How to setup Qt and openCV on Windows

How to setup Qt and openCV on Windows

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Introduction

WARNING: The below procedures are incomplete, and not functional.

This article shows how to install both Qt and openCV, and build a basic OpenCV example. This article assumes Windows 7 has just been installed.

This article uses information from the following pages: http://docs.opencv.org/2.4/doc/tutorials/introduction/windows_install/windows_install.html?highlight=installation http://www.laganiere.name/opencvCookbook/chap1s1_2.shtml

Windows, source of openCV, old version

This section is a direct copy of this guide. Only minor changes are done to make it work with a newer version of Qt.

Qt

Installation

Download the Qt installer from www.qt.io, then choose "Download now". This will then download qt-unified-windows-x86-2.0.5-online.exe. Execute the program, then choose the following settings:

Welcome to the Qt online installer: next
Qt Account - your unified login to everything Qt: skip
Setup-Qt: next
installation folder: D:\Qt
select components: Qt-Qt5.8-MingGW 5.3.0 32 bit
select components: Qt-Tools-MinGW 5.3.0
License Agreement: agree and next
start menu shortcuts: next
ready to install: install

Testing

Run D:\Qt\Tools\QtCreator\bin\qtcreator.exe

 File-New file or project-Qt Widgets Application-choose
 enter a name and a location: next
 select all kits: next
 Class information: MainWindow (defaults): Next
 Project management: Finish

Now a new project is made. Start debugging by choosing

 Debug-Start Debugging-Start debugging (F5)

Now the Qt tab in the windows task bar should turn into a progress bar. After some time a new empty window should pop up. Stop debugging either by pressing the red cross in the top right of this new window, or choose

 Debug-Stop debugging  

Adjust Qt

When you need to add, remove or update a component of Qt, this can be done by running D:\Qt\MaintenanceTool.exe:

maintain Qt: Qt Account: Skip
Setup Qt: Add or remove components: Next
Select components: 
next :update 

Cmake

Download cmake from cmake.org. In this guide, 3.7.2 is used. Start cmake-3.7.2-win64-x64.msi, then choose the following settinge:

 Welcome to the CMake etup Wizzard: next
 End-User License Agreement: [X] Accept and next
 Install options: [X] Add CMake to the system PATH for all users, next
 Destination folder: C:\Program Files\CMake (default), next
 Ready to install CMake, Install

OpenCV

Getting OpenCV

Download openCV from sourceforge. In this guide, version 2.3.1 is used. Start OpenCV-2.3.1-win-superpack.exe and let it extract to d:\ Now the folder d:\opencv is created.

Compiling OpenCV

Start C:\Program Files\CMake\bin\cmake-gui.exe then choose the following settings:

 Where is the source code: D:/openv
 where to build the binaries: D:\opencv-build

Then click Configure and choose the following settings:

 Specify the generator for this project: MinGW Makefiles
 Specify native compilers, next
 Compilers C: D:/Qt/Tools/mingw530_32/bin/gcc.exe
 Compilers C++: D:/Qt/Tools/mingw530_32/bin/g++.exe
 Finish

Now the error "Error in configuration process, project files may be invalid" comes up

 Click the checkbox [Advanced], then click the red line
 CMAKE_MAKE_PROGRAM and browse to D:/Qt/Tools/mingw530_32/bin/mingw32-make.exe

Then click Configure. Now the error "the system can't start because libwinpthread-1.dll is missing from your computer. Try reinstalling the program to fix this problem."

The C compiler "D:/Qt/Tools/mingw530_32/bin/gcc.exe" is not able to compile a simple test program. It fails with the following output: CMakeFiles\cmTC_9c5ad.dir\build.make:64: recipe for target

 'CMakeFiles/cmTC_9c5ad.dir/testCCompiler.c.obj' failed
 

Add to the system path solves above problems.

 Change CMAKE_BUILD_TYPE from Debug to Release
 Check the box [X]WITH_QT
 Check the box [X]WITH_QT_OPENGL

Then click configure again Then click generate

Next open cmd, and type the following commands:

 cd d:\
 cd opencv-build
 ming32-make -j 8
 ming32-make install

Building and running an example

add D:\opencv-build\install\bin to path

modify the .pro file like this:

1. -------------------------------------------------
3. Project created by QtCreator 2017-03-05T12:30:06
5. -------------------------------------------------

QT += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = untitled TEMPLATE = app

1. The following define makes your compiler emit warnings if you use
2. any feature of Qt which as been marked as deprecated (the exact warnings
3. depend on your compiler). Please consult the documentation of the
4. deprecated API in order to know how to port your code away from it.

DEFINES += QT_DEPRECATED_WARNINGS

1. You can also make your code fail to compile if you use deprecated APIs.
2. In order to do so, uncomment the following line.
3. You can also select to disable deprecated APIs only up to a certain version of Qt.
4. DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0

SOURCES += main.cpp\

       mainwindow.cpp

HEADERS += mainwindow.h

FORMS += mainwindow.ui

INCLUDEPATH += D:\opencv-build\install\include LIBS += -LD:\opencv-build\install\lib \

   -lopencv_core231.dll \
   -lopencv_highgui231.dll \
   -lopencv_imgproc231.dll \
   -lopencv_features2d231.dll \
   -lopencv_calib3d231.dll

Windows, Binary Qt, openCV from source

Todo: Qt instructions the same as above, 
Todo: Cmake instructions the same as above

OpenCV

Getting OpenCV

Download openCV from sourceforge. In this guide, version 3.2.0 is used. Start opencv-3.2.0-vc14.exe and let it extract to d:\ Now the folder d:\opencv is created.

