Pix4D products read the information from the image EXIF data.
In order to create a photogrammetric project and successfully process the calibration, certain EXIF metadata are required in the images. Other metadata are optional but improve the results.
The Exif/Xmp tags required or optionally used during the radiometric correction are described in the below support article. Exif/Xmp tags required for radiometric correction for multispectral camera
The document below lists the EXIF and XMP tags needed for project creation in: