OpenCV不会加载图片

Question

So I linked all the libraries for OpenCV, I've added all the .lib's and .dll's needed for it to work but when i go to try and get a picture to show it says that the picture is not there. All the paths are correct and the image is in the main directory of the solution here's the code.

Mat color = imread("wall.jpg");

also tried:

• D:\\\\wall.jpg and D:\\wall.jpg

• D:/wall.jpg and D://wall.jpg

     #include<opencv2/opencv.hpp>
     #include<opencv2/imgcodecs.hpp>

      using namespace std;

      using namespace cv;
      int main()
      {

    Mat color = imread("wall.jpg");
    if (color.empty())
    {
        cout << "image is empty" << endl;
        system("pause");
        exit(-1);
    }
    else
    {
        cout << "image is displayed" << endl;
        imshow("window", color);
    }



    waitKey();

    }

Output of the code

image is empty Press any key to continue . . .

its suppose to say

image displayed

Answer 1

My answer assumes you are using Windows since you used the word solution in your description.

At least one of the following is true:

• Your paths are incorrect. If you are running your code from visual studio, using a relative path like "wall.jpg" uses the working directory, which is not necessarily the solution directory.
  • Use another mechanicm to verify your path is correct, like running the following from the command line on Windows: start D:\\wall.jpg . If that command returns a file not found error, your path is wrong.
• You are be using an unsupported file format.
  • Make sure you can open the file and view it.
  • Make sure it is a JPEG, TIFF, or PNG. The extension may be incorrect. Try with a file you know is one of these types if you aren't certain.
• You don't have permission to read the file.
  • Open the file and verify you can view it. If you can, and your opencv process is running as the same user, you should be okay.

From the imread docs :

Loads an image from a file.

The function imread loads an image from the specified file and returns it. If the image cannot be read (because of missing file, improper permissions, unsupported or invalid format), the function returns an empty matrix ( Mat::data==NULL ).

...

On Microsoft Windows* OS and MacOSX*, the codecs shipped with an OpenCV image (libjpeg, libpng, libtiff, and libjasper) are used by default. So, OpenCV can always read JPEGs, PNGs, and TIFFs.

...

Note

• The function determines the type of an image by the content, not by the file extension.

Command Line Working Directory

If running from the command line, the working directory is the directory you are in. If you run the file listing command on your OS and can see your "wall.jpg" image, then you are in the correct place. Run your OpenCV executable from here with a relative path like .\\path\\to\\my\\opencv-program.exe .

Visual Studio Debug Working Directory