/*
 *  Template program for computing features 
 *
 *  Feature program fpstat computes pixel mean and standard deviation
 *  Limitations: only accepts unsigned byte images
 *
 */
#include "VisXV4.h"    /* VisionX structure include file       */
#include "Vutil.h"     /* VisionX utility header files         */

VXparam_t par[] =      /* command line structure               */
{
{    "if=",    0, " input file,  vpstat: evaluate fpstat "},
{    "of=",    0, " output file "},
{     0,       0,    0}
};
#define  INIMAGE   par[0].val
#define  OUTCSV    par[1].val

int fpstat ( float *, VisXimage_t * );

int main(int argc, char** argv)
{
Vfstruct (im);
float result [3];
FILE *outfile;

VXparse(&argc, &argv, par);  /* parse the command line         */

  outfile = stdout;
  if (OUTCSV) { outfile = fopen (OUTCSV,"w"); }
  fprintf (outfile, "Count,Mean,Std.Dev\n");

  while ( Vfread( &im, INIMAGE) ) {
    if ( im.type != VX_PBYTE ) {
           fprintf (outfile, "error: image not byte type\n");
           exit (1);
    }
    fpstat (result, &im );
    fprintf (outfile, "%5.3f,%5.3f,%5.3f\n",result[0],result[1],result[2]);
  }

  if ( OUTCSV) { fclose (outfile); }
  exit(0);
}

/* feature subprogram  */

int fpstat ( float * result, VisXimage_t *im ) {
int x, y;
float sum, sum2, mean, sdev;
int count;
    count = 0;
    sum = 0.0;
    sum2 = 0.0;
    for ( y= im->ylo; y <= im->yhi; y++) {
       for ( x= im->xlo; x <= im->xhi; x++) {
          sum += im->u[y][x];
          sum2 += im->u[y][x] * im->u[y][x];
	  count++;
       }
    }
    mean = sum/count;
    result[0] = count;  
    result[1] = mean;  
    result[2] = sqrt(sum2/count - mean * mean);  
    return (1);
}