Install OpenCV in Windows 10

edit

I guess you are not setting the INCLUDEPATH and LIBS in your *.pro file in QT appropriate.

In opencv.pri I have

INCLUDEPATH += c:/opencv/install/include
Debug: {
LIBS += -lc:/opencv/install/x86/vc14/lib/opencv_world343d
}
Release: {
LIBS += -lc:/opencv/install/x86/vc14/lib/opencv_world343
}

In Test.pro I have

QT -= gui
CONFIG += c++11 console
CONFIG -= app_bundle
DEFINES += QT_DEPRECATED_WARNINGS
SOURCES += \
        main.cpp

add

include(opencv.pri)

to your Test.pro

I had to do some other changes also and it works now.

Test.pro:

QT += core
QT -= gui
CONFIG += c++11 console
CONFIG -= app_bundle
DEFINES += QT_DEPRECATED_WARNINGS
TEMPLATE = app
SOURCES += \
        main.cpp
TARGET = Test
include(C:\opencv\opencv.pri)

main.cpp:

#include "opencv/cv.hpp"
#include <QCoreApplication>
#include <QDebug>
using namespace cv;
using namespace std;

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    cv::Mat image = cv::imread("test.jpg");

    if ( image.empty() ) {

        qDebug() << "Problem";
        return -1;
    }

    cv::imshow("Output", image);

    return a.exec();
}