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Using opencv3.1 with Qt5.5 in Windows 10

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  • mrdebugM mrdebug

    Hi. You have to build OpenCV with MinGW only if you want to use Qt on Windows builded with MinGW.
    The OpenCV package already has the vs libraries.
    Anyway which are your cmake switches?

    brotifyB Offline
    brotifyB Offline
    brotify
    wrote on last edited by brotify
    #9

    @mrdebug
    I have to say that I am not experienced developer. Therefore I did not fully understand what are saying. I used Mingw because in the tutorials thay were using Cmake and Mingw. If there are another method to use opencv in Qt project, it will be good to me to know.

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    • mrdebugM Offline
      mrdebugM Offline
      mrdebug
      wrote on last edited by
      #10

      Sorry but all the tutorials that I have tried in order to to use OpenCV in all platforms are not perfectly usable. To setup OpenCV with Qt is more difficult than to write a OpenCV program.
      To start: what qt version are you using? The Qt version based on mingw32 or the version based on vc?

      Need programmers to hire?
      www.labcsp.com
      www.denisgottardello.it
      GMT+1
      Skype: mrdebug

      brotifyB 1 Reply Last reply
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      • brotifyB brotify

        @jsulm

        INCLUDEPATH += C:\opencv2\release\install\include
        LIBS += -LC:/opencv2/release/install/x86/mingw/bin\
            -lopencv_core310 \
            -lopencv_highgui310 \
            -lopencv_imgproc310 \
            -lopencv_features2d310 \
            -lopencv_calib3d310 \
        
        INCLUDEPATH += C:/opencv2/release/install/include
        LIBS += -LC:/opencv2/release/install/x86/mingw/bin\
            -lopencv_core310 \
            -lopencv_highgui310 \
            -lopencv_imgproc310 \
            -lopencv_features2d310 \
            -lopencv_calib3d310 \
        

        I tried both of them but this time I get this error:
        LNK1104: cannot open file 'opencv_core310.lib'

        Let me show the screenshot of what is inside "C:\opencv2\release\install\x86\mingw\bin"
        http://i.hizliresim.com/0nkDAY.png

        jsulmJ Offline
        jsulmJ Offline
        jsulm
        Lifetime Qt Champion
        wrote on last edited by
        #11

        @brotify Can you search for opencv_core310.lib (and other needed *.lib files) in the installation directory?

        https://forum.qt.io/topic/113070/qt-code-of-conduct

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        • A Offline
          A Offline
          asanka424
          wrote on last edited by
          #12

          It seems like you are trying to use OpenCV built using MinGW with Qt built with Visual Studio. There are two things you can do.

          1. use OpenCV pre built. Which is in your build folder of OpenCV downloaded zip

          2. change the kit in your Qt Creator to use MinGW build of Qt.

          Hope this helps

          brotifyB 1 Reply Last reply
          0
          • A asanka424

            It seems like you are trying to use OpenCV built using MinGW with Qt built with Visual Studio. There are two things you can do.

            1. use OpenCV pre built. Which is in your build folder of OpenCV downloaded zip

            2. change the kit in your Qt Creator to use MinGW build of Qt.

            Hope this helps

            brotifyB Offline
            brotifyB Offline
            brotify
            wrote on last edited by brotify
            #13

            Please note that I have solved my problem but I will not delete this post because it may help other people.
            @asanka424
            Thanks, I selected Mingw32 as the kit and it worked but this time I get a different error. I tried a simple opencv program which shows the image however it gives this error:
            undefined reference to `cv::imread(cv::String const&, int)'

            Here is my code,

            #include <opencv2/core/core.hpp>
            #include <opencv2/highgui/highgui.hpp>
            #include <iostream>
            
            using namespace cv;
            using namespace std;
            
            int main(  )
            {
            
            
                Mat image;
                image = imread("img.jpg", CV_LOAD_IMAGE_COLOR);   
            
                if(! image.data )                       
                {
                    cout <<  "Could not open or find the image" << std::endl ;
                    return -1;
                }
            
                namedWindow( "Display window", WINDOW_AUTOSIZE );// Create a window for display.
                imshow( "Display window", image );             
            
                waitKey(0);                                      
                return 0;
            }
            
            

            and here is my .pro file

            QT += core
            QT -= gui
            
            CONFIG += c++11
            
            TARGET = untitled
            CONFIG += console
            CONFIG -= app_bundle
            
            INCLUDEPATH += C:/opencv2/release/install/include
            LIBS += -LC:/opencv2/release/install/x86/mingw/bin\
                -lopencv_core310 \
                -lopencv_highgui310 \
                -lopencv_imgproc310 \
                -lopencv_features2d310 \
                -lopencv_calib3d310 \
            
            
            TEMPLATE = app
            
            SOURCES += main.cpp
            

            And lastly can you show me how to use first method that is using opencv pre-built?

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            • mrdebugM mrdebug

              Sorry but all the tutorials that I have tried in order to to use OpenCV in all platforms are not perfectly usable. To setup OpenCV with Qt is more difficult than to write a OpenCV program.
              To start: what qt version are you using? The Qt version based on mingw32 or the version based on vc?

              brotifyB Offline
              brotifyB Offline
              brotify
              wrote on last edited by brotify
              #14

              @mrdebug
              I was not aware of that Qt has two different versions. So far I was using VC. Now I am using MinGw and it seems that the problem was this. Yet I have another problem which I posted before this post.

