動態闕值

int ihist[256] = {0}; // 映像長條圖，256個點int otsu (unsigned char *image, int rows, int cols, int x0, int y0, int dx, int dy, int vvv){   unsigned char *np; // 映像指標int thresholdValue=1; // 閾值int i, j, k; // various countersint n, n1, n2, gmin, gmax;double m1, m2, sum, csum, fmax, sb;//初始化灰階長條圖//for (k = 0; k <= 255; k++) //{//ihist[k] = 0;//}//gmin=255; gmax=0;//映像閾值範圍設定初始gmin=200; gmax=60;// 產生長條圖for (i = y0 + 1; i < y0 + dy - 1; i++) {   np = &image[i*cols+x0+1];   for (j = x0 + 1; j < x0 + dx - 1; j++) {   ihist[*np]++;   if(*np > gmax) gmax=*np;   if(*np < gmin) gmin=*np;   np++; /* next pixel */   }}// set up everythingsum = csum = 0.0;n = 0;for (k = 0; k <= 255; k++) {   sum += (double) k * (double) ihist[k]; /* x*f(x) 品質矩*/   n += ihist[k]; /* f(x) 品質 */}if (!n) {   // if n has no value, there is problems...//   fprintf (stderr, "NOT NORMAL thresholdValue = 160\n");   return (160);}// do the otsu global thresholding methodfmax = -1.0;n1 = 0;for (k = 0; k < 255; k++) {   n1 += ihist[k];   if (!n1) { continue; }   n2 = n - n1;   if (n2 == 0) { break; }   csum += (double) k *ihist[k];   m1 = csum / n1;   m2 = (sum - csum) / n2;   sb = (double) n1 *(double) n2 *(m1 - m2) * (m1 - m2);   /* bbg: note: can be optimized. */   if (sb > fmax) {   fmax = sb;   thresholdValue = k;   }}return(thresholdValue);}