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function [val_UWattsPerSrCm2,limit_UWattsPerSrCm2] = ISO2007MPEComputeType1ContinuousRadianceTHWeightedValue(...
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S,radiance_WattsPerSrM2,weightingR,stimulusDurationSecs)
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%[val_UWattsPerSrCm2,limit_UWattsPerSrCm2] = ISO2007MPEComputeType1ContinuousRadianceTHWeightedValue(...
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% S,radiance_WattsPerSrM2,weightingR,stimulusDurationSecs)
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% Compute the weighted thermal radiance for Type 1 instruments as given on page 9, Table 2,
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% 5.4.1.6.b. Note. The limit specified there is 6 W/[sr-cm2]. I reduced to 5.88 because
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% this is the worst-case Type 2 limit (largest retinal diameter spot, see Table 4, 5.5.1.5b),
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% and it seemed more conservative to do so.
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% Input spectrum is radiance in units of Watts/[sr-m2-wlinterval].
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% Also return the exposure limit for this quantity.
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% See page 6 for a definition of a Type 1 instrument. As far as I can tell, the key
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% criterion is that it doesn't put out more light that exceeds the Type 1 limits.
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% If the exposure time is longer than 2 hours the specified limits should be reduced by
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% 1/exposureDuration in hours. This routine implements that adjustment for its returned
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% limit value. It does not implement a further reduction of of the limit (by a factor of 2)
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% specifed for microscopes and endoilluminators.
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% The standard specifies that the passed radiance should be the highest averaged over
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% an aperture of a specified size, where the size depends on the instrument. This
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% routine does not worry about that aspect. The most conservative thing to do is
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% to pass the highest localized power that will be presented.
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% The indicates that radiance should be measured through a 7 mm aperture at the cornea.
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% I believe this refers to the case where you are measuring radiance by measuring radiant
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% flux through two apertures at a known distance apart. It would then make sense that you'd
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% want to know the radiance defined by the direction subtended by a 7 mm aperture at the
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% cornea, e.g. right where a large pupil would be. If you measure using some other device
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% (e.g. a PhotoResearch PR-XXX that directly obtains radiance and do so from the eye position,
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% that also seems reasonable.
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% ****************************************************************************
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% IMPORTANT: Before using the ISO2007MPE routines, please see the notes on usage
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% and responsibility in PsychISO2007MPE/Contents.m (type "help PsychISO2007MPE"
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% at the Matlab prompt.
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% ****************************************************************************
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% 6/26/13 dhb Wrote it.
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%% Specify the limit (from table, see note above about why
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% 5.88 rather than 6.)
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exposureDurationHours = stimulusDurationSecs/3600;
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if (exposureDurationHours <= 2)
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limit_UWattsPerSrCm2 = 5.88*(10^6);
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limit_UWattsPerSrCm2 = 5.88*(10^6)/(exposureDurationHours/2);
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radiance_UWattsPerSrM2 = (10^6)*radiance_WattsPerSrM2;
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radiance_UWattsPerSrCm2 = (10^-4)*radiance_UWattsPerSrM2;
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%% Get weighted sum. The weighting function is zero outside the
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% specified wavelength range, so we don't have to worry about the
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% wavelength limits in the standard. We do perform a sanity check
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% that something got passed in the wavelength region of interest.
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index = find(wls >= 380 & wls <= 1400, 1);
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error('Should not call this routine with no spectral sampling between 380 and 1400');
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val_UWattsPerSrCm2 = sum(radiance_UWattsPerSrCm2 .* weightingR);