Accession Number : ADA118491

Title :   Masking Effects on Visual Target Detection and Tracking.

Descriptive Note : Final research rept.,


Personal Author(s) : Zeevi,Yehoshua Y ; Longridge,T M ; De Maio,J C

PDF Url : ADA118491

Report Date : May 1982

Pagination or Media Count : 56

Abstract : Since eye movements are required for the detection and tracking of a point target, their concomitant signal can provide physiological objective measures of performance in target acquisition tasks. Saccadic latency, misses, and false alarm rate were used in assessing and comparing the effects of static and dynamic masks on target detection and tracking. A point target with an effective diameter of 0.4 degrees was displayed in either of two fixed positions separated by 18 degrees symmetrically with respect to the egocentric axis. Timing of target displacement was either periodic, or aperiodic. The masking field was generated by projection of a polarized texture pattern, characterized by a spectrum below 1 cpd, superimposed on the visual axis via a beam splitter. Masking dynamics were generated by a rotating polarizer situated in front of the masking field projector. As target luminance decreased from 11 to 6 ft-L, reaction time measured as saccadic latency, increased. This effect of target luminance was further substantiated once static masking was introduced. Aperiodic target displacements resulted in false alarm saccades to the right position. It was found that dynamic mask of the same spatial spectrum and contrast had a significantly more detrimental effect on subject performance.

Descriptors :   *Visual perception, *Target detection, *Eye movements, Tracking, Target acquisition

Subject Categories : Personnel Management and Labor Relations

Distribution Statement : APPROVED FOR PUBLIC RELEASE