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International Journal of Reconfigurable Computing
Volume 2012, Article ID 148190, 16 pages
http://dx.doi.org/10.1155/2012/148190
Research Article

An FPGA-Based Omnidirectional Vision Sensor for Motion Detection on Mobile Robots

1Faculty of Technology, University of Brasilia, 70910-900 Brasilia, DF, Brazil
2Faculty of Gama, University of Brasilia, 72405-610 Brasilia, DF, Brazil

Received 20 February 2012; Accepted 4 April 2012

Academic Editor: Alisson Brito

Copyright © 2012 Jones Y. Mori et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This work presents the development of an integrated hardware/software sensor system for moving object detection and distance calculation, based on background subtraction algorithm. The sensor comprises a catadioptric system composed by a camera and a convex mirror that reflects the environment to the camera from all directions, obtaining a panoramic view. The sensor is used as an omnidirectional vision system, allowing for localization and navigation tasks of mobile robots. Several image processing operations such as filtering, segmentation and morphology have been included in the processing architecture. For achieving distance measurement, an algorithm to determine the center of mass of a detected object was implemented. The overall architecture has been mapped onto a commercial low-cost FPGA device, using a hardware/software co-design approach, which comprises a Nios II embedded microprocessor and specific image processing blocks, which have been implemented in hardware. The background subtraction algorithm was also used to calibrate the system, allowing for accurate results. Synthesis results show that the system can achieve a throughput of 26.6 processed frames per second and the performance analysis pointed out that the overall architecture achieves a speedup factor of 13.78 in comparison with a PC-based solution running on the real-time operating system xPC Target.