title: OpenCV 3.0 Beta - Python - Face Detection via Webcam - code gives me error
body: <p>I wrote and looked over this code multiple times and it seems right to me especially that it's very simple and straight forward (Took snippet out of opencv tutorial), however it is still giving me an error. I've checked the error and I understand that it's missing channels, however, I don't know how to fix it. Any help would be appreciated. I'm using Windows x64 and Spyder (from Anaconda distribution) as my IDE. Could it be hardware issue? (webcam)</p>
  
  <pre><code>    #####################################################
      #               Face Detection (Video)              # 
      #####################################################
  
      import numpy as np
      import cv2
  
      face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
      eye_cascade = cv2.CascadeClassifier('haarcascade_eye.xml')
  
      video = cv2.VideoCapture(0)
      ret, frame = video.read()
      gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
  
  
      faces = face_cascade.detectMultiScale(gray, 1.3, 5)
  
      for (x,y,w,h) in faces:
          cv2.rectangle(frame,(x,y),(x+w,y+h),(255,0,0),2)
          roi_gray = gray[y:y+h, x:x+w]
          roi_color = frame[y:y+h, x:x+w]
          eyes = eye_cascade.detectMultiScale(roi_gray)
          for (ex,ey,ew,eh) in eyes:
              cv2.rectangle(roi_color,(ex,ey),(ex+ew,ey+eh),(0,255,0),2)
  
  
          cv2.imshow('Video', frame)
          if cv2.waitKey(1) &amp; 0xFF == ord('q'):
              break
  
      video.release()
      cv2.destroyAllWindows()
  </code></pre>
  
  <p>Here's the error I get:</p>
  
  <pre><code>error: ..\..\..\..\opencv\modules\imgproc\src\color.cpp:5731:
  error: (-215)    scn == 3 || scn == 4 in function cv::cvtColor
  </code></pre>