Optical character recognition

Here is a script that uses the 'tesseract' optical character recognition software to extract recognizable text from a PDF file:

#!/bin/bash

# Purpose: 

#   To carry out OCR on a PDF file

if [[ $# -ne 1 ]]; then

  echo "This script expects one argument."

  echo "  This argument is the name of the pdf file" 

  echo "  including the .pdf extension"

  echo "Usage: $0 file.pdf "

else

filename=$(basename "$1")

filename="${filename%.*}"

echo "Converting $1 to a tiff file named $filename.tiff"

echo "... "

convert -density 300 $1 -depth 8 -strip -background white -alpha off $filename.tiff

echo "Carrying out OCR on $filename.tiff to create $filename.txt"

tesseract $filename.tiff $filename

echo "The recognizable text in $1 has been output to the $filename.txt file."

fi

For information on how to install the needed software, see this web page.