用于查找轮廓的OpenCV示例代码:向量释放问题

Question

我正在尝试在OpenCV 2.4.2中开始使用轮廓检测​​.为此,我为OpenCV设置了一个项目,并复制了文档中的完整示例代码.供将来参考,以下是代码:

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
#include <stdio.h>
#include <stdlib.h>

using namespace cv;
using namespace std;

Mat src; Mat src_gray;
int thresh = 100;
int max_thresh = 255;
RNG rng(12345);

/// Function header
void thresh_callback(int, void* );

/** @function main */
int main( int argc, char** argv )
{
  /// Load source image and convert it to gray
  src = imread( argv[1], 1 );

  /// Convert image to gray and blur it
  cvtColor( src, src_gray, CV_BGR2GRAY );
  blur( src_gray, src_gray, Size(3,3) );

  /// Create Window
  char* source_window = "Source";
  namedWindow( source_window, CV_WINDOW_AUTOSIZE );
  imshow( source_window, src );

  createTrackbar( " Canny thresh:", "Source", &thresh, max_thresh, thresh_callback );
  thresh_callback( 0, 0 );

  waitKey(0);
  return(0);
}

/** @function thresh_callback */
void thresh_callback(int, void* )
{
  Mat canny_output;
  vector<vector<Point> > contours;
  vector<Vec4i> hierarchy;

  /// Detect edges using canny
  Canny( src_gray, canny_output, thresh, thresh*2, 3 );
  /// Find contours
  findContours( canny_output, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) );

  /// Draw contours
  Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 );
  for( int i = 0; i< contours.size(); i++ )
     {
       Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );
       drawContours( drawing, contours, i, color, 2, 8, hierarchy, 0, Point() );
     }

  /// Show in a window
  namedWindow( "Contours", CV_WINDOW_AUTOSIZE );
  imshow( "Contours", drawing );

  contours.clear(); // Error!!
}

它在Visual Studio 11 RC(Windows 7 SP1)中编译良好,但在thresh_callback函数结束时出现错误.这是堆栈跟踪:

msvcr110d.dll!_CrtIsValidHeapPointer(const void * pUserData) Line 2036
msvcr110d.dll!_free_dbg_nolock(void * pUserData, int nBlockUse) Line 1322
msvcr110d.dll!_free_dbg(void * pUserData, int nBlockUse) Line 1265
msvcr110d.dll!operator delete(void * pUserData) Line 54
std::allocator<cv::Point_<int> >::deallocate(cv::Point_<int> * _Ptr, unsigned int __formal) Line 586
std::_Wrap_alloc<std::allocator<cv::Point_<int> > >::deallocate(cv::Point_<int> * _Ptr, unsigned int _Count) Line 888
std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > >::_Tidy() Line 1542
std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > >::~vector<cv::Point_<int>,std::allocator<cv::Point_<int> > >() Line 901
std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > >::`scalar deleting destructor'(unsigned int)
std::allocator<std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > >::destroy<std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > >(std::<cv::Point_<int>,std::allocator<cv::Point_<int> > > * _Ptr) Line 624
std::allocator_traits<std::allocator<std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > > >::destroy<std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > >(std::allocator<std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > > & _Al, std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > * _Ptr)758
std::_Wrap_alloc<std::allocator<std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > > >::destroy<std::vector<cv::Point_<int>,std::allocator<cv::Poin> > > >(std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > * _Ptr) Line 909
std::_Destroy_range<std::_Wrap_alloc<std::allocator<std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > > > >(std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > * _First, std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > * _Last, std::_Wrap_alloc<std::allocator<std::vector<cv::Point_<int>,std::allocator<cv::<int> > > > > & _Al, std::_Nonscalar_ptr_iterator_tag __formal) Line 89
std::_Destroy_range<std::_Wrap_alloc<std::allocator<std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > > > >(std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > * _First, std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > * _Last, std::_Wrap_alloc<std::allocator<std::vector<cv::Point_<int>,std::allocator<cv::<int> > > > > & _Al) Line 80
std::vector<std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > >,std::allocator<std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> >::_Destroy(std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > * _First, std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > * _Last) Line 1480
std::vector<std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > >,std::allocator<std::vector<cv::Point_<int>,std::allocator<cv::Point_<int> > > > >::c Line 1416
thresh_callback(int __formal, void * __formal) Line 143
opencv_highgui242d.dll!icvUpdateTrackbar(CvTrackbar * trackbar, int pos) Line 1938
opencv_highgui242d.dll!HGToolbarProc(HWND__ * hwnd, unsigned int uMsg, unsigned int wParam, long lParam) Line 1982

(注意,实际上我有一个稍微修改过的示例代码版本,添加了一些printf-s和一个contours.clear()调用,它位于第143行,并触发了向量释放[会在函数末尾自动发生]这似乎是问题的根源.同样的问题也出现在确切的示例代码中.)

问题似乎在于contours矢量的重新分配.如果我试着打电话也会发生同样的情况contours.clear().我已经在VS调试器中检查了变量的内容,但据我所知,没有什么不寻常的.

我试图在不再需要时(在for循环之后)清除矢量,但它没有帮助.我还试图将Platform Toolset切换到Visual Studio 10,而Visual Studio 10甚至不会使用超出我的错误消息进行编译:

error C1083: Cannot open include file: 'SDKDDKVer.h': No such file or directory (C:\<project path>\targetver.h) (Line 8, Column 1)
IntelliSense: cannot open source file "SDKDDKVer.h" (C:\<project path>\targetver.h) (Line 8, Column 1)
IntelliSense: cannot open source file "windows.h" (C:\<opencv path>\build\include\opencv2\core\operations.hpp (Line 83, Column 3)

任何帮助将不胜感激.请注意,我不是C++程序员:我的知识很少,对C++编程和本机编程的总体经验也很少.

编辑:事实证明调试器显示错误的行作为错误源.我应该在调用堆栈中看到问题出在vector>.所以有问题的载体contours不是hierarchy!

编辑#2:我还尝试用最小代码重现问题,创建一个vector<vector<cv::Point> >,放入一些项目,然后清除它,但我无法重现问题.

Answer 1

您正在以调试模式构建应用程序并链接到多线程调试DLL CRT.你知道OpenCV DLL链接到哪个CRT吗？如果它与静态CRT链接,它将使用从单独的堆分配的数据填充向量,这会导致您正在使用的Debug CRT中的断言.

如果在Release模式下构建应用程序,则不应再看到断言,但最终可能会泄漏内存.最好的办法是确保您的应用程序和OpenCV DLL都链接到同一个多线程DLL CRT.

编辑:如果您无法重建OpenCV以使用与您的应用程序相同的CRT,您可以尝试通过修改应用程序清单告诉链接器为您的应用程序使用与OpenCV相同的CRT版本.请参阅如何强制使用C++编译器以使用特定的CRT版本？有关如何执行此操作的详细信息.