Qt 4 - simple GUI for a OpenCV program

[antrofite]

I been trying to make a simple interface for an image processing task using OpenCV with C++ using Qt for the GUI. I'm able to load the image through the GUI but when I press the pushbutton_3, to convert the image to grayscale gives an error regarding OpenCV. I'm sure I'm doing something wrong. Can some one give me a help?

Please see below the files:

//mainwindow.h
 
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include <QFileDialog>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <vector>
 
#include <QtCore/QCoreApplication>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/core/types_c.h>
#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_pushButton_clicked();
 
    void on_pushButton_2_clicked();
 
    void on_pushButton_3_clicked();
 
 
 
 
private:
    Ui::MainWindow *ui;
    //Images variables
    cv::Mat image_Idl;
    cv::Mat image_Lit;
    cv::Mat image_Idl_G;
    cv::Mat image_Lit_G;
    double threshHold;
 
};
 
#endif // MAINWINDOW_H

//mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QFileDialog>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <vector>

#include <QtCore/QCoreApplication>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/core/types_c.h>
#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_pushButton_clicked();

    void on_pushButton_2_clicked();

    void on_pushButton_3_clicked();




private:
    Ui::MainWindow *ui;
    //Images variables
    cv::Mat image_Idl;
    cv::Mat image_Lit;
    cv::Mat image_Idl_G;
    cv::Mat image_Lit_G;
    double threshHold;

};

#endif // MAINWINDOW_H

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//mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <iostream>
#include <QtCore/QCoreApplication>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/core/types_c.h>
#include <opencv2/imgproc/imgproc.hpp>
#include <QSpinBox>
#include <QSlider>
#include <stdio.h>
#include <stdlib.h>
#include <vector>
 
using namespace std;
 
 
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
 
    ui->horizontalSlider->setRange(0,255);
    ui->spinBox->setRange(0,255);
 
    connect(ui->horizontalSlider,SIGNAL(valueChanged(int)),ui->spinBox,SLOT(setValue(int)));
    connect(ui->spinBox,SIGNAL(valueChanged(int)),ui->horizontalSlider,SLOT(setValue(int)));
 
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
 
void MainWindow::on_pushButton_clicked()
{
    QString fileName = QFileDialog::getOpenFileName(this,tr("Load Lit Image"),".",tr("Image Files (*.png *.jpg *.jpeg *.bmp)"));
    image_Lit = cv::imread(fileName.toAscii().data());
    cv::namedWindow("Lit Image");
    cv::imshow("Lit Image", image_Lit);
}
 
void MainWindow::on_pushButton_2_clicked()
{
    QString fileName = QFileDialog::getOpenFileName(this,tr("Load Lit Image"),".",tr("Image Files (*.png *.jpg *.jpeg *.bmp)"));
    image_Idl = cv::imread(fileName.toAscii().data());
    cv::namedWindow("Ideal Lit");
    cv::imshow("Ideal Lit", image_Idl);
 
}
 
 
 
 
 
 
void MainWindow::on_pushButton_3_clicked()
{
    //Converstions
 
 
    //Convert Lit to gray
 
 
 
        cv::cvtColor(image_Lit, image_Lit_G,CV_RGB2GRAY);
 
    //Convert Ideal gray
 
 
        cv::cvtColor(image_Idl, image_Idl_G,CV_RGB2GRAY);
 
 
      //Threshold the Images to a designated value
                // Lit
 
        threshHold = ui->horizontalSlider->value();
 
          cv::threshold(image_Lit_G,image_Lit_G, threshHold,255,cv::THRESH_BINARY);
          cv::namedWindow("Gray Scaled Image");
          cv::imshow("Gray Scaled Image", image_Lit_G);
 
 
}

//mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <iostream>
#include <QtCore/QCoreApplication>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/core/types_c.h>
#include <opencv2/imgproc/imgproc.hpp>
#include <QSpinBox>
#include <QSlider>
#include <stdio.h>
#include <stdlib.h>
#include <vector>

using namespace std;



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

    ui->horizontalSlider->setRange(0,255);
    ui->spinBox->setRange(0,255);

    connect(ui->horizontalSlider,SIGNAL(valueChanged(int)),ui->spinBox,SLOT(setValue(int)));
    connect(ui->spinBox,SIGNAL(valueChanged(int)),ui->horizontalSlider,SLOT(setValue(int)));

}

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


void MainWindow::on_pushButton_clicked()
{
    QString fileName = QFileDialog::getOpenFileName(this,tr("Load Lit Image"),".",tr("Image Files (*.png *.jpg *.jpeg *.bmp)"));
    image_Lit = cv::imread(fileName.toAscii().data());
    cv::namedWindow("Lit Image");
    cv::imshow("Lit Image", image_Lit);
}

void MainWindow::on_pushButton_2_clicked()
{
    QString fileName = QFileDialog::getOpenFileName(this,tr("Load Lit Image"),".",tr("Image Files (*.png *.jpg *.jpeg *.bmp)"));
    image_Idl = cv::imread(fileName.toAscii().data());
    cv::namedWindow("Ideal Lit");
    cv::imshow("Ideal Lit", image_Idl);

}






void MainWindow::on_pushButton_3_clicked()
{
    //Converstions


    //Convert Lit to gray



        cv::cvtColor(image_Lit, image_Lit_G,CV_RGB2GRAY);

    //Convert Ideal gray


        cv::cvtColor(image_Idl, image_Idl_G,CV_RGB2GRAY);


      //Threshold the Images to a designated value
                // Lit

        threshHold = ui->horizontalSlider->value();

          cv::threshold(image_Lit_G,image_Lit_G, threshHold,255,cv::THRESH_BINARY);
          cv::namedWindow("Gray Scaled Image");
          cv::imshow("Gray Scaled Image", image_Lit_G);


}

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qt_GUI_homo.jpg


Error from the compiler:

Invalid parameter passed to C runtime function. Invalid parameter passed to C runtime function. OpenCV Error: Assertion failed (scn == 3 || scn == 4) in cvtColor, file C:\OpenCV\modules\imgproc\src\color.cpp, line 2834 The program has unexpectedly finished.

[wysota]

Shouldn't you be asking that question on an OpenCV forum?