Temporal filtering enhances direction discrimination in random-dot patterns
نویسندگان
چکیده
منابع مشابه
Temporal filtering enhances direction discrimination in random-dot patterns
In conventional presentations of random-dot kinematograms, two frames of random dots are presented in temporal sequence, separated by a blank inter-stimulus interval, and a coherent offset in spatial position is added to dots in one frame relative to dots in the other frame. Direction discrimination performance is limited temporally to inter-stimulus intervals below about 100 msec (Tmax). Exper...
متن کاملHuman velocity and direction discrimination measured with random dot patterns.
In the present experiments three different motion discrimination tasks were studied using a random dot pattern as stimulus: velocity discrimination, direction discrimination and discrimination of opposite directions. The analysis of the motion of random dot patterns is based on motion sensitive mechanisms without the confounding interference of position sensitive mechanisms (Nakayama and Tyler,...
متن کاملEffects of dot density, patch size and contrast on the upper spatial limit for direction discrimination in Random-dot Kinematograms
Two-frame random-dot kinematograms (RDKs) of different dot density, area and contrast were used to study the spatial properties of the human visual motion system. It was found that the maximum spatial displacement at which observers could reliably discriminate the direction of motion (dmax) increased gradually by a factor of up to 6.4 as dot density was decreased from 50 to 0.025% for high Mich...
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Previous research has shown that a field of random dots in which each dot alternates between a slow and a fast speed, can give rise to the percept of two superimposed sheets of moving dots when the alternations are out of phase or asynchronous with each other [Vis. Res. 35 (1995) 1691]. Under those conditions, observers can discriminate changes in the slow speed independent of changes in the fa...
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Two computational strategies have been proposed for motion analysis in the human visual system. Energy-based schemes involve detection of spatiotemporal Fourier energy in the frequency components comprising a moving pattern. Edge-based schemes track shifts in the position of local edges in the pattern over time. This paper describes a stimulus manipulation, spatial phase randomisation, that act...
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ژورنال
عنوان ژورنال: Vision Research
سال: 1995
ISSN: 0042-6989
DOI: 10.1016/0042-6989(94)00297-5