Using QT with openCV on Maverick osX

Ben_Pflaenz

Hello

I am new to openCV and I would like to install openCV and use it with QT.
I used macports to install it and i set the path in the terminal.

What I did was;

I installed macports
I typed in the terminal
@
export PATH=$PATH:/opt/local/bin
source .profile
sudo port -v selfupdate
sudo port install opencv
@
restart
Thats all...

Now i try to compile a Helloworld but i get unknown variable error. Looks like something with the linker gone wrong or i included the wrong libs? I searched google and I found some hints but nothing helped yet. Maybe someone got a suggestion?
Thank you very much for your time and answer!

My settings:
@
#-------------------------------------------------
#
# Project created by QtCreator 2014-02-04T22:10:07
#
#-------------------------------------------------

QT       += core

QT       -= gui

TARGET = opencvTest
CONFIG   += console
CONFIG   -= app_bundle

TEMPLATE = app

SOURCES += main.cpp

INCLUDEPATH += /opt/local/include

LIBS += -L/opt/local/lib
LIBS += -lopencv_core
        -lopencv_highgui

@

@
#include <iostream>
#include <opencv2/highgui/highgui.hpp>

using namespace std ;
using namespace cv ;

int main()
{
    Mat img ;

    img = imread("unknown.jpg") ;

    return 0;
}

@
Error message

@
10:39:10: Running steps for project opencvTest...
10:39:10: Configuration unchanged, skipping qmake step.
10:39:10: Starting: "/usr/bin/make"
/Users/Ben/Qt/5.2.0/clang_64/bin/qmake -spec macx-g++ CONFIG+=debug CONFIG+=x86 CONFIG+=declarative_debug CONFIG+=qml_debug -o Makefile ../opencvTest/opencvTest.pro
/Applications/Xcode.app/Contents/Developer/usr/bin/g++ -headerpad_max_install_names -Wl,-syslibroot,/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk -mmacosx-version-min=10.6 -o opencvTest main.o -F/Users/Ben/Qt/5.2.0/clang_64/lib -L/opt/local/lib -lopencv_core -framework QtCore
Undefined symbols for architecture x86_64:
"cv::imread(std::string const&, int)", referenced from:
_main in main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [opencvTest] Error 1
10:39:10: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project opencvTest (kit: Unnamed)
When executing step 'Make'
10:39:10: Elapsed time: 00:00.@

SGaist

Hi and welcome to devnet,

Check your opencv install to see if it was build for x86_64

Ben_Pflaenz

Hmm it should be, Macport installs it as a 64bit as default as I know from google.
I don't know how I can check that honestly.

SGaist

call

@file /opt/local/lib/libopencv_core.dylib@

in your console

Ben_Pflaenz

so....
/opt/local/lib/libopencv_core.dylib: Mach-O 64-bit dynamically linked shared library x86_64

thats the result so I think its the right one? isn't it?

Ben_Pflaenz

Yeaah it works! Finally!

/Users/Ben/Qt/5.2.0/clang_64/mkspecs/macx-clang/qmake.conf

had to change

QMAKE_MACOSX_DEPLOYMENT_TARGET = 10.6

to

QMAKE_MACOSX_DEPLOYMENT_TARGET = 10.9

Ben_Pflaenz

BUT... other libs like boost won't work anymore...

I have to add
QMAKE_MACOSX_DEPLOYMENT_TARGET = 10.9
to the pro file in the project for the opencv projects separately

SGaist

You'll have to check that all your libraries have the same deployment target. That might also mean rebuild Qt