#!/bin/bash
#
# Developed by Fred Weinhaus 6/20/2015 .......... revised 6/21/2025
#
# ------------------------------------------------------------------------------
# 
# 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: negative2positive [-a autostretch] [-l cliplow] [-h cliphigh] 
# [ -c color] [-d density] [-cb colorbalance] [-P1 percent1] [-P2 percent2] 
# infile outfile
#
# USAGE: negative2positive [-h or -help]
#
# OPTIONS:
#
# -a      autostretch      autostretch image channels; options are: 
#                          none (n), together (t), or separate (s); 
#                          default=separate
# -l      cliplow          clip percent on low end of histogram; 
#                          float; 0<=cliplow<=100; default=1
# -h      cliphigh         clip percent on high end of histogram;
#                          float; 0<=cliphigh<=100; default=1
# -c      color            desired filter color; any valid IM opaque color 
#                          value is valid default=yellow
# -d      density          density of filter; 0<=integer<=100; 0 is no change; 
#                          100 is most change towards the color;
#                          default=15 for colorbalance != level and  
#                          default=0 for colorbalance = level 
# -cb     colorbalance     color balance mode; choices are level, gray,  
#                          white, both, auto or none; default=auto
# -P1     percent          percent1 threshold for autolevel processing; 
#                          0<float<100; default=1
# -P2     percent          percent threshold for detecting gray/white 
#                          for auto gray and auto white balance; 0<float<100;
#                          default=1
#
###
#
# NAME: NEGATIVE2POSITIVE
# 
# PURPOSE: To convert from a (scanned film) negative image to a positive image.
# 
# DESCRIPTION: NEGATIVE2POSITIVE converts from a (scanned film) negative image 
# to a positive image. Options include: autostretching the image channels with 
# or without clipping, color filtering and to color balance via white balance, 
# gray balance, both, automatic or via levels.
# 
# OPTIONS: 
# 
# -a autostretch --- autostretch image channels as preprocessing step. The options
# are: together (t), separate (s) or none (n). The default=separate. 
# Note, for some images with severe channel autostretch, the option separate 
# can cause severe color shifts.
# 
# -l cliplow ... CLIPLOW is the cumulative percent at the low end of the 
# histogram whose graylevel will be autostretched to full black. Values are 
# floats between 0 and 100. If cliplow=0, then the autostretch will locate 
# the minimum value in the channel histogram. The default=1.
# 
# -h cliphigh ... CLIPHIGH is the cumulative percent at the high end of  
# the histogram whose graylevel will be autostretched to full white. Values are 
# floats between 0 and 100. If cliplow=0, then the autostretch will locate 
# the maximum value in the channel histogram. The default=1.
#
# -c color ... COLOR is the desired filter color. Any valid IM opaque color 
# value is valid. The default=yellow, since yellow is the complement of blue.
# (After the image is negated, the color is mostly bluish and yellow will 
# remove most of the blue tint).
# 
# -d density ... DENSITY of the color filter. Values are 0<=integers<=100. 
# 0 is no color filter processing. 100 is most change towards the selected 
# color. The default=15 for colorbalance != level and the default=0 for 
# colorbalance = level. Density, generally, will not make any significant 
# change when colorbalance = level.
# 
# -cb colorbalance ... COLORBALANCE mode. The choices are none, gray, white, 
# both, auto or level. The default=auto. Both will be an equal blend of gray and 
# white. Auto will try to choose the better of gray or white depending upon 
# which one's percent selected pixels' rmse value (from gray or white, 
# respectively is the smallest value. Level uses an autolevel process to get 
# the black point, white point and (gray point converted to) gamma values.
# 
# -P1 percent2 ... PERCENT2 threshold for level processing. Values are 
# 0<floats<100; default=1.
#
# -P2 percent2 ... PERCENT2 is the percent threshold for detecting gray/white 
# in the image for auto color balance. Values are 0<floats<100. The default=1.
# 
# NOTE: I thank Dr. Guenter Grau for the suggestion to normalize the r,g,b 
# ratios by their average in the color balance part of the code.
# 
# REFERENCES AND TUTORIALS:
# http://www.colorpilot.com/silver.html
# http://www.instructables.com/id/How-to-Convert-Digitized-Film-Negatives-into-Quali/?ALLSTEPS
# http://www.computer-darkroom.com/tutorials/tutorial_6_1.htm
# https://stefanofoletti.wordpress.com/tag/silverfast/
# http://photo.stackexchange.com/questions/23942/does-a-filter-exist-to-color-correct-color-negatives-when-copying-them-with-a-ds
# http://howtoresolved.com/tube/NM5XzDYfG60/convert-film-negatives-to-positive-tutorial
# https://www.youtube.com/watch?v=B2gLT0SWzpQ
# http://petapixel.com/2012/05/18/how-to-scan-film-negatives-with-a-dslr/
# https://www.youtube.com/watch?v=iMO50AlGyrw
#
# 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. 
# 
######
#

