blurry photos detection

blur_detector

#! /bin/bash

#
# Author: Pasquale Ceres (pasquale_c@hotmail.com)
# License: GPL ver. 3
#
# Script originally developed for the 
# "San Lorenzo Martire Caposele Church Records Digitalization Project"
# 
# http://www.facebook.com/group.php?gid=188973755117&v=photos
# http://ars.altervista.org/PhpGedView/index.php
#

#
# parameters
#
image_ext=JPG                    # image extension
logfile=report.txt               # logfile with the list of all photos sorted by blur level
logfile_full=report_unsorted.txt # logfile with the list of all photos not sorted
temp_folder=/tmp                 # temporary folder
output_folder=blurry_folder      # folder into which the most blurred photos are copied
perc_output_images=20            # [%] percentage of most blurred images to be copied into output folder



#
# show usage if no params in input
#
if [ ! $# == 1 ]; then
  echo "Usage:"
  echo "$0 <filename> : analyse the single image, determining its blur factor"
  echo "$0 <folder>   : analyse the images inside the folder"
  exit
fi


#
# calculations
#
input=$1

if [ -d $input ]; then
  # report on the files in the folder
  #
  # usage:
  # blur_detector <folder_with_images>
  #

  echo "batch blur estimator..."
  
  touch $logfile_full
  rm $logfile_full
  find $input -name "*.$image_ext" -exec blur_detector {} >> $logfile_full \;
  
  
  # sort by blur index (from worst to best)
  cat $logfile_full | sort -d -k 8.2 > $logfile
  
 
  # copy blurred images to output folder
  num_files=`cat $logfile | wc -l` # number of image files found
  num_output_images=`echo $num_files*$perc_output_images/100.0 | bc | gawk '{printf("%d\n",int($1)+1)}'` # take a percentage

  echo "copying $num_output_images (out of $num_files) blurriest photos into output folder..."

  mkdir $output_folder
  head $logfile -n $num_output_images | gawk '{n=split($1,a,"/");filename=sprintf("%03d_%s", FNR, a[n]);print filename; system("cp " $1 " ./'$output_folder'/" filename)}'  
  
else 
  # report on single file
  #
  # usage:
  # blur_detector <image_filename>
  #

  filename=$input

  # original size
  size0=`identify $filename | gawk '{print $3}'`

  # reduce size, just take upper part of image
  convert $filename -gravity north -crop 100x20% +repage $temp_folder/check0.jpg

  size=`identify $temp_folder/check0.jpg | gawk '{print $3}'`

  # create black image
  convert -size $size xc:black $temp_folder/black.jpg

  # create check image
  convert -noise 2 -sigmoidal-contrast 6x25% -edge 2 $temp_folder/check0.jpg $temp_folder/check.jpg

  # calculate blur factor
  blur_value=`compare -metric RMSE $temp_folder/check.jpg $temp_folder/black.jpg $temp_folder/out.jpg 2>&1`

  echo "$filename : $size0 -> $size : $blur_value"
  
  # remove work files
  rm $temp_folder/check0.jpg $temp_folder/check.jpg $temp_folder/black.jpg $temp_folder/out.jpg
fi

This script is used to determine a number related to one photos's blur level.
I used it to determine, among many images shot at an ancient book, which were blurry (and needed to be shot again)

Usage:
blur_detector : analyse the image and determine its blur level (it is a relative value)
blur_detector : analyse all images inside , and write report.txt with all images and their blur level