Threshold Segmentation: Basic global threshold method, upper and lower threshold method, iterative method

/*---------------------------------------------------------------------------*/* Basic Global threshold method */iplimage*
    Imgbasicglobalthreshold = Cvcreateimage (Cvgetsize (Imggrey), ipl_depth_8u,1);
Cvcopyimage (Srcimggrey,imgbasicglobalthreshold);    
int Pg[256],i,thre;
for (i=0;i<256;i++) pg[i]=0; for (i=0;iimagesize;i++)//Histogram statistics pg[(BYTE) Imgbasicglobalthreshold->imag    
    edata[i]]++;    thre = Basicglobalthreshold (pg,0,256);
     Determine threshold cout<< "The Threshold of this Image in Basicglobalthreshold is:" <<thre<<endl;//output display threshold  Cvthreshold (imgbasicglobalthreshold,imgbasicglobalthreshold,thre,255,cv_thresh_binary);
    Binary Cvnamedwindow ("Basicglobalthreshold", cv_window_autosize); Cvshowimage ("Basicglobalthreshold", imgbasicglobalthreshold);//Display Image Cvreleaseimage (&imgbasicglobalthreshold)
; /*---------------------------------------------------------------------------*/* Upper and lower threshold method: Use normal distribution to find confidence interval */Iplimage* Imgtopdown = Cvcreateimage (Cvgetsize (Imggrey), ipl_depth_8u, 1);
    Cvcopyimage (Srcimggrey,imgtopdown);
    Cvscalar mean, std_dev;//average, standard deviation double u_threshold,d_threshold;    
    CVAVGSDV (Imgtopdown,&mean,&std_dev,null); U_threshold = mean.val[0] +2.5* std_dev.val[0];//upper threshold d_threshold = mean.val[0] -2.5* std_dev.val[0];//lower threshold//u_threshol D = mean + 2.5 * STD_DEV;
    Error//d_threshold = mean-2.5 * STD_DEV; cout<< "The topthreshold of this Image in Topdown is:" <<d_threshold<<endl;//output shows threshold cout<< "the D
    Ownthreshold of this Image in Topdown is: "<<u_threshold<<endl; Cvthreshold (IMGTOPDOWN,IMGTOPDOWN,D_THRESHOLD,U_THRESHOLD,CV_THRESH_BINARY_INV);//up/Down threshold CvNamedWindow ("
    Imgtopdown ", cv_window_autosize);
Cvshowimage ("Imgtopdown", imgtopdown);//Display Image cvreleaseimage (&imgtopdown); /*---------------------------------------------------------------------------*/* Iterative method */iplimage* Imgiteration = CvcreateimaGE (cvgetsize (imggrey), ipl_depth_8u, 1);
Cvcopyimage (srcimggrey,imgiteration);
    int Thre3,ndiffrec;
    Thre3 =detectthreshold (imgiteration, Ndiffrec); cout<< "The Threshold of this Image in Imgiteration is:" <<thre3<<endl;//output shows threshold Cvthreshold (Imgiterati
    ON,IMGITERATION,THRE3,255,CV_THRESH_BINARY_INV);//upper and lower threshold Cvnamedwindow ("imgiteration", cv_window_autosize);
    Cvshowimage ("Imgiteration", imgiteration); Cvreleaseimage (&imgiteration);

/*======================================================================*//* Iterative method *//*============================ ==========================================*///Nmaxiter: Maximum number of iterations; Ndiffrec: The average gray difference between the light and dark areas using the given threshold value int Detectthreshold (iplimage*img, int nmaxiter, int& idiffrec)//Threshold Segmentation: Iterative Method {//image information int height = img->height; int width = Img->widt
H
    int step = img->widthstep/sizeof (Uchar);

    Uchar *data = (uchar*) img->imagedata;
Idiffrec = 0; int f[256]={0};
    Histogram array int itotalgray=0;//gray value and int itotalpixel =0;//pixels and byte bt;//pixel value Uchar ithrehold,inewthrehold;//threshold, new threshold

The maximum gray value and the minimum gray value Uchar imeangrayvalue1,imeangrayvalue2 in the original image of Uchar imaxgrayvalue=0,imingrayvalue=255;//; Gets the value of (i,j), stored in the histogram array f for (int i=0;i<width;i++) {for (int j=0;j 

 
/*============================================================================ = Code content: Basic Global Threshold method ==============================================================================*/int BasicGlobalThreshold (INT*PG    
    , int start,int end) {//Basic global threshold method int i,t,t1,t2,k1,k2; double u,u1,u2;     
    t=0;
u=0;        
        for (i=start;i<end;i++) {t+=pg[i];
    U+=i*pg[i];                          } k2= (int) (U/T);
        Calculates the mean of this range grayscale do {k1=k2;    
        t1=0;
u1=0;    
            for (i=start;i<=k1;i++) {//calculates the accumulation and t1+=pg[i of low gray groups];
        U1+=i*pg[i];
        } t2=t-t1;
U2=U-U1;                     if (t1) u1=u1/t1;
Calculates the average of the low gray group else u1=0;                     if (T2) u2=u2/t2;
        Calculates the average of the high gray group else u2=0;                 k2= (int) ((U1+U2)/2); Get a new threshold estimate} while (k1!=K2);
The data is not stable, continue//cout<< "The Threshold of this Image in Basicglobalthreshold is:" <<k1<<endl;                              return (K1); Return threshold}