commission internationale de l'eclairage international ... - CIE Australia

Further important input came from Kohji Kawakami (JP) : A Japanese Industry Standard
on sports lighting is planned for publication in 2008 (the targets are e.g. the game balls and
the human faces) described by the space illumination characteristics ECyl and ESC (work on the
Standard has been started 7 years ago).
Axel Stockmar of Germany has published in the early 1980’s some papers on threedimensional
illuminances, the lighting field and cubic illumination where the accuracy of the
concepts and of the measurements is seriously put into question (see the lighting journals
“Lichtforschung” and “Lichttechnik”). These papers have to be studied thoroughly again
for implementation in the TC 5-23 document. In here, Axel Stockmar has proven that
approximating cubic illumination by means of 4 vertical illuminance values (from the
approximation formula of cubic illumination) is introducing very important errors (during that
period huge computer capabilities were not yet available). Counting the negative term in the
formula or not was not influencing the result; even when increasing the number of planes to
11 for instance.
Axel Stockmar has stated after this TC meeting that cubic illumination can better be directly
calculated without any problem, and not be estimated by very inaccurate measurements.
Axel Stockmar is questioning the validity of application of cubic illumination in outdoor
environments because of its nature as “general field”. Petr Zák replies on this by stating that
the outdoor lighting applications are no general field issues but on the contrary restricted
fields, with formulae even simplier. Petr Zák wishes to express his agreement on the
statement of poor accuracy of the cubic illumination measurements.
5. Next meeting
The next meeting will be held in Budapest_Hungary on the occasion of the Midterm Meeting
of the CIE Divisions 4 & 5 between 1 and 3 June 2009.
6. Activities to be carried out
� C. Cuttle could be invited for the next meeting.
� Tom Lemons will send a photocopy of the chapter of the book “Cubic Illumination” by
C. Cuttle to P. Rombauts. Tom Lemons will also prepare a text on “Cubic Illumination”
and send the proposal to Kit Cuttle for approval.
� Petr Zák (Czech Republic) will translate his paper of 1999 on the integral
characterisation of the lighting field from Czech to English.
� The papers that Axel Stockmar of Germany has published in the early 1980’s in
“Lichtforschung” and “Lichttechnik” on three-dimensional illuminances, the lighting
field and cubic illumination have to be studied thoroughly again for implementation in
the TC 5-23 document.
� A Work Scheme will be established by P. Rombauts to meet the new terms of reference
and to solve the issue of people face’s brightness, characterised by illuminance
parameters, by setting up a student’s Master thesis project.
� Eduardo Manzano (ES; AR) will be contacted for eventual input.
CIE TC 5-23 Meeting Report 2_9_2008 Helsinki - Finland 4/6