# defaults
autostretch="separate"		# autolevel preprocess
cliplow=1					# clip low end of histogram percent
cliphigh=1					# clip low end of histogram percent
color="yellow"				# color for color filter
density=""					# color filter density; see below for actual defaults depending upon colorbalance
colorbalance="auto"			# colorbalance mode; level, auto, gray, white, both, none
percent1=1					# percent for autolevel processing
percent2=1					# percent near white/gray from combined S and B channels of HSB to use for whitebalance
midrange=0.5				# midrange gray for gray to gamma processing

# 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 18 ]
	then
	errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---"
else
	while [ $# -gt 0 ]
		do
			# get parameter values
			case "$1" in
		      help)    # help information
					   echo ""
					   usage2
					   exit 0
					   ;;
				-a)    # get  autostretch
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID AUTOSTRETCH SPECIFICATION ---"
					   checkMinus "$1"
					   autostretch=`echo "$1" | tr '[A-Z]' '[a-z]'`
					   case "$autostretch" in 
							together|t) autostretch="together" ;;
							separately|separate|s) autostretch="separate" ;;
							none|n) autostretch="none" ;;
							*) errMsg "--- AUTOSTRETCH=$autostretch IS AN INVALID VALUE ---" ;;
						esac
					   ;;
				-l)    # get cliplow
					   shift  # to get the next parameter - radius,sigma
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID CLIPLOW SPECIFICATION ---"
					   checkMinus "$1"
					   cliplow=`expr "$1" : '\([.0-9]*\)'`
					   [ "$cliplow" = "" ] && errMsg "--- CLIPLOW=$cliplow MUST BE A NON-NEGATIVE FLOAT ---"
					   cliplowtestA=`echo "$cliplow < 0" | bc`
					   cliplowtestB=`echo "$cliplow > 100" | bc`
					   [ $cliplowtestA -eq 1 -o $cliplowtestB -eq 1 ] && errMsg "--- CLIPLOW=$cliplow MUST BE AN FLOAT BETWEEN 0 AND 100 ---"
					   ;;
				-h)    # get cliphigh
					   shift  # to get the next parameter - radius,sigma
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID CLIPHIGH SPECIFICATION ---"
					   checkMinus "$1"
					   cliphigh=`expr "$1" : '\([.0-9]*\)'`
					   [ "$cliphigh" = "" ] && errMsg "--- CLIPHIGH=$cliphigh MUST BE A NON-NEGATIVE FLOAT ---"
					   cliphightestA=`echo "$cliphigh < 0" | bc`
					   cliphightestB=`echo "$cliphigh > 100" | bc`
					   [ $cliphightestA -eq 1 -o $cliphightestB -eq 1 ] && errMsg "--- CLIPHIGH=$cliphigh MUST BE AN FLOAT BETWEEN 0 AND 100 ---"
					   ;;
			   -cb)    # get colorbalance mode
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID COLORBALANCE SPECIFICATION ---"
					   checkMinus "$1"
					   colorbalance=`echo "$1" | tr '[A-Z]' '[a-z]'`
					   case "$colorbalance" in 
							none|n) colorbalance="none" ;;
							gray|g) colorbalance="gray" ;;
							white|w) colorbalance="white" ;;
							both|b) colorbalance="both" ;;
							auto|a) colorbalance="auto" ;;
							level|l) colorbalance="level" ;;
							*) errMsg "--- COLORBALANCE=$colorbalance IS AN INVALID VALUE ---" ;;
						esac
					   ;;
				-c)    # get  color
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID COLOR SPECIFICATION ---"
					   checkMinus "$1"
					   color="$1"
					   ;;
				-d)    # get density
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID DENSITY SPECIFICATION ---"
					   checkMinus "$1"
					   density=`expr "$1" : '\([0-9]*\)'`
					   [ "$density" = "" ] && errMsg "--- DENSITY=$density MUST BE A NON-NEGATIVE INTEGER VALUE (with no sign) ---"
					   test1=`echo "$density < 0" | bc`
					   test2=`echo "$density > 100" | bc`
					   [ $test1 -eq 1 -o $test2 -eq 1 ] && errMsg "--- DENSITY=$density MUST BE AN INTEGER BETWEEN 0 AND 100 ---"
					   ;;
			   -P1)    # get percent1
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID PERCENT1 SPECIFICATION ---"
					   checkMinus "$1"
					   percent1=`expr "$1" : '\([.0-9]*\)'`
					   [ "$percent1" = "" ] && errMsg "--- PERCENT1=$percent1 MUST BE A NON-NEGATIVE FLOAT ---"
					   testA=`echo "$percent1 <= 0" | bc`
					   testB=`echo "$percent1 >= 100" | bc`
					   [ $testA -eq 1 -o $testB -eq 1 ] && errMsg "--- PERCENT1=$percent1 MUST BE A FLOAT GREATER THAN 0 AND SMALLER THAN 100 ---"
					   ;;
			   -P2)    # get percent2
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID PERCENT2 SPECIFICATION ---"
					   checkMinus "$1"
					   percent2=`expr "$1" : '\([.0-9]*\)'`
					   [ "$percent2" = "" ] && errMsg "--- PERCENT2=$percent2 MUST BE A NON-NEGATIVE FLOAT ---"
					   testA=`echo "$percent2 <= 0" | bc`
					   testB=`echo "$percent2 >= 100" | bc`
					   [ $testA -eq 1 -o $testB -eq 1 ] && errMsg "--- PERCENT2=$percent2 MUST BE A FLOAT GREATER THAN 0 AND SMALLER THAN 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"

