splitblend(1)                                                    splitblend(1)



NAME
       splitblend - Produce command files for running blendmont in parallel

SYNOPSIS
       splitblend  [options]  Blendmont_command_file

DESCRIPTION
       Splitblend is a Python script that takes a command file for running
       Blendmont and produces files that can be run in parallel with Pro-
       cesschunks(1).  Blendmont performs two distinct operations.  First,
       it finds the displacement between adjacent pieces and the detailed map-
       pings between pieces in their overlap zones; the latter are referred to
       as edge functions.  Second, it uses this information to make the
       blended images.  The first operation can only be divided into two
       parts, one for all of the edges between pieces in the X direction, the
       other for edges in Y.  The second operation can be divided into many
       more chunks, where each chunk is either a set of sections in Z or a set
       of lines in Y.  The latter is useful when blending a single large
       image.  Which operations Blendmont does is ordinarily controlled by
       two parameters, OldEdgeFunctions and ReadInXcorrs.  There are three
       common situations:
       1) Doing all operations on an initial run of Blendmont:
           OldEdgeFunctions  0
           ReadInXcorrs      0
       2) Computing new edge functions after fixing displacements in Midas:
           OldEdgeFunctions  0
           ReadInXcorrs      1
       3) Just blending images with the existing displacements and edge func-
       tions:
           OldEdgeFunctions  1
           ReadInXcorrs      1

       If you enter no options to indicate otherwise, Splitblend will set up
       command files to blend images after doing the operations determined by
       the values of these options in the command file.  However, you can
       override what is in the file with the "-r" option to tell it to compute
       new edge functions with existing displacements, and with the "-u"
       option to tell it just to blend images using existing displacements and
       edge functions.  You can also use the "-e" option to compute edge func-
       tions only, without blending images.

       The command file can contain commands before and after the Blendmont
       run, but should not contain more than one run of Blendmont.

       When X and Y edge functions are computed in parallel, a sync command
       file is used to combine the edge correlation displacements from the X
       and Y edges into one ".ecd" file.

       Blending can be dominated by file input/output, particularly if overlap
       zones are small and there are no distortion corrections.  If disk
       access is slow, there may be little value in running Blendmont in
       parallel in such cases.

OPTIONS
       Splitblend uses the PIP package for input (see the manual page for
       pip).  Options can be specified either as command line arguments
       (with the -) or one per line in a command file (without the -).
       Options can be abbreviated to unique letters; the currently valid
       abbreviations for short names are shown in parentheses.

       -n    Integer
              Expected number of machines or processors.  The default is 4.
              The number of chunks will be 4 times the number of processors,
              unless specified with "-t".

       -t    Integer
              The desired number of chunks to set up.  The actual number will
              be limited by the number of sections when chunks are in Z.

       -y     Do chunks in Y instead of in Z.  Chunks in Y are chosen automat-
              ically if there is only one section in Z.

       -e     Compute edge functions without blending images.  This option is
              not allowed if the command file specifies to use old edge func-
              tions, unless you enter the "-r" option too.

       -u     Just blend images using existing edge functions and displace-
              ments, regardless of the values of the corresponding options in
              the command file.

       -r     Recompute edge functions using existing displacements between
              pieces, regardless of the values of the corresponding options in
              the command file.

       -b    Integer
              Set the number of boundary pixels saved in separate files to the
              given value.  The boundary pixels are rewritten to the output
              file after all chunks are done.

       -StandardInput
              Read parameter entries from standard input


AUTHOR
       David Mastronarde


SEE ALSO
       blendmont, processchunks, midas


BUGS
       Email bug reports to mast at colorado dot edu.



BL3DEMC                              4.7.3                       splitblend(1)