to catch a thief -- you need at least 8 frames per second: the impact of frame rates on user performance in a CCTV detection task

ABSTRACT

The new generation of digital CCTV systems can be tailored to serve a wide range of security requirements. However, many digital CCTV systems produce video which is insufficient in video quality to support specific security tasks, such as crime detection. We report a study investigating the impact of lowering frame rates on an observer's ability to distinguish between crime and no crime events from post-event recorded video. 80 participants viewed 32 video scenes at 1, 5, 8, and 12 frames per second (fps). The task required observers to determine if one of three possible events had occurred. Results showed that the number of correct detections, task confidence decreased significantly at 8 fps and lower. Our results provide CCTV practitioners with a minimum frame rate level (8 fps) for event detection, a task performed by CCTV users of varying skill and experience.

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INDEX TERMS

Primary Classification:
  H. Information Systems
  H.5 INFORMATION INTERFACES AND PRESENTATION (I.7)
      H.5.1 Multimedia Information Systems
          Subjects: Video (e.g., tape, disk, DVI)

Additional Classification:
  H. Information Systems
  H.5 INFORMATION INTERFACES AND PRESENTATION (I.7)
      H.5.1 Multimedia Information Systems
          Subjects: Evaluation/methodology

General Terms:
Human Factors, Security

Keywords:
cctv video, crime detection, frame rate, multimedia, security, task performance, video quality