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#!/bin/csh -f |
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# RCSid: $Id: psquish.csh,v 3.4 2005/02/16 05:40:11 greg Exp $ |
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set Lmin=.0001 # minimum visible world luminance |
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set Ldmin=1 # minimum display luminance |
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set Ldmax=100 # maximum display luminance |
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set nsteps=100 # number of steps in perceptual histogram |
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set cvratio=0.05 # fraction of pixels to ignore in envelope clipping |
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set td=/tmp |
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set tf0=$td/tf$$ |
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set tf1=$td/hist$$ |
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set tf1b=$td/hist$$.diff |
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set tf2=$td/cumt$$ |
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set tf3=$td/histeq$$.cal |
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set tf4=$td/cf$$.cal |
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set tf=($tf0 $tf1 $tf1b $tf2 $tf3 $tf4) |
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if ( "$argv[1]" == "-a" ) then |
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set adaptive |
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shift argv |
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endif |
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if ( $#argv != 1 ) then |
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echo "Usage: $0 [-a] input.hdr > output.hdr" |
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exit 1 |
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endif |
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set ifile=$1 |
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set ibase=$ifile:t |
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if ( "$ibase" =~ *.hdr ) set ibase=$ibase:r |
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set ibase=$ibase:t |
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onintr quit |
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pextrem -o $ifile > $tf0 |
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set Lmin=`rcalc -e 'L=179*(.265*$3+.67*$4+.065*$5)' -e 'cond=1.5-recno;$1=if('L-$Lmin,L,$Lmin')' $tf0` |
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set Lmax=`rcalc -e 'L=179*(.265*$3+.67*$4+.065*$5)' -e 'cond=recno-1.5;$1=if('$Ldmax-L,$Ldmax,L')' $tf0` |
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cat > $tf3 << _EOF_ |
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min(a,b) : if(a-b, b, a); |
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WE : 179; { Radiance white luminous efficacy } |
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Lmin : $Lmin ; { minimum visible luminance } |
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Lmax : $Lmax ; { maximum picture luminance } |
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Ldmin : $Ldmin ; { minimum output luminance } |
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Ldmax : $Ldmax ; { maximum output luminance } |
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Stepsiz : (Bl(Lmax)-Bl(Lmin))/ $nsteps ; { brightness step size } |
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{ Logarithmic brightness function } |
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Bl(L) : log(L); |
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Lb(B) : exp(B); |
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BLw(Lw) : Bl(Ldmin) + (Bl(Ldmax)-Bl(Ldmin))*cf(Bl(Lw)); |
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{ first derivative functions } |
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Bl1(L) : 1/L; |
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Lb1(B) : exp(B); |
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{ histogram equalization function } |
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lin = li(1); |
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Lw = WE/le(1) * lin; |
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Lout = Lb(BLw(Lw)); |
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mult = if(Lw-Lmin, (Lout-Ldmin)/(Ldmax-Ldmin)/lin, 0) ; |
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_EOF_ |
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if ( $?adaptive ) then |
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cat >> $tf3 << _EOF_ |
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{ Ferwerda contrast sensitivity function } |
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{ log10 of cone threshold luminance } |
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ltp(lLa) : if(-2.6 - lLa, -.72, if(lLa - 1.9, lLa - 1.255, |
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(.249*lLa + .65)^2.7 - .72)); |
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{ log10 of rod threshold luminance } |
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lts(lLa) : if(-3.94 - lLa, -2.86, if(lLa - -1.44, lLa - .395, |
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(.405*lLa + 1.6)^2.18 - 2.86)); |
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{ threshold is minimum of rods and cones } |
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ldL2(lLa) : min(ltp(lLa),lts(lLa)); |
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dL(La) : 10^ldL2(log10(La)); |
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{ derivative clamping function } |
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clamp2(L, bLw) : dL(Lb(bLw))/dL(L)/Lb1(bLw)/(Bl(Ldmax)-Bl(Ldmin))/Bl1(L); |
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clamp(L) : clamp2(L, BLw(L)); |
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{ shift direction for histogram } |
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shiftdir(B) : if(cf(B) - (B - Bl(Lmin))/(Bl(Ldmax) - Bl(Lmin)), 1, -1); |
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{ Scotopic/Photopic color adjustment } |
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sL(r,g,b) : .062*r + .608*g + .330*b; { approx. scotopic brightness } |
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BotMesopic : 10^-2.25; { top of scotopic range } |
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TopMesopic : 10^0.75; { bottom of photopic range } |
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incolor = if(Lw-TopMesopic, 1, if(BotMesopic-Lw, 0, |
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(Lw-BotMesopic)/(TopMesopic-BotMesopic))); |
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slf = (1 - incolor)*sL(ri(1),gi(1),bi(1)); |
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ro = mult*(incolor*ri(1) + slf); |
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go = mult*(incolor*gi(1) + slf); |
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bo = mult*(incolor*bi(1) + slf); |
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_EOF_ |
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else |
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cat >> $tf3 << _EOF_ |
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{ derivative clamping function } |
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clamp2(L, bLw) : Lb(bLw)/L/Lb1(bLw)/(Bl(Ldmax)-Bl(Ldmin))/Bl1(L); |
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clamp(L) : clamp2(L, BLw(L)); |
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{ shift direction for histogram } |
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shiftdir(B) : -1; |
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ro = mult*ri(1); |
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go = mult*gi(1); |
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bo = mult*bi(1); |
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_EOF_ |
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endif |
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# Compute brightness histogram |
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pfilt -1 -p 1 -x 128 -y 128 $ifile | pvalue -o -b -d -h -H \ |
