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.
Usage:
f1 = cief1(lam,spec,'reference')
Where:
| Parameter | Description |
f1 | Is the returned f1 deviation, 0 for a perfect match. |
lam | Specifies the wavelengths. |
spec | Specifies the spectral filter function. |
reference | 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. |
Examples
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
plot(lam,[VL;spec])
legend('V(\lambda)','test filter function')
xlim([380 780])
See also: ciespec
Result:
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
Result:
f1x = 2.7693
References: