title: opencv 3 python feature detection error on function cv2.detectAndCompute and also on cv2.compute
body: <p>i use opencv 3.0.0 and python 2.7.5_x32</p>
  
  <p>This is my code (ORB_feature_detection):</p>
  
  <pre><code>import numpy as np
  import cv2
  from matplotlib import pyplot as plt
  
  img1 = cv2.imread('C:\\Python27\\madar1.jpg',0)          # queryImage
  img2 = cv2.imread('C:\\Python27\\madar2.jpg',0) # trainImage
  
  # Initiate SIFT detector
  orb = cv2.ORB_create()
  
  # line 12
  # find the keypoints and descriptors with SIFT
  kp1, des1 = orb.detectAndCompute(img1,None)
  kp2, des2 = orb.detectAndCompute(img2,None)
  
  # create BFMatcher object
  
  bf = cv2.BFMatcher(cv2.NORM_HAMMING, crossCheck=True)
  
  # Match descriptors.
  matches = bf.match(des1,des2)
  
  # Sort them in the order of their distance.
  matches = sorted(matches, key = lambda x:x.distance)
  
  # Draw first 10 matches.
  img3 = cv2.drawMatches(img1,kp1,img2,kp2,matches[:10], flags=2)
  
  plt.imshow(img3),plt.show()
  
  cv2.waitKey()
  cv2.destroyAllWindows()
  </code></pre>
  
  <p>and this is the error message, the error message is on the
  kp1, des1 = orb.detectAndCompute(img1,None) part,
  i did work on opencv 2.4.11 and it doesn't work on opencv 3.0.0 !</p>
  
  <pre><code>    Traceback (most recent call last):
    File "C:\Python27\orb_matcher.py", line 12, in &lt;module&gt;
     kp1, des1 = orb.detectAndCompute(img1,None)
  error: ..\..\..\modules\python\src2\cv2.cpp:163: error: (-215) The data should normally be NULL! in function NumpyAllocator::allocate
  </code></pre>
  
  <p>please help me, what should i do to make this work?</p>