Results 281 to 290 of about 3,367,707 (346)

Retinal noise and absolute threshold.

Journal of the Optical Society of America, 1956
It is shown that the absorption of one quantum can excite a rod in the human retina, but that at least two, and probably many more, excited rods are needed to give a sensation of light. It is suggested that noise in the optic pathway limits its sensitivity, and this idea is subjected to an experimental test.
H. Barlow
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Absolute threshold conditions for visual perception.

Journal of the Optical Society of America, 1955
A quantitative approach to an understanding of fluctuating phenomena encountered near the threshold of vision has involved an analysis of frequency of seeing curves. The results of various investigators are discussed with reference to the possibility of an explanation based exclusively on the statistical fluctuations in the stimulating energy ...
M. A. Bouman
semanticscholar   +3 more sources

Behavioral estimates of absolute threshold in rat

Visual Neuroscience, 1994
AbstractDark-adapted thresholds of albino and pigmented rats were estimated using behavioral methods. Albino and pigmented rats who had been water deprived learned to bar press for water reinforcement when a light stimulus was presented. Absolute threshold was defined to be the light intensity at which bar pressing behavior was significantly modified ...
C. Muñoz Tedó, P. Herreros de Tejada, D. G. Green   +2 more
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Human binocular summation at absolute threshold.

Vision Research, 1974
Abstract Psychophysical data are presented which indicate that the neural inputs of two stimuli presented simultaneously to corresponding retinal areas summate physiologically to lower the binocular absolute threshold. This binocular summation is not present when the stimuli are separated by more than 100 msec or are delivered to noncorresponding ...
F. Thorn, R. M. Boynton
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Absolute threshold and frequency-of-seeing curves.

Journal of the Optical Society of America, 1955
The simplest interpretation of the uncertainty of seeing observed at the absolute threshold is based on the theory of quantum fluctuations and assumes that in any given trial the light is seen when the retina has been acted upon by at least n quanta. When this assumption is true the frequency-of-seeing curve is a simple Poisson sum of parameter n, and ...
M. Pirenne, F. Marriott
semanticscholar   +3 more sources

Absolute auditory threshold: testing the absolute

European Journal of Neuroscience, 2017
AbstractThe mechanisms underlying the detection of sounds in quiet, one of the simplest tasks for auditory systems, are debated. Several models proposed to explain the threshold for sounds in quiet and its dependence on sound parameters include a minimum sound intensity (‘hard threshold’), below which sound has no effect on the ear.
Peter Heil, Artur Matysiak
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Absolute Thresholds and Night Myopia

Journal of the Optical Society of America, 1949
The first measurements of night myopia showed a clear decrease in the minimum quantity of light needed to reach a certain visual acuity when the night myopia was compensated. The results indicated a possible decrease in absolute thresholds. In the present paper we study, with four observers using binocular vision and white light, the influence of night
J M, OTERO, L, PLAZA, F, SALAVERRI
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Absolute Thresholds of Human Hearing

American Industrial Hygiene Association Journal, 1967
Abstract Data obtained from high school students indicate that distributions of hearing thresholds determined by puretone audiometry are log-normal. A graphically simplified mathematical method for determining the loci of absolute thresholds of human hearing is presented.
E R, Hermann, B R, Holzman
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Absolute Thresholds for Moving Point Sources

Journal of the Optical Society of America, 1953
The theoretical treatment of absolute and contrast thresholds for moving point sources is presented. The thresholds are tested as functions of the velocity v and observation time t on the assumption that, under all conditions for minimum perceptibility, p quanta must be effectively absorbed in the retina within τ seconds the δ minutes of arc; within τ ...
M A, BOUMAN, G, VAN DEN BRINK
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TEMPORAL SUMMATION AND ABSOLUTE BRIGHTNESS THRESHOLDS

British Journal of Mathematical and Statistical Psychology, 1967
Three normative models based on the Change Detector analogies of Shallice (1964) are investigated to see how well they account for the integration of input over time that occurs in absolute brightness threshold experiments. Of the three, the geometric moving average receives no support. The perceptual moment and moving average models give about equally
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