Storing Emulsion Images

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Storing Emulsion Images

• Dominique Boutigny
• LAPP - CNRS/IN2P3
• September 16, 2004

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• GenIma is producing MC simulated images
• At the moment 1 simulation 32 frames
• 32 files in ppm format (very big) then convert in
  bmp format, possibly convert with gzip
• OK but very complicated to handle and error prone

• For real scanning images, it may be interesting
  to store some image samples
• Test new tracking ideas
• Compare with MC
• Have a visual look to emulsion without microscope
  
• .

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• OPERA is not the first physics experiment to
  handle pictures
• Astrophysics is doing that, every day since years
• By the way, both are using CCD techniques
• OPERA ? multiple layers within the emulsion
• Astro ? multiple filters or wavelength

• The astrophysics community has developed a
  worldwide adopted standard
• FITS
• Flexible Image Transport System
• A complete maintained and optimized library is
  available for C and Fortran at the High Energy
  Astrophysics Science Archive Research Center
  (NASA)
• CFITSIO
• Many utilities and viewers exists and are
  maintained

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Inside a FITS file

• Can store bitmaps, ASCII or binary arrays
• As many images as necessary (within 2 GB limits)
• On the fly "loss-less" (de)compression
• Each image is associated with a header
• Standard mandatory part
• User keywords Can put many
• Run / event number
• View coordinates (x, y, depth)
• The header is not compressed in order to speed up
  header based image selection

• Complete library to manage FITS files
• Read / Write
• Insert new header / bitmap
• Partial reading
• Filtering
• Etc
• Available on many (all ?) platforms (already
  tested on Linux and Alpha station)
• Interface to MathLab, PhotoShop, etc available

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Status

• At the moment
• cfitsio Fortran interface for GenIma ? Done
• Next step
• Write an interface for the EdbImage class in
  Fedra libEdb
• Easy will be ready by next week
• Root interface ?
• Don't re-invent the wheel, we are not the first
  to manipulate images !
• ? Demo

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References

• FITS format
• ftp//legacy.gsfc.nasa.gov/fits_info/fits_office/f
  its_standard.pdf
• http//www.edpsciences-usa.org/articles/aa/full/20
  01/34/aah2901/aah2901.html
• cfitsio http//legacy.gsfc.nasa.gov/docs/software
  /fitsio/fitsio.html
• Viewers and converters http//fits.gsfc.nasa.gov/
  fits_viewer.html