title: convert vector to mat in OpenCV
body: <p>I am using opencv 2.4.3 to perform vector to matrix conversion using the following code: </p>
  
  <pre><code>struct Component
  {
      cv::Rect box;
      double area;
      double circularity; 
  }
  
  int main ( ... )
  {
       cv::vector &lt; Component &gt; components;         
       cv::Mat componentMat ( components, true );
       std::cout &lt;&lt; componentMat;
       return 0; 
  }
  </code></pre>
  
  <p>But it gives out an error, saying:</p>
  
  <pre><code>OpenCV Error: Unsupported format or combination of formats() in unknown function, file ...\opencv\modules\core\src\out.cpp, line 111
  </code></pre>
  
  <p>What am I doing wrong here? Is there any other method to convert this vector into matrix form? Thank you. </p>