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              0
              • brotifyB Offline
                brotifyB Offline
                brotify
                wrote on last edited by brotify
                #15

                Ok, I want to thanks all of you who tried to help me. Hopefully I solved my problem. I solved the last problem by adding to .pro file

                LIBS += "C:\opencv2\release\lib\libopencv_imgcodecs310.dll.a"
                
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                • B Offline
                  B Offline
                  beginMyCoding
                  wrote on last edited by
                  #16

                  Hello
                  I am also in a same situation, i did not find any solution till now.
                  I am using Qt creator 5.5 with mingw492_32 and openCv 3.10 with VC.
                  When i try to write a small code to read the image matrix using cv::imread() it gives me error.

                  error: undefined reference to `cv::imread(cv::String const&, int)
                  

                  this is my

                  test.pro

                  QT       += core gui
                  
                  greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
                  
                  TARGET = Test
                  TEMPLATE = app
                  
                  
                  SOURCES += main.cpp\
                          mainwindow.cpp
                  
                  HEADERS  += mainwindow.h
                  
                  FORMS    += mainwindow.ui
                  
                  INCLUDEPATH += LC:\opencv\build\include
                  
                          LIBS += C:\opencv\build\x64\vc14\lib\opencv_world310.lib \
                                  C:\opencv\build\bin\opencv_ffmpeg310.dll
                  

                  i have only one library file in the openCV folder
                  Do you have any idea what i am suppose to do?

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                  • mrdebugM Offline
                    mrdebugM Offline
                    mrdebug
                    wrote on last edited by
                    #17

                    Hi.
                    You can't use the vc libraries of OpenCV with Qt built with Mingw. If you want to use Qt with mingw you have to build OpenCV with Mingw.
                    I confirm Qt 5.5 works perfectly with OpenCV 3.
                    http://www.denisgottardello.it/ComputerVisionStudio/index.php

                    Need programmers to hire?
                    www.labcsp.com
                    www.denisgottardello.it
                    GMT+1
                    Skype: mrdebug

                    1 Reply Last reply
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                    • B Offline
                      B Offline
                      beginMyCoding
                      wrote on last edited by
                      #18

                      Is there any link which explains perfect installation of OpenCV 3 and Qt5.5?

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                      0
                      • mrdebugM Offline
                        mrdebugM Offline
                        mrdebug
                        wrote on last edited by
                        #19

                        These lines of code work perfectly with Qt 5.5.0 and OpenCV 3.0
                        set PATH=%PATH%;C:\Qt\Qt5.5.0\Tools\mingw492_32\bin;C:\Program Files (x86)\CMake 2.8\bin
                        cmake -G "MinGW Makefiles" -DWITH_FFMPEG=OFF -DCMAKE_BUILD_TYPE=RELEASE -DBUILD_opencv_videoio=ON -DWITH_IPP=OFF -DWITH_OPENCL=OFF -DWITH_JASPER=OFF -DWITH_OPENEXR=OFF -DBUILD_SHARED_LIBS=OFF -DBUILD_TESTS=OFF -DBUILD_PERF_TESTS=OFF -DOPENCV_EXTRA_MODULES_PATH=modules/opencv_contrib-master/modules .

                        mingw32-make -j 4

                        I have only some problems with webcams in some 64 bit machines.

                        Another hard problem is to setup the pro file. You have to include the libraries in a particular order (depends from your program). Some libraries can be included more than one time.
                        This solution sounds to be very strange but I assure, to have OpenCV working I have spent a lot of time.

                        If you need professional support please send me an email at info@denisgottardello.it

                        Need programmers to hire?
                        www.labcsp.com
                        www.denisgottardello.it
                        GMT+1
                        Skype: mrdebug

                        B 1 Reply Last reply
                        0
                        • mrdebugM mrdebug

                          These lines of code work perfectly with Qt 5.5.0 and OpenCV 3.0
                          set PATH=%PATH%;C:\Qt\Qt5.5.0\Tools\mingw492_32\bin;C:\Program Files (x86)\CMake 2.8\bin
                          cmake -G "MinGW Makefiles" -DWITH_FFMPEG=OFF -DCMAKE_BUILD_TYPE=RELEASE -DBUILD_opencv_videoio=ON -DWITH_IPP=OFF -DWITH_OPENCL=OFF -DWITH_JASPER=OFF -DWITH_OPENEXR=OFF -DBUILD_SHARED_LIBS=OFF -DBUILD_TESTS=OFF -DBUILD_PERF_TESTS=OFF -DOPENCV_EXTRA_MODULES_PATH=modules/opencv_contrib-master/modules .

                          mingw32-make -j 4

                          I have only some problems with webcams in some 64 bit machines.

                          Another hard problem is to setup the pro file. You have to include the libraries in a particular order (depends from your program). Some libraries can be included more than one time.
                          This solution sounds to be very strange but I assure, to have OpenCV working I have spent a lot of time.

                          If you need professional support please send me an email at info@denisgottardello.it

                          B Offline
                          B Offline
                          beginMyCoding
                          wrote on last edited by
                          #20

                          @mrdebug
                          I seriously did not understand from 3rd line (cmake).

                          I set the paths of Qt and CMake
                          Below are my paths
                          C:\Qt\5.5\mingw492_32\bin
                          C:\CMake\bin

                          I don't understand what I have to do in CMake?
                          Can you say me any step by step procedure or any other way?

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