# Last edited on 2008-02-04 20:17:26 by stolfi


  Converting the images from color PNG to color PPM:
  
    foreach f ( *.png ) 
      echo ${f}
      convert ${f} ${f:r}.ppm
      pnmfile ${f:r}.ppm
    end
    ls -l ??.ppm

  Cropping, aligning:
  
    foreach f ( r0 r1 )
      echo ${f}
      pnmcut 170 310 600 900 ${f}.ppm \
        | pnmflip -r270 \
        > ${f}-c.ppm
    end
    xv r*-c.ppm &

    foreach n ( 0 1 )
      echo $n
      @ xpos = 320 + $n + $n
      @ ypos = 165
      pnmrotate -noantialias 0.65 v${n}.ppm \
        | pnmdepth 255 \
        | pnmflip -r90 \
        | pnmshear -noantialias -0.56 \
        | pnmcut ${xpos} ${ypos} 900 600 \
        | pnmflip -lr \
        > v${n}-c.ppm
    end

  Converting to grayscale, and checking the alignment between front and back:

    foreach n ( 0 1 )
      foreach s ( r v )
        echo ${s}${n}
        cat ${s}${n}-c.ppm \
          | ppmtopgm \
          > ${s}${n}-c.pgm
      end
      rgb3toppm r${n}-c.pgm v${n}-c.pgm r${n}-c.pgm \
        > d${n}-c.ppm
    end
    xv {r,v}0-c.pgm d0-c.ppm {r,v}1-c.pgm d1-c.ppm &

  Checking alignment between black- and white-backed images,
  and computing the transmission terms:

    foreach s ( r v )
      rgb3toppm ${s}0-c.pgm ${s}1-c.pgm ${s}0-c.pgm \
        > ${s}d-c.ppm
      pnmarith -subtract ${s}1-c.pgm ${s}0-c.pgm \
        | pgmnorm -bvalue 0 -wvalue 100 \
        | pnmdepth 255 \
        > ${s}t-c.pgm
    end
    rgb3toppm rt-c.pgm vt-c.pgm rt-c.pgm \
      > dt-c.ppm
    xv rd-c.ppm rt-c.pgm vd-c.ppm vt-c.pgm dt-c.ppm &
   
    PGMRemoveGhost \
      -inName test \
      -outName out \
      -gamma 0.667 \
      -paperColor 1.000 \
      -blackColor 0.010 \
      -whiteColor 1.000 \
      -debug 20 20 \
      -writePixels

    xv out-*.pgm &