www.pudn.com > segment.zip > segment-image.h

#ifndef SEGMENT_IMAGE 
#define SEGMENT_IMAGE 
 
#include  
#include  
#include  
#include  
#include "segment-graph.h" 
 
// random color 
rgb random_rgb(){  
  rgb c; 
  double r; 
   
  c.r = (uchar)random(); 
  c.g = (uchar)random(); 
  c.b = (uchar)random(); 
 
  return c; 
} 
 
// dissimilarity measure between pixels 
static inline float diff(image *r, image *g, image *b, 
			 int x1, int y1, int x2, int y2) { 
  return sqrt(square(imRef(r, x1, y1)-imRef(r, x2, y2)) + 
	      square(imRef(g, x1, y1)-imRef(g, x2, y2)) + 
	      square(imRef(b, x1, y1)-imRef(b, x2, y2))); 
} 
 
/* 
 * Segment an image 
 * 
 * Returns a color image representing the segmentation. 
 * 
 * im: image to segment. 
 * sigma: to smooth the image. 
 * c: constant for treshold function. 
 * min_size: minimum component size (enforced by post-processing stage). 
 * num_ccs: number of connected components in the segmentation. 
 */ 
image *segment_image(image *im, float sigma, float c, int min_size, 
			  int *num_ccs) { 
  int width = im->width(); 
  int height = im->height(); 
 
  image *r = new image(width, height); 
  image *g = new image(width, height); 
  image *b = new image(width, height); 
 
  // smooth each color channel   
  for (int y = 0; y < height; y++) { 
    for (int x = 0; x < width; x++) { 
      imRef(r, x, y) = imRef(im, x, y).r; 
      imRef(g, x, y) = imRef(im, x, y).g; 
      imRef(b, x, y) = imRef(im, x, y).b; 
    } 
  } 
  image *smooth_r = smooth(r, sigma); 
  image *smooth_g = smooth(g, sigma); 
  image *smooth_b = smooth(b, sigma); 
  delete r; 
  delete g; 
  delete b; 
  
  // build graph 
  edge *edges = new edge[width*height*4]; 
  int num = 0; 
  for (int y = 0; y < height; y++) { 
    for (int x = 0; x < width; x++) { 
      if (x < width-1) { 
	edges[num].a = y * width + x; 
	edges[num].b = y * width + (x+1); 
	edges[num].w = diff(smooth_r, smooth_g, smooth_b, x, y, x+1, y); 
	num++; 
      } 
 
      if (y < height-1) { 
	edges[num].a = y * width + x; 
	edges[num].b = (y+1) * width + x; 
	edges[num].w = diff(smooth_r, smooth_g, smooth_b, x, y, x, y+1); 
	num++; 
      } 
 
      if ((x < width-1) && (y < height-1)) { 
	edges[num].a = y * width + x; 
	edges[num].b = (y+1) * width + (x+1); 
	edges[num].w = diff(smooth_r, smooth_g, smooth_b, x, y, x+1, y+1); 
	num++; 
      } 
 
      if ((x < width-1) && (y > 0)) { 
	edges[num].a = y * width + x; 
	edges[num].b = (y-1) * width + (x+1); 
	edges[num].w = diff(smooth_r, smooth_g, smooth_b, x, y, x+1, y-1); 
	num++; 
      } 
    } 
  } 
  delete smooth_r; 
  delete smooth_g; 
  delete smooth_b; 
 
  // segment 
  universe *u = segment_graph(width*height, num, edges, c); 
   
  // post process small components 
  for (int i = 0; i < num; i++) { 
    int a = u->find(edges[i].a); 
    int b = u->find(edges[i].b); 
    if ((a != b) && ((u->size(a) < min_size) || (u->size(b) < min_size))) 
      u->join(a, b); 
  } 
  delete [] edges; 
  *num_ccs = u->num_sets(); 
 
  image *output = new image(width, height); 
 
  // pick random colors for each component 
  rgb *colors = new rgb[width*height]; 
  for (int i = 0; i < width*height; i++) 
    colors[i] = random_rgb(); 
   
  for (int y = 0; y < height-1; y++) { 
    for (int x = 0; x < width-1; x++) { 
      int comp = u->find(y * width + x); 
      imRef(output, x, y) = colors[comp]; 
    } 
  }   
 
  delete [] colors;   
  delete u; 
 
  return output; 
} 
 
#endif