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sinestar.c

Go to the documentation of this file.

#include        "sadie.h"

/*-Copyright Information------------------------------------------------------*/
/* Copyright (c) 1993 by the University of Arizona Digital Image Analysis Lab */
/*----------------------------------------------------------------------------*/
/*-General Information--------------------------------------------------------*/
/*                                                                            */
/*   This function creates a sine star test pattern.                          */
/*                                                                            */
/*----------------------------------------------------------------------------*/
/*-Interface Information------------------------------------------------------*/
void
SINESTAR (short nlin,           /*  I   Number of lines in the output image.                  */
          short npix,           /*  I   Number of pixels/line in the output image.            */
          double period,        /*  I   Number of sine periods.                               */
          IMAGE ** out          /*  O   Address of a pointer to the output image.             */
/*----------------------------------------------------------------------------*/
  )
{
  register short j, k;
  char msg[SLEN];
  double x, y, angle;

  if (TIMES)
    TIMING (T_SINESTAR);
  if (NAMES)
    {
      MESSAGE ('I', "");
      MESSAGE ('I', "SINESTAR");
      MESSAGE ('I', "");
      sprintf (msg, " Image size: lines:           %d", nlin);
      MESSAGE ('I', msg);
      sprintf (msg, "             pixels:          %d", npix);
      MESSAGE ('I', msg);
      sprintf (msg, " Period(s):                 %12.4e", period);
      MESSAGE ('I', msg);
      MESSAGE ('I', " ...............");
    }

  /* create image of appropriate size */
  if (!CHECKIMG (*out))
    GETMEM (1, nlin, npix, out);

  /* create sine star test pattern */
  for (j = 0; j < nlin; j++)
    {
      y = (double) (j - nlin / 2);
      for (k = 0; k < npix; k++)
        {
          x = (double) (k - npix / 2);
          if (x == 0.0)
            {
              if (y > 0.0)
                {
                  angle = PI / 2.0;
                }
              else if (y < 0.0)
                {
                  angle = -PI / 2.0;
                }
              else
                {
                  angle = 0.0;
                }
            }
          else
            {
              angle = atan2 (y, x);
            }
          (*out)->data[0][j][k] = (PIXEL) cos (angle * period);
        }
    }

the_end:
  if (TIMES)
    TIMING (T_EXIT);
}

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