# set directory for temporary files
tmpdir="$dir"

dir="$tmpdir/NEGATIVE2POSITIVE.$$"

mkdir "$dir" || errMsg "--- FAILED TO CREATE TEMPORARY FILE DIRECTORY ---"
trap "rm -rf $dir;" 0
trap "rm -rf $dir; exit 1" 1 2 3 15
#trap "rm -rf $dir; exit 1" ERR

# 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`

# set up for -negate or profiles
# currently profiles are not specified or detected
if [ "$profilepath1" = "" -a "$profilepath2" = "" ]; then
	inversion="-negate"
elif [ "$profilepath1" != "" -a "$profilepath2" = "" ]; then
	errMsg "--- ONLY ONE PROFILE PATH PROVIDED ---"
elif [ "$profilepath1" = "" -a "$profilepath2" != "" ]; then
	errMsg "--- ONLY ONE PROFILE PATH PROVIDED ---"
else
	# test that both profilepath1 and profilepath2 are valid
	if ! [ -f "$profilepath1" -a -e "$profilepath1" -a -r "$profilepath1" -a -s "$profilepath1" ]; then
		errMsg  "--- FILE $profilepath1 DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE  ---"
	fi
	if ! [ -f "$profilepath2" -a -e "$profilepath2" -a -r "$profilepath2" -a -s "$profilepath2" ]; then
		errMsg  "--- FILE $profilepath2 DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE  ---"
	fi
	inversion="-set colorspace CMYK -profile $profilepath1 -profile $profilepath2"
fi


# set up for autostretch
if [ "$cliplow" = "0" -a "$cliphigh" = "0" -a "$im_version" -gt "06050501" ]; then
	if [ "$autostretch" = "separate" ]; then
		aproc="-channel rgb -auto-level"
	elif [ "$autostretch" = "together" ]; then
		aproc="-auto-level"
	elif [ "$autostretch" = "none" ]; then
		aproc=""
	fi
else 
	if [ "$autostretch" = "separate" ]; then
		aproc="-channel rgb -contrast-stretch $cliplow,$cliphigh%"
	elif [ "$autostretch" = "together" ]; then
		aproc="-contrast-stretch $cliplow,$cliphigh%"
	elif [ "$autostretch" = "none" ]; then
		aproc=""
	fi
fi
#echo "aproc=$aproc;"


