Installing OpenCV 2.4.x with Qt

Installing OpenCV

2.4.x with Qt

Luigi De Russis

Politecnico di Torino Dipartimento di Automatica e Informatica (DAUIN)

Torino - Italy

[email protected]

This work is licensed under the Creative Commons (CC BY-SA)

License. To view a copy of this license, visit

http://creativecommons.org/licenses/by-sa/3.0/

mailto:[email protected]

11/9/2012 Luigi De Russis - Computer Vision - OpenCV

Installation

2

0. Getting started…

Official installation guides

Currently, only for Linux and Windows

http://docs.opencv.org/doc/tutorials/introduction/table_of_c

ontent_introduction/table_of_content_introduction.html

Prerequisites:

[Mac OS X] Xcode with command line tools installed

[Linux] GCC 4.4 or later

N.B. This tutorial has been tested with OpenCV

2.3.1, 2.4.2, and 2.4.3 under Windows 7 and Mac

OS X 10.7+

http://docs.opencv.org/doc/tutorials/introduction/table_of_content_introduction/table_of_content_introduction.html



Luigi De Russis - Computer Vision - OpenCV 3

1. Qt SDK (I)

Download and install Qt SDK from http://qt-

project.org/downloads, using the offline installer

(current SDK release 1.2.1)

[Windows-only] Perform a custom installation,

installing all the MinGW stuff. Components about

Harmattan, Symbian, etc. are not necessary for our

purpose (see next slide)

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http://qt-project.org/downloads





1. Qt SDK (II) - Windows

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1. Qt SDK (II) - Windows

At the end, check if the folder

C:\QtSDK\mingw\bin (or similar)

is included in the PATH variable

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2. OpenCV 2.4.x

Download and unpack OpenCV 2.4.x from

http://opencv.org/

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http://opencv.org/


3. Cmake (I)

Download and install Cmake from

http://www.cmake.org/

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http://www.cmake.org/cmake/resources/software.html




3. Cmake (II)

Create two new folders named “cmake-debug” and

“cmake-release” inside the opencv folder

Create a folder named “build_with_Qt” (or similar)

wherever you want

create two new folders named “debug” and “release” inside

the “build_with_Qt” folder

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3. Cmake (II)

Create two new folders named “cmake-debug” and

“cmake-release” inside the opencv folder

Create a folder named “build_with_Qt” (or similar)

wherever you want

create two new folders named “debug” and “release” inside

the “build_with_Qt” folder

It is not strongly mandatory… it

is only a “best practice”!

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3. Cmake (IV)

Run Cmake

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3. Cmake (V)

“Where is the source code” field requires the

location of the opencv folder

“Where to build the binaries” field requires the

location of the “cmake-debug” folder, previously

created

Now press the button “Configure”…

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3. Cmake (VI)

In the next window, select “MingGW Makefiles”

under Windows, “Unix Makefiles” otherwise

Then, press “Finish”

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3. Cmake (VII)

The Cmake window should appear in this way:

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3. Cmake (VIII)

Open the CMAKE entry

assign the value Debug to the CMAKE_BUILD_TYPE

variable

change the CMAKE_INSTALL_PREFIX to match the

“build_with_Qt/debug” folder

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3. Cmake (IX)

Open the WITH entry: check WITH_QT

uncheck useless values (CUDA, CUFFT, EIGEN, and PVAPI, typically)

Press “Configure”, again

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3. Cmake (X)

Open the Ungrupped Entries (or QT) with a red

background and add the location of qmake to the

variable QT_QMAKE_EXECUTABLE

[Windows] qmake is in /Desktop/Qt/4.8.1/mingw/bin inside

the folder where Qt SDK has been installed

[Linux/Mac] qmake is in /Desktop/Qt/4.8.1/gcc/bin inside

the folder where Qt SDK has been installed

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3. Cmake (XI)

Click again on “Configure” (until the entries

background becomes totally white)

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3. Cmake (XII)

Press “Generate”

Repeat the steps reported on slides 11 - 18,

changing:

the build destination folder from “cmake-debug” to “cmake-

release”

the value of the CMAKE_BUILD_TYPE variable (in the

CMAKE entry) to Release

the value of the CMAKE_INSTALL_PREFIX variable (in the

CMAKE entry) to match the “build_with_Qt/release” folder

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4a. Final steps, on Linux/Mac

(I)

Open the terminal, move to the “cmake-debug”

folder, type “make -jN”, where N is the number of

threads to use, and press enter

Wait…

Type “make install” to complete the OpenCV

installation

Repeat the previous three steps for the “cmake-

release” folder

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4a. Final steps, on Linux/Mac

(II)

Add the following folders:

/build_with_Qt/debug/bin

/build_with_Qt/release/bin

to the DYLD_LIBRARY_PATH (Mac) or

LD_LIBRARY_PATH (Linux) environment variable.

You can perform this operation right inside QtCreator (“Build

Environments” field inside the Projects” tab).

Copy the file “opencv.hpp” from “/include/opencv2”

to “include” (in your “builds_with_Qt” folder)

Done: you can start to use OpenCV with Qt!

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4b. Final steps, on Windows (I)

Open the command prompt, move to the “cmake-debug”

folder, type “mingw32-make –j N”, where N is the

number of threads to use, and press enter

Wait…

Type “mingw32-make install” and press enter

Repeat the previous three steps for the “cmake-release”

folder

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4b. Final steps, on Windows

(II)

Add to the PATH environment variable the following

folders:

/build_with_Qt/debug/bin

/build_with_Qt/release/bin

QtSDK/Desktop/Qt/4.8.1/mingw/bin

How do I set the PATH

variable? Read here. You can also perform this

operation inside QtCreator (“Build

Environments” field inside the

Projects” tab).

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http://www.java.com/en/download/help/path.xml

http://www.java.com/en/download/help/path.xml


4b. Final steps, on Windows

(III)

Copy the file “opencv.hpp” from “/include/opencv2”

to “include” (in your “build_with_Qt” folder)

Done: you can start to use OpenCV with Qt!

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Installing OpenCV 2.4.x with Qt

Education

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