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PubMed · 6639980

The frequency of seeing square wave density modulations in random dot patterns.

A M Lelkens·P M Oppeneer
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Abstract

A theoretical and experimental study on the detection of a square wave pattern of random dots is presented. Our theory applies to two-alternative forced choice experiments as well as to "seen"-"not seen" discrimination experiments. In our experiments we used the forced choice method. The theory provides a good description of the psychometric function of the percentage of correct decisions versus contrast. From these frequency of seeing (FOS) curves the apparent signal-to-noise ratio of the detection mechanism of human subjects can be derived. It is found that this ratio can have values of up to 100% and that it decreases with the number of dots in the stimulus and with the number of periods of the square wave. It is shown that a more precise description of the human performance can be obtained from the mid-points of the FOS-curves (i.e. the thresholds) rather than from the slopes.

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BionicsForm PerceptionHumansModels, BiologicalPattern Recognition, VisualStatistics as TopicComparative StudyJournal ArticleResearch Support, Non-U.S. Gov't

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A M Lelkens, P M Oppeneer. 1983. The frequency of seeing square wave density modulations in random dot patterns.. https://doi.org/10.1007/bf00318084

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