Help for RANDPIXEL

PURPOSE:

   RANDPIXEL is an Applications program to fill in a blank image
with random data points.  If no input file is given then it computes
the random x,y locations for the pixel and enters the RANDFILL value.
If an input file is given it computes the random x,y locations and extracts
the corresponding data value from the input file and places it in that 
location.

OPERATION:

	RANDPIXEL is an Applications program to fill in a blank image
with random data points.  If no input file is given then it computes
the random x,y locations for the pixel and enters the RANDFILL value.
If an input file is given it computes the random x,y locations and extracts
the corresponding data value from the input file and places it in that 
location.

	There is no bkg value.
	

	2nd output is ibis-2 table of random values (x,y, fillval)

	may want to put symmetrical points around the center, i.e., 
	one random point is followed by its reflected pair.


PARAMETERS

        RANDPIXEL has a variety of options specified by paramters.  INP= is
optional. If given then the output data set will contain only the pixels
copied from the points selected by the random pixels. PIXFILL is ignored.
ONS, ONL and OUTFMT are ignored.
 
	OUT is the output image file name. The second output is an IBIS-2 
format table. (The second output file is not available yet).

	ONL, ONS and OUTFMT control the format of the output data set. They
are ignored if an input file is given. 

	POINTS tells how many random points to generate.

	SYMMETRY is a keyword which says to choose symmetric points around 
center of image. If this is chosen only half the points are random.

	SHAPE tells the shape of the random points to fit in a square or a 
circle.

	SLSHAPE, NLSHAPE, SSSHAPE, NSSHAPE tell what area to put random numbers
in. Default is whole frame.

	RANDFILL is the value to place in the random pixel. It is ignored if
an input image is given. It will select the value of that pixel to be
placed in the output image.

	RANDSEED is the value to give to the random number generator to start.
If not given then it will choose its own seed from the date & time.

	LIST means type out random pixels to screen.

ERROR MESSAGES



LIMITATIONS

      1. The program has not been implemented for multiple band images
	  2. Only BYTE and HALFWORD images supported
	  3. Output IBIS table is not generated yet
      4. Circular apertures still do not work
      5. Maximum of 4,194,304 pixels (2048x2048) with max samples of 4096

PROGRAM HISTORY:

  1996-07-18 R.J. Bambery - Original release
  2010-03-15 R.J. Bambery - Made compatible with 64-bit Linux MacOSX (intel/PowerPC) 10.5.8
  2010-03-16 R.J. Bambery - Made 64-bit clean for chkstat routine
  2011-05-06 R.J. Bambery - Fixed input modes for symmetric and non-symmetric 
  2012-06-06 R.J. Bambery - Fixed parameter list for subcircgen_img subroutine
  2012-06-07 R.J. Bambery - gfortran 4.6.3 revealed that rangen
    parameters are (long,float) so created integer*8 dseed replacement for
    integer*4 seed - sigma always became zero when seed was entered into
    rangen
  2012-07-03 R.J. Bambery - Removed <tab> in front of continuation
    lines to make backward compatible with 32-bit Linux gfortran 4.2.1,
    otherwise compatible 64-bit Linux gfortran 4.6.3
  2013-09-16 R.J. Bambery - Changed internal call from rangen to rangen_big
  2016-06-08 W.L. Bunch - Migrated to MIPL.

EXAMPLES:

       RANDPIXEL OUT=SPARSE.OUT PARAMS (for random points of RANDFILL)

       RANDPIXEL INP=DATA OUT=SPARSE.OUT PARAMS  (for extracting pixel valuess)

Parameters are defined above and in the TUTOR mode.

REFERENCE

PARAMETERS: