opencv学习_矩阵运算和绘制图像

Posted 2021-10-20 Leslie X徐

opencv 矩阵运算和绘制图像

5.矩阵运算

矩阵的创建和加减

void MainWindow::test()
{
    double Anum[3][3] = {{1,1,1},
                         {2,2,2},
                         {3,3,3}};
    double Bnum[3][3] = {{1,1,1},
                         {2,2,2},
                         {3,3,3}};
    double Cnum[3][3] = {{1,0,0},
                         {0,1,0},
                         {0,0,1}};

    Mat Amat(3,3,CV_64F,Anum);
    Mat Bmat(3,3,CV_64F,Bnum);
    Mat Cmat(3,3,CV_64F,Cnum);
    Mat Dmat(3,3,CV_64F);

    Dmat = Amat + Bmat;
    std::cout<<Dmat<<std::endl;

    Dmat = Amat * Cmat;
    std::cout<<Dmat<<std::endl;

    double Enum[5]={1,2,3,4,5};
    Mat Emat(1,5,CV_64F,Enum);
    std::cout<<Emat.t()*Emat<<std::endl;
    std::cout<<Emat*Emat.t()<<std::endl;
}

/*输出
[2, 2, 2;
  4, 4, 4;
  6, 6, 6]
[1, 1, 1;
  2, 2, 2;
  3, 3, 3]
  
  [1, 2, 3, 4, 5;
  2, 4, 6, 8, 10;
  3, 6, 9, 12, 15;
  4, 8, 12, 16, 20;
  5, 10, 15, 20, 25]
[55]
*/

2维向量类型的加减

void MainWindow::test()
{
    Point2i a(1,1),b(1,1);

    Point2i pt;
    pt = (a+b)*10;
    std::cout<<pt<<std::endl;

    int c = a.dot(b); //点乘
    std::cout<<c<<std::endl;
}

/*
输出
[20, 20]
2
*/

特殊矩阵

    Mat Amat;
    Amat = Mat::eye(5,5,CV_64F)*3;
    std::cout<<Amat<<std::endl;

/*
输出
[3, 0, 0, 0, 0;
 0, 3, 0, 0, 0;
 0, 0, 3, 0, 0;
 0, 0, 0, 3, 0;
 0, 0, 0, 0, 3]
*/

6.绘制图形

创建图形函数：

• cv::ellipse(Mat,Point,Size,double angle,startAngle,endAngle,Scalar,thickness,lineType);
• cv::circle(Mat,Point center,double radius,Scalar,thickness,lineType);

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    w=200;
    imgInit();
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::imgInit()
{
    Mat imgData = Mat::zeros(w,w,CV_8UC3);
    cvtColor(imgData,imgData,COLOR_BGR2RGB);
    myImg=imgData;
    myQImg = QImage((const uchar*)(imgData.data),
                    imgData.cols,imgData.rows,
                    QImage::Format_RGB888);
    imgShow();
}

void MainWindow::imgShow()
{
    ui->label->setPixmap(QPixmap::fromImage(myQImg.scaled(ui->label->size())));
}

void MainWindow::MyEllipse(Mat img, double angle)
{
    int thickness = 1;
    int lineType = 8;
    //创建椭圆函数
    cv::ellipse(img,Point(w/2,w/2),
                Size(w/4,w/16),angle,0,360,
                Scalar(0,0,255),thickness,lineType);
}

void MainWindow::MyFilledCircle(Mat img, Point center)
{
    int thickness = -1; //填充
    int lineType = 8;
	//创建圆函数
    cv::circle(img,center,w/32,
               Scalar(255,0,0),thickness,lineType);
}


void MainWindow::on_btnDraw_clicked()
{
    /// 1.a. 创建椭圆
    MyEllipse( myImg, 90 );
    MyEllipse( myImg, 0 );
    MyEllipse( myImg, 45 );
    MyEllipse( myImg, -45 );

    /// 1.b. 创建圆
    MyFilledCircle( myImg, Point( w/2.0, w/2.0) );

    myQImg = QImage((const uchar*)(myImg.data),
                    myImg.cols,myImg.rows,
                    QImage::Format_RGB888);
    imgShow();
}