Tristimulus colorimeter

A Tristimulus colorimeter, colloquially shortened to colorimeter, is used in digital imaging, to profile and calibrate output devices. It takes a limited number of wideband spectral energy readings along the visible spectrum by using filtered photodetectors; e.g. silicon photodiodes.[1]

Originally, three glass filters whose transmittance spectra mimicked the CIE color matching functions (shown on the right) were employed.[2] A filter bank may be used to decompose the individual color matching functions if more accuracy is desired.[3]

A camera or colorimeter is said to be colorimetric if it satisfies the Luther condition (de) by Robert Luther (de) (1868–1945) (also called the "Maxwell-Ives criterion"),[4] reducing observer metamerism color errors, if the product of the spectral responsivity of the photoreceptor and the spectral transmittance of the filters is a linear combination of the CMFs.[5]

A colorimeter or a digital camera with a color filter array can, under certain conditions, be used as an alternative to a spectrophotometer.[6][7]

The illuminant and observer conditions should be specified when citing a measurement (e.g. D65/10°).[8]

The quality of a colorimeter may be assessed using the means in CIE publication 179:2007.[9]

There are various calibration methods for tristimulus colorimeters.[10]

References

  1. ^ Schanda, János; George Eppeldauer, Georg Sauter (2007). "Tristimulus Color Measurement of Self-Luminous Sources". In János Schanda. Colorimetry: Understanding the CIE System. Wiley Interscience. doi:10.1002/9780470175637.ch6. ISBN 978-0-470-04904-4. 
  2. ^ Hunter, Richard Sewall (September 1942). "Photoelectric tristimulus colorimetry with three filters". JOSA 32 (9): 509–538. doi:10.1364/JOSA.32.000509. http://www.opticsinfobase.org/abstract.cfm?URI=josa-32-9-509. 
  3. ^ Eppeldauer, George (Nov/Dec 1998). "Spectral Response Based Calibration Method of Tristimulus Colorimeters" (PDF). Journal of Research of the National Institute of Standards and Technology 103 (6): 615. http://nvl.nist.gov/pub/nistpubs/jres/103/6/j36epp.pdf. 
  4. ^ Luther, Robert T.D. (1927). "Aus dem Gebiet der Farbreizmetrik". Zeitschrift für technische Physik 8: 540–558. 
  5. ^ Ohta, Noboru; Robertson, Alan R. (2005). "Measurement and Calculation of Colorimetric Values". Colorimetry. John Wiley & Sons, Ltd.. p. 154. doi:10.1002/0470094745.ch5. ISBN 9780470094723. 
  6. ^ Imai, Francisco H.; Berns, Roy S. (1999). "Spectral estimation using trichromatic digital cameras" (PDF). Proceedings of the International Symposium on Multispectral Imaging and Color Reproduction for Digital Archives 42. http://www.cis.rit.edu/research/mcsl2/online/Spectral/TechnicalPapers/SpecEstimRGBCamera_Chiba99.pdf. Retrieved 2008-05-06. 
  7. ^ Solli, Martin (December 16 2004) (PDF). Filter characterization in digital cameras. http://www.diva-portal.org/diva/getDocument?urn_nbn_se_liu_diva-2667-1__fulltext.pdf. Retrieved 2008-05-06. 
  8. ^ Sangwine, Stephen J.; Horne; Robin E. N. (1998). The Colour Image Processing Handbook. Springer. p. 41. ISBN 0412806207. http://books.google.com/books?id=oEsZiCt5VOAC&pg=PA42&dq=%22tristimulus+colorimeter%22+OR+spectrocolorimeter&ei=__upR-P9J5O0yQTa3ZzdCA&ie=ISO-8859-1&sig=fQJn9ijlQT4b5vjeFIQpOqCkdNY#PPA41,M1. 
  9. ^ CIE TC 2-16 "Characterization of the Performance of Tristimulus Colorimeters" (2007). Methods for characterising tristimulus colorimeters for measuring the colour of light. Publication 179:2007. Vienna: CIE Central Bureau. ISBN 9783901906602. http://www.cie.co.at/publ/abst/179-07.html. 
  10. ^ Gardner, James L. (May-June 2007). "Comparison of Calibration Methods for Tristimulus Colorimeters". Journal of Research of the National Institutes of Standards and Technology 112 (3): 129–138. http://nvl.nist.gov/pub/nistpubs/jres/112/3/V112.N03.A01.pdf.