在opencv (QT)运行时空指针

Question

你好，我有一台osx 10.7的Macbook pro。我刚刚安装了Qt(诺基亚)，opencv, cmake。我从来没有和他们一起工作过。所以我开始了我的第一个教程。我创建了一个新的QT Gui应用程序。我把main.cpp改成:

#include <QtGui/QApplication>
#include <opencv/cv.h>
#include <opencv/highgui.h> 
#include "mainwindow.h"
int main(int argc, char *argv[])
{
   QApplication a(argc, argv);
   MainWindow w;
   w.show();
   IplImage* img = 0;
   img = cvLoadImage("cat.jpg");
   cvNamedWindow("Example1", CV_WINDOW_AUTOSIZE);
   cvShowImage("Example1", img);
   cvWaitKey(0);
   cvReleaseImage(&img);
   cvDestroyWindow("Example1");
   return a.exec();

}

我也改变了我的。pro文件:

QT       += core gui
TARGET = untitled1
TEMPLATE = app

INCLUDEPATH = /usr/local/include
SOURCES += main.cpp
        mainwindow.cpp
HEADERS  += mainwindow.h
LIBS += -lm -lopencv_core -lopencv_highgui -lopencv_video -lopencv_imgproc
FORMS    += mainwindow.ui

:

cat.jpg在qt项目文件夹中(在main.cpp旁边)

现在，当我构建这个并运行它。我得到这个错误:

Starting /Users/olivierjanssens/untitled1-build-desktop-Desktop_Qt_4_7_4_for_GCC__Qt_SDK__Debug/untitled1.app/Contents/MacOS/untitled1...
OpenCV Error: Null pointer (NULL array pointer is passed) in cvGetMat, file /Users/olivierjanssens/source/OpenCV-2.3.1/modules/core/src/array.cpp, line 2382
terminate called throwing an exceptionThe program has unexpectedly finished.
/Users/olivierjanssens/untitled1-build-desktop-Desktop_Qt_4_7_4_for_GCC__Qt_SDK__Debug/untitled1.app/Contents/MacOS/untitled1 exited with code 0

窗口打开，但随后崩溃，没有图像显示。

我做错了什么?

Answer 1

cat.jpg可能不在正确的目录中。

如果不提供路径，则搜索当前目录，可能是/Users/olivierjanssens/untitled1-build-desktop-Desktop_Qt_4_7_4_for_GCC__Qt_SDK__Debug或/Users/olivierjanssens/untitled1-build-desktop-Desktop_Qt_4_7_4_for_GCC__Qt_SDK__Debug/untitled1.app/Contents/MacOS。没有搜索包含main.cpp的目录。

尝试提供cvLoadImage()的完整路径(例如"/Users/olivierjanssens/untitled1/cat.jpg")