Question

如何在MFC中给矩阵赋值。

比方说 CV::Mat x x的矩阵值由自己输入确定。 求教。。。

Answer 1

OpenCv cv::Mat类用法
http://www.360doc.com/content/13/0415/16/10724725_278435687.shtml 1/2
1、使用准备：
using namespace cv;
2、Mat的声明
Mat m=Mat(rows, cols, type);
Mat m=Mat(Size(width,height), type);
Mat A=Mat(3,4,CV_32FC1);
Mat B=Mat(4,3,CV_32FC1);
3、Mat赋值
vector<Point3f>v;//suppose it is already full
Mat m1=Mat(v,true);//boolean value true is necessary in order to copy data from v to m1
CvMat *p1=====??
Mat m2=Mat(p1);
4、Mat之间运算
MatC=2*A*B;
Mat C=C.inv();//Now C is its own inverse matrix
Mat D=A.t();//D is the transposed matrix of A
Mat a=Mat(4,1, CV_32FC3);//a is 4x1, 3 channels
Mat b=a.reshape(1);//b is 4x3, 1 channel
5、单通道Mat元素读写
Mat a=Mat(4,3, CV_32FC1);
floatelem_a=a.at<float>(i,j);/慎高厅/access element aij, with i from 0 to rows-1 and j from 0 to cols-1
Point p=Point(x,y);
floatelem_a=a.at<float>(p);//Warning: y ranges from 0 to rows-1 and x from 0 to cols-1
6、多通道Mat元素读写
template<typename _Tp> _Tp& at(int y,int x); // cxcore.hpp (868)
template<typename _Tp>const _Tp& at(int y,int x)const; // cxcore.hpp (870)
template<typename _Tp> _Tp& at(Point pt); // cxcore.hpp (869)
template<typename _Tp>宽隐const _Tp& at(Point pt)const; // cxcore.hpp (871)
// defineded in cxmat.hpp (454-468)
typedefVec<float,2>Vec2f;// cxcore.hpp (254)2014年5月17日 OpenCv cv::Mat类用法
http://www.360doc.com/content/13/0415/16/10724725_278435687.shtml 2/2
// we can access the element like this :
Mat m(Size(3,3), CV_32FC2 );
Vec2f& elem = m.at<Vec2f>( row , col );// or m.at<Vec2f>( Point(col,row) );
elem[0]=1212.0f;
elem[1]=326.0f;
float c1 = m.at<念敏Vec2f>( row , col )[0];// or m.at<Vec2f>( Point(col,row) );
float c2 = m.at<Vec2f>( row , col )[1];
m.at<Vec2f>( row, col )[0]=1986.0f;
m.at<Vec2f>( row, col )[1]=326.0f;

7.选取Mat上指定区域方法
Mat src; Rect rect;
Mat dst = src(rect); 或者Mat dst(src,rect);

注意：cv::Mat A;
A.row(i) = A.row(j); // 错误
A.row(i) = A.row(j) + 0; // 正确