The cief1 functions calculates the f'_1 error of photometers, or more precisely the mismatch index to the V(\lambda) curve. Any errors in the data set or in results generated with the Lighting Toolbox are not in the liability of the CIE nor me, see licence.

Note: with CIE 179 the f'_1 error was extended for colorimetric photometers and hence for the CIE \bar{x}, \bar{y}, \bar{z} functions.


f1 = cief1(lam,spec,'reference')


f1Is the returned f1 deviation, 0 for a perfect match.
lamSpecifies the wavelengths.
specSpecifies the spectral filter function.
Defines the target function:
‘VL’ for V(\lambda) (default)
‘x’ for \bar{x}
‘y’ for \bar{y}
‘z’ for \bar{z}
Note: these represent the official CIE f1 errors, but the function accepts any reference as in the ciespec function or an vector.


Determine the f'_1 mismatch index for a given filter function:

% create V(lambda) function
lam = 380:780;
VL = ciespec(lam,'VL');
% change VL function slightly
spec = VL.^(1.05);
% determine f1 error
f1 = cief1(lam,spec)
% plot both functions
legend('V(\lambda)','test filter function')
xlim([380 780])

See also: ciespec


f1 = 2.4148

Determine the f'_{1,x} mismatch index for a given \bar{x} colour filter function:

% create x-bar function
lam = 380:780;
x = ciespec(lam,'x');
% change x-bar function slightly
spec = x.^(1.05);
% determine f1,x error
f1x = cief1(lam,spec,'x')

See also: ciespec


f1x = 2.7693


ISO/CIE 19476:2014(E): Characterization of the performance of illuminance meters and luminance meters. Commission International de l’Éclairage (CIE), Vienna Austria, 2014.

CIE 179:2007: Methods for Characterising Tristimulus Colorimeters for Measuring the Colour of Light. Commission International de l’Éclairage (CIE), Vienna Austria, 2007, ISBN: 978 3 901906 60 2.

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