# set up -recolor or -color-matrix for color balancing
if [ "$im_version" -lt "06060100" ]; then
	process="-recolor"
else
	process="-color-matrix"
fi
#echo "process=$process;"

# 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 
# with IM 6.7.4.10, 6.7.6.10, 6.7.8.6
if [ "$im_version" -lt "06070607" -o "$im_version" -gt "06070707" ]; then
	setcspace="-set colorspace RGB"
else
	setcspace=""
fi
if [ "$im_version" -lt "06070607" ]; then
	cspace1="RGB"
	cspace2="sRGB"
else
	cspace1="sRGB"
	cspace2="RGB"
fi
# no need for setcspace for grayscale or channels after 6.8.5.4
if [ "$im_version" -gt "06080504" ]; then
	setcspace="-set colorspace sRGB"
	cspace1="sRGB"
	cspace2="RGB"
fi
#echo "setscpace=$setscpace; cspace1=$cspace1; cspace2=$cspace2;"

# read input image into temporary memory mapped (mpc) format image, 
# do inversion using either -negate or CMYK to sRGB profiles
# autostretch
convert -quiet "$infile" $inversion $aproc +repage $dir/tmpI.mpc ||
	errMsg  "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE  ---"

# set up default density
if [ "$colorbalance" = "level" -a "$density" = "" ]; then
	density=0
elif [ "$colorbalance" != "level" -a "$density" = "" ]; then
	density=15
fi
#echo "cb=$colorbalance; density=$density;"

# set density to mimic photoshop values
#echo "density=$density; color=$color;"
density=`convert xc: -format "%[fx:$density/2]" info:`

# process color filter
if [ "$density" != "0" ]; then
#echo "colorfilter"
	convert $dir/tmpI.mpc -colorspace $cspace2 \
		\( -clone 0 -fill "$color" -colorize $density% \) \
		+swap -compose luminize -composite -colorspace $cspace1 \
		$dir/tmpI.mpc
fi




# do color balance
if [ "$colorbalance" = "level" ]; then
	# process autolevel colorbalance

	#echo "process autolevel colorbalance"
	#echo ""
	#echo "black"

	# get black point
	black_point=`convert $dir/tmpI.mpc \
		\( -clone 0 -channel rgb -contrast-stretch ${percent1}x0% -separate +channel \
		-fill white +opaque black -combine -negate \) \
		+channel -alpha off -compose copy_opacity -composite \
		-scale 1x1! -format "%[fx:100*mean.r],%[fx:100*mean.g],%[fx:100*mean.b]" info:`
	red_bp=`echo "$black_point" | cut -d, -f1`
	green_bp=`echo "$black_point" | cut -d, -f2`
	blue_bp=`echo "$black_point" | cut -d, -f3`
	#echo "bp=$black_point, red_bp=$red_bp; green_bp=$green_bp; blue_bp=$blue_bp;"

	#echo "white"

	# get white point
	white_point=`convert $dir/tmpI.mpc \
		\( -clone 0 -channel rgb -contrast-stretch 0x${percent1}% -separate +channel \
		-fill black +opaque white -combine \) \
		+channel -alpha off -compose copy_opacity -composite \
		-scale 1x1! -format "%[fx:100*mean.r],%[fx:100*mean.g],%[fx:100*mean.b]" info:`
	red_wp=`echo "$white_point" | cut -d, -f1`
	green_wp=`echo "$white_point" | cut -d, -f2`
	blue_wp=`echo "$white_point" | cut -d, -f3`
	#echo "wp=$white_point, red_wp=$red_wp; green_wp=$green_wp; blue_wp=$blue_wp;"

	#echo "gray"

