I use a Sentra Calibrated Reflectance Panel and am struggling to find out how I can obtain and update Radiometric Correction values when processing Multispectral images using DJI Terra.
Please advise...

If the question is regarding DJI drone picture, P4M or M3M, this workflow is completely useless. Both drones are natively equipped with sun sensor.

If despite everything you have time to devote to this and you absolutely want to do it, with DJI Terra I have never managed to obtain a correct result.
There are much more powerful software, Metashape, Pix4D Field...

Also, the reflectance target is calibrated, ok that's good but is the camera?
Again if it's a DJI camera, there is no calibration file provided. They are made to be used as it is with their sun sensor, and by following the workflow recommended in the manual, it works very well to obtain basic indexes, NDVI...

Be careful however when comparing with data from other sensors of different brands, or Landsat images. DJI uses particular bands. Especially for the RedEdge.

https://dl.djicdn.com/downloads/p4-multispectral/20200717/P4_Multispectral_Image_Processing_Guide_EN.pdf

https://dl.djicdn.com/downloads/DJI_Mavic_3_Enterpri

LV_Forestry Posted at 8-27 20:58
If the question is regarding DJI drone picture, P4M or M3M, this workflow is completely useless. Both drones are natively equipped with sun sensor.

If despite everything you have time to devote to this and you absolutely want to do it, with DJI Terra I have never managed to obtain a correct result.

Thanks, LV_Forestry, I appreciate you making the time to respond.