Calibrated photometer model

ID: calibrated-photometer-model

Use the triangular in equal radiant power under visual weighting and stipulate the detector's spectral responsivity
This model has nonnegative response: is zero outside –. For a ideal calibration line at , and , so . An equal-radiant flux test line at gives , and . The unchanged conversion indicates , whereas the model's intended weighted result is . The required spectral mismatch correction is : the uncorrected result is 50% too large. All these numbers are declared model outputs, not instrument measurements or standard photometry data.
Figure 1.
Calibration at one wavelength leaves a spectral mismatch at another
. Original schematic and analytic model. The apparatus shows the signal path of a filtered photodiode photometer, with shutter-closed subtraction; it is not a drawing to scale of a specific instrument. The lower panels use the declared triangular weighting and detector response, not CIE tables. The two ideal lines carry the same collected radiant flux; the source-dependent factor corrects the test indication within this model only. Details.

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