Why is imread() always returning null data?

Question

Here is my code:

    #include<opencv\cv.h>
    #include<opencv\highgui.h>
    using namespace cv;
    using namespace std;

    int main()
         {
          Mat src;
          //src.create(200,500,CV_8UC3);
          src = imread( "a.bmp", 1 );
          namedWindow( "Display window", WINDOW_AUTOSIZE );
          if(!src.data)                              
                 cout<<"Could not open or find the image" << std::endl ;
          else
                imshow( "Display window", src);
          waitKey(0);
          return 0;
         }

It is always executing the if part
when I am using src.create instead of imread() it shows an empty image.

Answer 1

To debug your issue you should try to confirm that the image path is correct.

As suggested in the comments, try specifying the full absolute path of the file. Remember to to use escape slashes if you are on windows (e.g. c:\a.bmp will need to be "c:\a.bmp")

OR

If you are executing your application from Visual Studio then you can configure the working directory to be that of the bitmap too! (OpenCV cvLoadImage() does not load images in visual studio debugger?)

You can also try using cvLoadImage instead of imread. If cvLoadImage can open the file then it is possible that you have a mix of release and debug libraries causing you an issue as per:

• OpenCV imread(filename) fails in debug mode when using release libraries