OpenCV Install Guide

8/13/2019 OpenCV Install Guide

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1/9/14 OpenCV 2 Cookbook

www.laganiere.name/opencvCookbook/chap1s1_2.shtml#3

OpenCV 2 Computer Vision Application ProgrammingCookbook

Welcome to the Author's Website

1. Installing the OpenCV Library2. Creating an OpenCV project with MS

Visual C++3. Creating an OpenCV project with Qt4. Loading, displaying andsaving

images5. Creating a GUI application using Qt

1. Playing with Images

1.1.2 Installing the OpenCV Library for Qt

The Qt SDKis probably the best tool to build cross-platform OpenCV applications. Inaddition, it offers nice UI tools and a complete API. Finally, it comes with Qt Creator, afriendly IDE for developing C++ projects. This recipe will show you, in details, how toinstall Qt, compile the OpenCVlibrary for it and finally run your first OpenCVapplication.

At the time of writing this recipe, the latest Qt version was 4.7.3 (Qt Creator 2.2.1).Current version of OpenCV was 2.3.1 (August 2011). We will also use CMake whichwas at version 2.8.5. The installation has been done on Windows 7. Please refer to theOpenCV Cookbookfor more details.

1. The first step is obviously to download Qt. Simply run the installer with alldefault option. Once installed, you can run Qt Creator.

2. Lets start by creating a simple Hello Worldapplication on the Windows console,just to make sure everyt ing is working properly. Click on Create Project...

and choose Qt Console Application.

