Accession Number : ADA332390

Title :   Target Acquisition in Complex Scenes, Part A: Search and Conspicuity Models.

Descriptive Note : Final rept. 15 Aug 95-14 Aug 96,

Corporate Author : HUMAN FACTORS RESEARCH INST TNO SOESTERBERG (NETHERLANDS)

Personal Author(s) : Toet, A.

PDF Url : ADA332390

Report Date : NOV 1996

Pagination or Media Count : 75

Abstract : A visual search and detection experiment is performed on a set of complex natural images with military vehicles as targets. The area under the resulting cumulative detection probability curve of each target is adopted as a characteristic measure for its visual distinctness. The visual distinctness rank order induced by this measure is adopted as the reference rank order. This study investigates the capability of several digital target distinctness metrics and the psychophysically determined target visual lobe (i.e. the minimal distance between target and eye-fixation at which the target is no longer distinguishable from its surroundings) to reproduce the abovementioned reference rank order. The visual lobe indeed appears a useful predictor of human performance in a visual search and detection task. Models of the early human visual system, a normalized root-mean square metric, and the edge distance metric introduced in this report, all seem to induce a visual distinctness rank ordering that agrees with human visual perception. Metrics based (I) on first order statistics of the graylevel histogram, (2) on the intersection of (oriented) graylevel histograms of target and background, and (3) on a combination of area and edge contrast, all correlate poorly with human observer performance. The CAMAELEON model (based on histogram intersection) is also highly sensitivity to variations in the definition (size and shape) of the target and background masks. The Perceptual Distortion model induces a visual target distinctness rank ordering identical to the one resulting from human observer performance, and therefore shows the best overall performance of all models and metrics tested in this study.

Descriptors :   *TARGET ACQUISITION, *MILITARY VEHICLES, DIGITAL SYSTEMS, CONTRAST, DETECTION, PERFORMANCE(HUMAN), PROBABILITY, IMAGES, SEARCHING, VISUAL PERCEPTION, PILOT STUDIES, RANGE(DISTANCE), DISTORTION, PERCEPTION, VISUAL TARGETS, PSYCHOPHYSICS, RANK ORDER STATISTICS.

Subject Categories : Target Direction, Range and Position Finding
      Logistics, Military Facilities and Supplies

Distribution Statement : APPROVED FOR PUBLIC RELEASE