Start working with Tesseract
crop images to superset of boxes
Add white lines to split wide characters.

This definitely improves the accuracy!
New approach to OCR cropping using Canny.

General outline is:
- Run Canny edge detector
- Remove sharp, isolated features (i.e. borders) with a rank_filter.
- Dilate the canny image to get just a few connected components.
- Form an optimal subset of these components:
  - Include all components with >= 10% of the edges
  - Include other components which improve f1 score.