	# get gray point
	gray_point=`convert $dir/tmpI.mpc \
		\( -clone 0 -channel rgb -solarize 50% -level 0x50% \
			-contrast-stretch 0x${percent1}% -separate +channel -fill black +opaque white -combine \) \
		+channel -alpha off -compose copy_opacity -composite \
		-scale 1x1! -format "%[fx:100*mean.r],%[fx:100*mean.g],%[fx:100*mean.b]" info:`
	red_gp=`echo "$gray_point" | cut -d, -f1`
	green_gp=`echo "$gray_point" | cut -d, -f2`
	blue_gp=`echo "$gray_point" | cut -d, -f3`
	#echo "gp=$gray_point, red_gp=$red_gp; green_gp=$green_gp; blue_gp=$blue_gp;"

	#echo "gamma"

	# convert gray point to gamma values
	red_gamma=`convert xc: -format "%[fx:log($red_gp/100)/log($midrange)]" info:`
	green_gamma=`convert xc: -format "%[fx:log($green_gp/100)/log($midrange)]" info:`
	blue_gamma=`convert xc: -format "%[fx:log($blue_gp/100)/log($midrange)]" info:`
	#echo "rgam=$red_gamma: ggam=$green_gamma; bgam=$blue_gamma;"

	#echo "proc"

	# process image
	convert $dir/tmpI.mpc \
		-channel red -level ${red_bp}%,${red_wp}%,$red_gamma +channel \
		-channel green -level ${green_bp}%,${green_wp}%,$green_gamma +channel \
		-channel blue -level ${blue_bp}%,${blue_wp}%,$blue_gamma +channel \
		$dir/tmpI.mpc
else

	#echo "process gray/white colorbalance"

	# Process graybalance
	if [ "$colorbalance" = "gray" -o "$colorbalance" = "both" -o "$colorbalance" = "auto" ]; then
	#echo "gray"

		# get ratios for graybalance
		# get mask of top percent closest to gray
		# approximation using negated saturation and solarized brightness multiplied
		ref=0.5
		ave=`convert $dir/tmpI.mpc $setcspace \
			\( -clone 0 -colorspace HSB -channel G -negate -separate +channel \) \
			\( -clone 0 -colorspace HSB -channel B -separate +channel -solarize 50% -level 0x50% \) \
			\( -clone 1 -clone 2 -compose multiply -composite \) \
			\( -clone 3 -contrast-stretch 0,${percent2}% -fill black +opaque white +write $dir/tmpM.mpc \) \
			-delete 1-3 -compose over -alpha off -compose copy_opacity -composite \
			-scale 1x1! -format "%[fx:mean.r],%[fx:mean.g],%[fx:mean.b]" info:`
		#echo "ave=$ave"
		redave=`echo "$ave" | cut -d, -f1`
		greenave=`echo "$ave" | cut -d, -f2`
		blueave=`echo "$ave" | cut -d, -f3`
		redratio=`convert xc: -format "%[fx:$ref/$redave]" info:`
		greenratio=`convert xc: -format "%[fx:$ref/$greenave]" info:`
		blueratio=`convert xc: -format "%[fx:$ref/$blueave]" info:`
		#echo "R: ave=$redave; redratio=$redratio"
		#echo "G: ave=$greenave; greenratio=$greenratio;"
		#echo "B: ave=$blueave; blueratio=$blueratio;"
	
		# normalize r,g,b ratios by ave ratio, so no added increase in brightness
		gnormfact=`convert xc: -format "%[fx: ($redratio+$greenratio+$blueratio)/3]" info:`
		redratio=`convert xc: -format "%[fx: $redratio/$gnormfact]" info:`
		greenratio=`convert xc: -format "%[fx: $greenratio/$gnormfact]" info:`
		blueratio=`convert xc: -format "%[fx: $blueratio/$gnormfact]" info:`
		#echo "R: ave=$redave; ratio=$redratio"
		#echo "G: ave=$greenave; ratio=$greenratio;"
		#echo "B: ave=$blueave; ratio=$blueratio;"
		convert $dir/tmpI.mpc $process "$redratio 0 0 0 $greenratio 0 0 0 $blueratio" $dir/tmpG.mpc

