Minimum Requirements for Taxicab Security Cameras ()
ABSTRACT
Problem: The homicide rate of taxicab-industry is 20 times greater than
that of all workers. A NIOSH study showed that cities with taxicab-security
cameras experienced significant reduction in taxicab driver homicides. Methods:
Minimum technical requirements and a standard test protocol for
taxicab-security cameras for effective taxicab-facial identification were determined.
The study took more than 10,000 photographs of human-face charts in a
simulated-taxicab with various photographic resolutions, dynamic ranges,
lens-distortions, and motion-blurs in various light and cab-seat conditions.
Thirteen volunteer photograph-evaluators evaluated these face photographs and
voted for the minimum technical requirements for taxicab-security cameras. Results:
Five worst-case scenario photographic image quality thresholds were suggested: the
resolution of XGA-format, highlight-dynamic-range of 1 EV,
twilight-dynamic-range of 3.3 EV, lens-distortion of 30%, and shutter-speed of
1/30 second. Practical
Applications: These minimum requirements will help taxicab regulators and
fleets to identify effective taxicab-security cameras, and help taxicabsecurity
camera manufacturers to improve the camera facial identification capability.
Share and Cite:
Zeng, S. , Amandus, H. , Amendola, A. , Newbraugh, B. , Cantis, D. and Weaver, D. (2014) Minimum Requirements for Taxicab Security Cameras.
Journal of Transportation Technologies,
4, 216-255. doi:
10.4236/jtts.2014.43022.