Compiling OpenCV

Start C:\Program Files\CMake\bin\cmake-gui.exe then choose the following settings:

 Where is the source code: D:/opencv/sources
 where to build the binaries: D:\opencv-build

Then click Configure, let cmake create the build directory, and choose the following settings:

 Specify the generator for this project: MinGW Makefiles
 Specify native compilers, next
 Compilers C: D:/Qt/Tools/mingw530_32/bin/gcc.exe
 Compilers C++: D:/Qt/Tools/mingw530_32/bin/g++.exe
 Finish

 Check the box [X]WITH_QT

Then click configure again

 Set CMAKE_BUILD_TYPE to Release or RelWithDebInfo
 Set Qt5Core_DIR to D:\Qt\5.8\mingw53_32\lib\cmake\Qt5Core
 Set Qt5Concurrent_DIR D:\Qt\5.8\mingw53_32\lib\cmake\Qt5Concurrent
 Set Qt5Core_DIR D:\Qt\5.8\mingw53_32\lib\cmake\Qt5Core
 Set Qt5Gui_DIR D:\Qt\5.8\mingw53_32\lib\cmake\Qt5Gui
 Set Qt5Test_DIR D:\Qt\5.8\mingw53_32\lib\cmake\Qt5Test
 Set Qt5Widgets_DIR D:\Qt\5.8\mingw53_32\lib\cmake\Qt5Widgets

Then click configure again Then click generate

Next open cmd, and type the following commands. To speed up the compile, the -j flag can be used to run multiple compile jobs simultaneously. On an 8 core CPU, you can set it to 8 or higher, so all cores are used.

 d:
 cd d:\
 cd opencv-build  
 mingw32-make -j 8
 mingw32-make install  
 
 
 
 
 
 
 
 
 
 
 

Windows, precompiled binaries, new versions

Install OpenCV

Download the newest version from sourceforge . At the time of this writing, opencv-3.2.0-vc14.exe (118MB) is the latest version. Execute the program, then enter a location with at least 460MB free. This how to assumes OpenCV to be extracted to "d:\", so the folder d:\opencv exists.

Install Qt

Download the Qt installer from www.qt.io, then choose "Download now" This will then download qt-unified-windows-x86-2.0.5-online.exe Execute the program, then choose the following settings:

welcome next
qt account skip
setup-Qt next
installation folder: D:\Qt
select components: next (accept defaults)
License Agreement: agree and next
start menu shortcuts: next
ready to install: install

Adjust Qt

Run D:\Qt\MaintenanceTool.exe then use the following options:

maintain Qt: Qt Account: Skip
Setup Qt: Add or remove components: Next
Select components: Qt-Qt5.8-MinGW 5.3.0 32 bit
Select components: tools-MinGW 5.3.0 32 bit: next :update

Compile and run the example

modify the .pro file like this:

1. -------------------------------------------------
3. Project created by QtCreator 2017-03-05T12:30:06
5. -------------------------------------------------

QT += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = untitled TEMPLATE = app

1. The following define makes your compiler emit warnings if you use
2. any feature of Qt which as been marked as deprecated (the exact warnings
3. depend on your compiler). Please consult the documentation of the
4. deprecated API in order to know how to port your code away from it.

DEFINES += QT_DEPRECATED_WARNINGS

1. You can also make your code fail to compile if you use deprecated APIs.
2. In order to do so, uncomment the following line.
3. You can also select to disable deprecated APIs only up to a certain version of Qt.
4. DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0

SOURCES += main.cpp\

       mainwindow.cpp

HEADERS += mainwindow.h

FORMS += mainwindow.ui

INCLUDEPATH += D:\opencv-build\install\include LIBS += -LD:\opencv-build\install\x86\mingw\lib \

   -lopencv_core320.dll \
   -lopencv_highgui320.dll \
   -lopencv_imgcodecs320.dll \
   -lopencv_imgproc320.dll \
   -lopencv_features2d320.dll \
   -lopencv_calib3d320.dll

and modify mainwindow.cpp like this:

1. include "mainwindow.h"
2. include "ui_mainwindow.h"

1. include <opencv2/core/core.hpp>
2. include <opencv2/highgui/highgui.hpp>

/*

1. include <opencv2/core/core.hpp>
2. include <opencv2/highgui/highgui.hpp>*/

MainWindow::MainWindow(QWidget *parent) :

   QMainWindow(parent),
   ui(new Ui::MainWindow)

{

   ui->setupUi(this);

   // read an image
   cv::Mat image = cv::imread("f://1.jpg" , 1 );
   // create image window named "My Image"
   cv::namedWindow("My Image");
   // show the image on window
   cv::imshow("My Image", image);

}

MainWindow::~MainWindow() {

   delete ui;

}

NOTE: after changing the PATH variable, restart QtCreator to load the new value

When this example is run, 2 windows pop up. One with the image, and one with an empty window.