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Author Srimant P. Tripathy, A. ♦ Er J. Mussap, B. ♦ Horace B. Barlow, A.
Source CiteSeerX
Content type Text
File Format PDF
Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Target Element ♦ Collinear Dot ♦ Target Detection ♦ Random Jitter ♦ Single Mechanism ♦ Maximum Density ♦ Aperiodic Noise Dot ♦ Noise Array ♦ Additional Experiment ♦ Ciba Foundation Symposium ♦ Two-stage Process ♦ 6isual System ♦ Noise Element ♦ Target Location ♦ Target Array ♦ Linear Slope ♦ Collinear Target Element ♦ Jitter Experiment ♦ Horizontal Versus ♦ Target Element Number ♦ Single Mechanism Explanation ♦ Target Axis ♦ Additional Target Element ♦ Binary Choice ♦ Perceptual Grouping ♦ Pre-existing Noise Element ♦ Higher-order Processing ♦ Intrinsic Positional Uncertainty ♦ Right Angle ♦ Correct Detection
Abstract We estimated the sensitivity for detecting a row of collinear target elements (usually dots) by measuring the maximum density of randomly positioned noise elements that allowed 75 % correct detection of the orientation of alignment (binary choice: horizontal versus vertical) of the target elements. We varied the number of target elements, their mode of generation, and their accuracy of positioning. As reported previously (Moulden (1994) Higher-order processing in the 6isual system. Ciba Foundation Symposium 184. Chichester: Wiley), target detection improved rapidly until the number of target elements reached about seven, and then improved more slowly beyond this point. However, this break was reduced (and often removed entirely) when the target array was formed by repositioning pre-existing noise elements lying close to the target location, rather than by superimposition of additional target elements onto the noise array. This almost linear slope of improvement, coupled with the observation that target detection was disrupted more by random jitter of target elements at right angles to their axis of alignment than by jittering along this axis, argues against a two-stage process of perceptual grouping (Moulden, 1994) and supports instead an explanation based on the operation of a single mechanism. This single mechanism explanation is further supported by the observation that intrinsic positional uncertainty (estimated from the results of jitter experiments) was independent of target element number. Additional experiments showed that target detection is facilitated by aperiodic noise dots that fall close to the target axis. The
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Research
Education Level UG and PG ♦ Career/Technical Study
Publisher Date 1999-01-01