OpenCV Sub-matrix operations

Author: gnuhpc
Source: Http://www.cnblogs.com/gnuhpc/view plain print? #include   "highgui.h"    #include   "cv.h"    #include  <iostream>    #include  <iomanip>         using namespace std;       Void main ()    {   int i=0;   int j=0;   Cvrect mat_rect=cvrect (1,1,3,3);//Specifies the range of array subsets    Cvmat *mat=cvcreatemat (6,6,CV_64FC1);//original array    Cvmat *submat=cvcreatemat (3,3,CV_64FC1);//The subset of arrays obtained by mat_rect specified    cvmat *mat_rows= Cvcreatemat (2,6,CV_64FC1);//the array subset   /* that is obtained by a line within a certain span */   for  (i=0;i<6;i++) for this 6*6 matrix initialization    {   for  (j=0;j<6;j++)    {   Cv_mat_elem (*mat,double,i,j) =i*6+j;   }  }  /* Print source Matrix */   for  (i=0;i<6;i++)    {   for  (j=0;j<6;j++)    {  COUT&LT;&LT;SETW (3) <<cv_mat_elem (*mat,double,i,j);  }   cout<<endl;   }   cout<<endl;  /* Takes a subarray, size is determined according to Mat_rect, and then prints */   cvgetsubrect (mat,submat,mat _rect);   for  (i=0;i<3;i++)    {   for  (j=0;j<3;j++)    {    COUT&LT;&LT;SETW (3) <<cv_mat_elem (*submat,double,i,j);  }   cout<< endl;  }   cout<<endl;  /* Take the first line (starting from 0) to Line 2 (3-1=) and print */   cvGetRows ( mat,mat_rows,1,3,1);   for  (i=0;i<2;i++)    {   for  (j=0;j<6;j++)    {   COUT&LT;&LT;SETW (3) <<cv_mat_elem (*mat_rows,double,i,j);  }    cout<<endl;  }   Cvreleasemat (&mat);   cvReleaseMat (&submat);    Cvreleasemat (&mat_rows);  }  

In OpenCV, it is common to take elements with defined macros:
The macro that takes the element of the MAT structure is Cv_mat_elem, it is the most convenient to take 2D matrix.
The macro that takes the Iplimage element is Cv_image_elem, such as the grayscale value of an image (X, y) point:
Uchar *ptr=cv_iamge_elem (image,uchar,i,j*3);
PTR[0],PTR[1],PTR[2] is the corresponding B/G/R three components.

Author: gnuhpc
Source: http://www.cnblogs.com/gnuhpc/
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