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FLIR IR Camera A655sc Greyscale to Temperature Conversion

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Hey Community,

I am looking for a little bit of help from your side, because the support of FLIR is a little bit disappointing, to state it mildly.

 

We have a FLIR A655sc camera that I can read out without any trouble with IMAQdx via GigE interface. The camera has 16bit and I easily get the greyscale image.

To make that an useful piece of information, I need to convert 16bit greyscale to temperature. But the conversion factor is nowhere to be found.

Does anybody here now?

I took two comparison images in the FLIR software, one with Counts as scale, on with Temperature as scale. See attached screenshots.

 

I found this link, but the scaling factor as 10 or 100 does not really match what I see here, where 13155 Counts convert to 293.9 Kelvin or 20.4 °C.

Screenshot DegK.png

Screenshot Counts.png

 

Thanks for your help.

Cheers, Niko

  

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Solution
Accepted by topic author Universaldilletant

Okay, so after a LOOOOOT of digging here is the answer in two flavors:

1) The camera can either give raw 16bit images and the software has to do the conversion itself with 3 steps:

- Subtract the global offset from each pixel and divide by gain (easy!)

- To the result, apply the universal thermography equation, with the object parameters (f****** hard and a lot of work!)

- To the result apply equation 2.2.4.8 from the GenICam standard: Temperature (in Kelvin) = B / log(R / S + F), where S is the 16-bit digital signal value. log(x) is the base-e logarithm of the x parameter. (easy again!)

Voila, there you go. I found this out after digging through FLIR's C++ code, that can be found here

 

2) You take the easy way and set the camera attribute 'CameraAttributes::ImageStreamControl::IRFormat' to the following:

Universaldilletant_0-1620129993657.png

Use either value 1 or 2 and then you get the temperature in °K by dividing the 16bit value by 10 (for 100mK resolution) or 100 (for 10mK resolution).

It could have been so easy. Thanks for nothing FLIR support, btw.

Cheers, Niko

 

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