Calibration Flir T360 - DYI Help

[Therm1]

Anyone with experience calibrating a Flir camera with the hidden menus?  I'm looking to get my camera closer to the actual temperatures.   I'm not looking for perfection for the calibration, just ball park.  I have a Flir T360 and a Flir T640.  The 640 was recently calibrated in the lab by FLIR, so I can use that for comparison.  I heard you could use a cheap black body intended only human temperatures, but most of these are Ambient plus a small range.   

I hacked into the menus, and it does't appear that you can just override any temperature   You have to measure a precise temperature with the camera and record the value.  The temperatures in the lower range that it's asking, as I interpret it (if I'm correct) is Amb=Ambient, BB0=0 C, BB55=55C, and BB120=120C.  Buying a black body with that range is cost prohibited.  Is there a work around?  I was hoping I could just use the T640 as reference and measure random things instead of buying a black body.  I'm mainly interested in getting it adjusted in the 0 C to 50 C range. 

With only two calibration points by default from 0 to 55C and it doesn't provide much adjustment.  I compared the camera to my T640 and the amount out of calibration varies between 0 C and 100C. It's not a constant variable.

[Fraser]

You are at the mercy of the particular calibration routine installed in the camera. Some cameras dictate the calibration points, whilst others allow the user to enter any temperature for the calibration points so long as they fall within the selected range. Sadly, in your case, it seems that you need to provide specific temperature references. Simple if you have a suitable dual Blackbody, not so simple if you do not. You would normally need a Blackbody that is Peltier cooler based to create temperatures below Ambient and up to around +80C and another Blackbody that is heater based to cover from Ambient up to the temperature you require for the high calibration point. You sometimes see these two Blackbody units combined into one casing and called a dual Blackbody. Sadly they are very expensive, even when bought used. If less than great calibration calibration accuracy is acceptable, a simple DIY Blackbody may be an option.

Options ?

1.There may be the option to rent a suitable Blackbody at reasonable cost ?

2. It is possible to create simple temperature reference plates in a DIY build and the complexity ranges from simple unregulated to PID controlled. The simple unregulated type uses other a heater or Peltier module to beat or cool a copper/aluminium target plate to the correct temperature required by the camera. The emission plate needs to be coated with a event high Emissivity paint. An accurate contact temperature sensor or a known accurate IR thermometer may be used to monitor the emission plate as the Peltier module or heater acts upon it. There is no regulation except the manual varying of the supply to the Peltier module or heater. This has awful temperature stability issues but if monitored in real time with the contact or IR thermometer, a measurement point temperature may be created for long enough to set the calibration point. Remember to consider the Emissivity of the emission plate coating !

A flat field calibration plate can usually be operated at ambient temperature and is evenly coated with high Emissivity Matt paint to provide the camera with a nice flat field that completely fills the cameras frame. Dead pixel detection is often possible using the same flat field plate.

Building your own Blackbody units has previously been discussed on this forum. Note that the Dahua COVID-19 screening Blackbody units may be easily unlocked to provide Ambient to +80C at the emission plate. Ambient is with the PID set below Ambient temperature so not driving the plate heater and +80C is the highest I would risk as the casing of the unit starts to get pretty hot…short term +80C only ! The Dahua units could be used as the basis of custom built Peltier and Heater type Blackbodies but thermal coupling if the emission plate to the case and materials used in the heater section would need modifications if temperatures exceeding +80C are required. The Dahua units contain good quality PID controllers driving the heater via a solid state relay.

Never leave a very hot Blackbody unattended !

Fraser

[Therm1]

Thanks Fraser, that was what I was afraid of.  Are you familiar with the Flir menu system, shown in my photos. Are there any options in those menus that I've might of overlooked to input the temperatures I want to adjust?

[Fraser]

Sadly no. This is a standard FLIR calibration menu. The more advanced menus were to be found on science cameras that could store many more calibration points for greater accuracy over a specified operating range.