title: CascadeClassifier in OpenCV generates error
body: <p>I am trying to develop a simple application to detect faces as well as eyes in a given image:</p>
  
  <pre><code>from cv2 import *
  face_cascade = CascadeClassifier('haarcascade_frontalface_default.xml')
  eye_cascade = CascadeClassifier('haarcascade_eye.xml')
  
  img = imread("123.jpg")
  gray = cvtColor(img, COLOR_BGR2GRAY)
  rows,cols = gray.shape
  gray = getRotationMatrix2D((cols/2,rows/2),-90,1)
  
  faces = face_cascade.detectMultiScale(gray, 1.3, 5, 0)
  print faces
  
  for (x,y,w,h) in faces:
      img = rectangle(img, (x,y), ((x+w),(x+h)), (255,0,0), 2)
      #gray = rectangle(gray, (x,y), ((x+w), (x+y)), (0, 255, 0), 4)
      roi_gray = gray[y:y+h, x:x+w]
      roi_color = img[y:y+h, x:x+w]
      eyes = eye_cascade.detectMultiScale(roi_grey)
      for (ex,ey, ew, eh) in eyes:
          roi_color = rectangle(roi_color, (x,y), ((x+w), (y+h)), (50, 50, 50), 3)
  
  imshow("img", img)
  waitKey(9)
  destroyAllWindows()
  </code></pre>
  
  <p>(Note: The rotation is necessary, as after using the <code>cvtColor</code> function, the output image is generated with a rotation of 90 degrees counter clockwise.)</p>
  
  <p>I am getting the following error:</p>
  
  <blockquote>
    <p>Traceback (most recent call last): File "/home/namit/Codes/wow.py",
    line 10, in  faces = face_cascade.detectMultiScale(gray, 1.3,
    5, 0) error:
    /home/namit/OpenCV/opencv-2.4.9/modules/objdetect/src/cascadedetect.cpp:1081:
    error: (-215) scaleFactor > 1 &amp;&amp; image.depth() == CV_8U in function
    detectMultiScale</p>
  </blockquote>