title: How to determine if a cv::Mat is a zero matrix?
body: <p>I have a matrix that is dynamically being changed according to the following code;</p>
  
  <pre><code> for( It=all_frames.begin(); It != all_frames.end(); ++It)
  {
      ItTemp = *It;
  
      subtract(ItTemp, Base, NewData);
  
      cout &lt;&lt; "The size of the new data for ";
      cout &lt;&lt; " is \n" &lt;&lt; NewData.rows &lt;&lt; "x" &lt;&lt; NewData.cols &lt;&lt; endl;
      cout &lt;&lt; "The New Data is: \n" &lt;&lt; NewData &lt;&lt; endl &lt;&lt; endl;
  
      NewData_Vector.push_back(NewData.clone());
  
  }
  </code></pre>
  
  <p>What I want to do is determine the frames at which the cv::Mat NewData is a zero matrix.
  I've tried comparing it to a zero matrix that is of the same size, using both the cv::compare() function and simple operators (i.e NewData == NoData), but I can't even compile the program. </p>
  
  <p>Is there a simple way of determining when a cv::Mat is populated by zeroes?</p>