Consideration of the effects of background on sign conspicuity.

Author(s)
Jenkins, S.E.
Year
Abstract

TWO CHARACTERISTICS OF BACKGROUND WHICH MAY AFFECT OBJECT CONSPICUITY OF REFLECTIVE SIGNS IN DAYLIGHT CONDITIONS ARE CONSIDERED IN THIS PAPER. ONE IS THE OVERALL COMPLEXITY OF A BACKGROUND AS DESCRIBED BY THE AMOUNT OF 'VISUAL CLUTTER' IN THE SCENE, THE OTHER IS THE IMMEDIATE ENVIRONMENT SURROUNDING AN OBJECT. THE CONTRAST OF AN OBJECT DEPENDS ON THE DIFFERENCE BETWEEN ITS LUMINANCE AND THAT OF THE SURROUNDING LOCAL BACKGROUND, THUS FOR EXAMPLE A HIGH LUMINANCE OBJECT WILL HAVE A LOW CONTRAST WHEN SEEN AGAINST A HIGH LUMINANCE BACKGROUND. THIS PAPER INVESTIGATES WHETHER IT IS THE LUMINANCE OR THE CONTRAST OF THE OBJECT WHICH DETERMINES ITS CONSPICUITY. SLIDES WERE MADE OF A VARIETY OF TYPICAL ROAD SCENES, VIEWED FROM THE POSITION OF A DRIVER, WITH A DISC TARGET SUPERIMPOSED. THE TARGETS WERE BLACK, GREY AND WHITE AND CONCOMITANTLY HIGH, MEDIUM AND LOW CONTRAST. THE SCENES WERE PRESENTED FOR 250 MS TO TEN SUBJECTS WHO WERE ASKED TO DECIDE IN WHICH HALF OF THE SCENE THE DISK TARGET WAS LOCATED. IT WAS CONVINCINGLY FOUND THAT THE CONTRAST OF THE TARGET, NOT ITS LUMINANCE, DETERMINED ITS CONSPICUITY. IT IS SUGGESTED THAT IT WOULD BE ADVANTAGEOUS FOR TRAFFIC ENGINEERS TO HAVE SOME CONTROL OVER THE CONTRAST OF SIGNS AND MEANS OF ACHIEVING THIS IS DISCUSSED. THE DIFFERENT SCENES WERE RATED AS TO THEIR COMPLEXITY OR AMOUNT OF 'VISUAL CLUTTER' BY A GROUP OF 20 OBSERVERS. THIS WAS THEN COMPARED TO THE RANKING OF THE SCENES ACCORDING TO THE PERFORMANCE SHOWN BY THE FIRST TEN SUBJECTS. A SUBSTANTIAL MEASURE OF AGREEMENT WAS FOUND BETWEEN THE TWO RANKINGS INDICATING THAT BACKGROUND COMPLEXITY DOES HAVE AN ADVERSE EFFECT ON TARGET DETECTION. HOWEVER THE AGREEMENT BETWEEN THE TWO RANKINGS WAS NOT COMPLETE AND A CRITICAL EVALUATION OF THE ANOMALOUS SCENES SUGGEST THAT ELEMENTS IN A SCENE WHICH ARE NOT JUDGED AS CONTRIBUTING GREATLY TO VISUAL CLUTTER MAY HAVE A MAJOR DISTRACTIVE EFFECT ON TARGET DETECTION, AT LEAST WHEN MEASURED USING BRIEF PRESENTATIONS (A). THE NUMBER OF THE COVERING ABSTRACT OF THE CONFERENCE IS IRRD NO 255423.

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Publication

Library number
C 51416 (In: B 23527 [electronic version only]) /73 /83 / IRRD 255482
Source

In: Proceedings of the 11th Conference of the Australian Road Research Board, Melbourne, August 23-27, 1982. Volume 11, Part 5, p. 182-205 (12 Photos; 4 Figs.; 3 Tbls.; 10 Refs.)

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This publication is one of our other publications, and part of our extensive collection of road safety literature, that also includes the SWOV publications.