FIR SC645 Cam Options and 16 bit Image to temperature conversion

[Sylvania]

Hello,

I conected a FLIR SC645 camera through a ethernet conection to my pc.

In NI Max a can see the camera unther NI IMAQdx devices. Here I can snap a picture and change the focus through the Camera Atributes.

I made a small test program with the "IMAQdx-Snap.vi" so now i have a Grayscaled 16 bit image.

   This Image isnow saturated it start in black as room temperature and becomes white at high temp +-90°C.

   When i measure a halogen lamp that is around 115°C the gray color wil go dark again starting above 90°C.

   How can I change the measuring range.

   How can I change the focus distance ?

   How do I convert 16- bit Image gray values to Temperature depending on the measured range ?

I hope sombody can help me with this,

[BlueCheese]

I think the default for 16-bit images may be as I16 rather than U16. This is fine unless your camera uses the entire dynamic range for the 16-bits (which FLIR does). You can either adjust the pixel signedness attribute or set the output image type attribute to U16.

[Sylvania]

Thanks for Replying:

I recieve gray values from 0 until 4096 and then it starts over again from 200 rising up.

In NI MAX I selected unther Acquisition Atributes - Pixel Format 16 bit mono.

In my Labview vi I created a image I16 bit ore U16 bit no change.

When I read the propertys of the camera like Bitsperpixel ==> Use Hardware defined

                                                                        Pixelsignedness ==> Signed

I tried to write to these properties but they do not change.

I add a screenshot to make everything easier to understand.

[BlueCheese · Accepted solution]

The input image type doesn't matter because IMAQdx will convert it to its expected output format. The pixel signedness attribute should work. I suggest playing with the attributes in MAX first. You can then save the settings and use them in your app.

[Sylvania]

Thanks BlueCheese,

I adapted the settings in NI MAX. Image Type is now Mono 16bit and now I have a nicely increasing Gray image.

Indeed Saving the settings in NI Max will cause that the labview aplication will use these settings. That i missed.

So now I have a Gray value of 9000 for room temperature 25°C

and                  a Gray value of 14600 for 120°C Lamp surface.

Is there a methode to reconvert this gray values to temperature ?

The camera is calibrated but how do i know wich gray value is wich exact temperature ?

[BlueCheese]

For scaling the 16-bit values to temperatures, I suggest you look a bit at the FLIR manuals (and perhaps other posts within this forum). There are many features on the camera that affect the scaling, and you'll have to understand how they work to accurately convert to temperature. I believe there should be a mode where it is a simple linear scaling factor, but the coefficients for it might change based on your camera configuration.

[Sylvania]

Thanks for the information.