Hi
We are using the Zenmuse XT and are keen also on radiometric output. Correct me if any of this is wrong but here is my understanding of the work being done by DJI and FLIR on this?
Zenmuse XT is a FLIR TAU2 Sensor, so goes by understanding that the same options and specifications will be available for the XT as the TAU2. For users buying the TAU2 sensor you had an optional OEM part number and additional charge to get "
Advanced Radiometry" enabled from the factory and this being "
Improved accuracy, moveable spot meter, image metric data, T-Linear (digital output)"
This is explained really well here; extract from:
Tau 2 LWIR Camera Cores | FLIR Systems
"The Tau2 camera compensates for variations of the camera temperature and outputs 14-bit digital video that is stabilized and normalized. That means that a scene with a given temperature will always correspond to a certain digital value in the video independent of the camera’s temperature. We call this a “temperature stable video”. The Tau2 can have two types of 14-bit temperature stable video: flux-linear and T-linear. Flux-linear is the standard output on all Tau2 cameras but T-linear is an option only available on Tau2 cameras with Advanced Radiometry enabled (e.g.: 466400019H-FROEM).
The Advanced Radiometric Tau2 camera allows customers to derive temperature information per pixel from objects in the scene (using the T-Linear 14-bit video output). Additionally external scene parameters can be compensated (such as emissivity, window transmission, etc.) to more accurately determine temperature. The Advanced Radiometric cameras also provide an image metric feature where the user can query the camera for scene temperature data via serial command (such as maximum, minimum, and standard deviation for user defined regions).
If the Tau2 camera doesn’t have Advanced Radiometry then the user will get flux-linear video and the ability to display the center spot temperature meter information on the analog and BT.656 video (external scene parameters can be adjusted for this center spot meter). They will also be able to use the isotherm functions. If a customer would like to retrieve image metric functions, the T-linear output option, and the ability to tune external parameters across all pixels they will need Advanced Radiometry and an OEM number.
The 8-bit video and the analog video are optimized for best visual appearance using AGC (automatic gain control) and are not radiometric."
Ralph from FlyingUSA has been very helpful in his previous posts around the XT specifications, and I agree with his comments posted yesterday in the forum and look forward to seeing some update from DJI for their existing XT users (
DJI XT Powered by Flir is here!!!) "
That being said the existing units we have been told will be able to do basic radiometry functions very soon. The detailed haven't been released yet on how they will do this for existing XT users but I was told it would be sooner than later. I will keep you posted as I learn more from DJI"
Is there anyone out there that might have more TAU2 / FLIR knowledge in this space. I would be interested especially is understanding the radiometric data being saved per pizel (and compare to functionality of something like the FLIR A315 and A615)
Thanks in advance and welcome comment.
