Message Board Thread - "Could not get the accurate temperature in my program"

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Could not get the accurate temperature in my program robertbaggio 9/11/2006
I used FLIR A40 and SDK 2.5 in our program. But when I adjusted the temperature of a normal black body to 30 degree centigrade, then got the temperature of the black body via FLIR A40, I always got 32 degree centigrade or so. It is abnormal, isn't it?

Following is my C# code segment, could you please tell me where is wrong or what I missed?

Camera.Connect(5, 0, 3, 3, "ircam00171");
//Connect to camera with 16 bit Firewire

//After received Connected event

Camera.SetCameraProperty(41, 8);
//Noise reduction

Camera.SetCameraProperty(47, 1);
//Turn on Automatic shutter.

Camera.DoCameraAction(8);
//Internal image correction(shutter maneuver)

//After receive End of recalibration event

varImage=Camera.GetImage(3);
//Get pixel image from camera control

float[,] data = new float[320,240];
data = (float[,])varImage;

//From now on we get the raw temperature array
//For each value in the array: data, it is a
//degree Fahrenheit value, then we minus 273.15
// for each one.
 
Re:Could not get the accurate temperature in my program Bob Berry 9/12/2006
The accuracy of the A40 is ± 2°C or ± 2%, so this is not that surprising. Having said that you may be able to improve it a little if you use the correct emisivity and other settings.
 
Re:Could not get the accurate temperature in my program Pelle 9/12/2006
Robert

When you use the SDK all measurements are done in the SDK. You need to use the SetCameraProperty 0 to 7 to set the correct Object Parameters. Remember that almost all references do not have an emissivity of 1.00 and they might even have different emissivity depending on Wave length.
The only test you can do to make sure your software is working is to compare the measurement in your software with the measurements done in the camera and displayed in the Video output.

P.S. Remember that the SDK and the Camera Processor uses the same raw data and that settings in the Camera are for the camera only and does not change the data in the SDK.

Pelle
 
Re:Could not get the accurate temperature in my program Pelle 9/12/2006
Robert

One more thing

The Temperatures received in the float array is in degrees Kelvin

Conversion Kelvin - 273.15 = Celsius
Farenheit = (K-273.15) * 9/5 +32

Pelle


 
Re:Could not get the accurate temperature in my program robertbaggio 9/12/2006
Hi,Pelle

Sorry for my typo error in my last messge, actually it should be Kelvin rather than Farenheit.

I realize that the importancy of Object Parameters, such as emissivity,Relative humidity etc.

Any way, big thanks to you!
 


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