR/AR applications throughout medium and small modern companies in Brazil, the BraTrack Project was designed to fill the gap of most available low-cost solutions in marker-based optical tracking: suitability for professional applications due to the usual insufficience on accuracy, tracking range, or latency time. Demanded by the biggest VR/AR solutions‘ re-seller of the country and also supported by an oil company, BraTrack has the goal of achieving the actual local market growth, providing a competitive cost-benefit and being the first commercial tracking system developed in South America.
The projects' starting point was PTrack, an academic marker-based single-camera tracker developed at Fraunhofer IGD in cooperation with CETA SENAI, which showed that accurate optical tracking system can be built from components that are affordable for a much wider group of users, from the academic community to companies’ developers.
The BraTrack system can be used as one-camera tracking as well as in sets of pairs for room and desktop stereo tracking. In addition, it is designed to work with Track-d and OpenTracker interfaces; and performs a so-called pseudo motion tracking, which 3D positions of individual markers are sampled along time instances.
BraTrack has a modular architecture where each task is performed by a specific software or hardware component. The camera modules are hardware components consisting of off-the-shelf USB cameras and custom-made electronic boards, providing flash strobes that use a balanced number of highly efficient infrared LEDs.
Image acquisition by all cameras is synchronized by a software module, which manages circular buffers that store last captured frames together with respective timestamps in order to access most recent pair of frames with the same timestamp in every interaction.
A 2D pre-processing identifies visible markers in each camera. Just after, a 3D reconstruction module finds co-related markers visible in more than one camera and identifies calibrated artifacts using epipolar geometry. For that purpose, each artifact is tracked and identified with an ID, position, and orientation.
This project was developed under a research contract with the Brazilian company Absolut Technologies. Thanks are given to the project partners MAMS Tecnologia and UFRGS. The Project has been financially supported by FINEP - Brazilian Development Agency.
Prof. Dr-Ing. Carlos Eduardo Pereira
Márcio Soares Torres
CENTRO DE EXCELÊNCIA EM TECNOLOGIAS AVANÇADAS SENAI - CETA, AV. ASSIS
BRAZIL, 8450 91140000 PORTO ALEGRE/RS
Phone +55 51 33478414
Fax +55 51 33648605