#!/bin/bash # # Developed by Fred Weinhaus 12/1/2108 .......... revised 11/17/2023 # # ------------------------------------------------------------------------------ # # 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: adaptivegamma2 [-t type][-m meanthresh] [-f fraction] [-c cumthresh] # [-bg brightgain] [-dg darkgain] [-ba brightalpha] [-da darkalpha] [-C colormode] # infile outfile # # USAGE: adaptivegamma2 [-h or -help] # # OPTIONS: # # -t type type of mean threshold to use; choices are: orginial or simple; # default=simple # -m meanthresh threshold of the mean used to test if the image is bright # or dark; 0<=integer<=255; default=128 (use 112 for original) # -f fraction fraction to use with the meanthresh to test if the image # is bright or dark for type=original; ignored if type=simple; # 0<=float<=1; default=0.3 # -c cumthresh threshold used to clip the cumulative distribution for dark # images; 0<=float<=1; default=0.55 # -bg brightgain gain on cumulative distribution for bright images; # 0<=float<=1; default=1 (no change) # -dg darkgain gain on cumulative distribution for dark images; # 0<=float<=1; default=1 (no change) # -ba brightalpha alpha exponent for weighting the normalize histogram for # bright images; 0<=float<=1; default=0.25 # -da darkalpha alpha exponent for weighting the normalize histogram for # dark images; 0<=float<=1; default=0.75 # -C colormode colorspace for processing; choices are srgb, lab, hcl, hsl, # hsv, hsi, ycbcr and ohta; default=hsv # ### # # NAME: ADAPTIVEGAMMA2 # # PURPOSE: To enhance the contrast/brightness in an image using an adaptive gamma method. # # DESCRIPTION: ADAPTIVEGAMMA2 is an adaptive gamma technique used to enhance an # image's brightness and contrast. It is based upon an exponentiation of the # the image's values using an exponent, gamma, that is evaluated differently for # each graylevel in the image based upon values in the cumulative normalized and # weight histogram in the form, gamma(value)=1-cumulative_histogram(value). The # fraction along with the meanthresh value are used to categorize the image as # bright, dark (or neutral if type=original). Neutral images will have no processing # applied. For dark images the cumulative distribution is clipped not to exceed # cumthresh. For bright images, no clipping is used, but the input is negated before # gamma processing and then negated back after processing. # # Arguments: # # -t type ... TYPE of mean threshold to use. The choices are: orginial or simple. # The default=simple. # # -m meanthresh ... MEANTHRESH is a threshold of the mean that is used to test if the # image is bright or dark. Values are 0<=integer<=255. The default=128. # (Use 112 for original). # # -f fraction ... FRACTION to use with the meanthresh to test if the image is bright # or dark. Values are 0<=float<=1. The default=0.3. # # -c cumthresh ... CUMTHRESH is a threshold used to clip the cumulative distribution # for dark images. Values are 0<=float<=1. The default=0.55. # # -bg brightgain ... BRIGHTGAIN ia a gain on cumulative distribution for bright images. # Values are 0<=float<=1. The default=1 (no change). # # -dg darkgain ... DARKGAIN is a gain on cumulative distribution for dark images. # Values are 0<=float<=1. The default=1 (no change). # # -ba brightalpha ... BRIGHTALPHA is an alpha exponent for weighting the normalize # histogram for bright images. Values are 0<=float<=1. The default=0.25. # # -da darkalpha ... DARKALPHA is an alpha exponent for weighting the normalize # histogram for dark images. Values are 0<=float<=1. The default=0.75. # # -C colormode ... COLORMODE is the colorspace for processing; choices are srgb, # lab, hcl, hsl, hsv, hsi, ycbcr and ohta; default=hsv # # REFERENCE1: # https://arxiv.org/pdf/1709.04427.pdf # Contrast Enhancement of Brightness-Distorted Images by Improved Adaptive Gamma Correction # Gang Cao1*, Lihui Huang1, Huawei Tian2, Xianglin Huang3, Yongbin Wang1, Ruicong Zhi4 # # REFERENCE2: # https://in.mathworks.com/matlabcentral/answers/uploaded_files/4242/AGCWD.pdf # Efficient Contrast Enhancement Using Adaptive Gamma Correction With Weighting Distribution # Shih-Chia Huang, Fan-Chieh Cheng, and Yi-Sheng Chiu # IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 22, NO. 3, MARCH 2013 # # NOTE: This script may be a bit slow due for non-HDRI compile Imagemagick to the # use of -fx. # # 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 type="simple" meanthresh=128 fraction=0.3 cumthresh=0.55 brightalpha=0.25 darkalpha=0.75 brightgain=1 darkgain=0.7 colormode="hsv" debug="false" # set directory for temporary files # tmpdir="/tmp" tmpdir="." # 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 20 ] then errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---" else while [ $# -gt 0 ] do # get parameters case "$1" in -h|-help) # help information echo "" usage2 ;; -t) # get type shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID TYPE SPECIFICATION ---" checkMinus "$1" type=`echo "$1" | tr '[A-Z]' '[a-z]'` case "$type" in simple|s) type="simple" ;; original|o) type="original" ;; *) errMsg "--- TYPE=$type IS AN INVALID VALUE ---" ;; esac ;; -m) # get meanthresh shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID MEANTHRESH SPECIFICATION ---" checkMinus "$1" meanthresh=`expr "$1" : '\([0-9]*\)'` [ "$meanthresh" = "" ] && errMsg "--- MEANTHRESH=$meanthresh MUST BE A NON-NEGATIVE INTEGER ---" testA=`echo "$meanthresh > 255" | bc` [ $testA -eq 1 ] && errMsg "--- MEANTHRESH=$meanthresh MUST BE AN INTEGER BETWEEN 0 AND 255 ---" ;; -f) # fraction shift # to get the next parameter - maxgain # test if parameter starts with minus sign errorMsg="--- INVALID FRACTION SPECIFICATION ---" checkMinus "$1" fraction=`expr "$1" : '\([.0-9]*\)'` [ "$fraction" = "" ] && errMsg "--- FRACTION=$fraction MUST BE A POSITIVE FLOATING POINT VALUE (with no sign) ---" testA=`echo "$fraction > 1.0" | bc` [ $testA -eq 1 ] && errMsg "--- FRACTION=$fraction MUST BE A FLOAT BETWEEN 0 AND 1 ---" ;; -c) # cumthresh shift # to get the next parameter - maxgain # test if parameter starts with minus sign errorMsg="--- INVALID CUMTHRESH SPECIFICATION ---" checkMinus "$1" cumthresh=`expr "$1" : '\([.0-9]*\)'` [ "$cumthresh" = "" ] && errMsg "--- CUMTHRESH=$cumthresh MUST BE A POSITIVE FLOATING POINT VALUE (with no sign) ---" testA=`echo "$cumthresh > 1.0" | bc` [ $testA -eq 1 ] && errMsg "--- CUMTHRESH=$cumthresh MUST BE A FLOAT BETWEEN 0 AND 1 ---" ;; -bg) # brightgain shift # to get the next parameter - maxgain # test if parameter starts with minus sign errorMsg="--- INVALID BRIGHTGAIN SPECIFICATION ---" checkMinus "$1" brightgain=`expr "$1" : '\([.0-9]*\)'` [ "$brightgain" = "" ] && errMsg "--- BRIGHTGAIN=$brightgain MUST BE A POSITIVE FLOATING POINT VALUE (with no sign) ---" testA=`echo "$brightgain > 1.0" | bc` [ $testA -eq 1 ] && errMsg "--- BRIGHTGAIN=$brightgain MUST BE A FLOAT BETWEEN 0 AND 1 ---" ;; -dg) # darkgain shift # to get the next parameter - maxgain # test if parameter starts with minus sign errorMsg="--- INVALID DARKGAIN SPECIFICATION ---" checkMinus "$1" darkgain=`expr "$1" : '\([.0-9]*\)'` [ "$darkgain" = "" ] && errMsg "--- DARKGAIN=$darkgain MUST BE A POSITIVE FLOATING POINT VALUE (with no sign) ---" testA=`echo "$darkgain > 1.0" | bc` [ $testA -eq 1 ] && errMsg "--- DARKGAIN=$darkgain MUST BE A FLOAT BETWEEN 0 AND 1 ---" ;; -ba) # brightalpha shift # to get the next parameter - maxgain # test if parameter starts