Camera calibration tab and camera color space

Question

Hi, I need a confirmation about the hue and saturation sliders on the camera calibration tab. They are there for fine tuning the camera color space primaries in a DNG profile? Thanks a lot.

Answer 1

Hello, here I'm again.
I'm probably in the wrong forum, because I can't tell you anything about the DNG secrets
(though I have the specs).
About your second question (more an issue for a color science forum), I've found something:
Estimation of the primaries for a digital camera:
Please refer to these docs:
(1)
Concerning the Calculation of the Color Gamut in a Digital Camera
Francisco Martínez-Verdú et al.
http://www.google.de/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CEMQFjAB&url=http%3A%2F %2Frua.ua.es%2Fdspace%2Fbitstream%2F10045%2F973%2F1%2Fproof_final.pdf&ei=uL8UU8-dKYO9ygORs IKADQ&usg=AFQjCNGKNGHQZJoHu_dc2JwQwtLXOpsTBQ&bvm=bv.61965928,d.bGQ&cad=rja
(2)
http://docs-hoffmann.de/leastsqu16112006.pdf
Given is an equation
(*) X = C R
We have two applications:
(1)  Original question
X = Matrix  X1 X2 ... Xm
                Y1 Y2 ... Ym
                 Z1 Z2 ... Zm
m=41 values in each row for CIE CMFs (color matching functions) 380nm...780nm
R = Matrix  R1 R2 ... Rm
                 G1 G2 ... Gm
                 B1 B2 ... Bm  
41 values in each row for the sensor sensitivities for red, green and blue CCD array elements
Matrix C is found by solving equation (*), using the pseudoinverse.
Matrix C contains the XYZ-coordinates of the primaries red, green, blue as columns 1, 2 and 3.
(2) About the mathematics
X = Matrix  X1 X2  ...  Xm
                 Y1 Y2 ... Ym
                 Z1 Z2 ... Zm
m=24 values for the GretagMacbeth ColorChecker
R = Matrix  R1 R2 ... Rm
                  G1 G2 ... Gm
                  B1 B2 ... Bm  
24 values in each row for the RGB results als delivered by the camera, for instance in sRGB.
Matrix C contains the XYZ-coordinates of the effective primaries(including sRGB)  red, green, blue as columns.
(2) explains the principle of the pseudoinverse for overdetermined systems of linear equations.
(1) explains the application for the identification of camera primaries for given sensor sensitivities.
Unfortunately, the whole concept will fail, if the camera sensor sensitivities (CMFs) are not
linear combinations of the CIE CMFs x-bar, y-bar, z-bar. In this case, a camera does not have
primaries, but the computational result can be used as an approximation.
CMF = color matching function (CIE)
I regret –it cannot be explained 'for the layman'.
Best regards --Gernot Hoffmann