Message Board Thread - "Imaging of Semi-Transparent Objects"

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Imaging of Semi-Transparent Objects atticmouse 6/2/2010
I am trying to put together some guidelines for measuring semi-transparent objects with IR imaging. What are some recommendations for minimizing error of temperature measurements for IR transparent materials? Are there any easy ways to 'check' if something is IR transparent?

I had the idea of using a small heat source behind the object with a cardboard shield with a window in front of the object--the window would only allow the IR camera to see the target.
So the set up would be

shield-->object-->camera T1
heat source (far enough away to not increase object temperature)-->object-->'window' -->camera/pyrometer T2

The idea here is that if T1 and T2 are the same, the object is not IR transparent, and that if T2 >T1 the object is IR transparent.

Does this make sense?
Re:Imaging of Semi-Transparent Objects IRJay 6/3/2010
The guideline is ASTM E1897.4369-1 Measuring and Compensating for Transmittance of an Attenuating Medium Using Infrared Imaging Radiometers.

It is also the method of compensation for looking through infrared windows in the electrical and mechanical world.

Some of the newer cameras have a external optics feature and this is the parameter for the transmissity attenuation of the material.

Determining the "transparency" for infrared wavelengths is quite simple. Measure the energy from a known good constant emitter,then place the material in front of this emitter and adjust the emissivity or external optics (whichever) until the temps through the material is the same as without and that is the transmissivity of that material.

This is all common training lessons in infrared classes.

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