% @(#)computpixe.hlq	19.1 (ESO-IPG) 02/25/03 14:03:03 
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1990 European Southern Observatory
%.IDENT      computpixe.hlq
%.AUTHOR     KB, IPG/ESO
%.KEYWORDS   MIDAS, help files, COMPUTE/PIXEL
%.PURPOSE    On-line help file for the command: COMPUTE/PIXEL
%.VERSION    1.0  12-OCT-1983 : Creation, KB
%.VERSION    1.1  26-SEP-1991 : Update, KB
%.VERSION    1.2  05-JAN-1993 : Update, KB
%----------------------------------------------------------------
\se
SECTION./PIXE
\es\co
COMPUTE/PIXEL					 05-JAN-1993  KB
\oc\su
COMPUTE/PIXEL [outspec =] expression
	compute expression on pixel basis
\us\pu
Purpose: 
          Perform arithmetic operations on images, using pixel coordinates.
\up\sy
Syntax:
          COMPUTE/PIXEL [outspec =] expression
\ys\pa
          outspec = frame to get result of expression, it will be created
              by MIDAS with the size of common area of all images involved in
              the expression
\\
              If descriptor copying is enabled (which is the default,
\\
              see also the command SET/MIDAS_SYSTEM DSCCOPY=..),
\\
              all non-standard descriptors of the 1. input frame in the
              expression are copied to the result frame unless you enter
              `frame,dscname' as outspec with dscname the name of a frame
              in the expression;
\\
              then, the non-standard descriptors of that frame are copied
              instead of the ones of the 1. frame in the expression
\ap\pa
          expression = arithmetic expression with up to 21 operands, which may
               be functions and frames or/and constants in the usual algebraic
               notation
\ap\sa
See also:
          COMPUTE/IMAGE, REPLACE/IMAGE
\as\no
Note:  
          Spaces before and after the "=" sign are required. If the name of
          frame begins with a digit or contains a special char. like, e.g.
          `+',`-',... the name (with filetype!) has to be enclosed in double
          quotes.
\\
          Inside the expression may be spaces or not. However, if your
          expression is longer than 100 chars. (the current max. token length)
          without spaces, you should include spaces between some operands,
          then the limit is 256 chars. for the complete command line.
\\
          This command works exactly like COMPUTE/IMAGE but uses pixel coords;
          i.e. all images involved are treated like arrays ranging from 1 to
          NPIX in each dimension regardless what stepsize they have.
\\
          Computations are done only on the common pixel area of all images.
\\
          Consult the help of COMPUTE/IMAGE for a detailed description of all
          available functions.
\\
          This command uses single precision (floating point) calculations,
          if you need higher precision, use COMPUTE/DPIXEL instead.
\on\exs
Examples:
\ex
          COMPUTE/PIXEL nero = caligula + claudius
           Add contents of image frame `caligula.bdf' and `claudius.bdf' and
           store result into frame `nero.bdf'.
\\
           If descriptor copying is enabled, all non-standard descriptors of
           `caligula.bdf' (the 1. frame in the expression) are copied to the
           result frame `nero.bdf'.
\xe \sxe
