Transcript [Atsuyuki Harada]

THE CYBER-PHYSICAL BIKE:
A STEP TOWARDS SAFER GREEN TRANSPORTATION
S. Smaldone
C. Tonde
V. K. Ananthanarayanan
A. Elgammal
L. Iftode
Summarized by Yuki
Outline
• Analysis
• Design
• Implementation
• Evaluation
• Conclusion
Analysis
• Problem
• A biker must spend cognitive and physical ability to periodically
scan for a rear-approaching vehicle. As a result, the biker can not
maintain continual awareness for the forward situation.
• Solution
• The Cyber-Physical bicycle system continuously monitors the
environment behind the biker, automatically detects rearapproaching vehicles, and alerts the biker prior to the approach.
Design
• Roadway segmentation analysis using optical flow
• Reduces computational load
Design
• Vehicle tracking
• Determines if each vehicle passes the biker in either a safe or
unsafe manner
Implementation
• Development environment
• C/C++
• NVIDIA CUDA library (v2.3)
• Open source optical flow library[1]
• Bike computer - HP Mini 311 notebook
• Intel Atom N280 1.67 GHz CPU
• 3 GB RAM
• NVIDIA ION GPU (16 CUDA cores and 256 MB memory)
• 80 GB SSD hard disk
• 3.26 pounds / 1.48 kilograms (the worst case with peripherals)
1. WERLBERGER, M., TROBIN, W., POCK, T., WEDEL, A., CREMERS, D., AND BISCHOF, H. Anisotropic Huber-L1 optical flow. In BMVC’09 (London, UK, 2009).
Implementation (cont.)
• Rear-facing video camera - Sony DCR-SX40
• Over 3 hours of video recordings of real-world roadway cycling
traces (repeatability of experiment)
• Every interaction between the biker and a vehicle (approaching
and departing) are manually annotated using the timestamps
• Ordinary road bicycle - Trek FX7.5
Evaluation
• How accurate are video-based techniques in detecting
rear-approaching vehicles?
Accuracy = TP / (TP + FP + FN) = 19 / (19 + 6 + 1) = 73.1%
A vehicle hidden by another biker
A sudden vibration caused by uneven roadway
Evaluation (cont.)
• Can detection be performed timely?
• Alerting to occur an average of 3.5 seconds prior to a vehicle
encounter at reduced frame rates (3 FPS)
• 3.5 seconds is 92% of the potential time (the difference between
the first appearance of the vehicle and the time it passes the
cyclist)
Conclusion
• The Cyber-Physical bicycle is a system that augments
normal bicycles with video processing capabilities
for automated rear-approaching vehicle detection.
• This system directly improves the safety of bikers by
reducing their cognitive overheads of continuously
probing for rear-approaching vehicles.
• The prototype can perform rear-vehicle detection with
good accuracy at full frame rates (30 FPS), and can
operate in real-time at reduced frame rates (3 FPS).