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| rcalc -f $tf3 -e 'Lw=WE*$1;$1=if(Lw-Lmin,Bl(Lw),-1)' \ |
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| histo `ev "log($Lmin)" "log($Lmax)"` $nsteps > $tf1 |
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# Clamp frequency distribution |
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set totcount=`sed 's/^.*[ ]//' $tf1 | total` |
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set margin=`ev "floor($totcount*$cvratio+.5)"` |
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while ( 1 ) |
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# Compute mapping function |
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sed 's/^.*[ ]//' $tf1 | total -1 -r \ |
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| rcalc -e '$1=$1/'$totcount | rlam $tf1 - \ |
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| tabfunc -i 0 cf > $tf4 |
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# Compute difference with visible envelope |
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rcalc -f $tf4 -f $tf3 -e "T:$totcount*Stepsiz" \ |
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-e 'clfq=floor(T*clamp(Lb($1))+.5)' \ |
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-e '$1=$2-clfq;$2=shiftdir($1)' $tf1 > $tf1b |
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if (`sed 's/[ ].*$//' $tf1b | total` >= 0) then |
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# Nothing visible? -- just normalize |
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pfilt -1 -e `pextrem $ifile | rcalc -e 'cond=recno-1.5;$1=1/(.265*$3+.67*$4+.065*$5)'` $ifile |
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goto quit |
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endif |
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# Check to see if we're close enough |
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if (`rcalc -e '$1=if($1,$1,0)' $tf1b | total` <= $margin) break |
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# Squash frequency distribution |
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set diffs=(`sed 's/[ ].*$//' $tf1b`) |
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set shftd=(`sed 's/^.*[ ]//' $tf1b`) |
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while ( 1 ) |
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set maxi=0 |
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set maxd=0 |
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set i=$nsteps |
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while ( $i > 0 ) |
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if ( $diffs[$i] > $maxd ) then |
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set maxd=$diffs[$i] |
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set maxi=$i |
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endif |
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@ i-- |
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end |
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if ( $maxd == 0 ) break |
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set i=0 |
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tryagain: |
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set r=$shftd[$maxi] |
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while ( $i == 0 ) |
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@ t= $maxi + $r |
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if ( $t < 1 || $t > $nsteps ) then |
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@ shftd[$maxi]= -($shftd[$maxi]) |
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goto tryagain |
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endif |
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if ( $diffs[$t] < 0 ) set i=$t |
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@ r+= $shftd[$maxi] |
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end |
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if ( $diffs[$i] <= -$diffs[$maxi] ) then |
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@ diffs[$i]+= $diffs[$maxi] |
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set diffs[$maxi]=0 |
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else |
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@ diffs[$maxi]+= $diffs[$i] |
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set diffs[$i]=0 |
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endif |
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end |
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# Mung histogram |
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echo $diffs | tr ' ' '\012' | rlam $tf1 - \ |
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| rcalc -f $tf4 -f $tf3 -e "T:$totcount*Stepsiz" \ |
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-e 'clfq=floor(T*clamp(Lb($1))+.5)' \ |
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-e '$1=$1;$2=$3+clfq' > $tf1b |
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mv -f $tf1b $tf1 |
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end |
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# Plot the mapping function if we are in debug mode |
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if ( $?DEBUG ) then |
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cat > ${ibase}_histo.plt << _EOF_ |
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include=curve.plt |
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title="Brightness Frequency Distribution" |
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subtitle= $ibase |
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ymin=0 |
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xlabel="Perceptual Brightness B(Lw)" |
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ylabel="Frequency Count" |
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Alabel="Histogram" |
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Alintype=0 |
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Blabel="Envelope" |
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Bsymsize=0 |
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Adata= |
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_EOF_ |
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(cat $tf1; echo \;; echo Bdata=) >> ${ibase}_histo.plt |
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rcalc -f $tf4 -f $tf3 -e "T:$totcount*Stepsiz" \ |
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-e '$1=$1;$2=T*clamp(Lb($1))' $tf1 \ |
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>> ${ibase}_histo.plt |
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cat > ${ibase}_brmap.plt << _EOF_ |
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include=line.plt |
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title="Brightness Mapping Function" |
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subtitle= $ibase |
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xlabel="World Luminance (log cd/m^2)" |
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ylabel="Display Luminance (cd/m^2)" |
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ymax= $Ldmax |
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Adata= |
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_EOF_ |
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cnt 100 | rcalc -f $tf4 -f $tf3 -e '$1=lx;$2=Lb(BLw(10^lx))' \ |
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-e 'lx=$1/99*(log10(Lmax)-log10(Lmin))+log10(Lmin)' \ |
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>> ${ibase}_brmap.plt |
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if ( $?DISPLAY ) then |
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bgraph ${ibase}_histo.plt ${ibase}_brmap.plt | x11meta & |
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endif |
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endif |
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# Map our picture |
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getinfo < $ifile | egrep '^((VIEW|PIXASPECT|PRIMARIES)=|[^ ]*(rpict|rview|pinterp) )' |
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pcomb -f $tf4 -f $tf3 $ifile |
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quit: |
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rm -f $tf |
