نتایج جستجو برای: flicker
تعداد نتایج: 3028 فیلتر نتایج به سال:
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...
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...
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...
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 ...
Balance between pattern and flicker sensitivities in the visual fields of ophthalmological patients.
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...
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 ...
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...
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...
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...
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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