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Declaration of function and use it

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  • G gauravsharma0190

    @gauravsharma0190
    Hey jslum
    thanks very mush i did it without error
    Now new problem arises when i clicked the push button it tells
    The program has unexpectedly finished.
    /home/pi/Desktop/qt /build-Desktop1-GCC Local/Desktop crashed.

    jsulmJ Offline
    jsulmJ Offline
    jsulm
    Lifetime Qt Champion
    wrote on last edited by
    #71

    @gauravsharma0190 Most probably it crashes because of an invalid pointer. Debug your application step by step to see where exactly it crashes.

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

    G 1 Reply Last reply
    0
    • jsulmJ jsulm

      @gauravsharma0190 Most probably it crashes because of an invalid pointer. Debug your application step by step to see where exactly it crashes.

      G Offline
      G Offline
      gauravsharma0190
      wrote on last edited by
      #72

      @jsulm
      Hello sir
      i debug the programme but when i press button it tells
      the inferior stooped because it receives signal from OS
      Signal name SIGABRT
      Signal mean Aborted.
      Now how to solve it

      jsulmJ 1 Reply Last reply
      0
      • G gauravsharma0190

        @jsulm
        Hello sir
        i debug the programme but when i press button it tells
        the inferior stooped because it receives signal from OS
        Signal name SIGABRT
        Signal mean Aborted.
        Now how to solve it

        jsulmJ Offline
        jsulmJ Offline
        jsulm
        Lifetime Qt Champion
        wrote on last edited by jsulm
        #73

        @gauravsharma0190 Put a breakpoint in the slot which is called when you press the button and check where exactly it crashes.

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

        G 1 Reply Last reply
        1
        • G Offline
          G Offline
          gauravsharma0190
          wrote on last edited by gauravsharma0190
          #74

          IT CRASHES WHERE FUNCTION ontrack()
          defination
          Canny(edge, edge, edgeThresh, edgeThresh*3, 3);
          kernel_size issue i think.
          int kernel_size =3;
          here

          1 Reply Last reply
          0
          • jsulmJ jsulm

            @gauravsharma0190 Put a breakpoint in the slot which is called when you press the button and check where exactly it crashes.

            G Offline
            G Offline
            gauravsharma0190
            wrote on last edited by
            #75

            @jsulm
            It crashes when i press the push button .
            I debugged it and found it creshes when my function call.
            Error found->it takes signal from OS.
            Now How to fix it.

            jsulmJ 2 Replies Last reply
            0
            • G gauravsharma0190

              @jsulm
              It crashes when i press the push button .
              I debugged it and found it creshes when my function call.
              Error found->it takes signal from OS.
              Now How to fix it.

              jsulmJ Offline
              jsulmJ Offline
              jsulm
              Lifetime Qt Champion
              wrote on last edited by
              #76

              @gauravsharma0190 How to fix what?
              What do you mean by "Error found->it takes signal from OS" - what OS signal do you mean? Do you mean SIGABRT?
              I don't know how to fix it because I have no idea what the problem is. But usually such problems are caused by bugs in applications. You have to check your code and see what is wrong at the line where your application crashes.

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

              1 Reply Last reply
              0
              • G gauravsharma0190

                @jsulm
                It crashes when i press the push button .
                I debugged it and found it creshes when my function call.
                Error found->it takes signal from OS.
                Now How to fix it.

                jsulmJ Offline
                jsulmJ Offline
                jsulm
                Lifetime Qt Champion
                wrote on last edited by
                #77

                @gauravsharma0190 Can you post the code and mark the line where it crashes?

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

                G 1 Reply Last reply
                0
                • jsulmJ jsulm

                  @gauravsharma0190 Can you post the code and mark the line where it crashes?

                  G Offline
                  G Offline
                  gauravsharma0190
                  wrote on last edited by gauravsharma0190
                  #78

                  @jsulm
                  Mainwindow.cpp

                  void MainWindow::on_onTrackball_clicked()
                  {
                      int threshold_value = 0;
                      int threshold_type = 3;
                      int const max_value = 255;
                      int const max_type = 4;
                     // int const max_BINARY_value = 255;
                  
                      Mat src, src_gray, dst;
                    //  char* window_name = "Threshold Demo";
                  
                      //char* trackbar_type = "Type: \n 0: Binary \n 1: Binary Inverted \n 2: Truncate \n 3: To Zero \n 4: To Zero Inverted";
                      //char* trackbar_value = "Value";
                  
