Controversial results from different studies of the luminance required in the entrance zone of vehicular tunnels lead to the development of the method described to obtain the actual adaptation luminance of the observer in approaching the tunnel. The equivalent veiling luminance following from the luminances occurring in the visual field can be computed for different fixation points and distances to the tunnel. (Ls)eq superimposes on the luminance of the area around the fixation point and has the effect of decreasing the contrast of a small target to be perceived in its centre. Since its contrast reduced in such a way has always to be 0.2 to ensure visibility under practical conditions the required entrance luminances for different (Ls)eq levels and target contrasts can be derived by calculation.


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    Title :

    Method of calculating the required luminances in tunnel entrances


    Additional title:

    Verfahren zur Berechnung der erforderlichen Beleuchtung beim Tunnelanfang


    Contributors:
    Adrian, W. (author)

    Published in:

    Publication date :

    1976


    Size :

    4 Seiten, 5 Quellen



    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English





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