title: Create blank image in OpenCV C++
body: <p>I'm trying to create a blank image (later to be filled) using OpenCV, but it has to be in the same size with the predefined image as a new image. I tried the following code:</p>
  
  <p>(image would be the picture of lena which is successfully displayed)</p>
  
  <pre><code>    Mat lena1(Size(image.cols,image.rows),CV_8UC1);
      namedWindow( "Display Image", CV_WINDOW_AUTOSIZE );
      //imshow( "Display Image", image );
      imshow("blank", lena1);
  </code></pre>
  
  <p>But for some reason, it still shows "image" and not lena1 (that would be the blank image with the same sizes of the predefined image).</p>
  
  <p>Thank you!</p>