                  
                  
                  
                      /// Load image
                      src = imread( "/home/pi/Desktop/b4.jpg");
                  
                  
                        /// Convert the image to Gray
                        cvtColor( src, src_gray, CV_BGR2GRAY );
                  
                        /// Create a window to display results
                        namedWindow( "Threshold", CV_WINDOW_AUTOSIZE );
                  
                        /// Create Trackbar to choose type of Threshold
                        createTrackbar( "Type: \n 0: Binary \n 1: Binary Inverted \n 2: Truncate \n 3: To Zero \n 4: To Zero Inverted","Threshold", &threshold_type, max_type, Threshold_Demo );
                  
                        createTrackbar( "value","Threshold", &threshold_value, max_value, Threshold_Demo );
                  
                        /// Call the function to initialize
                  @@@   ***Threshold_Demo( 0, 0)***
                  
                  
                  }
                  

                  onTrack.h

                  #ifndef ONTRACKBALL_H_
                  #define ONTRACKBALL_H_
                    void Threshold_Demo( int, void* );
                  #endif
                  

                  ontrack.cpp

                  void Threshold_Demo( int, void* )
                  {
                    /* 0: Binary
                       1: Binary Inverted
                       2: Threshold Truncated
                       3: Threshold to Zero
                       4: Threshold to Zero Inverted
                     */
                  
                  @@threshold( src_gray, dst, threshold_value, max_BINARY_value,threshold_type );
                  
                    imshow("Threshold", dst );
                  

                  Here @---> Error

                  jsulmJ 1 Reply Last reply
                  0
                  • G gauravsharma0190

                    @jsulm
                    Mainwindow.cpp

                    void MainWindow::on_onTrackball_clicked()
                    {
                        int threshold_value = 0;
                        int threshold_type = 3;
                        int const max_value = 255;
                        int const max_type = 4;
                       // int const max_BINARY_value = 255;
                    
                        Mat src, src_gray, dst;
                      //  char* window_name = "Threshold Demo";
                    
                        //char* trackbar_type = "Type: \n 0: Binary \n 1: Binary Inverted \n 2: Truncate \n 3: To Zero \n 4: To Zero Inverted";
                        //char* trackbar_value = "Value";
                    
                    
                    
                    
                        /// Load image
                        src = imread( "/home/pi/Desktop/b4.jpg");
                    
                    
                          /// Convert the image to Gray
                          cvtColor( src, src_gray, CV_BGR2GRAY );
                    
                          /// Create a window to display results
                          namedWindow( "Threshold", CV_WINDOW_AUTOSIZE );
                    
                          /// Create Trackbar to choose type of Threshold
                          createTrackbar( "Type: \n 0: Binary \n 1: Binary Inverted \n 2: Truncate \n 3: To Zero \n 4: To Zero Inverted","Threshold", &threshold_type, max_type, Threshold_Demo );
                    
                          createTrackbar( "value","Threshold", &threshold_value, max_value, Threshold_Demo );
                    
                          /// Call the function to initialize
                    @@@   ***Threshold_Demo( 0, 0)***
                    
                    
                    }
                    

                    onTrack.h

                    #ifndef ONTRACKBALL_H_
                    #define ONTRACKBALL_H_
                      void Threshold_Demo( int, void* );
                    #endif
                    

                    ontrack.cpp

                    void Threshold_Demo( int, void* )
                    {
                      /* 0: Binary
                         1: Binary Inverted
                         2: Threshold Truncated
                         3: Threshold to Zero
                         4: Threshold to Zero Inverted
                       */
                    
                    @@threshold( src_gray, dst, threshold_value, max_BINARY_value,threshold_type );
                    
                      imshow("Threshold", dst );
                    

                    Here @---> Error

                    jsulmJ Offline
                    jsulmJ Offline
                    jsulm
                    Lifetime Qt Champion
                    wrote on last edited by
                    #79

                    @gauravsharma0190 What are src_gray, dst, threshold_value, max_BINARY_value,threshold_type? Where are they defined and initialized? Please note: these are NOT same as in MainWindow::on_onTrackball_clicked()!

                    void Threshold_Demo( int, void* )
                    {
                      /* 0: Binary
                         1: Binary Inverted
                         2: Threshold Truncated
                         3: Threshold to Zero
                         4: Threshold to Zero Inverted
                       */
                    
                    @@threshold( src_gray, dst, threshold_value, max_BINARY_value,threshold_type );
                    
                      imshow("Threshold", dst );
                    
