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 [edit]
- ^ 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.
- ^ Hunter, Richard Sewall (September 1942). "Photoelectric tristimulus colorimetry with three filters". JOSA 32 (9): 509–538. doi:10.1364/JOSA.32.000509.
- ^ 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.
- ^ Luther, Robert T.D. (1927). "Aus dem Gebiet der Farbreizmetrik". Zeitschrift für technische Physik 8: 540–558.
- ^ 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 978-0-470-09472-3.
- ^ 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. Retrieved 2008-05-06.
- ^ Solli, Martin (December 16 2004). Filter characterization in digital cameras (PDF). Retrieved 2008-05-06.
- ^ Sangwine, Stephen J.; Horne; Robin E. N. (1998). The Colour Image Processing Handbook. Springer. p. 41. ISBN 0-412-80620-7.
- ^ 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 978-3-901906-60-2.
- ^ 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.