with minus sign errorMsg="--- INVALID BRIGHTALPHA SPECIFICATION ---" checkMinus "$1" brightalpha=`expr "$1" : '\([.0-9]*\)'` [ "$brightalpha" = "" ] && errMsg "--- BRIGHTALPHA=$brightalpha MUST BE A POSITIVE FLOATING POINT VALUE (with no sign) ---" testA=`echo "$brightalpha > 1.0" | bc` [ $testA -eq 1 ] && errMsg "--- BRIGHTALPHA=$brightalpha MUST BE A FLOAT BETWEEN 0 AND 1 ---" ;; -da) # darkalpha shift # to get the next parameter - maxgain # test if parameter starts with minus sign errorMsg="--- INVALID DARKALPHA SPECIFICATION ---" checkMinus "$1" darkalpha=`expr "$1" : '\([.0-9]*\)'` [ "$darkalpha" = "" ] && errMsg "--- DARKALPHA=$darkalpha MUST BE A POSITIVE FLOATING POINT VALUE (with no sign) ---" testA=`echo "$darkalpha > 1.0" | bc` [ $testA -eq 1 ] && errMsg "--- DARKALPHA=$darkalpha MUST BE A FLOAT BETWEEN 0 AND 1 ---" ;; -C) # get colormode shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID COLORMODE SPECIFICATION ---" checkMinus "$1" colormode=`echo "$1" | tr '[A-Z]' '[a-z]'` case "$colormode" in srgb|s|r) colormode="srgb" ;; lab|l) colormode="lab" ;; hcl) colormode="hcl" ;; hsl) colormode="hsl" ;; hsv) colormode="hsv" ;; hsi) colormode="hsi" ;; ycbcr|y) colormode="ycbcr" ;; ohta|o) colormode="ohta" ;; *) errMsg "--- COLORMODE=$colormode IS AN INVALID VALUE ---" ;; esac ;; -) # 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 [ "$outfile" = "" ] && errMsg "NO OUTPUT FILE SPECIFIED" dir="$tmpdir/ADAPTIVEGAMMA2.$$" mkdir "$dir" || errMsg "--- FAILED TO CREATE TEMPORARY FILE DIRECTORY ---" trap "rm -rf $dir; exit 0" 0 trap "rm -rf $dir; exit 1" 1 2 3 15 # read the input image into the temporary cached image and test if valid convert -quiet "$infile" -auto-orient -auto-level +repage $dir/tmpA.mpc || echo "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO size ---" # compute mean of image in 8-bit range # need -channel rgb for IM 7 otherwise it includes the alpha # mean=`convert $dir/tmpA.mpc -channel rgb -format "%[fx:255*mean]" info:` # bug in IM6 computing mean above -- do not know how many releases were bad - so compute using -scale # mean=`convert $dir/tmpA.mpc -channel rgb -scale 1x1! -format "%[fx:255*(u.r+u.g+u.b)/3]" info:` # get better results with mean of intensity (gray channel) mean=`convert $dir/tmpA.mpc -alpha off -colorspace gray -scale 1x1! -format "%[fx:255*u]" info:` [ "$debug" = "true" ] && echo "mean=$mean" # determine if bright or dark image if [ "$type" = "original" ]; then test=`convert xc: -format "%[fx:($mean-$meanthresh)/$meanthresh>$fraction?1:($mean-$meanthresh)/$meanthresh<-$fraction?-1:0]" info:` elif [ "$type" = "simple" ]; then test=`convert xc: -format "%[fx:($mean>=$meanthresh)?1:-1]" info:` fi if [ $test -eq 1 ]; then test="bright" elif [ $test -eq -1 ]; then test="dark" elif [ $test -eq 0 ]; then test="neutral" fi [ "$debug" = "true" ] && echo "test=$test;" # set alpha based upon brightness test if [ "$test" = "bright" ]; then alpha=$brightalpha cumthresh=0 gain=$brightgain elif [ "$test" = "dark" ]; then alpha=$darkalpha gain=$darkgain fi [ "$debug" = "true" ] && echo "alpha=$alpha;" if [ "$test" = "neutral" ]; then # just copy input to output cp "$infile" "$outfile" else # process bright and dark images if [ "$test" = "bright" ]; then # negate the image convert $dir/tmpA.mpc -negate $dir/tmpA.mpc fi # 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` if [ "$im_version" -ge "07000000" ]; then identifying="magick identify" else identifying="identify" fi # get colorspace and type colorspace=`$identifying -ping -verbose -strip $dir/tmpA.mpc | sed -n 's/^.*Colorspace: \(.*\)$/\1/p'` type=`$identifying -ping -verbose -strip $dir/tmpA.mpc | sed -n 's/^ Type: \(.