	# compute rmse difference from gray for masked pixels
	gray_pixels=`convert $dir/tmpM.mpc -format "%[fx:mean*w*h]" info:`
	#echo "gray_pixels=$gray_pixels;"

	rmse_gray=`convert xc: -format "%[fx: ((0.5-$redave)^2 + (0.5-$greenave)^2 + (0.5-$blueave)^2)/(3*$gray_pixels) ]" info:`
	#echo "rmse_gray=$rmse_gray"

	fi



	# Process whitebalance
	if [ "$colorbalance" = "white" -o "$colorbalance" = "both" -o "$colorbalance" = "auto" ]; then
	#echo "white"

		# get ratios for whitebalance
		# get mask of top percent closest to white
		# approximation using negated saturation and brightness channels multiplied
		ref=1
		ave=`convert $dir/tmpI.mpc $setcspace \
			\( -clone 0 -colorspace HSB -channel G -negate -channel GB -separate +channel \
			-compose multiply -composite \
			-contrast-stretch 0,${percent2}% -fill black +opaque white +write $dir/tmpM.mpc \) \
			-compose over -alpha off -compose copy_opacity -composite \
			-scale 1x1! -format "%[fx:mean.r],%[fx:mean.g],%[fx:mean.b]" info:`
		#echo "ave=$ave"
		redave=`echo "$ave" | cut -d, -f1`
		greenave=`echo "$ave" | cut -d, -f2`
		blueave=`echo "$ave" | cut -d, -f3`
		redratio=`convert xc: -format "%[fx:$ref/$redave]" info:`
		greenratio=`convert xc: -format "%[fx:$ref/$greenave]" info:`
		blueratio=`convert xc: -format "%[fx:$ref/$blueave]" info:`
		#echo "R: ave=$redave; redratio=$redratio"
		#echo "G: ave=$greenave; greenratio=$greenratio;"
		#echo "B: ave=$blueave; blueratio=$blueratio;"

		# normalize r,g,b ratios by ave ratio, so no added increase in brightness
		wnormfact=`convert xc: -format "%[fx: ($redratio+$greenratio+$blueratio)/3]" info:`
		redratio=`convert xc: -format "%[fx: $redratio/$wnormfact]" info:`
		greenratio=`convert xc: -format "%[fx: $greenratio/$wnormfact]" info:`
		blueratio=`convert xc: -format "%[fx: $blueratio/$wnormfact]" info:`
		#echo "R: ave=$redave; ratio=$redratio"
		#echo "G: ave=$greenave; ratio=$greenratio;"
		#echo "B: ave=$blueave; ratio=$blueratio;"
		convert $dir/tmpI.mpc $process "$redratio 0 0 0 $greenratio 0 0 0 $blueratio" $dir/tmpW.mpc

	# compute per pixel rmse difference from white for masked pixels
	white_pixels=`convert $dir/tmpM.mpc -format "%[fx:mean*w*h]" info:`
	#echo "white_pixels=$white_pixels;"
	rmse_white=`convert xc: -format "%[fx: ((1-$redave)^2 + (1-$greenave)^2 + (1-$blueave)^2)/(3*$white_pixels) ]" info:`
	#echo "rmse_white=$rmse_white"

	fi
fi


# Save to output
if [ "$colorbalance" = "none" -o "$colorbalance" = "level" ]; then
#echo "none"
	convert $dir/tmpI.mpc "$outfile"
elif [ "$colorbalance" = "gray" ]; then
#echo "gray"
	convert $dir/tmpG.mpc "$outfile"
elif [ "$colorbalance" = "white" ]; then
#echo "white"
	convert $dir/tmpW.mpc "$outfile"
elif [ "$colorbalance" = "both" ]; then
#echo "both"
	convert \( $dir/tmpG.mpc $dir/tmpW.mpc -evaluate-sequence mean \) "$outfile"
elif [ "$colorbalance" = "auto" ]; then
#echo "auto"
	# test rmse difference and use smalles one; gray or white
	test=`convert xc: -format "%[fx:($rmse_white <= $rmse_gray)?1:0]" info:`
	#echo "test=$test;"
	if [ $test -eq 1 ]; then
		#echo "white"
		convert $dir/tmpW.mpc "$outfile"
	else
		#echo "gray"
		convert $dir/tmpG.mpc "$outfile"
	fi
fi

exit 0