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|
#!/bin/bash
#
# Developed by Fred Weinhaus 8/30/2012 .......... revised 11/3/2015
#
# ------------------------------------------------------------------------------
#
# Licensing:
#
# Copyright © Fred Weinhaus
#
# My scripts are available free of charge for non-commercial use, ONLY.
#
# For use of my scripts in commercial (for-profit) environments or
# non-free applications, please contact me (Fred Weinhaus) for
# licensing arrangements. My email address is fmw at alink dot net.
#
# If you: 1) redistribute, 2) incorporate any of these scripts into other
# free applications or 3) reprogram them in another scripting language,
# then you must contact me for permission, especially if the result might
# be used in a commercial or for-profit environment.
#
# My scripts are also subject, in a subordinate manner, to the ImageMagick
# license, which can be found at: http://www.imagemagick.org/script/license.php
#
# ------------------------------------------------------------------------------
#
####
#
# USAGE: ptilethresh [-p percentile] infile outfile
# USAGE: ptilethresh [-h or -help]
#
# OPTIONS:
#
# -p percentile percentile on cumulative histogram for desired threshold;
# 0<=float<=100; default=50
#
###
#
# NAME: PTILETHRESH
#
# PURPOSE: To automatically thresholds an image to binary (b/w) format
# at a specified percentile on the cumulative histogram.
#
# DESCRIPTION: PTILETHRESH automatically thresholds an image to binary
# (b/w) format at a specified percentile on the cumulative histogram. When
# the percentile is 50%, this technique is also known as balanced thresholding.
#
# OPTIONS:
#
# -p percentile ... PERCENTILE is the desired threshold point on the cumulative
# histogram. Values are floats between 0 and 100. The default=50.
#
# NOTE: It is highly recommended that the output not be specified
# as a JPG image as that will cause compression and potentially a
# non-binary (i.e. a graylevel) result. GIF is the recommended
# output format.
#
# REFERENCES:
# http://en.wikipedia.org/wiki/Balanced_histogram_thresholding
# http://www.pvv.org/~perchrh/papers/datasyn/paper2/report.pdf
#
# CAVEAT: No guarantee that this script will work on all platforms,
# nor that trapping of inconsistent parameters is complete and
# foolproof. Use At Your Own Risk.
#
######
#
# set default values
percentile=50
# set directory for temporary files
dir="." # suggestions are dir="." or dir="/tmp"
# set up functions to report Usage and Usage with Description
PROGNAME=`type $0 | awk '{print $3}'` # search for executable on path
PROGDIR=`dirname $PROGNAME` # extract directory of program
PROGNAME=`basename $PROGNAME` # base name of program
usage1()
{
echo >&2 ""
echo >&2 "$PROGNAME:" "$@"
sed >&2 -e '1,/^####/d; /^###/g; /^#/!q; s/^#//; s/^ //; 4,$p' "$PROGDIR/$PROGNAME"
}
usage2()
{
echo >&2 ""
echo >&2 "$PROGNAME:" "$@"
sed >&2 -e '1,/^####/d; /^######/g; /^#/!q; s/^#*//; s/^ //; 4,$p' "$PROGDIR/$PROGNAME"
}
# function to report error messages
errMsg()
{
echo ""
echo $1
echo ""
usage1
exit 1
}
# function to test for minus at start of value of second part of option 1 or 2
checkMinus()
{
test=`echo "$1" | grep -c '^-.*$'` # returns 1 if match; 0 otherwise
[ $test -eq 1 ] && errMsg "$errorMsg"
}
# test for correct number of arguments and get values
if [ $# -eq 0 ]
then
# help information
echo ""
usage2
exit 0
elif [ $# -gt 4 ]
then
errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---"
else
while [ $# -gt 0 ]
do
# get parameter values
case "$1" in
-h|-help) # help information
echo ""
usage2
exit 0
;;
-p) # get percentile
shift # to get the next parameter
# test if parameter starts with minus sign
errorMsg="--- INVALID PERCENTILE SPECIFICATION ---"
checkMinus "$1"
percentile=`expr "$1" : '\([.0-9]*\)'`
[ "$percentile" = "" ] && errMsg "--- PERCENTILE=$percentile MUST BE A NON-NEGATIVE FLOAT ---"
testA=`echo "$percentile < 0" | bc`
testB=`echo "$percentile > 100" | bc`
[ $testA -eq 1 -o $testB -eq 1 ] && errMsg "--- PERCENTILE=$percentile MUST BE A FLOAT BETWEEN 0 AND 100 ---"
;;
-) # STDIN and end of arguments
break
;;
-*) # any other - argument
errMsg "--- UNKNOWN OPTION ---"
;;
*) # end of arguments
break
;;
esac
shift # next option
done
#
# get infile and outfile
infile="$1"
outfile="$2"
fi
# test that infile provided
[ "$infile" = "" ] && errMsg "NO INPUT FILE SPECIFIED"
# test that outfile provided
[ "$outfile" = "" ] && errMsg "NO OUTPUT FILE SPECIFIED"
tmpA1="$dir/ptilethresh_1_$$.mpc"
tmpA2="$dir/ptilethresh_1_$$.cache"
trap "rm -f $tmpA1 $tmpA2 exit 0;" 0
trap "rm -f $tmpA1 $tmpA2; exit 1" 1 2 3 15
# get im_version
im_version=`convert -list configure | \
sed '/^LIB_VERSION_NUMBER /!d; s//,/; s/,/,0/g; s/,0*\([0-9][0-9]\)/\1/g' | head -n 1`
# colorspace RGB and sRGB swapped between 6.7.5.5 and 6.7.6.7
# though probably not resolved until the latter
# then -colorspace gray changed to linear between 6.7.6.7 and 6.7.8.2
# then -separate converted to linear gray channels between 6.7.6.7 and 6.7.8.2,
# though probably not resolved until the latter
# so -colorspace HSL/HSB -separate and -colorspace gray became linear
# but we need to use -set colorspace RGB before using them at appropriate times
# so that results stay as in original script
# The following was determined from various version tests using ptilethresh.
# with IM 6.7.4.10, 6.7.6.10, 6.7.9.10
if [ "$im_version" -lt "06070607" -o "$im_version" -gt "06070707" ]; then
setcspace="-set colorspace RGB"
else
setcspace=""
fi
# no need for setcspace for grayscale or channels after 6.8.5.4
if [ "$im_version" -gt "06080504" ]; then
setcspace=""
fi
if convert -quiet "$infile" +repage "$tmpA1"
then
: ' do nothing '
else
errMsg "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAG ZERO SIZE ---"
fi
bpt=$percentile
wpt=`convert xc: -format "%[fx:100-$bpt]" info:`
# process image
convert $tmpA1 $setcspace -colorspace gray -linear-stretch $bpt%,$wpt% "$outfile"
exit 0
|
