Browsing by Author "Einhorn, H D"

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    The assessment of light sources
    (1997) Paul, Brendon Mark; Einhorn, H D
    Discomfort glare from normal sources has been thoroughly researched over the last five decades and agreement has been reached by the CIE to express it by the Unified Glare Rating (UGR) formula: UGR = 8 log₁₀g where: g = (0.785/Eᵢ)Σ(L²ω/p²) (see Glossary) Hardly any research, however, has been done on discomfort glare from small sources, so the definition of a small source was just not known. It was not known whether to define it as an effective solid angle, ros or area, As. Two hypotheses were put forward concerning the effective size of a small source: Hypothesis # 1 ('constant omega' hypothesis) The effective size of a small source has a solid angle, ros. Any source with an actual solid angle less than ros shall be considered a small source and will have an effective solid angle equivalent to ros when viewed off the line of sight (LoS). This solid angle, ros is a constant. i.e. it remains the same irrespective of distance from the source. Hypothesis # 2 ('constant area' hypothesis) The effective size of a small source has an area, As. Any source with a projected area less than As shall be considered a small source and will have an effective area equivalent to As when viewed off the line of sight (LoS). This area, As is a constant. i.e. its solid angle varies inversely proportional to the square of the distance from the source.
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    Visual assessment of colour rendering. Volume One
    (1971) Corrigall, Michael Robert Vint; Einhorn, H D
    The first part describes experimental work done which led to the construction of a portable pocket filter instrument which made it possible to assess the C.I.E. Colour Rendering Index for fluorescent lamps by a simple visual testo Research !uork was done on filter devices in the laboratory, and the results processed by digital computer. The second part deals with a visual problem. Tests done using filter devices indicated two groups of observers with normal colour vision. After an experimental investigation on a few observers, this problem was overcome by using a pale yellow filter in the instrumentc Details of the computer programme and experimental details are described in appendices. Records are contained in a separate volume