نتایج جستجو برای: flicker

تعداد نتایج: 3028  

Journal: :Investigative ophthalmology & visual science 2015
Takafumi Yoshioka Taiji Nagaoka Youngseok Song Harumasa Yokota Tomofumi Tani Akitoshi Yoshida

PURPOSE To investigate how neuronal nitric oxide synthase (nNOS) contributes to regulation of the retinal circulation during rest and flicker stimulation in cats. METHODS Using laser Doppler velocimetry, we measured the vessel diameter and blood velocity simultaneously and calculated the retinal blood flow (RBF) in feline first-order retinal arterioles. After intravitreal injections of Nω-Nit...

Journal: :Archives of ophthalmology 2012
Chi D Luu Peter N Dimitrov Luba Robman Mary Varsamidis Galina Makeyeva Khin-Zaw Aung Algis J Vingrys Robyn H Guymer

OBJECTIVE To investigate the longitudinal changes in flicker perimetry in patients with age-related macular degeneration (AMD) as the condition progresses from early AMD to geographic atrophy (GA) or choroidal neovascularization (CNV). METHODS Patients with AMD and control subjects were recruited from a longitudinal study of retinal function in early AMD consisting of 187 participants. Only t...

2013
Yohay Swirski

The underwater environment is challenging for computer vision tasks. Poor visibility, geometrical distortions and spatio-temporal varying illumination are some of the physical sources of these challenges. Spatio-temporal varying illumination is created by refraction of light through the wavy water surface and is known as underwater flicker. In past studies, flicker has often been considered to ...

2004
Daniele Gallo Carmine Landi Nicola Pasquino

A new instrument for the evaluation of disturbances caused by variations in lamp voltage (light flicker) is proposed, based on light intensity measurements. Unlike current standard (IEC EN 61000-4-15), which determines flicker severity by filtering powering voltage measurements with a standard lamp model (230V/60W), the presented methodology includes the lamp itself in the measurement process, ...

2000
H. C. Huang P. W. Cheng H. S. Kwok

We have performed systematic characterizations of flicker in silicon light valves. It was found that there were four conduction mechanisms accounting for the flicker. These four mechanisms were residual dc charge on the silicon surface, voltage holding capability of the liquid crystal cell, voltage holding capability of the silicon panel, and parasitic capacitor coupling of the pixel. Major cau...

2009
J. L. Guan H. H. Chang

Voltage flicker problems have long existed in several of the distribution areas served by the Taiwan Power Company. In the past, those research results indicating that the estimated 10 V Δ value based on the conventional method is significantly smaller than the survey value. This paper is used to study the relationship between the voltage flicker problems and harmonic power variation for the po...

2017
Tiejun Cao

Hilbert Vibration Decomposition (HVD) is introduced to the voltage flicker analysis. When voltage flicker accompanies with high order harmonics, the instantaneous frequency of its analytic signal in principle consists of two different parts, power frequency and a rapidly varying asymmetrical oscillating part. The important property of the instantaneous frequency offers a direct way to estimate ...

Journal: :Circulation 1952
A KEYS E SIMONSON

Krasno and Ivy have claimed that the change after sublingual nitroglycerin in the frequency at which a flickering light appears to fuse (f.f.f.) sharply differentiates between cardiovascular normals and patients with coronary and /or hypertensive disease and that this test may be useful in detecting and evaluating such disease. On the basis of a detailed analysis of the original publication and...

Journal: :Vision Research 2007
Jan Kremers Ulrike Rimmele

We investigated the influence of the relative phase of a temporally modulated annulus on the perceived flicker strength of a center stimulus having the same temporal modulation. These measurements were performed in two subjects at two temporal frequencies and with different outer diameters of the annulus. The perceived flicker strength was strongly modulated by the phase difference between cent...

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