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Author: Fred H. Ireland Publisher: ISBN: Category : Airplanes Languages : en Pages : 48
Book Description
A common human factors recommendation states that, for good target visibility, the area surrounding a display should not be brighter than the background area within the display. However, this recommendation must often be violated in applications where the surround brightness cannot be adequately controlled (e.g. in an airplane cockpit) and/or display technique limitations prevent use of high brightness backgrounds (e.g. with cathode ray tubes). This literature review was undertaken to see what has been discovered thus far concerning the effects on target visibility of specific parameters of a surround-to-background. Well over 100 documents were reviewed. Seventy-five annotated references to the more pertinent documents are contained in this report. Quantitative effects of pertinent parameters have been studied by numerous investigators. Results of studies using extended surrounds, rather than point sources, have not been sufficiently comprehensive or consistent to support quantitative generalizations in this area. Attempts have been made by Holladay and by Moon and Spencer to make quantitative predictions for the extended surround case on the basis of the more extensive body of data dealing with point source effects. However, several of the findings upon which their formulas are based have been contradicted by other findings cited in this report. (Author).
Author: Fred H. Ireland Publisher: ISBN: Category : Airplanes Languages : en Pages : 48
Book Description
A common human factors recommendation states that, for good target visibility, the area surrounding a display should not be brighter than the background area within the display. However, this recommendation must often be violated in applications where the surround brightness cannot be adequately controlled (e.g. in an airplane cockpit) and/or display technique limitations prevent use of high brightness backgrounds (e.g. with cathode ray tubes). This literature review was undertaken to see what has been discovered thus far concerning the effects on target visibility of specific parameters of a surround-to-background. Well over 100 documents were reviewed. Seventy-five annotated references to the more pertinent documents are contained in this report. Quantitative effects of pertinent parameters have been studied by numerous investigators. Results of studies using extended surrounds, rather than point sources, have not been sufficiently comprehensive or consistent to support quantitative generalizations in this area. Attempts have been made by Holladay and by Moon and Spencer to make quantitative predictions for the extended surround case on the basis of the more extensive body of data dealing with point source effects. However, several of the findings upon which their formulas are based have been contradicted by other findings cited in this report. (Author).
Author: Fred H. Ireland Publisher: ISBN: Category : Airplanes Languages : en Pages : 60
Book Description
A visual display must often be used in a setting where the surrounding visual field is brighter than the background area within the display. Such use violates a common human factors recommendation that the brightness of the display surround should be equal to, or slightly less than, that of the background in the display itself. The purpose of this experiment was to determine, quantitatively, the degradation in visibility due to high surround brightness and thus to provide useful data for the display system designer. Measurements were made of the target-to-background contrast required for each of 5 Ss to determine, with 50% accuracy, the orientation of a light Landolt ring target centered on a darker circular background. The target gap subtended 1.93 minutes of arc. Background angular subtense was varied from 5° to 45°, background brightness from 0.17 to 18.43 millilamberts and surround-to-background brightness ratio from 0:1 to 100:1. A uniform surround, independently variable in brightness with respect to the background, filled the rest of the visual field. The scene was viewed monocularly with natural pupil. The contrast limen was found to vary directly with surround-to-background brightness ratio for ratios greater than one. The variation with background size was smaller than predicted by an equation for integrating the effects of point sources of glare. An apparent tendency for a slight increase in limen as the surround-to-background ratio decreased from 1:1 to 0:1 was not statistically significant. Results are described by equations, and a procedure for their practical application is illustrated.
Author: Agnieszka Wolska Publisher: CRC Press ISBN: 1000168107 Category : Technology & Engineering Languages : en Pages : 182
Book Description
The introduction of artificial lighting extends the time of wakefulness after dark and enables work at night, thus disturbing the human circadian rhythm. The understanding of the physiological mechanisms of visual and non-visual systems may be important for the development and use of proper light infrastructure and light interventions for different workplace settings, especially for shift work conditions. Visual and Non-Visual Effects of Light: Working Environment and Well-Being presents the impact of lighting in the working environment on human health, well-being and visual performance. The physiological explanation of the visual and non-visual effects of light on humans which discusses the biological bases of image and non-image forming vision at the cellular level may be of particular interest to any professional in the field of medicine, physiology, and biology. It is one of the intentions of this book to put forward some recommendations and examples of lighting design which take into account both the visual and non-visual effects of light on humans. These may be of particular interest to any professional in the field of lighting, occupational safety and health, and interior design. "What effects on health can a light ‘overdose’ or light deficiency have? What is bad light? The authors of the monograph provide answers to these questions. Just as for a physicist, the dual nature of light comprises an electromagnetic wave and a photon, the duality of light for a physician comprises visual and non-visual effects." --------------------------------------------------------Prof Jacek Przybylski, Medical University of Warsaw "This is a unique publication in the field of lighting technology. The authors have skillfully combined both the technical and biomedical aspects involved, which is unprecedented in the literature available. As a result, an important study has been created for many professional groups, with a significant impact on the assessment of risks associated with LED sources." --------------------------------------------Prof Andrzej Zając, Military University of Technology, Warsaw
Author: Fred H. Ireland
Author: Fred H. Ireland
Author: Fred H. Ireland
Author: Milton L. Rock
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Author: Agnieszka Wolska
Author: Defense Documentation Center (U.S.)
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Author: Patrick G. Meguire
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