Monitoring up to 16 Synthetic Television Pictures Showing a Great Deal of Movement

Abstract

A total of 204 observes watched usually 16 synthetic television pictures for 1 hr. The 8 pictures in the middle 2 columns of the display showed activity inside prison. The 8 pictures in the 2 side columns of the display showed activity just outside prison walls. There were 14 suspicious incidents inside prison, 7 of them serious, and 170 other movements. Just outside prison there were fl auspicious incidents, 1 of them serious, and 5,300 other movements. The observer had to press an alarm button whenever he or she saw a suspicious incident. Suspicious incidents were missed reliably more often when they were in the distance, or of brief duration. When matched for distance and duration, incidents were missed reliably less often inside prison, where there was less other activity, than just outside prison. Inside incidents were missed reliably less often when only 8 inside pictures were watched, than when 4 inside and 4 outside pictures were watched- A telephone call about 10 see before an incident reliably reduced the proportion of detections. If more than 1 picture has to be watched, the maximum desirable number is about 9 when there is a lot of movement. The maximum desirable duration for a spell of work is about 1 hr. Reducing the size of pictures from 40 × 30 cm to 20 × 1.1 cm reliably reduced the proportion of detections. Halving the distance of the observer from the small pictures from 9 to 4-5 ft still left a reliable reduction in the proportion of detections of distant incidents. Observers under 30 yr detected reliably more incidents, and made reliably fewer false detections, than observers over 45yr. When matched for age, prison officers who had previously monitored television pictures were reliably better than prison officers who had not. The experienced prison officers detected reliably more suspicious incidents inside prison than did the civilian observers.

Work exposure and vigilance decrements in closed circuit television surveillance

“…In both Andrew et al's (2003) and Davies and Thasen's (2000) studies, focal attention and detailed visual analysis were required for correct detection. CCTV research involving more complex and dynamic scenes contrasts with the studies by Tickner and Poulton (1968, 1973, 1975, colleagues (1972), van Voorthuijsen et al (2005), and Wallace et al (n.d.) where much higher detection rates were obtained with more visually conspicuous significant events of longer duration.…”

“…The significant events were conspicuous and involved two suspicious behaviours (running, and looking excessively at perimeters such as walls). A follow-up study with similar prison scenes but showing a lot of movement found that the range of detection rates decreased considerably in some instances (32%e 100% across experimental conditions) (Tickner and Poulton, 1973). Perfect detection rates were achieved only when one display was observed at a time.…”

Prediction of Abnormal Behaviors for Intelligent Video Surveillance Systems

“…This reality provokes an overcharge of responsibility and loss of efficiency in the surveillance personnel, as stated in previous psychological studies carried out by [1] and [2] in Cambridge University and by military experiments [3]. Thus, automatic video surveillance systems are crucial for security professionals.…”

The Application of a Dendritic Cell Algorithm to a Robotic Classifier

“…Very few sensors can be monitored by an individual effectively. Tickner et al estimated that the number of feeds that a single operator can effectively monitor is approximately 16, with the detection rate falling from 83% for a four camera system, to 64% for a 16 camera system, [2].…”