UBC Faculty Research and Publications

Determination of Sky View-Factors in Urban Environments Using Video Imagery. Steyn, Douw G.; Hay, J. E.; Watson, Ian D.; Johnson, Glenn T.


A technique is described whereby sky view-factors may be determined using a video camera equipped with a fish-eye lens. The video image is digitized and then analyzed to distinguish between “sky” and “non-sky” pixels. View-factors are calculated for each pixel and then summed for all “sky” pixels to yield a composite sky view-factor for the image. The technique is illustrated by applying it in three urban locations, all of which are characterized by high building densities (and hence complex skylines). The three images processed have sky, view-factors in the range 0.15 to 0.46 (as independently determined). It is shown that the present technique produces values in close agreement with these and appears quite robust when compared with calculations based on the work of Johnson and Watson. Copyright 1986 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a web site or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/) or from the AMS at 617-227-2425 or copyright@ametsoc.org.

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