Pupil diameter on flatiron

[mschart]

Some people would like to have pupil diameter on Flatiron. We could use DLC QC to filter for good-enough DLC results and then use this script to compute it. I can run it locally on some server (there's a prototype script), however, could use help for uploading results automatically and having a queue (as for DLC).

[k1o0]

I suggest we do this as part of the DLC pipeline. The first step is to integrate the prototype script into the DLC extraction code. Those functions can be put into brainbox then called by the extractor and saved into npy files. The dataset types need to be added to the Alyx init fixtures. Info on how to do this can be found here. Open a PR on cortex-lab/alyx and I can do the rest.