>Psychtoolbox>PsychRadiometric>PsychISO2007MPE

Psychtoolbox:PsychISO2007MPE.

Partial and in progress implementation of ISO 2007 standard for computing
maximum permissable exposure to broadband lights.

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IMPORTANT

Individuals using these routines must accept full responsibility
for light exposures they implement. We recommend that values computed
with these routines be carefully checked against independent calculations.
We have done our best to follow the standard, but it is very complex and
there may be errors.

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NOTES:

a) As of June, 2013, these routines are still very much a work
in progress and should thus be treated with special caution. See
ISO2007MPEBasicTest. If someone has some worked out test cases
it would be great to check those against the computations done
by this suite of routines. Please contact me (brainard@psych.upenn.edu)
if you can help.

b) Only the Type 1 limits are computed. My impression is that these are
more conservative, and that if you stay below them you good wrt the
standard content. I believe that technically, a Type 1 instrument is
one that *cannot* produce more light than the Type 1 limits, but it seems
to me that for research purposes the main point is to stay below those limits
independent of what the instrument could in principle produce.

In addition, for exposure durations of less than 2 hours (7200) seconds, the
Type 2 limits are more lenient than the Type 1 limits, except for 5.5.1.5b versus
5.4.1.6b, where the worst case Type 2 limit is a little lower (5.88 W/[sr-cm2]
than the Type 1 limit (6 W/[sr-cm2]). To be conservative, I used the 5.88 value
in the relevant routine.

If someone knows more or has a different view, please let me (DHB, brainard@psych.upenn.edu) know.

c) There is a limit (Table 2, 5.4.1.5) for convergent beams, which I think is what
a Maxwellian view produces. I wrote a placeholder routine for this limit, but since
I am not currently using such a rig I don’t have any application for it and have
not tested it.

d) The standard uses cm^2 based units for radiance, irradiance, etc. It switches
between uWatts, mWatts, and Watts depending on which limit is being considered.
For uniformity, these routines return all quantities and limits in uWatts, cm^2
based units.

For input, we typically measure radiance in Watts/[sr-m^22] and all the routines take
radiance as input and convert as necessary (with the help of passed ancilliary arguments).
To match the measurement instrumentation we use, the radiance units are kept in
units of Watts/[sr-m^22], and the routines do the appropriate converstions.
these are the input units expected. The one exception on the input is the convergent beam limit,
where the input is irradiance and should be passed in uWatts/cm^2. The help text is pretty
clear about what is desired for each routine.

e) For computations of retinal illumiance, these routines used a default eye length of 17 mm.
This does not seem to be specified in the standard, but is the number given in the Landry et.
al (2011) paper.

REFERENCES.
Ansi ISO 15004-2 (2007). Ophthalmic instruments - Fundamental requirements and test methods -
Part 2: Light hazard protection. [The standard document. Tables listed below are in
this document.]

Landry, R. J. et al. (2011). Retinal phototoxicity: A review of standard methodology for evaluating retinal optical
radiation hazards. Health Physics, 100(4), pp. 417-434. [This review paper unpacks the standard
a bit and is a helpful source.]

ISO2007MPEBasicTest - Test the suite of routines. Generates many figures that should match those in the standard.
ISO2007MPECheckType1ContinuousRadiance - Wrapper function for comparing a measured radiance to MPE limits.
ISO2007MPEComputeType1ContinuousAntConvrgUnweightedValue - Placeholder (not tested) for convergent beam limit. Table 2, 5.4.1.5.
ISO2007MPEComputeType1ContinuousCornealIRUnweightedValue - As the name indicates. Table 2, 5.4.1.4.
ISO2007MPEComputeType1ContinuousCornealUVUnweightedValue - As the name indicates. Table 2, 5.4.1.2.
ISO2007MPEComputeType1ContinuousCornealUVWeightedValue - As the name indicates. Table 2, 5.4.1.1.
ISO2007MPEComputeType1ContinuousRadiancePCWeightedValue - As the name indicates. Table 2, 5.4.1.3.b
ISO2007MPEComputeType1ContinuousRadianceTHWeightedValue - As the name indicates. Table 2, 5.4.1.6.b
ISO2007MPEComputeType1ContinuousRetIrradiancePCWeightedValue - As the name indicates. Table 2, 5.4.1.3.a
ISO2007MPEComputeType1ContinuousRetIrradianceTHWeightedValue - As the name indicates. Table 2, 5.4.1.6.a
ISO2007MPEGetWeigthtings - Get the spectral weighting functions needed by the standard.
ISO2007MPEPrintAnalysis - Formatted print of output returned by ISO2007MPECheckType1ContinuousRadiance.

ISO2007MPETableA1.txt - Table A1 of the standard as tab delimited text.
ISO2007MPETableA2.txt - Table A2 of the standard as tab delimited text.