Using ImageDifference.py with DECam data

Tags: #<Tag:0x00007fedf70ad7b8> #<Tag:0x00007fedf70ad6f0>

Hi everyone!
I am a complete newbie using th pipeline and I’m trying to do image difference on some decam data, but I’m not quite sure how to use it. This is what I tried:

$ imageDifference.py DATA_Javiera/pointing1/ --output output1
CameraMapper INFO: Loading exposure registry from /mnt/flock/jahumada/DATA_Javiera/pointing1/registry.sqlite3
root INFO: Running: /home/jahumada/lsst_stack-v21/stack/miniconda3-py37_4.8.2-cb4e2dc/Linux64/pipe_tasks/21.0.0+44ca056b81/bin/imageDifference.py DATA_Javiera/pointing1/ --output output1
conda.common.io INFO: overtaking stderr and stdout
conda.common.io INFO: stderr and stdout yielding back
root WARN: Not running the task because there is no data to process; you may preview data using “–show data”

imageDifference.py DATA_Javiera/pointing1/ --output output1 --show data
CameraMapper INFO: Loading exposure registry from /mnt/flock/jahumada/DATA_Javiera/pointing1/registry.sqlite3

But I don’t know why it doesn’t seem to be able to access the data, since it is in that folder (DATA_Javiera/pointing1). Maybe I skipped some previous steps?
The only thing I did before was to ingest the instcal data.

If someone has an idea why this is happening and points it out to me, I would really appreciate it :grinning_face_with_smiling_eyes:

Hello,

The error message is because there is no --id argument in your command line. One very unintuitive aspect of these scripts is the need to always provide --id, even if you intend to process all data (in which case, --id need not be followed by anything).

I am unfortunately not familiar with instcals, but I don’t think they can be differenced immediately after ingesting. I think you need to first run processCcd.py by creating a config override file as described in steps 6 and 5 (in that order!) of the obs_decam readme. You can then run imageDifference.py on the output of processCcd.py.

I hope this helps.

Thanks!
I’ll do that and see what happens :grin: