#+TITLE:Readme

This python package contains modules to help with finding and extracting tabular
data from a PDF or image into a CSV format.

Given an image that contains a table...

#+ATTR_HTML: :width 25%
[[file:resources/examples/example-page.png]]

Extract the the text into a CSV format...

#+BEGIN_EXAMPLE
PRIZE,ODDS 1 IN:,# OF WINNERS*
$3,9.09,"282,447"
$5,16.66,"154,097"
$7,40.01,"64,169"
$10,26.67,"96,283"
$20,100.00,"25,677"
$30,290.83,"8,829"
$50,239.66,"10,714"
$100,919.66,"2,792"
$500,"6,652.07",386
"$40,000","855,899.99",3
1,i223,
Toa,,
,,
,,"* Based upon 2,567,700"
#+END_EXAMPLE

The package is split into modules with narrow focuses.

- ~pdf_to_images~ uses Poppler and ImageMagick to extract images from a PDF.
- ~extract_tables~ finds and extracts table-looking things from an image.
- ~extract_cells~ extracts and orders cells from a table.
- ~ocr_image~ uses Tesseract to OCR the text from an image of a cell.
- ~ocr_to_csv~ converts into a CSV the directory structure that ~ocr_image~ outputs.

The outputs of a previous model can be used by a subsequent model so that they
can be chained together to create the entire workflow, as demonstrated by the
following shell script.

#+NAME: ocr_tables
#+BEGIN_SRC shell :results none :tangle ocr_tables :tangle-mode (identity #o755)
#!/bin/sh

PDF=$1

python -m table_ocr.pdf_to_images $PDF | grep .png > /tmp/pdf-images.txt
cat /tmp/pdf-images.txt | xargs -I{} python -m table_ocr.extract_tables {}  | grep table > /tmp/extracted-tables.txt
cat /tmp/extracted-tables.txt | xargs -I{} python -m table_ocr.extract_cells {} | grep cells > /tmp/extracted-cells.txt
cat /tmp/extracted-cells.txt | xargs -I{} python -m table_ocr.ocr_image {} --psm 7 -l table-ocr

for image in $(cat /tmp/extracted-tables.txt); do
    dir=$(dirname $image)
    python -m table_ocr.ocr_to_csv $(find $dir/cells -name "*.txt")
done
#+END_SRC

The package was written in a [[https://en.wikipedia.org/wiki/Literate_programming][literate programming]] style. The source code at
[[file:pdf_table_extraction_and_ocr.org]] is
meant to act as the documentation and reference material.
