（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;
}