Description Sums two spectrum of any type together and creates a new sampled spectrum from the resulting summation. The following rules apply: •If a sampled spectrum is included in the summation, data points in the new spectrum will include those from the sampled spectrum. •If two spectrum have sample points which are very close together (to precision around 10-4 ), then only one of the sample points is used. •Values outside of a spectrum's wavelength range are considered to be zero. •Values between sampled spectrum points are linearly interpolated in the summation. •If both spectrum used in the summation are sampled spectrum, then the suggested sample count specification is ignored.
Syntax spectNode = SpectrumCombine( scale1, spect1, scale2, spect2, suggestedSampleCount )
Parameters spectNode (Long) Node number of the newly created spectrum
scale1 As Double Scale factor for the values in the first spectrum being used in the combination.
spect1 As Long Node number of the first spectrum being used in the combination.
scale2 As Double Scale factor for the values in the second spectrum being used in the combination.
spect2 As Long Node number of the second spectrum being used in the combination.
suggestedSampleCount As Long Number of suggested sample points for the newly created spectrum. This IS NOT the number of sample points in the resulting spectrum due to the reduction of similar data points (see notes above). FRED will attempt to set the number of resulting sample points as close to this value as is reasonable.
Example The following example creates a Blackbody spectrum, a CIE Y color matching spectrum and combines the two into a new spectrum with 200 suggested sample points.
Dim spectNodeBB As Long Dim spectNodeY As long Dim spectNodeComb As Long
spectNodeBB = SpectrumCreateBlackbody( 5900, 0.3, 0.7 ) spectNodeY = SpectrumCreatePredefinedSampled( 2 )
spectNodeComb = SpectrumCombine( 1, spectNodeY, 3, spectNodeBB, 200 ) SpectrumSetName spectNodeComb, "Summed Spectrum"
See Also SpectrumComputeLuminousEfficacy
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