                    

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

                    G 1 Reply Last reply
                    0
                    • jsulmJ jsulm

                      @gauravsharma0190 What are src_gray, dst, threshold_value, max_BINARY_value,threshold_type? Where are they defined and initialized? Please note: these are NOT same as in MainWindow::on_onTrackball_clicked()!

                      void Threshold_Demo( int, void* )
                      {
                        /* 0: Binary
                           1: Binary Inverted
                           2: Threshold Truncated
                           3: Threshold to Zero
                           4: Threshold to Zero Inverted
                         */
                      
                      @@threshold( src_gray, dst, threshold_value, max_BINARY_value,threshold_type );
                      
                        imshow("Threshold", dst );
                      
                      
                      G Offline
                      G Offline
                      gauravsharma0190
                      wrote on last edited by
                      #80

                      @jsulm
                      Hey Good morning
                      These are defined in the same function .cpp files.
                      Yes These are not in mainwindow

                      jsulmJ 1 Reply Last reply
                      0
                      • G gauravsharma0190

                        @jsulm
                        Hey Good morning
                        These are defined in the same function .cpp files.
                        Yes These are not in mainwindow

                        jsulmJ Offline
                        jsulmJ Offline
                        jsulm
                        Lifetime Qt Champion
                        wrote on last edited by
                        #81

                        @gauravsharma0190 Did you initialize these variables? Do they have correct values when you call threshold()?

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

                        G 1 Reply Last reply
                        0
                        • jsulmJ jsulm

                          @gauravsharma0190 Did you initialize these variables? Do they have correct values when you call threshold()?

                          G Offline
                          G Offline
                          gauravsharma0190
                          wrote on last edited by
                          #82

                          @jsulm
                          Yes i initialize these with correct values.

                          jsulmJ 1 Reply Last reply
                          0
                          • G gauravsharma0190

                            @jsulm
                            Yes i initialize these with correct values.

                            jsulmJ Offline
                            jsulmJ Offline
                            jsulm
                            Lifetime Qt Champion
                            wrote on last edited by
                            #83

                            @gauravsharma0190 Are you sure? Did you verify using debugger? If they have correct values then I don't know why it's crashing...

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

                            G 1 Reply Last reply
                            1
                            • jsulmJ jsulm

                              @gauravsharma0190 Are you sure? Did you verify using debugger? If they have correct values then I don't know why it's crashing...

                              G Offline
                              G Offline
                              gauravsharma0190
                              wrote on last edited by
                              #84

                              @gauravsharma0190 said:

                              void MainWindow::on_onTrackball_clicked()
                              {
                              int threshold_value = 0;
                              int threshold_type = 3;
                              int const max_value = 255;
                              int const max_type = 4;
                              // int const max_BINARY_value = 255;

                              Mat src, src_gray, dst;
                              

                              // char* window_name = "Threshold Demo";

                              //char* trackbar_type = "Type: \n 0: Binary \n 1: Binary Inverted \n 2: Truncate \n 3: To Zero \n 4: To Zero Inverted";
                              //char* trackbar_value = "Value";
                              
                              
                              
                              
                              /// Load image
                              src = imread( "/home/pi/Desktop/b4.jpg");
                              
                              
                                /// Convert the image to Gray
                                cvtColor( src, src_gray, CV_BGR2GRAY );
                              
                                /// Create a window to display results
                                namedWindow( "Threshold", CV_WINDOW_AUTOSIZE );
                              
                                /// Create Trackbar to choose type of Threshold
                                createTrackbar( "Type: \n 0: Binary \n 1: Binary Inverted \n 2: Truncate \n 3: To Zero \n 4: To Zero Inverted","Threshold", &threshold_type, max_type, Threshold_Demo );
                              
                                createTrackbar( "value","Threshold", &threshold_value, max_value, Threshold_Demo );
                              
                                /// Call the function to initialize
                              

                              @@@ Threshold_Demo( 0, 0)

                              }

                              When I Comment the line Threshold _demo everything went OK!!!
                              Results are coming but when i uncomment it everything crashes.

                              jsulmJ 1 Reply Last reply
                              0
                              • mrjjM Offline
                                mrjjM Offline
                                mrjj
                                Lifetime Qt Champion
                                wrote on last edited by
                                #85

                                Hi
                                I have a teory ;)

                                namedWindow

                                void namedWindow(const string& winname, int flags=WINDOW_AUTOSIZE )

                                It wants a ref, so i assume that the crash is that
                                // char* window_name = "Threshold Demo";

                                will run out of scope

                                where as
                                namedWindow( "Threshold", CV_WINDOW_AUTOSIZE );
                                There "Threshold" is managed by the compiler and wont run out.

