     EPIC(1)                                                             EPIC(1)
                                     August 1989

     NAME
          epic - efficient image pyramid coder

     SYNOPSIS
          epic imagefile [ -o epicfile ] [ -x xdim ] [ -y ydim ] [ -l levels ] [
          -b binsize ] unepic epicfile [ resultfile ]

     DESCRIPTION
          Epic compresses raw (8-bit) image files, using an asymmetrical subband
          pyramid (biorthogonal wavelet) decomposition, and a combined run-
          length/Huffman entropy coder.  Epic is a lossy coder: it introduces
          errors in the compressed image.  Unepic decompresses the files that
          have been compressed using Epic.  The required Epic argument imagefile
          must be the name of a raw 8-bit image file.  The required Unepic
          argument epicfile must be the name of a compressed file created using
          epic.

        OPTIONS:
          epicfile is the name to be used for the compressed image file.  It
          defaults to a concatenation of the imagefile name and the extensions
          ".E".  resultfile is the name of the file in which unepic puts the
          de-compressed image.  It defaults to a concatenation of the epicfile
          name and the extension ".U".  xdim is the x dimension (line length) of
          the image in pixels.  It defaults to 256.  Note that this must be
          specified if the image width is not 256!  ydim is the y dimension
          (height) of the image in pixels.  It defaults to 256.  Note that this
          must be specified if the image height is not 256!  levels specifies
          the number of recursive pyramid levels to build.  This defaults to 4
          which is appropriate for images of size 256x256.  binsize specifies
          the quantization binsize to be used in compressing the image.  This
          parameter determines the amount of compression (or the loss of
          quality). Setting it to 0 will produce the highest quality (but least
          compressed) image.

     CAVEATS
          1. Code is currently limited to square images.  2. The dimensions of
          the image must be divisible by 2^levels.  3. Color images may be
          compressed by converting from RGB space to YIQ space and compressing
          each of the components separately.

     AUTHORS
          Written by Eero P. Simoncelli and Edward H. Adelson, August, 1989.

     REFERENCES
          Edward H. Adelson, Eero P. Simoncelli.  Subband Image Coding with
          Three-tap Pyramids.  Picture Coding Symposium, 1990.  Cambridge, MA.

                                        - 1 -         Formatted:  March 14, 2001

     EPIC(1)                                                             EPIC(1)
                                     August 1989

          Eero P. Simoncelli.  Orthogonal Sub-band Image Transforms.  Master's
          Thesis, EECS Department, Massachusetts Institute of Technology. May,
          1988.

          Edward H. Adelson, Eero P. Simoncelli and Rajesh Hingorani.
          Orthogonal pyramid transforms for image coding.  In Proceedings of
          SPIE, October 1987, Volume 845.

                                        - 2 -         Formatted:  March 14, 2001