（6综合实验）从零开始的嵌入式图像图像处理(PI+QT+OpenCV)实战演练

//by jsxyhelu 2017/12/6
# include "mainwindow.h"
# include "ui_mainwindow.h"
# include <QMouseEvent >
//全局变量
Mat src;
Mat gray;
Mat tmp;
Mat dst;
Mat matMatch; //template
double m_lastTime; //time
Mat grayLeft;
Mat grayRight;
Mat descriptorsLeft;
std : :vector <KeyPoint > keypointsLeft;
Mat descriptorsRight;
std : :vector <KeyPoint > keypointsRight;
std : :vector < DMatch > matches;
std : :vector < DMatch > good_matches;
Mat img_matches;
int imethod; //0-ORB 1-SIFT 2-SURF 3-BRISK
using namespace cv;
MainWindow : :MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui( new Ui : :MainWindow)
{
    ui - >setupUi( this);
    timer   = new QTimer( this);
    imag     = new QImage();         // 初始化
    connect(timer, SIGNAL(timeout()), this, SLOT(readFarme()));   // 时间到，读取当前摄像头信息
    bMethod = false; //是否使用算法
    on_pushButton_clicked(); //main process
    //take a picture
    clickLabel = new ClickedLabel( this);
    clickLabel - >setGeometry( 0, 0, 800, 400);
    connect(clickLabel,SIGNAL(clicked(ClickedLabel *)), this,SLOT(on_pushButton_3_clicked()));
    imethod = 0; //ORB
    setWindowState(Qt : :WindowMaximized); //max
}
MainWindow : : ~MainWindow()
{
    delete ui;
}
////////////////////////////////////事件驱动///////////////////////////////////////////////////////
//打开摄像头
void MainWindow : :on_pushButton_clicked()
{
    //打开摄像头，从摄像头中获取视频
    videocapture   = new VideoCapture( 0);
    // 开始计时，超时则发出timeout()信号
    timer - >start( 33);
}
//main process 读取下一Frame图像 when timeout()
void MainWindow : :readFarme()
{
    // 从摄像头中抓取并返回每一帧
    videocapture - >read(matFrame);
    src = matFrame.clone();
    m_lastTime = ( double)getTickCount();
    tmp = matFrame.clone();
    //final
    cv : :resize(tmp,tmp,Size( 200, 200));
    dst = Mat(Size(tmp.cols * 2,tmp.rows),tmp.type(),Scalar( 255));
    tmp.copyTo(dst(cv : :Rect( 0, 0, 200, 200)));
    //生成特征点算法及其匹配方法
    Ptr <Feature2D >  extractor;
    BFMatcher matcher;
    switch (imethod)
           {
                    case 1 : //"SIFT"
                        extractor = SIFT : :create();
                        matcher = BFMatcher(NORM_L2);
                        break;
                    case 2 : //"SURF"
                        extractor = SURF : :create();
                        matcher = BFMatcher(NORM_L2);
                        break;
                    case 3 : //"BRISK"
                        extractor = BRISK : :create();
                        matcher = BFMatcher(NORM_HAMMING);
                        break;
                    case 0 : //"ORB"
                        extractor = ORB : :create();
                        matcher = BFMatcher(NORM_HAMMING);
                        break;
             }

    if(matMatch.rows > 0)
    {
        //利用现有数据结构，对比对结构进行筛选
        double max_dist = 0; double min_dist = 100;
          //action
        cv : :resize(matMatch,matMatch,Size( 200, 200));
        //gray
        cvtColor(tmp,grayLeft,COLOR_BGR2GRAY);
        cvtColor(matMatch,grayRight,COLOR_BGR2GRAY);
        //寻找到特征点
        extractor - >detectAndCompute(grayLeft,Mat(),keypointsLeft,descriptorsLeft);
        extractor - >detectAndCompute(grayRight,Mat(),keypointsRight,descriptorsRight);
        matcher.match( descriptorsLeft, descriptorsRight, matches );
        //对现有距离进行排序
        for( int i = 0; i < descriptorsLeft.rows; i ++ )
        {
            double dist = matches[i].distance;
            if( dist < min_dist ) min_dist = dist;
            if( dist > max_dist ) max_dist = dist;
        }
        for( int i = 0; i < descriptorsLeft.rows; i ++ )
        {
            if( matches[i].distance < = max( 2 *min_dist, 0. 02) )
            {
                good_matches.push_back( matches[i]);
            }
        }
         drawMatches( tmp, keypointsLeft, matMatch, keypointsRight, good_matches, dst );
          //clear
         good_matches.clear();
    }
    cv : :resize(dst,dst,Size( 800, 400));
    switch (imethod)
    {
    case 0 :
    putText(dst, "METHOD:ORB",Point( 10, 350),CV_FONT_HERSHEY_DUPLEX, 1.0f,Scalar( 0, 0, 255));
    break;
    case 1 :
     putText(dst, "METHOD:SIFT",Point( 10, 350),CV_FONT_HERSHEY_DUPLEX, 1.0f,Scalar( 0, 0, 255));
    break;
    case 2 :
     putText(dst, "METHOD:SURF",Point( 10, 350),CV_FONT_HERSHEY_DUPLEX, 1.0f,Scalar( 0, 0, 255));
    break;
    case 3 :
     putText(dst, "METHOD:BRISK",Point( 10, 350),CV_FONT_HERSHEY_DUPLEX, 1.0f,Scalar( 0, 0, 255));
    break;
    }
    // 格式转换
    QPixmap qpixmap = Mat2QImage(dst);
    // 将图片显示到label上
    clickLabel - >setPixmap(qpixmap);
    m_lastTime = ( double)getTickCount();
}
//method
void MainWindow : :on_pushButton_2_clicked()
{   
    if(imethod == 4)
    {
        imethod = 1;
    } else
    {
        imethod += 1;
    }
}
//action
void MainWindow : :on_pushButton_3_clicked()
{
      matMatch = src.clone();
}

//exit
void MainWindow : :on_pushButton_4_clicked()
{
    timer - >stop();         // 停止读取数据。
    videocapture - >release();
    //exit
    QApplication * app;
    app - >exit( 0);
}
//////////////////////////helper函数//////////////////////////////////////////////////
//格式转换
QPixmap Mat2QImage(Mat src)
{
    QImage img;
    //根据QT的显示方法进行转换
    if(src.channels() == 3)
    {
        cvtColor( src, tmp, CV_BGR2RGB );
        img = QImage( ( const unsigned char *)(tmp.data), tmp.cols, tmp.rows, QImage : :Format_RGB888 );
    }
    else
    {
        img = QImage( ( const unsigned char *)(src.data), src.cols, src.rows, QImage : :Format_Indexed8 );
    }
    QPixmap qimg = QPixmap : :fromImage(img) ;
    return qimg;
}