نتایج جستجو برای: flicker

تعداد نتایج: 3028  

2016
David Alais Shannon M. Locke Johahn Leung Erik Van der Burg

We tested whether fast flicker can capture attention using eight flicker frequencies from 20-96 Hz, including several too high to be perceived (>50 Hz). Using a 480 Hz visual display rate, we presented smoothly sampled sinusoidal temporal modulations at: 20, 30, 40, 48, 60, 69, 80, and 96 Hz. We first established flicker detection rates for each frequency. Performance was at or near ceiling unt...

Journal: :The Journal of neuroscience : the official journal of the Society for Neuroscience 2017
Rasa Gulbinaite Tara van Viegen Martijn Wieling Michael X Cohen Rufin VanRullen

Rhythmic visual stimulation ("flicker") is primarily used to "tag" processing of low-level visual and high-level cognitive phenomena. However, preliminary evidence suggests that flicker may also entrain endogenous brain oscillations, thereby modulating cognitive processes supported by those brain rhythms. Here we tested the interaction between 10 Hz flicker and endogenous alpha-band (∼10 Hz) os...

Journal: :IEICE Transactions 2006
Lei Zhou Qiang Ni Yuanhua Zhou

An automatic and efficient algorithm for removal of intensity flicker is proposed. The novel repair process is founded on the blockbased estimation and restoration algorithm with regard to luminance variation. It is easily realized and controlled to remove most intensity flicker and preserve the wanted effects, like fade in and fade out. key words: image sequence process, intensity flicker, fli...

Journal: :Investigative ophthalmology & visual science 2015
Anthony E Felder Justin Wanek Norman P Blair Mahnaz Shahidi

PURPOSE Light flicker has been shown to stimulate retinal neural activity, increase blood flow, and alter inner retinal oxygen metabolism (MO2) and delivery (DO2). The purpose of the study was to determine the change in MO2 relative to DO2 due to light flicker stimulation in humans, as assessed by the inner retinal oxygen extraction fraction (OEF). METHODS An optical imaging system, based on ...

Journal: :The British journal of ophthalmology 1984
D Regan D Neima

We measured the balance between visual sensitivities to pattern and to flicker rather than measuring absolute sensitivities to pattern or flicker. The test target was a 2-cycle deg-1 sinewave grating that was counterphase modulated at 8 Hz. Seventeen points in the visual field were tested out to eccentricities of 24 degrees. We examined 10 control subjects, 6 patients with glaucoma 10 with ocul...

Journal: :Journal of the Optical Society of America. A, Optics, image science, and vision 1997
B L Beard S A Klein T Carney

The detection thresholds for oscillatory motion and flicker were compared across a wide range of pedestal contrasts, spatial frequencies, and temporal frequencies in both foveal and peripheral vision. Motion and flicker stimuli were both generated by summation of a counterphase test grating with a static pedestal grating. For the oscillatory motion task the test and the pedestal were presented ...

Journal: :Investigative ophthalmology & visual science 2017
Kumiko Kato Mineo Kondo Ryunosuke Nagashima Asako Sugawara Masahiko Sugimoto Hisashi Matsubara Daphne L McCulloch Kengo Ikesugi

Purpose A small, full-field flicker electroretinogram (ERG) recording system was recently developed to record flicker ERGs without mydriasis (RETeval). The device delivers a stimulus with constant retinal illuminance by adjusting the retinal luminance to compensate for changes in the pupillary area. The purpose of this study was to determine what factors affect the fundamental components of the...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2004
Sherif Shady Donald I A MacLeod Heidi S Fisher

Human ability to resolve temporal variation, or flicker, in the luminance (brightness) or chromaticity (color) of an image declines with increasing frequency and is limited, within the central visual field, to a critical flicker frequency of approximately 50 and 25 Hz, respectively. Much remains unknown about the neural filtering that underlies this frequency-dependent attenuation of flicker se...

1999
Zhaofeng Zhang Jack Lau

The flicker noise mechanism under switching conditions is studied. Experimental results show that the baseband flicker noise is a superposition of upconverted gate flicker noise at each harmonic of the output current. Methods to reduce the flicker noise are discussed. Based on the measured results, the large signal flicker noise model for RF applications under switching conditions is proposed a...

2005
K. K. Wong A. Das M. N. Chong HONG KONG

Studies show that all the published work in flicker correction to date only deals with black and white motion pictures. In this paper, we will look into the problem of flicker correction in color motion pictures and propose a method to address this problem. The method is based on a simplified flicker parameter model developed by us in [5] which was originally used for flicker correction in blac...

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