                                To test this, please move
                                char* window_name = "Threshold Demo";

                                OUTSIDE the function so it last longer than function call.

                                1 Reply Last reply
                                0
                                • G gauravsharma0190

                                  @gauravsharma0190 said:

                                  void MainWindow::on_onTrackball_clicked()
                                  {
                                  int threshold_value = 0;
                                  int threshold_type = 3;
                                  int const max_value = 255;
                                  int const max_type = 4;
                                  // int const max_BINARY_value = 255;

                                  Mat src, src_gray, dst;
                                  

                                  // char* window_name = "Threshold Demo";

                                  //char* trackbar_type = "Type: \n 0: Binary \n 1: Binary Inverted \n 2: Truncate \n 3: To Zero \n 4: To Zero Inverted";
                                  //char* trackbar_value = "Value";
                                  
                                  
                                  
                                  
                                  /// Load image
                                  src = imread( "/home/pi/Desktop/b4.jpg");
                                  
                                  
                                    /// Convert the image to Gray
                                    cvtColor( src, src_gray, CV_BGR2GRAY );
                                  
                                    /// Create a window to display results
                                    namedWindow( "Threshold", CV_WINDOW_AUTOSIZE );
                                  
                                    /// Create Trackbar to choose type of Threshold
                                    createTrackbar( "Type: \n 0: Binary \n 1: Binary Inverted \n 2: Truncate \n 3: To Zero \n 4: To Zero Inverted","Threshold", &threshold_type, max_type, Threshold_Demo );
                                  
                                    createTrackbar( "value","Threshold", &threshold_value, max_value, Threshold_Demo );
                                  
                                    /// Call the function to initialize
                                  

                                  @@@ Threshold_Demo( 0, 0)

                                  }

                                  When I Comment the line Threshold _demo everything went OK!!!
                                  Results are coming but when i uncomment it everything crashes.

                                  jsulmJ Offline
                                  jsulmJ Offline
                                  jsulm
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #86

                                  @gauravsharma0190 Please take a closer look at this code:

                                  void MainWindow::on_onTrackball_clicked()
                                  {
                                  int threshold_value = 0;
                                  int threshold_type = 3;
                                  int const max_value = 255;
                                  int const max_type = 4;
                                  // int const max_BINARY_value = 255;
                                  // These variables are LOCAL!
                                  Mat src, src_gray, dst;
                                  

                                  You use local variables in void MainWindow::on_onTrackball_clicked(). All these variables exist only in that function: Mat src, src_gray, dst;
                                  In Threshold_Demo() these variable are not visible (I have no idea why your code compiles? You probably defined these variables somewhere else again). I already pointed out this issue in one of my previous posts.

                                  void Threshold_Demo( int, void* )
                                  {
                                    /* 0: Binary
                                       1: Binary Inverted
                                       2: Threshold Truncated
                                       3: Threshold to Zero
                                       4: Threshold to Zero Inverted
                                     */
                                  // src_gray, dst, threshold_value, max_BINARY_value,threshold_type are GLOBAL! Where are they defined?
                                  @@threshold( src_gray, dst, threshold_value, max_BINARY_value,threshold_type );
                                  

                                  Please make really sure src_gray, dst, threshold_value, max_BINARY_value,threshold_type have valid values when you call threshold( )! Use debugger for this.

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

                                  G 1 Reply Last reply
                                  1
                                  • jsulmJ jsulm

                                    @gauravsharma0190 Please take a closer look at this code:

                                    void MainWindow::on_onTrackball_clicked()
                                    {
                                    int threshold_value = 0;
                                    int threshold_type = 3;
                                    int const max_value = 255;
                                    int const max_type = 4;
                                    // int const max_BINARY_value = 255;
                                    // These variables are LOCAL!
                                    Mat src, src_gray, dst;
                                    

                                    You use local variables in void MainWindow::on_onTrackball_clicked(). All these variables exist only in that function: Mat src, src_gray, dst;
                                    In Threshold_Demo() these variable are not visible (I have no idea why your code compiles? You probably defined these variables somewhere else again). I already pointed out this issue in one of my previous posts.

