ANALYSES OF ERRORS ASSOCIATED WITH PHOTOMETRIC DISTANCE IN GONIOPHOTOMETRY

Published

July 31, 2015

Author(s)

Yoshihiro Ohno, V. Jacobs, Peter Blattner, Tony Bergen, Udo Krueger, P. Rombauts, F. Schmidt, Peter Hanselaer

Abstract

In lighting calculations and simulations, the emission of a light source is conventionally modelled using the far-field intensity, also termed luminous intensity distribution (LID). Previous studies have indicated that the traditional limiting photometric distance, to reach far-field conditions, is not always easy to determine. The “limiting photometric distance”,also called the “photometric limiting distance” of a light source is the “shortest distance between the reference plane of a light source and the effective reference plane of a photometer, for a given acceptable error considering the photometric inverse square law” (ISO/CIE 19476:2014, 2014). This distance is dependent on the size of the light source, the luminous intensity distribution (beam angle), the spatial luminance distribution and the predetermined acceptable measurement error. In this paper the problems are analysed in detail for a disk-shaped light source, a linear light strip and a “worst case scenario” using two small (point) sources separated by a certain distance. The limiting photometric distance is investigated using different measures of error - not only for the main illumination direction but also at different angles of emission.

Proceedings Title

Proc., the 28the Session of CIE

Volume

1

Issue

1

Conference Dates

June 29-July 3, 2015

Conference Location

Manchester

Conference Title

The 28the Session of International Commission on Illumination

Pub Type

Conferences

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Keywords

photometric distance, far-field, near-field, goniophotometry, inverse-square law

Citation

Ohno, Y. , Jacobs, V. , Blattner, P. , Bergen, T. , Krueger, U. , Rombauts, P. , Schmidt, F. and Hanselaer, P. (2015), ANALYSES OF ERRORS ASSOCIATED WITH PHOTOMETRIC DISTANCE IN GONIOPHOTOMETRY, Proc., the 28the Session of CIE, Manchester, -1, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=918711 (Accessed October 31, 2024)