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.
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 Mat::row() and Mat::col() , this is an O(1) operation.
由于这两个函数返回的是指向原矩阵内部位置的指针，所以最好再利用clone()函数进行数据拷贝创建新的矩阵，代码如下：
[cpp] view plain copy #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; } 结果如下：
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]
这两个函数很有趣，它们让我实现不用调用opencv特有函数来实现相应功能，而是自己可以写函数随机应变地实现自己所需的任何图像方面功能。赞一个！
