OpenCV with Qt 图像处理GUI

• 本文为@源码人原创文章，转载请注明出处 
• 文章链接：https://blog.csdn.net/q_z_r_s 

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QImage>
#include <QFileDialog>
#include <QTimer>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private slots:
    void on_openButton_clicked();
    QImage Mat2QImage(const cv::Mat &mat);
    void display(QImage image);
    void salt(cv::Mat &image, int n);

    void on_saltButton_clicked();
    void on_reduceButton_clicked();
    void colorReduce0(cv::Mat &image, int div);

    void on_originalButton_clicked();

private:
    Ui::MainWindow *ui;
    cv::Mat image;
    cv::Mat originalimg; //store the original img
    QImage qimg;
    QImage imgScaled;
    cv::Mat rgb;
};

#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>

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

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

void MainWindow::on_openButton_clicked()
{
    QString fileName = QFileDialog::getOpenFileName(this,tr("Open Image"),
                                ".",tr("Image Files (*.png *.jpg *.bmp)"));
    qDebug()<<"filenames:"<<fileName;
    image = cv::imread(fileName.toLatin1().data());
    ui->imgfilelabel->setText(fileName);
    //here use 2 ways to make a copy
//    image.copyTo(originalimg);          //make a copy
    originalimg = image.clone();        //clone the img
    qimg = MainWindow::Mat2QImage(image);
    display(qimg);                      //display by the label
    if(image.data)
    {
        ui->saltButton->setEnabled(true);
        ui->originalButton->setEnabled(true);
        ui->reduceButton->setEnabled(true);
    }
}

QImage MainWindow::Mat2QImage(const cv::Mat &mat)
{
    QImage img;
    if(mat.channels()==3)
    {
        //cvt Mat BGR 2 QImage RGB
        cvtColor(mat,rgb,CV_BGR2RGB);
        img =QImage((const unsigned char*)(rgb.data),
                    rgb.cols,rgb.rows,
                    rgb.cols*rgb.channels(),
                    QImage::Format_RGB888);
    }
    else
    {
        img =QImage((const unsigned char*)(mat.data),
                    mat.cols,mat.rows,
                    mat.cols*mat.channels(),
                    QImage::Format_RGB888);
    }
    return img;
}

void MainWindow::display(QImage img)
{
    QImage imgScaled;
    imgScaled = img.scaled(ui->imagelabel->size(),Qt::KeepAspectRatio);
//  imgScaled = img.QImage::scaled(ui->imagelabel->width(),ui->imagelabel->height(),Qt::KeepAspectRatio);
    ui->imagelabel->setPixmap(QPixmap::fromImage(imgScaled));
}

void MainWindow::on_originalButton_clicked()
{
    qimg = MainWindow::Mat2QImage(originalimg);
    display(qimg);
}

void MainWindow::on_saltButton_clicked()
{
    salt(image,3000);
    qimg = MainWindow::Mat2QImage(image);
    display(qimg);
}
void MainWindow::on_reduceButton_clicked()
{
    colorReduce0(image,64);
    qimg = MainWindow::Mat2QImage(image);
    display(qimg);
}
void MainWindow::salt(cv::Mat &image, int n)
{

    int i,j;
    for (int k=0; k<n; k++)
    {

        i= qrand()%image.cols;
        j= qrand()%image.rows;

        if (image.channels() == 1)
        { // gray-level image

            image.at<uchar>(j,i)= 255;

        }
        else if (image.channels() == 3)
        { // color image

            image.at<cv::Vec3b>(j,i)[0]= 255;
            image.at<cv::Vec3b>(j,i)[1]= 255;
            image.at<cv::Vec3b>(j,i)[2]= 255;
        }
    }
}

// using .ptr and []
void MainWindow::colorReduce0(cv::Mat &image, int div)
{

      int nl= image.rows; // number of lines
      int nc= image.cols * image.channels(); // total number of elements per line

      for (int j=0; j<nl; j++)
      {

          uchar* data= image.ptr<uchar>(j);

          for (int i=0; i<nc; i++)
          {

            // process each pixel ---------------------
                data[i]= data[i]/div*div+div/2;

            // end of pixel processing ----------------

          } // end of line
      }
}

效果展示：
1. 打开图片

2. Salt Process

3.Color Reduce

参考文章：https://www.cnblogs.com/emouse/archive/2013/03/31/2991333.html