CIE XYZ values from spectral radiance (watts/nm/sr/m2) or irradiance (watts/nm/m2)
XYZ = ieXYZFromEnergy(energy,wave)
Calculate the XYZ values of the spectral radiance or irradiance
functions in the variable ENERGY. The input format of energy can be
either XW (space-wavelength) or RGB. The wavelength samples of energy
are stored in the variable WAVE.
Notice, that XW is AN UNUSUAL FORMAT for energy. Often, we put the
SPDs into the columns of the matrix. But in the XW format, the SPDs
are in the rows. Sorry.
The returned values, XYZ, are X,Y,Z in the columns of the matrix. Each
row of energy has a corresponding XYZ value in the corresponding row of XYZ.
The units of Y are candelas/meter-squared if energy is radiance and lux
if energy is irradiance.
Examples:
wave = 400:10:700;
energy = vcReadSpectra('crtSPD',wave)';
displayXYZ = ieXYZFromEnergy(energy,wave)
patchSize = 1;
macbethChart = sceneCreate('macbeth',patchSize);
p = sceneGet(macbethChart,'photons'); wave = sceneGet(macbethChart,'wave'); e = Quanta2Energy(wave,p);
XYZ = ieXYZFromEnergy(e,wave);
Copyright ImagEval Consultants, LLC, 2003.