Hi! Last month I was having issues processing multispectral datasets with GCPs; after a good amount of trial and error and a hint in the forum (Fault with gcp_list.txt processing - #6 by ITWarrior) I established that having GCPs labelled in multiple bands within one capture invariably causes ODM to fail at the OpenSfM reconstruction step.
Multispectral rigs (e.g. MicaSense) consist of multiple cameras with a fixed offset; a single capture would produce, say, 5 files – one in each band. The filename follows the format
capture-no_band.tif format, and GCPs will usually appear in all 5 images in a capture. However, including images from more than one band (eg. anything other than
gcp_list.txt leads to failure. I haven’t tested this further, but it seems irrespective of the
My understanding has been that, in addition to increasing georeferencing accuracy, the use of GCPs is a method for aligning the bands alternative (or supplementary) to the camera rig offsets. It looks like currently only one of the bands in a multispectral system is being georeferenced. Is this intentional behaviour? Since a given GCP will appear in at different pixel coordinates in different bands within the same capture, is it desirable (and wise) to ignore this information?