Qt run time error in using compute function of HOG descriptor

[Sai Kamat]

I am using Qt-Creator 5.2.0 to create a GUI to display the Image and a binary classifier to detect the object is present or absent using Dalal & triggs HOG extraction algorithm.

I am facing the mentioned Run time error & need help to solve this issue.
mainwindow.h
@#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include<QDebug>
#include <opencv2/calib3d/calib3d.hpp>
//#include <opencv2/calib3d/calib3d.hpp>
#include<opencv2/core/core.hpp>
#include<opencv2/features2d/features2d.hpp>
#include<opencv2/highgui/highgui.hpp>
#include<opencv2/imgproc/imgproc.hpp>
#include<opencv2/ml/ml.hpp>
#include<opencv2/objdetect/objdetect.hpp>
using namespace cv;

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

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

private:
Ui::MainWindow *ui;
};
float SVM_classifier(Mat image);

#endif // MAINWINDOW_H@

mainwindow.cpp
@#include "mainwindow.h"
#include "ui_mainwindow.h"

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

   IplImage *oMatDeltaImage  = cvLoadImage("E:\\Wihart\\Car_Images\\(785).jpg",CV_LOAD_IMAGE_UNCHANGED);

    Mat mat_img(oMatDeltaImage );
    float oMatResult =  SVM_classifier(mat_img);
//    qDebug()<<oMatResult;

}

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

float SVM_classifier(Mat image)
{

        resize(image, image, Size(64,128) );

        HOGDescriptor extract_features;
        vector<float> descriptorsValues;
        vector<Point> locations;
        extract_features.compute( image, descriptorsValues, Size(0,0), Size(0,0), locations);

        Mat feature_vector(descriptorsValues);// = Mat::zeros((descriptorsValues.size(),1));
        CvSVM SVM;
        SVM.load("SVM_classifier_data.xml");
        float result= SVM.predict(feature_vector);
        return result;
}@

main.cpp
@#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}@

This is the error i faced at
Line:
@ extract_features.compute( image, descriptorsValues, Size(0,0), Size(0,0), locations);@

Exception triggered:
"The inferior stopped because it triggered an exception.
Stopped in thread 0 by Exception 0xf8b3b11, code: 0xc0000005: write access violation at 0x1, flags= 0x0 (first chance)."

[SGaist]

Hi,

Since you don't tell exactly what error you have, I would say that your application can't find the OpenCV dlls. So you need to update the Run panel PATH environment variable and add the path to OpenCV dlls there

[Sai Kamat]

Hi SGaist, sorry about that. I've included the error now.

[SGaist]

Then you should run your application through the debugger to see exactly where you are accessing something invalid