ekleog/ocra-recog

Steps to build an OCR system for OCR-A using ocropus

Note: This document describes the setup for recognizing characters from a known font. It works especially well when the characters follow a logic that can be auto-generated.

For a more general tutorial, see two tutorials by Dan Vanderkam here and there.

Steps for generating your own recognizer for a known font for use with ocropus

1. Generate some text using the chars you want (in my case, a hexdump-like format, for paperkey): cat /dev/urandom | hexdump -e '"%_ad:" 22/1 " %02X" " " 3/1 "%02X" "\n"' | head -n 1000 | sed 's/^\([0-9][0-9][0-9]\).*:/\1:/' > train.txt
2. Generate the training data (here with high degradations as it's so restricted): ocropus-linegen -t train.txt -e hi -f OCR-A.ttf
3. Generate the model: ocropus-rtrain -o model linegen/*/*.png

Steps for using your own recognizer with ocropus

1. Binarize: ocropus-nlbin input.jpg -o input
2. Segment interesting parts: ocropus-gpageseg input/*.bin.png
3. Perform recognition: ocropus-rpred -n -m model-SOMETHING.pyrnn.gz input/*/*.bin.png
4. Put everything together: ocropus-hocr input/*.bin.png -o result.html