scholarly journals Observation Distance Property of PWM Flicker Light

2011 ◽  
Vol 124 (0) ◽  
pp. 243-248
Author(s):  
Kenji FURUKAWA ◽  
Kinji TAKEUCHI ◽  
Hideki NOGUCHI ◽  
Ko IGARASHI
Keyword(s):  
Observation Distance ◽  
Distance Property ◽  
Flicker Light

scholarly journals A low-cost technique to measure bank erosion proces ses along middle-size river reaches

2018 ◽  
Author(s):  
Gonzalo Duró ◽  
Alessandra Crosato ◽  
Maarten G. Kleinhans ◽  
Wim S. J. Uijttewaal
Keyword(s):  
Laser Scanning ◽  
Spatial Scales ◽  
Low Cost ◽  
Bank Erosion ◽  
Water Levels ◽  
Small Scale ◽  
Observation Distance ◽  
River Bank ◽  
Erosion Processes ◽  
Rtk Gps

Abstract. Diverse methods are currently available to measure river bank erosion at broad-ranging temporal and spatial scales. Yet, no technique provides low-cost and high-resolution to survey small-scale bank processes along a river reach. We investigate the capabilities of Structure-from-Motion photogrammetry applied with imagery from an Unmanned Aerial Vehicle (UAV) to describe the evolution of riverbank profiles in middle-size rivers. The bank erosion cycle is used as a reference to assess the applicability of different techniques. We surveyed 1.2 km of a restored bank of the Meuse River eight times within a year, combining different photograph perspectives and overlaps to identify an efficient UAV flight to monitor banks. The accuracy of the Digital Surface Models (DSMs) was evaluated compared with RTK GPS points and an Airborne Laser Scanning (ALS) of the whole reach. An oblique perspective with eight photo overlaps was sufficient to achieve the highest relative precision to observation distance of ~1:1400, with 10 cm error range. A complementary nadiral view increased coverage behind bank toe vegetation. The DSM and ALS had comparable accuracies except on banks, where the latter overestimates elevations. Sequential DSMs captured signatures of the erosion cycle such as mass failures, slump-block deposition, and bank undermining. Although this technique requires low water levels and banks without dense vegetation, it is a low-cost method to survey reach-scale riverbanks in sufficient resolution to quantify bank retreat and identify morphological features of the bank failure and erosion processes.

Visual acuity in 5-7-year-old children: individual variability and dependence on observation distance

2005 ◽  
Vol 25 (1) ◽  
pp. 66-80 ◽  
Author(s):  
Galina I. Rozhkova ◽  
Tatiana A. Podugolnikova ◽  
Nadezhda N. Vasiljeva
Keyword(s):  
Visual Acuity ◽  
Individual Variability ◽  
Observation Distance

Analysis of Retinal Vasodilation after Flicker Light Stimulation in Relation to Vasospastic Propensity

2006 ◽  
Vol 47 (9) ◽  
pp. 4034 ◽  
Author(s):  
Konstantin Gugleta ◽  
Claudia Zawinka ◽  
Ines Rickenbacher ◽  
Asan Kochkorov ◽  
Robert Katamay ◽  
...  
Keyword(s):  
Light Stimulation ◽  
Flicker Light

scholarly journals Retinal Vasculature Reactivity During Flicker Light Provocation, Cardiac Stress and Stroke Risk in Africans: The SABPA Study

2018 ◽  
Vol 10 (5) ◽  
pp. 485-494 ◽  
Author(s):  
Annemarie Wentzel ◽  
Leoné Malan ◽  
Wayne Smith ◽  
Roland von Känel ◽  
Nicolaas T. Malan
Keyword(s):  
Stroke Risk ◽  
Retinal Vasculature ◽  
Cardiac Stress ◽  
Flicker Light

Retinal Venous Oxygen Saturation Increases by Flicker Light Stimulation

2011 ◽  
Vol 52 (1) ◽  
pp. 274 ◽  
Author(s):  
Martin Hammer ◽  
Walthard Vilser ◽  
Thomas Riemer ◽  
Fanny Liemt ◽  
Susanne Jentsch ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Light Stimulation ◽  
Venous Oxygen Saturation ◽  
Flicker Light

Study on Building Materials and Building Color Attribute Changes in Cold Regional for Weather Factors and Distance

2014 ◽  
Vol 1014 ◽  
pp. 263-266
Author(s):  
Jie Liu ◽  
Qi Wang
Keyword(s):  
Visual Perception ◽  
Physical Properties ◽  
Building Materials ◽  
Sensory Experience ◽  
Cold Region ◽  
Weather Factors ◽  
Observation Distance ◽  
Weather Changes ◽  
Distance Conditions ◽  
Color Attribute

The sensory experience of visual perception and quantification of physical properties of colors are combined in this paper, and with the colors commonly used in buildings materials in the cold region of China as an example, based on the visual perception principle, the changes in such color attributes of buildings as chromaticness, blackness and hue in vision in different weather and observation distance conditions are analyzed. The result shows that the stimulus degree of chromaticness and blackness decreases with the increase in observation distance, directly related to weather changes, while hue basically remains unchanged. Keywords: cold regional, color attribute, weather factors

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