0. Introduction

1. Playing with Images

2.Manipulating the Pixels

3. Processing Images withClasses

4. Counting the Pixels withHistograms

5. Transforming images withmorphological operations

6. Filtering the Images

7. Extracting Lines, Contoursand Components

8. Detecting and MatchingInterest Points

9. Estimating ProjectiveRelations in Images

10. Processing VideoSequences
http://www.laganiere.name/opencvCookbook/chap5.shtmlhttp://www.laganiere.name/opencvCookbook/chap5.shtmlhttp://www.laganiere.name/opencvCookbook/chap4.shtmlhttp://www.laganiere.name/opencvCookbook/chap3.shtmlhttp://www.googleadservices.com/pagead/aclk?sa=L&ai=CdGnbTczOUp_OIcKAmwW0oIDYD-XlxbkElZr_kn2IxPGPLRABILXWqSVQ-tqw9P7_____AWAzoAHD-9DUA8gBAqgDAcgDwQSqBJ0BT9CpjrKqEsujcw9Qr7-6jDIPy8YxNtVclxiwe4iR_UWGJtzzsojoE6bvmixNDTaTYlPpLEDpJzpbfgwMLhQkSvzDKDh20Nr5CvAHv4cPvHLxxTvArXlN_m-Jl9AOCIZZ6BA5lM60GocXQhJs2gV39H-nu7BDKo7_oFyoN6y_FzELvrrOS2UJJX2_-9JtMwRZVXW6Pb1qjXk5LL4fIogGAaAGAoAHpYSvKw&num=1&cid=5GiW2j45317Yvssod0FuFTrZ&sig=AOD64_0Gy0Q--lsJAKXCgQc8-9jsXyID3Q&client=ca-pub-8501294875466025&adurl=http://k.keyade.com/kack/1/%3FkaPt%3Dgoogle%26kaTckM%3Dp%26kaPcId%3D98678%26kaTckId%3D33564446413%26kaAcId%3D191%26kaCpnId%3D%26kaNtw%3Dcontent%26kaKwd%3D%26kaDmn%3Dwww.laganiere.name%26kaTgt%3D%26kaNtw2%3Dd%26kaMtTp%3D%26kaAdPos%3Dnone%26kaDev%3Dchttp://www.googleadservices.com/pagead/aclk?sa=L&ai=CdGnbTczOUp_OIcKAmwW0oIDYD-XlxbkElZr_kn2IxPGPLRABILXWqSVQ-tqw9P7_____AWAzoAHD-9DUA8gBAqgDAcgDwQSqBJ0BT9CpjrKqEsujcw9Qr7-6jDIPy8YxNtVclxiwe4iR_UWGJtzzsojoE6bvmixNDTaTYlPpLEDpJzpbfgwMLhQkSvzDKDh20Nr5CvAHv4cPvHLxxTvArXlN_m-Jl9AOCIZZ6BA5lM60GocXQhJs2gV39H-nu7BDKo7_oFyoN6y_FzELvrrOS2UJJX2_-9JtMwRZVXW6Pb1qjXk5LL4fIogGAaAGAoAHpYSvKw&num=1&cid=5GiW2j45317Yvssod0FuFTrZ&sig=AOD64_0Gy0Q--lsJAKXCgQc8-9jsXyID3Q&client=ca-pub-8501294875466025&adurl=http://k.keyade.com/kack/1/%3FkaPt%3Dgoogle%26kaTckM%3Dp%26kaPcId%3D98678%26kaTckId%3D33564446413%26kaAcId%3D191%26kaCpnId%3D%26kaNtw%3Dcontent%26kaKwd%3D%26kaDmn%3Dwww.laganiere.name%26kaTgt%3D%26kaNtw2%3Dd%26kaMtTp%3D%26kaAdPos%3Dnone%26kaDev%3Dchttp://www.laganiere.name/opencvCookbook/chap8.shtmlhttp://www.laganiere.name/opencvCookbook/chap7.shtmlhttp://www.laganiere.name/opencvCookbook/chap2.shtmlhttp://www.laganiere.name/opencvCookbook/chap1.shtmlhttp://www.laganiere.name/opencvCookbook/index.shtmlhttp://www.laganiere.name/http://www.laganiere.name/http://www.laganiere.name/http://www.laganiere.name/opencvCookbook/chap10.shtmlhttp://www.laganiere.name/opencvCookbook/chap9.shtmlhttp://www.laganiere.name/opencvCookbook/chap8.shtmlhttp://www.laganiere.name/opencvCookbook/chap7.shtmlhttp://www.laganiere.name/opencvCookbook/chap6.shtmlhttp://www.laganiere.name/opencvCookbook/chap5.shtmlhttp://www.laganiere.name/opencvCookbook/chap4.shtmlhttp://www.laganiere.name/opencvCookbook/chap3.shtmlhttp://www.laganiere.name/opencvCookbook/chap2.shtmlhttp://www.laganiere.name/opencvCookbook/chap1.shtmlhttp://www.laganiere.name/opencvCookbook/index.shtmlhttp://www.googleadservices.com/pagead/aclk?sa=L&ai=CdGnbTczOUp_OIcKAmwW0oIDYD-XlxbkElZr_kn2IxPGPLRABILXWqSVQ-tqw9P7_____AWAzoAHD-9DUA8gBAqgDAcgDwQSqBJ0BT9CpjrKqEsujcw9Qr7-6jDIPy8YxNtVclxiwe4iR_UWGJtzzsojoE6bvmixNDTaTYlPpLEDpJzpbfgwMLhQkSvzDKDh20Nr5CvAHv4cPvHLxxTvArXlN_m-Jl9AOCIZZ6BA5lM60GocXQhJs2gV39H-nu7BDKo7_oFyoN6y_FzELvrrOS2UJJX2_-9JtMwRZVXW6Pb1qjXk5LL4fIogGAaAGAoAHpYSvKw&num=1&cid=5GiW2j45317Yvssod0FuFTrZ&sig=AOD64_0Gy0Q--lsJAKXCgQc8-9jsXyID3Q&client=ca-pub-8501294875466025&adurl=http://k.keyade.com/kack/1/%3FkaPt%3Dgoogle%26kaTckM%3Dp%26kaPcId%3D98678%26kaTckId%3D33564446413%26kaAcId%3D191%26kaCpnId%3D%26kaNtw%3Dcontent%26kaKwd%3D%26kaDmn%3Dwww.laganiere.name%26kaTgt%3D%26kaNtw2%3Dd%26kaMtTp%3D%26kaAdPos%3Dnone%26kaDev%3Dchttp://qt.nokia.com/downloadshttp://www.packtpub.com/opencv-2-computer-vision-application-programming-cookbook/bookhttp://qt.nokia.com/http://www.laganiere.name/


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We will call our project myHelloWorld; place it in the location of your choice

and click Next.

We c reate a Desktop applicat ion.

A default project is then created.


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This one does nothing except launching the concole. Click on the green arrowand you will see it.

3. Lets now write a true Hello World application. Simply copy and paste thefollowing C++ code over the preceding one.

#include

int main() {

std::cout > var;

return 1;

}


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And click again on the green arrow to run the new code.

