Adding a custom XMP tag to a Tif

Hi all,

I’m trying to calibrate my project in the Index Calculator on Step 3. DSM, Orthomosaic and Index but ONE of my UAV images is kicking back this error:

[Error]: Error e9035a: camera model name: Altum_8.0_2064x1544 (Blue), correction type: sunIrradianceAndAngleWithPoseFromIMU - Missing information for radiometric correction in 1/1155 images:
[Error]: 	IMG_0218_1.tif: No sun irradiance information No sun sensor pose information

I did some research and someone said you can just add in the sun irradiance information from a previous image capture. So in this case, IMG_0218_1.tif is missing the sun irradiance info and I want to copy the sun irradiance info from IMG_0217_1.tif over. I tried to do this in Exiftool using this command -XMP-Camera:Irradiance=“149.06368189895989” in the ExifToolGUI’s ExifTool direct tool but it just errors:

Warning: Tag 'XMP-Camera:Irradiance' is not defined
Nothing to do.

I figured out that the Irradiance tag is not pre-defined so you need to create a custom user-defined tag but I can’t figure out how. Can someone explain to me step by step how create user-defined tags in Exiftool? Or just how to add in the sun irradiance information in general. Thanks

Hi Michael,

Pix4D uses exiv2 to read the exif and xmp tags, so I would recommend you to use that. The tag would be Xmp.Camera.SunSensor. You can find the information about more XMP tags here:

The tags would need to be exact. You can also find some info here: Camera, Sun Irradiance and Sun angle in red text - #8 by Manuel_Cubero_Castan

If you need any help in tagging let me know.

Ok you said I should use exiv2 but in the thread you link to, everyone ends up using ExifTool anyways.

Second, I looked at the tags in IMG_0217_1.tif and there is no XMP.Camera.SunSensor. Even if I add this tag to IMG_0218_1.tif, I wouldn’t even know what to populate it with because IMG_0217_1.tif doesn’t have that tag.

How do I figure out which tags are present in 0217 that are missing in 0218? And how do I add them to 2018?

Hi Michael, Could you write us a support ticket and send me your images? I will have a look and give the detailed workflow here as well for future reference. Make sure to give a link to this community post in your personal support ticket. Thanks! I look forward to assisting you with the tags.