Add function to convert FLIR data to CSV

[HaleySchuhl]

I'm not sure how we originally converted FLIR images to CSV.. @DannieSheng shared some code that uses a package and it made me think that it could be a valuable function within the PlantCV utilities suite of tools.

[DannieSheng]

I agree.
The function I used relies on the exiftool, and the installation (as you showed in the link) is required.
I learned about this tool from Susan Meerdink's shared code.

[HaleySchuhl]

@nfahlgren would it be worthwhile to add exiftool as a dependency? I imagine it would fit into the suite of utils tools so does that mean not everyone would need to install it and still be able to use the namespace package?

[nfahlgren]

It would be best if we can avoid it. exiftool is an installable program, so it would have to be installed by the user outside of PlantCV. What I would propose looking at instead is using a Python package that reads EXIF metadata to try to keep that part of the process in Python, then connect it with the rest of the temperature conversion method in flirimageextractor or https://gist.github.com/gilgeorges/d68467b87bc50e04c41e

[dschneiderch]

I didn't find much for python for exif metadata except https://piexif.readthedocs.io/en/latest/
It doesn't support everything but maybe enough for this usecase.
exiftool and py3exiv2 are command line tools that are much more feature complete. pyexiftool links to exiftool but understandably not a dependency you want to include.

[dschneiderch]

I used piexif to add metadata to my images when doing a camera overlay based on a lens calibration
https://cougphenomics.github.io/camera_overlays.html
(in case its useful in addition to the docs, which I found confusing)

[nfahlgren]

I looked into this more. The reason all standard EXIF reading tools will not extract the FLIR data is because they only look for standard EXIF tags. There are a huge number of non-standard tags defined by camera manufacturers. exiftool is unique in that it supports many vendor tags, including FLIR: https://exiftool.org/TagNames/FLIR.html#FPF.