Integrate Border Removal Plugin

[ahankinson]

The border removal plugin (github:DDMAL/gamera-lyric-extraction) works now, and it would be great if we could integrate it into the workflow system.

Using it is pretty straightforward:

from gamera.toolkits import lyric_extraction

# requires an image of type GREYSCALE

im = load_image("blah.tiff")
im = im.to_greyscale()

# border_removal returns a mask.
mask = im.border_removal(**use the defaults**)

result = im.mask(mask)

The result should be a greyscale file with the borders (incl. colour bars) removed.

The technique behind it is pretty tricky, so not sure if we can do this interactively with JS, but the default settings seem to work fine, so this can probably be a non-interactive task.

[antonkhelou]

Ok, I will integrate it on monday. thanks for the code snippet - it will save me some time.

[ahankinson]

The installation process for this has changed slightly. I have split the toolkits into four separate ones, all found at:

https://github.com/DDMAL/document-preprocessing-toolkit

Installation is fairly straightforward for each:

python setup.py install

After that, the only line that has changed from my former example is from gamera.toolkits import border_removal.

Don't worry about the other toolkits; I think we just need to do border removal for now.