Minimum Requirements for Taxicab Security Cameras.

Shengke Zeng,Douglas M Cantis,Harlan E Amandus,Darlene Weaver,Bradley H Newbraugh,Alfred A Amendola

doi:10.4236/jtts.2014.43022

Abstract

ProblemThe 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.MethodsMinimum 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.ResultsFive 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 ApplicationsThese 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.

Highlights

Workplace violence has consistently been a leading cause of workplace fatalities and injuries since national oc-How to cite this paper: Zeng, S., Amandus, H.E., Amendola, A.A., Newbraugh, B.H., Cantis, D.M. and Weaver, D. (2014) Minimum Requirements for Taxicab Security Cameras
The findings from this study showed that the cities with taxicab security cameras experienced a threefold reduction in taxicab driver homicides compared with control cities
To comprehensively assess a taxicab security camera’s photographic quality, this study proposed five photographic-image quality metrics to evaluate an in-cab face photograph taken by the camera: 1) photographic resolution, 2) highlight dynamic range, 3) shadow dynamic range, 4) lens distortion, and 5) motion blur

Summary

Introduction

Workplace violence has consistently been a leading cause of workplace fatalities and injuries since national oc-How to cite this paper: Zeng, S., Amandus, H.E., Amendola, A.A., Newbraugh, B.H., Cantis, D.M. and Weaver, D. (2014) Minimum Requirements for Taxicab Security Cameras. Workplace violence has consistently been a leading cause of workplace fatalities and injuries since national oc-. The latest preliminary data available from the Bureau of Labor Statistics reveals that in 2011 there were 458 homicides, making homicides the fourth leading cause of work-related fatalities [2]. Within the transportation industry, were more likely to be victims of homicide than workers of any industry (7.4 per 100,000 workers), 20 times greater than that of all workers (0.37 per 100,000 workers) [4]. The epidemiology of safety risks for taxicab drivers is incomplete and scattered; the subject is discussed briefly in several summary research articles [5]-[10]. Because available literature focusing on the epidemiology of workplace violence among taxicab drivers is limited; very little is known conclusively about workplace violence risk factors in this industry

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