How the CIE 1931 color‐matching functions were derived from Wright‐Guild data

Fairman, Hugh S.; Brill, Michael H.; Hemmendinger, Henry

doi:10.1002/(sici)1520-6378(199702)22:1<11::aid-col4>3.3.co;2-f

Cited by 64 publications

(72 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The chromaticity coordinates have been calculated based on the standard observer CIE 1931 color matching functions [43]. This resulted in the coordinates of , very close to the (0.33,0.33) coordinates of ideal white light with a flat spectrum, as illustrated in the inset of Fig.…”

Section: Qw Design For Emitting Near White Lightmentioning

confidence: 90%

Design of a GaN White Light-Emitting Diode Through Envelope Function Analysis

Khoshnegar

Sodagar

Eftekharian

et al. 2010

IEEE J. Quantum Electron.

View full text Add to dashboard Cite

Abstract-In this paper, we present an envelope function analysis technique for the design of the emission spectra of a white quantum-well light-emitting diode (QWLED). The nanometric heterostructure that we are dealing with is a multiple QW, consisting of periods of three single QWs with various well thicknesses. With the aid of 6 6 Luttinger Hamiltonian, we employ the combination of two methods, k p perturbation and the transfer matrix method, to acquire the electron and hole wave functions numerically. The envelope function approximation was considered to obtain these wave functions for a special basis set. While adjacent valence sub-bands have been determined approximately, the conduction bands are approximated as parabolic. The effect of Stokes shift has also been taken into account. The dipole moment matrix elements for interband atomic transitions are evaluated via the correlation between the electron and hole envelope functions, for both orthogonal polarizations, thus simplifying the calculation of the photoluminescence intensity. Spatial variations in the hole/electron wave functions have been examined with the introduction of piezoelectric and spontaneous polarization internal fields. We theoretically establish the possibility of a highly efficient InGaN red emitter, resulting in a uniform luminescence in red, green, and blue emissions from a white light emitting diode by adjusting the material composition, internal field, and well thickness.Index Terms-Envelope function analysis, GaN, k p method, optical intensity spectrum, white LED.

show abstract

Section: Qw Design For Emitting Near White Lightmentioning

confidence: 90%

Design of a GaN White Light-Emitting Diode Through Envelope Function Analysis

Khoshnegar

Sodagar

Eftekharian

et al. 2010

IEEE J. Quantum Electron.

View full text Add to dashboard Cite

show abstract

“…The Commission Internationale de l'Eclairage (CIE 1931) introduced colorimetry as "a system for color measurements" and created "CIE 1931 XYZ color space" (Wright 1928;Thomas and Guild 1931;Guild 1932;Fairman et al 1997). This color space includes all the colors that an average person can experience.…”

Section: Srgb To Tristimulusmentioning

confidence: 99%

WACODI: A generic algorithm to derive the intrinsic color of natural waters from digital images

Novoa

Wernand

Woerd

2015

Limnology & Ocean Methods

View full text Add to dashboard Cite

This document presents the WAter COlor from Digital Images (WACODI) algorithm, which extracts the color of natural waters from images collected by low-cost digital cameras, in the context of participatory science and water quality monitoring. SRGB images are converted to the CIE XYZ color space, undergoing a gamma expansion and illumination correction that includes the specular reflection at the air-water interface.The XYZ values obtained for each pixel of the image are converted to chromaticity coordinates and Hue color angle (a w ), which is a measure of color. Based on the distributions of a w in sub-sections of the image, an approximation of the intrinsic color of the water is obtained. This algorithm was applied to images acquired in 2013 during two field campaigns in Northern Europe. The Hue color angles were derived from hyperspectral measurements above and below the surface, carried out simultaneously with image acquisition. When for each station a specific illumination correction was applied, based on the corresponding hyperspectral data, a good fit (r 2 5 0.93) was obtained between the image and the spectra Hue color angles (slope 5 0.98, intercept 5 20.03). When a more generic illumination correction was applied to the same images, based on the sky conditions at the time of the image acquisition (either overcast or sunny), a slightly inferior, but still satisfactory fit resulted. Results on the application of the WACODI algorithm to the first images collected by the public via the smartphone application or "APP," developed within the European FP7 Citclops, are presented at the end of this study.

show abstract

“…Hence, the transformation from the CIE RGB CMF's to CIE XYZ CMF's was determined so as to avoid negative values at all wavelengths [42]. Since an infinite number of transformations can be defined in order to meet this nonnegativity requirement, additional criteria were used in the choice of the CMF's [43], [44, p. 531]. Two of the important considerations were the choice of coincident with the luminous efficiency function [12] and the normalization of the three CMF's so as to yield equal tristimulus values for the equi-energy spectrum.…”

Section: ) Cie Standardsmentioning

confidence: 99%

Digital color imaging

Sharma

Trussell

1997

IEEE Trans. on Image Process.

367

200

View full text Add to dashboard Cite

Abstract-This paper surveys current technology and research in the area of digital color imaging. In order to establish the background and lay down terminology, fundamental concepts of color perception and measurement are first presented using vector-space notation and terminology. Present-day color recording and reproduction systems are reviewed along with the common mathematical models used for representing these devices. Algorithms for processing color images for display and communication are surveyed, and a forecast of research trends is attempted. An extensive bibliography is provided.

show abstract

How the CIE 1931 color‐matching functions were derived from Wright‐Guild data

Abstract: The principles that guided the founders of the Sons, Inc. Col Res Appl, 22, 11-23, 1997. World War, with the devastation of the European continent,

Cited by 64 publications

References 0 publications

Design of a GaN White Light-Emitting Diode Through Envelope Function Analysis

Design of a GaN White Light-Emitting Diode Through Envelope Function Analysis

WACODI: A generic algorithm to derive the intrinsic color of natural waters from digital images

Digital color imaging

Contact Info

Product

Resources

About