Data format standard for sharing light source measurements

G. Groot Gregory, Ian Ashdown, Willi Brandenburg, Dominique Chabaud, Oliver Dross, Sanjay Gangadhara, Kevin Garcia, Michael Gauvin, Dirk Hansen, Kei Haraguchi, Günther Hasna, Jianzhong Jiao, Ryan Kelley, John Koshel, Julius Muschaweck

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


Optical design requires accurate characterization of light sources for computer aided design (CAD) software. Various methods have been used to model sources, from accurate physical models to measurement of light output. It has become common practice for designers to include measured source data for design simulations. Typically, a measured source will contain rays which sample the output distribution of the source. The ray data must then be exported to various formats suitable for import into optical analysis or design software. Source manufacturers are also making measurements of their products and supplying CAD models along with ray data sets for designers. The increasing availability of data has been beneficial to the design community but has caused a large expansion in storage needs for the source manufacturers since each software program uses a unique format to describe the source distribution. In 2012, the Illuminating Engineering Society (IES) formed a working group to understand the data requirements for ray data and recommend a standard file format. The working group included representatives from software companies supplying the analysis and design tools, source measurement companies providing metrology, source manufacturers creating the data and users from the design community. Within one year the working group proposed a file format which was recently approved by the IES for publication as TM-25. This paper will discuss the process used to define the proposed format, highlight some of the significant decisions leading to the format and list the data to be included in the first version of the standard.

Original languageEnglish (US)
Title of host publicationLED-Based Illumination Systems
ISBN (Print)9780819496850
StatePublished - 2013
EventLED-Based Illumination Systems - San Diego, CA, United States
Duration: Aug 26 2013Aug 26 2013

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherLED-Based Illumination Systems
Country/TerritoryUnited States
CitySan Diego, CA


  • LED
  • illumination
  • illumination engineering
  • solid-state lighting
  • source modeling

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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