Declaration of function and use it

jsulm

@gauravsharma0190 What is Mat and where is it declared?

jsulm

using namespace cv;

in the cpp file?

gauravsharma0190

@jsulm
Mat is basically a class with two data parts: the matrix header (containing information such as the size of the matrix, the method used for storing, at which address is the matrix stored, and so on) and a pointer to the matrix containing the pixel values (taking any dimensionality depending on the method chosen for storing) . The matrix header size is constant, however the size of the matrix itself may vary from image to image and usually is larger by orders of magnitude

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.

jsulm

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

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

jsulm

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

gauravsharma0190

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

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.

jsulm

@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.

jsulm

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

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

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 );

gauravsharma0190

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

jsulm

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

gauravsharma0190

@jsulm
Yes i initialize these with correct values.

jsulm

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

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.

mrjj

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.

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.