Validation of the fisheye camera method for spatial non-uniformity corrections in luminous flux measurements with integrating spheres

Research output: Contribution to journalArticleScientificpeer-review


  • Alexander Kokka
  • Tomi Pulli
  • Alejandro Ferrero
  • Paul Dekker
  • Anders Thorseth
  • Petr Kliment
  • Adam Klej
  • Thorsten Gerloff
  • Klaus Ludwig
  • Tuomas Poikonen
  • Erkki Ikonen

Research units

  • Czech Metrology Institute
  • VSL Dutch Metrology Institute
  • Technical University of Denmark
  • Philips Lighting
  • Physikalisch-Technische Bundesanstalt (PTB)
  • Osram GmbH
  • CSIC
  • VTT Technical Research Centre of Finland


In this paper, the fisheye camera method is validated for spatial non-uniformity corrections in luminous flux measurements with integrating spheres. The method was tested in eight integrating spheres with six LED lamps, and the determined angular intensity distributions and spatial non-uniformity correction factors were compared with the results of five goniophotometers. The average closeness score, describing the similarity between any two distributions, was 94.6 out of 100 for the distributions obtained using the fisheye camera method when compared with the goniophotometric results. The average closeness score for the five goniophotometers, when each goniophotometer was compared with the other four, was 96.6. On average, the relative deviation between the two methods was 0.05% when calculating the spatial corrections. The most significant sources of uncertainty for the fisheye camera method were large, view-obstructing sphere elements residing close to the camera port.


Original languageEnglish
Pages (from-to)045002
Number of pages9
Issue number4
Publication statusPublished - 18 Jun 2019
MoE publication typeA1 Journal article-refereed

    Research areas

  • ERRORS, REALIZATION, UNIT, angular intensity distribution, fisheye camera method, integrating sphere, luminous flux, measurement uncertainty, photometry, spatial correction

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