title: Minimum Requirements for Taxicab Security Cameras.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  These minimum requirements will help taxicab regulators and fleets to identify effective taxicab-security cameras, and help taxicab-security camera manufacturers to improve the camera facial identification capability.
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA.
authors.forename: Shengke
authors.initials: S
authors.lastname: Zeng
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA.
authors.forename: Harlan E
authors.initials: HE
authors.lastname: Amandus
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA.
authors.forename: Alfred A
authors.initials: AA
authors.lastname: Amendola
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA.
authors.forename: Bradley H
authors.initials: BH
authors.lastname: Newbraugh
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA.
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Cantis
authors.affiliation: Division of Safety Research, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA.
authors.forename: Darlene
authors.initials: D
authors.lastname: Weaver
keywords: Dynamic Range; Facial Identification; Lens Distortion; Motion Blur; Photographic Resolution; Taxicab Homicide
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