Message Board Thread - "Temperature calculation"

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Temperature calculation Artem 2/25/2008
Temperature calculation
Hi Everyone!

Please help me with my problem.
I need calculate temperature T2 with known temperature T1, emissivity E1 and emissivty E2, (ambient temperature = Tamb and atmosphere temperature = Tatm, τ=tao).

I'm use Stefan-Boltzmann radiation law for a graybody radiator:

T2=(E1/E2)^0.25 * T1

and I have wrong results (I’m compare it with results of FLIR ThermaCam Researcher).
Inside FLIR SDK Manual I’m find this formula:

Wtot= ετ Tobj + (1 - ε) τ Tamb + (1 - τ) Tatm

But I don’t understand how I can use it in my problem.
Please give some advice or some links where I can read about this.

Sorry for my bad English. I’m just a Russian student.

Artem.
 
Re:Temperature calculation Raphael ITC Eurasia 2/25/2008
Some problems:
- The second formula is false. It works with luminances, not temperatures.
- A thermography camera does not work according to Stefan Boltzmann.
- Correspondance between what a camera "measures" on a blackbody and the temperature of this blackbody is given by the calibration curve.

Provided you enter the correct objects parameters, the calculation is done automatically by the software. There is no need to recalculate this yourself.
 
Re:Temperature calculation Artem 2/25/2008
Raphael ITC Eurasia wrote:
oblems:
- The second formula is false. It works with luminances, not temperatures.
- A thermography camera does not work according to Stefan Boltzmann.
- Correspondance between what a camera "measures" on a blackbody and the temperature of this blackbody is given by the calibration curve.

Provided you enter the correct objects parameters, the calculation is done automatically by the software. There is no need to recalculate this yourself.
I try to program my own software for FLIR A40 using FLIR SDK.
If a thermography camera does not work according to Stefan Boltzmann, can I find the radiation emitted from a blackbody using Plank’s law? I know that A40 has a spectral range for 7.5 to 13 um.
 
Re:Temperature calculation Pelle 2/27/2008
Artem wrote:
I try to program my own software for FLIR A40 using FLIR SDK.
If a thermography camera does not work according to Stefan Boltzmann, can I find the radiation emitted from a blackbody using Plank’s law? I know that A40 has a spectral range for 7.5 to 13 um.
Artem

If you have the SDK then all calculations are done by the SDK.
You can either ask for a Temperature image and get an array of temperatures or take the 16 bit value and use the ToTemperature method where you also submitt the Emissivity.

If you need more support for the SDK then use http://flir.custhelp.com where you can get the Help.

Pelle S/FLIR
 


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