title: OpenCV2.4.0 - facerec_demo runtime error
body: <p>I am new to OpenCV. I am specifically exploring Face recognition capabilities added in OpenCV2.4beta version. After compiling and executing <code>samples/cpp/facerec_demo.cpp</code>, I get following runtime error.</p>
  
  <pre><code>OpenCV Error: Assertion failed (depth == CV_8U || depth == CV_16U || depth == CV_32F) in cvtColor, file /home/truptivk/Desktop/Face Recognition /OpenCV-2.4.0-beta2/modules/imgproc/src/color.cpp, line 3143
  terminate called after throwing an instance of 'cv::Exception'
  what():  /home/truptivk/Desktop/Face Recognition /OpenCV-2.4.0-beta2/modules/imgproc/src/color.cpp:3143: error: (-215) depth == CV_8U || depth == CV_16U || depth == CV_32F in function cvtColor
  Aborted (core dumped)
  </code></pre>
  
  <p>After dumping the depth value it shows <code>CV_64F</code>.</p>
  
  <p>I have created csvfile.ext for AT&amp;T database. (Images have 8-bit grey levels.) and I am using Ubuntu 12.04 32 bit version. I am clueless from where its picking up <code>CV_64</code>F. </p>
  
  <p>Please help me to rectify this error. What needs to be one in order to avoid this?
  Thanks &amp; Regards</p>