ccoprrm@pyr.gatech.EDU (ROBERT E. MINSK) (06/27/89)
Does anyone have a program or know of an algorithm to convert from Frequency (or wavelength) to CIE XYZ coordinate space. I am not looking for CIE to RGB or for manipulations within the color space; this I already know how to do. -- ROBERT E. MINSK Georgia Insitute of Technology, Atlanta Georgia, 30332 uucp: ...!{akgua,allegra,amd,hplabs,ihnp4,seismo,ut-ngp}!gatech!gitpyr!ccoprrm ARPA: ccoprrm@pyr.gatech.edu
bdb@becker.UUCP (Bruce Becker) (06/28/89)
In article <8594@pyr.gatech.EDU> ccoprrm@pyr.gatech.edu.UUCP (ROBERT E. MINSK) writes: | | Does anyone have a program or know of an algorithm to convert from |Frequency (or wavelength) to CIE XYZ coordinate space. I am not looking |for CIE to RGB or for manipulations within the color space; this I |already know how to do. This is off the top of my head, so it will need some refinement... Tables exist in several places which map the periphery of the CIE standard visibility gamut in 5-nanometer increments (or sometimes other resolutions), expressed in CIE coordinates. Given this polygon, you can interpolate the wavelength into its border so as to arrive at the fully saturated CIE coordinate value. Other saturations occur monotonically on a line from there to the current reference white point. The transformation from the (x,y,Y) coordinate system (if needed), to (X,Y,Z) is simple. Cheers, -- __ Bruce Becker Toronto, Ont. w \cc/ Internet: bdb@becker.UUCP, bruce@gpu.utcs.toronto.edu `/v/-e BitNet: BECKER@HUMBER.BITNET _< >_ "Not only am I the Nair Club president, I'm also a client" - Y. Brynner
jlg@hpfcdq.HP.COM (Jeff Gerckens) (07/06/89)
> In article <8594@pyr.gatech.EDU> ccoprrm@pyr.gatech.edu.UUCP (ROBERT E. MINSK) writes: > | > | Does anyone have a program or know of an algorithm to convert from > |Frequency (or wavelength) to CIE XYZ coordinate space. I am not looking > |for CIE to RGB or for manipulations within the color space; this I > |already know how to do. > > This is off the top of my head, so it will need some > refinement... > > Tables exist in several places which map the periphery > of the CIE standard visibility gamut in 5-nanometer > increments (or sometimes other resolutions), expressed > in CIE coordinates. > Given this polygon, you can interpolate the wavelength > into its border so as to arrive at the fully saturated > CIE coordinate value. Other saturations occur monotonically > on a line from there to the current reference white point. > The transformation from the (x,y,Y) coordinate system > (if needed), to (X,Y,Z) is simple. Tables can be found in : Color in Business, Science, and Industry by Deanne Judd, and Color Science: Concepts and Methods, Quantitative Data and Formulae by Wyszecki and Stiles - Jeff Gerckens, Graphics Technology Division, Hewlett-Packard jlg%hpfcrg.fc.hp@hplabs.hp.com