If you obtain the result above, then everything is working well. Note that Qtautomatically created a directory called myHelloWorld-build-desktopwhere it

puts all the compiled and executable files. This way, the source code and thebinary files does not get mixed together. This is very useful, if you use a versioncontrol software such as Subversionin which you submit only the sourcedirectory.

4. Let's now proceed to OpenCV installation. To download the OpenCV library, justgo to the OpenCV official website at opencv.willowgarage.com. You'll find therethe current release version in a downloadable zip file or in a Windows install. Inthe case of version 2.3.1, a superpack installer is available:
http://opencv.willowgarage.com/http://www.laganiere.name/subversionTut


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Run it and extract it to the directory of your choice:

Once this is done, you now have all OpenCV source files in the specifieddirectory.

5. The next step is to compile the library for the compiler you want to use; here itwill be the basic mingw/g++compiler that Qt installed by default. Just before we

do this, let's include the folder that c ontains the makecommand in our Path

environment variable. Indeed, compiling the library will be done using this make

utility command that Qt installed together with the compilers themselves. Theyare located in C:\QtSDK\mingw\bin. Goto to your Control Panel (from the Start

menu) and to the Systemmenu.

In the Advanced system settingsmenu, you select the Advancedtab.


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Click on Environment Variables...

In the User variablesbox, look for the PATHvariable. If it is there, click on

Edit..., if not click on New...to create it. This variable contains all the folder

Windows will look in when you type a command. By setting it in the uservariables, this definition is available to you only. If you want it to be valid for allusers of your system then define it in the System variablesbox.


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6. To build the library from the source f iles, OpenCV uses CMake, a cross-platformand open source tool designed to build library packages. We need to installCMake. Go to cmake.organd download the Windows Win32 Installer.

7. Once CMake installed, you can start the gui-based applicat ion (cmake-gui)
http://www.cmake.org/


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In CMake, spec ify the directory containing the source code and the one that will

contain the builds.

Click on Configure. This will create the output directory.


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You then specify the c ompilers that will generate the project. In our case, theyare the compilers of MinGW installed by default by Qt.

These are gcc and g++.

CMake now displays the different build options.


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Select the build type, here Release. If you wish, at the end, you can repeat the

same process with the Debugmode.


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Since we want to use Qt, we also select the WITH_QToption

Once your options selected, you click on Configureagain.


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And you click on Generateto complete the installation.


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8. Now that you have completed the installation, you are ready to compile theOpenCV library. Start the Windows cmd console and go to the directory whereyou installed your builds. Type mingw32-make

Building everything will take time...

Once this built completed, you type mingw32-make install

This last step will install the library and the include files in the install

directory. Note that for clarity, you can rename this directory as releasesince

you ask CMake to build a Release install


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We are done with the installation! Congratulations!

9. Before we build our first OpenCV project, we need to add a few more folders tothe Pathenvironment variable. First, you need to tell your system where to find

the OpenCV dlls. From our installation process, they are in C:\OpenCV-

2.3.1\install\bin.

The Qt dlls are also required; you should find them at C:\QtSDK\QtCreator\bin

10. Our last step is to build a simple OpenCV project to make sure everything isworking properly. Start Qt and create a new Qt Console Application projectcalled here myFirstOpenCVProject. Goto to the projectsmenu and select the

Releasebuild configuration.


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Our test program will simply open and display an image:

#include

#include

int main() {

// read an image

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

// create image window named "My Image"

cv::namedWindow("My Image");

// show the image on window

cv::imshow("My Image", image);

// wait key for 5000 ms

cv::waitKey(5000);

return 1;

}

The project file must specify the OpenCV headers and libraries locations:

QT += core

QT -= gui

TARGET = myFirstOpenCVProject

CONFIG += console

CONFIG -= app_bundle

TEMPLATE = app

SOURCES += main.cpp

INCLUDEPATH += C:\\OpenCV-2.3.1\\install\\include

LIBS += -LC:\\OpenCV-2.3.1\\install\\lib \

-lopencv_core231.dll \

-lopencv_highgui231.dll \

-lopencv_imgproc231.dll \

-lopencv_features2d231.dll \

-lopencv_calib3d231.dll

You basically just have to add the last two definitions to the existing project:


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Make sure you have an image called img.jpgin your myFirstOpenCVProject-build-desktopdirectory that is the default directory when you run your project

from Qt.

and you should see the image displayed.


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Wow! But this is just the beginning, you can do much more with OpenCV... Goodluck!

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(c) Robert Laganiere 2011
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OpenCV Install Guide