                                    void Threshold_Demo( int, void* )
                                    {
                                      /* 0: Binary
                                         1: Binary Inverted
                                         2: Threshold Truncated
                                         3: Threshold to Zero
                                         4: Threshold to Zero Inverted
                                       */
                                    // src_gray, dst, threshold_value, max_BINARY_value,threshold_type are GLOBAL! Where are they defined?
                                    @@threshold( src_gray, dst, threshold_value, max_BINARY_value,threshold_type );
                                    

                                    Please make really sure src_gray, dst, threshold_value, max_BINARY_value,threshold_type have valid values when you call threshold( )! Use debugger for this.

                                    G Offline
                                    G Offline
                                    gauravsharma0190
                                    wrote on last edited by
                                    #87

                                    @jsulm
                                    Hey the ontrack.cpp file has these variable defined i havn't sent you full code
                                    here it is

                                    #include"onTrack.h"
                                    #include<imgproc.hpp>
                                     using namespace cv;
                                    using namespace std;
                                    int threshold_value=0;
                                    int threshold_type=3;
                                    int const max_BINARY_value=255;
                                    Mat src_gray,dst;
                                    
                                    void Threshold_Demo( int, void* )
                                    {
                                      /* 0: Binary
                                         1: Binary Inverted
                                         2: Threshold Truncated
                                         3: Threshold to Zero
                                         4: Threshold to Zero Inverted
                                       */
                                    
                                      threshold( src_gray, dst, threshold_value, max_BINARY_value,threshold_type );
                                    
                                      imshow( window_name, dst );
                                    }
                                    ......
                                    jsulmJ 1 Reply Last reply
                                    0
                                    • G gauravsharma0190

                                      @jsulm
                                      Hey the ontrack.cpp file has these variable defined i havn't sent you full code
                                      here it is

                                      #include"onTrack.h"
                                      #include<imgproc.hpp>
                                       using namespace cv;
                                      using namespace std;
                                      int threshold_value=0;
                                      int threshold_type=3;
                                      int const max_BINARY_value=255;
                                      Mat src_gray,dst;
                                      
                                      void Threshold_Demo( int, void* )
                                      {
                                        /* 0: Binary
                                           1: Binary Inverted
                                           2: Threshold Truncated
                                           3: Threshold to Zero
                                           4: Threshold to Zero Inverted
                                         */
                                      
                                        threshold( src_gray, dst, threshold_value, max_BINARY_value,threshold_type );
                                      
                                        imshow( window_name, dst );
                                      }
                                      ......
                                      jsulmJ Offline
                                      jsulmJ Offline
                                      jsulm
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #88

                                      @gauravsharma0190 That is the problem I'm talking all the time! You do not initialize src_gray,dst from ontrack.cpp, so you use not properly initialized variables in Threshold_Demo(). As I said in MainWindow::on_onTrackball_clicked() you use local variables rc_gray,dst, not the ones from ontrack.cpp!
                                      So, again where are these variables initialized?

                                      // Where are they initialized?
                                      Mat src_gray,dst;
                                      
                                      void Threshold_Demo( int, void* )
                                      {
                                        /* 0: Binary
                                           1: Binary Inverted
                                           2: Threshold Truncated
                                           3: Threshold to Zero
                                           4: Threshold to Zero Inverted
                                         */
                                      

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

                                      G 1 Reply Last reply
                                      0
                                      • jsulmJ jsulm

                                        @gauravsharma0190 That is the problem I'm talking all the time! You do not initialize src_gray,dst from ontrack.cpp, so you use not properly initialized variables in Threshold_Demo(). As I said in MainWindow::on_onTrackball_clicked() you use local variables rc_gray,dst, not the ones from ontrack.cpp!
                                        So, again where are these variables initialized?

                                        // Where are they initialized?
                                        Mat src_gray,dst;
                                        
                                        void Threshold_Demo( int, void* )
                                        {
                                          /* 0: Binary
                                             1: Binary Inverted
                                             2: Threshold Truncated
                                             3: Threshold to Zero
                                             4: Threshold to Zero Inverted
                                           */
                                        
                                        G Offline
                                        G Offline
                                        gauravsharma0190
                                        wrote on last edited by
                                        #89

                                        @jsulm said:

                                        That is the problem I'm talking all the time! You do not initialize src_gray,dst from ontrack.cpp, so you use not properly initialized variables in Threshold_Demo(). As I said in MainWindow::on_onTrackball_clicked() you use local variables rc_gray,dst, not the ones from ontrack.cpp!
                                        So, again where are these variables initialized?

