% @(#)sort_row.hlq	19.1 (ESO-IPG) 02/25/03 13:19:19 
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1990 European Southern Observatory
%.IDENT      sort_row.hlq
%.AUTHOR     PB, IPG/ESO
%.KEYWORDS   MIDAS, help files, SORT/ROW
%.PURPOSE    On-line help file for the command: SORT/ROW
%.VERSION    1.0  19-JUN-1991 : Creation, PB
%----------------------------------------------------------------
\se
SECTION./ROW
\es\co
SORT/ROW						19-JUN-1991 PB
\oc\su
SORT/ROW input output
	row oriented sorting of the pixels of a frame.
\us\pu
Purpose:    
            Sort pixel values of a frame along rows
\up\sy
Syntax:       
            SORT/ROW  input  output
\ys\pa
            input  =   name of input frame
\ap\pa
            output =   name of output frame
\ap\no
Note:       This command enables to correct CCD images for bad rows
            patterns by the following procedure:

            If ima_org is the science frame containing bad rows,
            and ncol, nrow are respectively the number of columns and of
            rows in ima_org. It is possible to prepare a mask of the
            bad rows using:

                      SORT/ROW    ima_org   ima_sort

                      AVERAGE/COL mask1d =  ima_sort  @<col1>,@<col2>

                      where col1, col2 delimit an area of the sorted image
                      containing only pixels due to the background of
                      ima_org.

                      GROW/IMAGE  mask2dr = mask1d  1.,1.,<ncol>

                      where ncol is the number of columns in ima_org.
                      Descriptors start and step of ima_org are
                      suppposed to be equal to 1.,1.

                      ROTATE/COUNTER  mask2dr mask2d
                      WRITE/DESCR     mask2d  start  1.,1.
                      WRITE/DESCR     mask2d  step   1.,1.

                      COMPUTE/IMA  ima_cor = ima_org - mask2d

                      This method is based on Pojmanski (1991, How To
                      Remove Easily the Unpleasant Column Pattern,
                      Proceedings of the 3rd ESO/ST-ECF Data Analysis
                      Workshop, pp. 101-105)
\on\exs
Examples:
\ex
            none
\xe \sxe
