NAME
      pyrmask - Blend two images together using
      Gaussian pyramids.

 SYNOPSIS
      pyrmask [ -l levels ] [ -o outfile ] inmask outmask maskfile

 DESCRIPTION
      Pyrmask blends two images together by first
      breaking the images down into separate
      bandpass images, combining these separate
      images, and then adding the new bandpass
      images back into a single output image.  This
      can produce very seamless blends of digital
      images.  The two images are combined on the
      basis of a third "mask" image.  The resulting
      image will contain the inmask image where the
      mask contains a maximum value (255) and the
      outmask image where the mask contains zeros.
      This is done on a channel by channel basis,
      i.e. the maskfile should have data in each
      channel describing how to combine each
      channel of the inmask and outmask images.
      All three images must have exactly the same
      dimensions (both image size and number of
      channels).  For best results, it's often
      useful to filter the mask image a little with
      smush(1) first.

 OPTIONS
      -l levels
           How many pyramid levels to use (maximum
           is log(2) of image size).

      -o outfile
           If specified, output will be written to
           this file, otherwise it will go to
           stdout.

 SEE ALSO
      smush(1), rleswap(1), urt(1), RLE(5),
      Burt and Adelson, "A Multiresolution Spline
      With Applications to Image Mosaics", ACM
      Transactions on Graphics, October 1983, V2
      #4, p. 217.
      Ogden, Adelson, Bergen and Burt, "Pyramid-
      based Computer Graphics", RCA Engineer,
      Sept/Oct 1985, p. 4.

 AUTHOR
      Rod Bogart

 BUGS
      The current implementation has very strict
      requirements for image sizes and dimensions.
      The extensive use of floating point
      computation makes it very slow for normal
      sized images.  It also keeps all of the
      bandpass images in core at once, which
      requires considerable amounts of memory.

      Pyrmask is built on top of a library of
      functions for working with Gaussian pyramids.
      This library has yet to be documented or
      fully tested.





































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