Mat的rowRange和colRange可以獲取某些範圍內行或列的指標：

Mat::rowRange

Creates a matrix header for the specified row span.

C++:Mat Mat::rowRange(int startrow, int endrow) const

C++:Mat Mat::rowRange(const Range& r) const

Parameters:	startrow – An inclusive 0-based start index of the row span. endrow – An exclusive 0-based ending index of the row span. r – Range structure containing both the start and the end indices.

The method makes a new header for the specified row span of the matrix. Similarly to Mat::row() and Mat::col() , this is an O(1) operation.

Mat::colRange

Creates a matrix header for the specified column span.

C++:Mat Mat::colRange

(int startcol, int endcol) const

C++:Mat Mat::colRange(const Range& r) const

Parameters:	startcol – An inclusive 0-based start index of the column span. endcol – An exclusive 0-based ending index of the column span. r – Range structure containing both the start and the end indices.

The method makes a new header for the specified column span of the matrix. Similarly to 

由於這兩個函式返回的是指向原矩陣內部位置的指標，所以最好再利用clone()函式進行資料拷貝建立新的矩陣，程式碼如下：

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>

using namespace cv;
using namespace std;

int main(){
	 Mat C = (Mat_<double>(3,3) << 0, -1, 0, -1, 5, -1, 0, -1, 0);
	 cout << "Total matrix:" << endl;
	 cout << C << endl;

	 Mat row = C.rowRange(1,3).clone();
	 cout << "Row range:" << endl;
	 cout << row << endl;
	
	 Mat col = C.colRange(1,3).clone();
	 cout << "Col range:" << endl;
	 cout << col << endl;
}

Total matrix
[0, -1, 0;
  -1, 5, -1;
  0, -1, 0]
Row range:
[-1, 5, -1;
  0, -1, 0]
Col range:
[-1, 0;
  5, -1;
  -1, 0]