# Last edited on 2008-03-21 09:07:56 by stolfi

Processing test images for photometric stereo

2007-06-29 IC-UNICAMP

  Two sets of images were taken by Jorge Stolfi and Rafael Saracchini 
  on 2007-06-29.  The scene consists of three mouse balls and 
  two cardboard shapes.

    Mouse ball g-ms-a was originally black. It was lightly painted
    with white correcting fluid, so that it got a smooth surface but 
    blotchy albedo varying from near black to near white.

    Mouse ball g-ms-b, originally gray, was painted with white
    correcting fluid so that it became fully white.  The paint 
    was fairly thick, so the surface became noticeably bumpy.
    
    Mouse ball g-ms-b, gray, was used without modification.
    It has a slightly uneven color and an dark "equator",
    which in the scene was tilted some 45 degrees from horizontal.
    
    The mouse balls wer placed on shiny back plastic pedestals.
    
    The scene also included a three-sided pyramid and a cone,
    made with thick paper.  The shapes were visibly imperfect.
    Some coloed letters were painted on the cone with felt-tip
    pen.  The pyramid had some text and diagrams printed on it,
    in red and black.
    
    The objects were placed over a gridded graph paper, off-white
    with light gray lines, spaced 3 mm apart.

  Pictures taken with Sony Cyershot DSC-W50 camera, "fine" resolution.

  Camera was mounted on the photo-stand, activated manually (without
  timer).

  Flash was turned off. Illumination provided by a 500 W halogen lamp,
  hand-held at different positions. Lamp-to-scene distance about 1 m.

  The pictures were originally named DSC00615.JPG through DSC00655.JPG
  by the camera (downloaded through Rafael's gizmo), then renamed with
  lowercase ("dsc00{NNN}.jpg") for compatibility with previous runs.
  
  They were placed in two directories

    bpyco-a 
      23 photos (615 -- 637).
      Camera placed about 60 cm from objects.

    bpyco-b
      18 photos (638 -- 655).
      Camera placed about 35 cm from objects.

  Generating the reduced pictures:
  
    cd ${STOLFIHOME}/projects/photostereo/test-images
    
    foreach s ( photo/bpyco-a photo/bpyco-b )
      foreach f ( `cd $s && ls dsc00???.jpg` )
        echo $s/$f
        convert $s/$f -resize '50%' $s/${f:r}-r.png
      end
    end
    
  Extracting the image information:
  
    foreach s ( photo/bpyco-a photo/bpyco-b )
      foreach f ( `cd $s && ls dsc00???.jpg` )
        set ifile = "$s/${f:r}.info"
        set efile = "$s/${f:r}.exif"
        echo $s/$f ' -> ' $ifile $efile
        identify -verbose $s/$f > $ifile
      end
    end

  Moved original images to depot/2007-06-29-uec

  Renamed derived images "dsc00{NNN}-r.png", "dsc00{NNN}.info"
  to "f-{MM}.png", "f-{MM}.info":

    mv -vi photo/bpyco-a/{dsc00615-r,f-00}.png
    mv -vi photo/bpyco-a/{dsc00616-r,f-01}.png
    ...                                                              
    mv -vi photo/bpyco-a/{dsc00637-r,f-22}.png
                                                                        
                                                                            
    mv -vi photo/bpyco-b/{dsc00638-r,f-00}.png
    mv -vi photo/bpyco-b/{dsc00639-r,f-01}.png
    ...                                                              
    mv -vi photo/bpyco-b/{dsc00655-r,f-17}.png

ALIGNING THE IMAGES

  We mist extract four sub-images 32x32 near the corners to find the 
  best possible alignment.
  
    # sz = Size of extracted images
    # mr = Distance from border
  
    set mr = 32
    set sz = 32
    @ hx = ( 816 - ${mr} ) - ${sz}
    @ hy = ( 612 - ${mr} ) - ${sz}
    echo ${hx} ${hy}
    foreach dir ( photo/bpyco-a photo/bpyco-b )
      foreach f ( `cd $dir && ls f-??.png` )
        foreach dx ( $mr $hx )
          foreach dy ( $mr $hy )
            set ifile = ${dir}/${f}
            set ofile = `printf "%s/%s-%04d-%04d.png" ${dir} ${f:r} $dx $dy`
            echo "${ifile} -> ${ofile}"
            convert ${ifile} -crop "${sz}x${sz}+${dx}+${dy}!" -colorspace GRAY -normalize ${ofile}
          end
        end
        display -title '%f' -resize '400%' ${dir}/${f:r}-*.png
      end
    end
    display -title '%f' -resize '400%' photo/bpyco-a/f-??-0032-0032.png &