Accessing multiple images

This example (proc.c) shows how IMG can access more than one image per function call:

   /*  Declare pointers for images. */
   float *ip[3], *ipproc, *ipbias, *ipflat, *ipraw ;              [1]
   int nx, ny, i;

   /*  Access input images. */
   imgIn( "bias,flat,raw", &nx, &ny, ip, istat );                 [2]
   ipbias = ip[0];
   ipflat = ip[1];
   ipraw = ip[2];

   /*  Create a new output image by copying the raw input image. */
   imgOut( "raw", "proc", &ipproc, istat );

   /*  Debias and flatfield data. */
   for( i=0; i <nx*ny; i++ ) {
      *ipproc++ = ( *ipraw++ - *ipbias++ ) / *ipflat++;
   }

   /*  Free all the images.*/
   imgFree( "*", istat );

The following notes refer to the numbered statements:

1.

Note that the variable ip is declared as an array of pointers to float.

2.

After this call each of the elements of ip is set to point to a different image. The advantage of such a call is that all the images are guaranteed to be the same shape and data type.