                                        // Where are they initialized?
                                        Mat src_gray,dst;

                                        void Threshold_Demo( int, void* )
                                        {
                                        /* 0: Binary
                                        1: Binary Inverted
                                        2: Threshold Truncated
                                        3: Threshold to Zero
                                        4: Threshold to Zero Inverted
                                        */

                                        I initalized it in Mainwindow::onTrackBall_clicked().
                                        I am sending you.
                                        mainWindow.cpp*******

                                        #include "mainwindow.h"
                                        #include "ui_mainwindow.h"
                                        #include<opencv2/opencv.hpp>
                                        #include <opencv2/highgui/highgui.hpp>
                                        #include <opencv2/core/core.hpp>
                                        #include <opencv2/imgproc/imgproc.hpp>
                                        #include<QFileDialog>
                                        #include<QMessageBox>
                                        #include <iostream>
                                        #include<QProcess>
                                        #include "onTrackBall.h"
                                        #include<syscall.h>
                                        #include<signal.h>
                                        #include <string>
                                        #include<stdlib.h>
                                        #include<sys/ioctl.h>
                                        #include <fstream>
                                        #include<time.h>
                                        #include<QTimer>
                                        #include<QDateTime>
                                        //#include"onTrackBall.h"
                                        //#include"onTrackBall.c"
                                        using namespace cv;
                                        using namespace std;
                                        
                                        
                                        MainWindow::MainWindow(QWidget *parent) :
                                            QMainWindow(parent),
                                            ui(new Ui::MainWindow)
                                        {
                                            ui->setupUi(this);
                                            QTimer *timer=new QTimer(this);
                                            connect(timer,SIGNAL(timeout()),this,SLOT(showTime()));
                                                    timer->start();
                                                    QDateTime dateTime=QDateTime::currentDateTime();
                                                    QString datetimetext=dateTime.toString();
                                                    ui->DateTime->setText(datetimetext);
                                        
                                        }
                                        void MainWindow::on_onTrackball_clicked()
                                        {
                                            int threshold_value = 0;
                                            int threshold_type = 3;
                                            int const max_value = 255;
                                            int const max_type = 4;
                                           // int const max_BINARY_value = 255;
                                        
                                            Mat src, src_gray;
                                        
                                        
                                        
                                        
                                        
                                            /// Load image
                                            src = imread( "/home/pi/Desktop/b4.jpg");
                                        
                                        
                                              /// Convert the image to Gray
                                              cvtColor( src, src_gray, CV_BGR2GRAY );
                                        
                                              /// Create a window to display results
                                              namedWindow( "Threshold", CV_WINDOW_NORMAL );
                                        
                                              /// Create Trackbar to choose type of Threshold
                                              createTrackbar( "Type: \n 0: Binary \n 1: Binary Inverted \n 2: Truncate \n 3: To Zero \n 4: To Zero Inverted","Threshold", &threshold_type, max_type, Threshold_Demo );
                                        
                                              createTrackbar( "value","Threshold", &threshold_value, max_value, Threshold_Demo );
                                        
                                              /// Call the function to initialize
                                            Threshold_Demo( 0, 0 );
                                        
                                        
                                            /// Separate the image in 3 places ( B, G and R )
                                            vector<Mat> bgr_planes;
                                            split( src, bgr_planes );
                                        
                                            /// Establish the number of bins
                                            int histSize = 256;
                                        
                                            /// Set the ranges ( for B,G,R) )
                                            float range[] = { 0, 256 } ;
                                            const float* histRange = { range };
                                        
                                            bool uniform = true;
                                            bool accumulate = false;
                                        
                                            Mat b_hist, g_hist, r_hist;
                                        
                                            /// Compute the histograms:
                                            calcHist( &bgr_planes[0], 1, 0, Mat(), b_hist, 1, &histSize, &histRange, uniform, accumulate );
                                            calcHist( &bgr_planes[1], 1, 0, Mat(), g_hist, 1, &histSize, &histRange, uniform, accumulate );
                                            calcHist( &bgr_planes[2], 1, 0, Mat(), r_hist, 1, &histSize, &histRange, uniform, accumulate );
                                        
                                            // Draw the histograms for B, G and R
                                            int hist_w = 512; int hist_h = 400;
                                           int bin_w = cvRound( (double) hist_w/histSize );
                                        
                                            Mat histImage( hist_h, hist_w, CV_8UC3, Scalar( 0,0,0) );
                                        
