Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

ANALYSES OF ERRORS ASSOCIATED WITH PHOTOMETRIC DISTANCE IN GONIOPHOTOMETRY

Published

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

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 April 13, 2024)
Created July 31, 2015, Updated February 19, 2017