Real-time and low latency embedded computer vision hardware based on a combination of FPGA and mobile CPU

Recent developments in smartphones create an ideal platform for robotics and computer vision applications: they are small, powerful, embedded devices with low-power mobile CPUs. However, though the computational power of smartphones has increased substantially in recent years, they are still not capable of performing intense computer vision tasks in real time, at high frame rates and low latency. We present a combination of FPGA and mobile CPU to overcome the computational and latency limitations of mobile CPUs alone. With the FPGA as an additional layer between the image sensor and CPU, the system is capable of accelerating computer vision algorithms to real-time performance. Low latency calculation allows for direct usage within control loops of mobile robots. A stereo camera setup with disparity estimation based on the semi global matching algorithm is implemented as an accelerated example application. The system calculates dense disparity images with 752×480 pixels resolution at 60 frames per second. The overall latency of the disparity estimation is less than 2 milliseconds. The system is suitable for any mobile robot application due to its light weight and low power consumption.

[1]  Marc Pollefeys,et al.  Vision-based autonomous mapping and exploration using a quadrotor MAV , 2012, 2012 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[2]  Hideaki Murayama,et al.  Design of a miniature, multi-directional optical flow sensor for Micro Aerial Vehicles , 2011, 2011 IEEE International Conference on Robotics and Automation.

[3]  Jean-Yves Bouguet,et al.  Camera calibration toolbox for matlab , 2001 .

[4]  Uwe Franke,et al.  Dense, Robust, and Accurate Motion Field Estimation from Stereo Image Sequences in Real-Time , 2010, ECCV.

[5]  Markus H. Gross,et al.  An FPGA-based processing pipeline for high-definition stereo video , 2011, EURASIP J. Image Video Process..

[6]  Russ Tedrake,et al.  Flying between obstacles with an autonomous knife-edge maneuver , 2014, 2014 IEEE International Conference on Robotics and Automation (ICRA).

[7]  Jae Wook Jeon,et al.  FPGA Design and Implementation of a Real-Time Stereo Vision System , 2010, IEEE Transactions on Circuits and Systems for Video Technology.

[8]  Dean Brown,et al.  Decentering distortion of lenses , 1966 .

[9]  Marc Pollefeys,et al.  Real-time velocity estimation based on optical flow and disparity matching , 2012, 2012 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[10]  Heiko Hirschmüller,et al.  Stereo vision and IMU based real-time ego-motion and depth image computation on a handheld device , 2013, 2013 IEEE International Conference on Robotics and Automation.

[11]  Peter Pirsch,et al.  Real-time stereo vision system using semi-global matching disparity estimation: Architecture and FPGA-implementation , 2010, 2010 International Conference on Embedded Computer Systems: Architectures, Modeling and Simulation.

[12]  Stefan K. Gehrig,et al.  A Real-Time Low-Power Stereo Vision Engine Using Semi-Global Matching , 2009, ICVS.

[13]  Ramin Zabih,et al.  Non-parametric Local Transforms for Computing Visual Correspondence , 1994, ECCV.

[14]  H. Hirschmüller Accurate and Efficient Stereo Processing by Semi-Global Matching and Mutual Information , 2005, CVPR.