circle.c File Reference

Functions for simulating circular image region. More...

#include "libtpcidi.h"

Go to the source code of this file.

Functions
int	imgCircleMask (IMG *img, int zi, double cx, double cy, double r, double mv, double *smv, int verbose)
int	imgRingMask (IMG *img, int zi, double cx, double cy, double r1, double r2, double mv, double *smv, int verbose)

Detailed Description

Functions for simulating circular image region.

Author

Vesa Oikonen

Definition in file circle.c.

Function Documentation

imgCircleMask()

int imgCircleMask	(	IMG *	img,
		int	zi,
		double	cx,
		double	cy,
		double	r,
		double	mv,
		double *	smv,
		int	verbose )

Simulate a mask image of circle with specified radius.

The applied method is only approximate at pixel borders (pixel is divided into 5x5 subpixels).

See also

imgRingMask, imgSimulateSphere, idiSimulateTubeVol, imgMaskInvert

Returns

Returns 0 if successful.

Parameters

img	Pointer to allocated static or dynamic image; image must contain pixel sizes and dimensions; mask values are added to pixel values, thus you may need to set pixel values to zero before calling this function.
zi	Plane index [0..dimz-1].
cx	X distance of circle centre (mm) from the upper left corner of the image.
cy	Y distance of circle centre (mm) from the upper left corner of the image.
r	Radius of circle (mm).
mv	Mask value; this value is added to each pixel value that fits inside the radius; the pixels that are partially inside the radius will get fraction of mask value.
smv	Pointer to value where the sum of added mask pixel values is written; enter NULL if not needed. Use this to validate the results.
verbose	Verbose level; set to <=0 to prevent all prints to stdout.

Definition at line 16 of file circle.c.

  {
  if(verbose>0) printf("%s(img, %d, %g, %g, %g, %g, ...)\n", __func__, zi, cx, cy, r, mv);
 
  int n, xi, yi, fi, i, j;
  double dx[5], dy[5], r2, v;
 
  if(img->status<IMG_STATUS_OCCUPIED) return(1);
  if(zi<0 || zi>=img->dimz) return(2);
  if(img->sizey<=0.0 || img->sizex<=0.0) return(3);
  if(img->sizey!=img->sizex) return(4);
  if(img->dimt<1) return(5);
 
  if(smv!=NULL) *smv=0.0;
  /* Compare r^2 to sum of squared distances instead of square root */
  r2=r*r;
  for(yi=0; yi<img->dimy; yi++) {
    dy[0]=(0.1+(double)yi)*img->sizey - cy;
    for(j=1; j<5; j++) dy[j]=dy[j-1]+0.2*img->sizey;
    for(xi=0; xi<img->dimx; xi++) {
      dx[0]=(0.1+(double)xi)*img->sizex - cx;
      for(i=1; i<5; i++) dx[i]=dx[i-1]+0.2*img->sizex;
      for(i=0, n=0; i<5; i++) for(j=0; j<5; j++) if((dx[i]*dx[i]+dy[j]*dy[j])<r2) n++;
      if(n==0) continue;
      v=(double)n*mv/25.0;
      for(fi=0; fi<img->dimt; fi++) img->m[zi][yi][xi][fi]+=v;
      if(smv!=NULL) *smv+=v;
    }
  }
 
  return(0);
}

Referenced by imgRingMask().

imgRingMask()

int imgRingMask	(	IMG *	img,
		int	zi,
		double	cx,
		double	cy,
		double	r1,
		double	r2,
		double	mv,
		double *	smv,
		int	verbose )

Simulate a mask image of ring with specified inner and outer radius.

The applied method is only approximate at pixel borders (pixel is divided into 5x5 subpixels).

See also

imgCircleMask, imgSimulateRing, imgSimulateSphere, imgMaskInvert

Returns

Returns 0 if successful.

Parameters

img	Pointer to allocated static or dynamic image; image must contain pixel sizes and dimensions; mask values are added to pixel values, thus you may need to set pixel values to zero before calling this function.
zi	Plane index [0..dimz-1].
cx	X distance of circle centre (mm) from the upper left corner of the image.
cy	Y distance of circle centre (mm) from the upper left corner of the image.
r1	Inner radius of circle (mm).
r2	Outer radius of circle (mm).
mv	Mask value; this value is added to each pixel value that fits inside the radius; the pixels that are partially inside the radius will get fraction of mask value.
smv	Pointer to value where the sum of added mask pixel values is written; enter NULL if not needed. Use this to validate the results.
verbose	Verbose level; set to <=0 to prevent all prints to stdout.

Definition at line 77 of file circle.c.

  {
  int ret;
  double mv1, mv2, d;
 
  if(verbose>0) printf("%s(img, %d, %g, %g, %g, %g, %g, ...)\n", __func__, zi, cx, cy, r1, r2, mv);
  if(r1>=r2 || r1<0.0) {
    if(verbose>0) fprintf(stderr, "Error: invalid radius.\n");
    return(1);
  }
 
  /* Simulate circle with the larger radius */
  ret=imgCircleMask(img, zi, cx, cy, r2, mv, &mv1, verbose);
  if(ret!=0) {
    if(verbose>0) fprintf(stderr, "Error: cannot simulate circle 1.\n");
    return(ret);
  }
  /* Subtract circle with the smaller radius */
  ret=imgCircleMask(img, zi, cx, cy, r1, -mv, &mv2, verbose);
  if(ret!=0) {
    if(verbose>0) fprintf(stderr, "Error: cannot simulate circle 2.\n");
    return(ret);
  }
  /* Calculate the sum of mask pixel values */
  d=mv1+mv2; if(smv!=NULL) *smv=d;
  if(d==0.0 && verbose>0) {fprintf(stderr, "Warning: empty mask image created.\n"); fflush(stderr);}
  return(0);
}