                                            /// Normalize the result to [ 0, histImage.rows ]
                                            normalize(b_hist, b_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
                                            normalize(g_hist, g_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
                                            normalize(r_hist, r_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
                                        
                                            /// Draw for each channel
                                            for( int i = 1; i < histSize; i++ )
                                            {
                                                line( histImage, Point( bin_w*(i-1), hist_h - cvRound(b_hist.at<float>(i-1)) ) ,
                                                                 Point( bin_w*(i), hist_h - cvRound(b_hist.at<float>(i)) ),
                                                                 Scalar( 255, 0, 0), 2, 8, 0  );
                                                line( histImage, Point( bin_w*(i-1), hist_h - cvRound(g_hist.at<float>(i-1)) ) ,
                                                                 Point( bin_w*(i), hist_h - cvRound(g_hist.at<float>(i)) ),
                                                                 Scalar( 0, 255, 0), 2, 8, 0  );
                                                line( histImage, Point( bin_w*(i-1), hist_h - cvRound(r_hist.at<float>(i-1)) ) ,
                                                                 Point( bin_w*(i), hist_h - cvRound(r_hist.at<float>(i)) ),
                                                                 Scalar( 0, 0, 255), 2, 8, 0  );
                                            }
                                        
                                            /// Display
                                            namedWindow("calcHist Demo", CV_WINDOW_NORMAL );
                                            imshow("calcHist Demo", histImage );
                                          imwrite("calcHist Demo2.jpg", histImage);
                                        waitKey(-1);
                                        
                                        
                                          }
                                        ...
                                        jsulmJ 1 Reply Last reply
                                        0
                                        • G gauravsharma0190

                                          @jsulm said:

                                          That is the problem I'm talking all the time! You do not initialize src_gray,dst from ontrack.cpp, so you use not properly initialized variables in Threshold_Demo(). As I said in MainWindow::on_onTrackball_clicked() you use local variables rc_gray,dst, not the ones from ontrack.cpp!
                                          So, again where are these variables initialized?

                                          // Where are they initialized?
                                          Mat src_gray,dst;

                                          void Threshold_Demo( int, void* )
                                          {
                                          /* 0: Binary
                                          1: Binary Inverted
                                          2: Threshold Truncated
                                          3: Threshold to Zero
                                          4: Threshold to Zero Inverted
                                          */

                                          I initalized it in Mainwindow::onTrackBall_clicked().
                                          I am sending you.
                                          mainWindow.cpp*******

                                          #include "mainwindow.h"
                                          #include "ui_mainwindow.h"
                                          #include<opencv2/opencv.hpp>
                                          #include <opencv2/highgui/highgui.hpp>
                                          #include <opencv2/core/core.hpp>
                                          #include <opencv2/imgproc/imgproc.hpp>
                                          #include<QFileDialog>
                                          #include<QMessageBox>
                                          #include <iostream>
                                          #include<QProcess>
                                          #include "onTrackBall.h"
                                          #include<syscall.h>
                                          #include<signal.h>
                                          #include <string>
                                          #include<stdlib.h>
                                          #include<sys/ioctl.h>
                                          #include <fstream>
                                          #include<time.h>
                                          #include<QTimer>
                                          #include<QDateTime>
                                          //#include"onTrackBall.h"
                                          //#include"onTrackBall.c"
                                          using namespace cv;
                                          using namespace std;
                                          
                                          
                                          MainWindow::MainWindow(QWidget *parent) :
                                              QMainWindow(parent),
                                              ui(new Ui::MainWindow)
                                          {
                                              ui->setupUi(this);
                                              QTimer *timer=new QTimer(this);
                                              connect(timer,SIGNAL(timeout()),this,SLOT(showTime()));
                                                      timer->start();
                                                      QDateTime dateTime=QDateTime::currentDateTime();
                                                      QString datetimetext=dateTime.toString();
                                                      ui->DateTime->setText(datetimetext);
                                          
                                          }
                                          void MainWindow::on_onTrackball_clicked()
                                          {
                                              int threshold_value = 0;
                                              int threshold_type = 3;
                                              int const max_value = 255;
                                              int const max_type = 4;
                                             // int const max_BINARY_value = 255;
                                          
                                              Mat src, src_gray;
                                          
                                          
                                          
                                          
                                          
                                              /// Load image
                                              src = imread( "/home/pi/Desktop/b4.jpg");
                                          