*\)$/\1/p'` [ "$debug" = "true" ] && echo "colorspace=$colorspace; type=$type;" # select intensity like channel if [ "$colorspace" = "srgb" -a "$colormode" = "srgb" ] ; then convert $dir/tmpA.mpc -colorspace gray $dir/tmpI.mpc elif [ "$type" = "Grayscale" -o "$colorspace" = "Gray" ]; then colormode="gray" convert $dir/tmpA.mpc $dir/tmpI.mpc elif [ "$colorspace" = "sRGB" -a "$colormode" = "hsv" ] ; then convert $dir/tmpA.mpc -colorspace $colormode -separate +channel -depth 8 $dir/tmpAA.mpc convert $dir/tmpAA.mpc[2] $dir/tmpI.mpc elif [ "$colorspace" = "sRGB" -a "$colormode" = "hsl" ] ; then convert $dir/tmpA.mpc -colorspace $colormode -separate +channel -depth 8 $dir/tmpAA.mpc convert $dir/tmpAA.mpc[2] $dir/tmpI.mpc elif [ "$colorspace" = "sRGB" -a "$colormode" = "hsi" ] ; then convert $dir/tmpA.mpc -colorspace $colormode -separate +channel -depth 8 $dir/tmpAA.mpc convert $dir/tmpAA.mpc[2] $dir/tmpI.mpc elif [ "$colorspace" = "sRGB" -a "$colormode" = "hcl" ] ; then convert $dir/tmpA.mpc -colorspace $colormode -separate +channel -depth 8 $dir/tmpAA.mpc convert $dir/tmpAA.mpc[2] $dir/tmpI.mpc elif [ "$colorspace" = "sRGB" -a "$colormode" = "ycbcr" ] ; then convert $dir/tmpA.mpc -colorspace $colormode -separate +channel -depth 8 $dir/tmpAA.mpc convert $dir/tmpAA.mpc[0] $dir/tmpI.mpc elif [ "$colorspace" = "sRGB" -a "$colormode" = "lab" ] ; then convert $dir/tmpA.mpc -colorspace $colormode -separate +channel -depth 8 $dir/tmpAA.mpc convert $dir/tmpAA.mpc[0] $dir/tmpI.mpc elif [ "$colorspace" = "sRGB" -a "$colormode" = "ohta" ] ; then convert $dir/tmpA.mpc -colorspace $colormode -separate +channel -depth 8 $dir/tmpAA.mpc convert $dir/tmpAA.mpc[0] $dir/tmpI.mpc fi # compute total pixels in image totpix=`convert $dir/tmpA.mpc -format "%[fx:w*h]" info:` [ "$debug" = "true" ] && echo "totpix=$totpix" # compute normalize pdf (probability density function, i.e. histogram normalize by total pixels) for the intensity-like channel [ "$debug" = "true" ] && echo "pdf" pdfArr=(`convert $dir/tmpI.mpc -depth 8 -format "%c" histogram:info:- \ | sed -n 's/[ ]*\([0-9]*\).*gray[(]\([0-9]*\).*$/\1 \2/p' | \ awk -v totpix=$totpix ' { bin[int($2)] += $1; max = 0; } { for (i=0;i<256;i++) max = bin[i]>max?bin[i]:max; } END { for (i=0;i<256;i++) {pdf = (bin[i]+0)/totpix; print pdf; } } '`) [ "$debug" = "true" ] && echo ${pdfArr[*]} [ "$debug" = "true" ] && echo ${#pdfArr[*]} # compute min of pdf # bc does not understand scientific notation, such 1e-3. so use printf to reformat pdfmin=`echo "${pdfArr[*]}" | tr " " "\n" | \ awk -v min=1 ' { ($1max)?max=$1:max=max } END { print max; }'` [ "$debug" = "true" ] && echo "pdfmax=$pdfmax;" # compute pdfdiff=pdfmax-pdfmin pdfdiff=`echo "scale=6; $pdfmax-$pdfmin" | bc` [ "$debug" = "true" ] && echo "pdfdiff=$pdfdiff;" # compute weighted pdf [ "$debug" = "true" ] && echo "pdfw" pdfwArr=(`echo "${pdfArr[*]}" | tr " " "\n" | \ awk -v pdfmax=$pdfmax -v pdfmin=$pdfmin -v pdfdiff=$pdfdiff -v alpha=$alpha ' { pdfw=pdfmax*(($1-pdfmin)/pdfdiff)**alpha; print pdfw }'`) [ "$debug" = "true" ] && echo ${pdfwArr[*]} [ "$debug" = "true" ] && echo ${#pdfwArr[*]} # compute summed pdfw pdfwSum=`echo "${pdfwArr[*]}" | tr " " "\n" | \ awk ' { pdfwSum += $1; } END { print pdfwSum; }'` [ "$debug" = "true" ] && echo "pdfwSum=$pdfwSum;" # compute cummulative weighted probabity density function [ "$debug" = "true" ] && echo "cdfw" cdfwArr=(`echo "${pdfwArr[*]}" | tr " " "\n" | \ awk ' { cdfw += $1; print cdfw; }'`) [ "$debug" = "true" ] && echo ${cdfwArr[*]} [ "$debug" = "true" ] && echo ${#cdfwArr[*]} # compute gamma scaled by 65535 (16-bit range) [ "$debug" = "true" ] && echo "gamma" gammaArr=(`echo "${cdfwArr[*]}" | tr " " "\n" | \ awk -v pdfwSum=$pdfwSum -v cumthresh=$cumthresh -v gain=$gain ' { cumvalue=(1-$1/pdfwSum); if (cumvalue