                                          
                                                /// Convert the image to Gray
                                                cvtColor( src, src_gray, CV_BGR2GRAY );
                                          
                                                /// Create a window to display results
                                                namedWindow( "Threshold", CV_WINDOW_NORMAL );
                                          
                                                /// Create Trackbar to choose type of Threshold
                                                createTrackbar( "Type: \n 0: Binary \n 1: Binary Inverted \n 2: Truncate \n 3: To Zero \n 4: To Zero Inverted","Threshold", &threshold_type, max_type, Threshold_Demo );
                                          
                                                createTrackbar( "value","Threshold", &threshold_value, max_value, Threshold_Demo );
                                          
                                                /// Call the function to initialize
                                              Threshold_Demo( 0, 0 );
                                          
                                          
                                              /// Separate the image in 3 places ( B, G and R )
                                              vector<Mat> bgr_planes;
                                              split( src, bgr_planes );
                                          
                                              /// Establish the number of bins
                                              int histSize = 256;
                                          
                                              /// Set the ranges ( for B,G,R) )
                                              float range[] = { 0, 256 } ;
                                              const float* histRange = { range };
                                          
                                              bool uniform = true;
                                              bool accumulate = false;
                                          
                                              Mat b_hist, g_hist, r_hist;
                                          
                                              /// Compute the histograms:
                                              calcHist( &bgr_planes[0], 1, 0, Mat(), b_hist, 1, &histSize, &histRange, uniform, accumulate );
                                              calcHist( &bgr_planes[1], 1, 0, Mat(), g_hist, 1, &histSize, &histRange, uniform, accumulate );
                                              calcHist( &bgr_planes[2], 1, 0, Mat(), r_hist, 1, &histSize, &histRange, uniform, accumulate );
                                          
                                              // Draw the histograms for B, G and R
                                              int hist_w = 512; int hist_h = 400;
                                             int bin_w = cvRound( (double) hist_w/histSize );
                                          
                                              Mat histImage( hist_h, hist_w, CV_8UC3, Scalar( 0,0,0) );
                                          
                                              /// Normalize the result to [ 0, histImage.rows ]
                                              normalize(b_hist, b_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
                                              normalize(g_hist, g_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
                                              normalize(r_hist, r_hist, 0, histImage.rows, NORM_MINMAX, -1, Mat() );
                                          
                                              /// Draw for each channel
                                              for( int i = 1; i < histSize; i++ )
                                              {
                                                  line( histImage, Point( bin_w*(i-1), hist_h - cvRound(b_hist.at<float>(i-1)) ) ,
                                                                   Point( bin_w*(i), hist_h - cvRound(b_hist.at<float>(i)) ),
                                                                   Scalar( 255, 0, 0), 2, 8, 0  );
                                                  line( histImage, Point( bin_w*(i-1), hist_h - cvRound(g_hist.at<float>(i-1)) ) ,
                                                                   Point( bin_w*(i), hist_h - cvRound(g_hist.at<float>(i)) ),
                                                                   Scalar( 0, 255, 0), 2, 8, 0  );
                                                  line( histImage, Point( bin_w*(i-1), hist_h - cvRound(r_hist.at<float>(i-1)) ) ,
                                                                   Point( bin_w*(i), hist_h - cvRound(r_hist.at<float>(i)) ),
                                                                   Scalar( 0, 0, 255), 2, 8, 0  );
                                              }
                                          
                                              /// Display
                                              namedWindow("calcHist Demo", CV_WINDOW_NORMAL );
                                              imshow("calcHist Demo", histImage );
                                            imwrite("calcHist Demo2.jpg", histImage);
                                          waitKey(-1);
                                          
                                          
                                            }
                                          ...
                                          jsulmJ Offline
                                          jsulmJ Offline
                                          jsulm
                                          Lifetime Qt Champion
                                          wrote on last edited by
                                          #90

                                          @gauravsharma0190 Please read what I'm writing more carefully!
                                          In Mainwindow::onTrackBall_clicked() you don't initialize them! Because you use local variables there with same names:

                                          void MainWindow::on_onTrackball_clicked()
                                          {
                                               // Here src and src_gray are not the same as in ontrack.cpp!
                                               // Values you're assigning here to src and src_gray are only visible here but not in ontrack.cpp!
                                              Mat src, src_gray;
                                          

                                          I'm running out of ideas how to explain it. You should learn C++, especially the visibility and scope of variables.

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

                                          G 1 Reply Last reply
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