title: Opencv TypeError: points is not a numpy array, neither a scalar
body: <p>Basically, I have this code that detects changes in background and boxed them. When I run the code, I get this error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "cam2.py", line 28, in &lt;module&gt;
      vertices = cv2.boundingRect(list(contours))
  TypeError: points is not a numpy array, neither a scalar
  </code></pre>
  
  <p>Code:</p>
  
  <pre><code>import cv2
  import numpy as np
  
  c = cv2.VideoCapture(0)
  _,f = c.read()
  
  avg1 = np.float32(f)
  
  while(1):
      _,f = c.read()
  
      cv2.accumulateWeighted(f,avg1,0.1)
  
      res1 = cv2.convertScaleAbs(avg1)
  
      absdiff = cv2.absdiff(f,res1)
  
      graydiff = cv2.cvtColor(absdiff, cv2.COLOR_BGR2GRAY)
  
      retval, mask = cv2.threshold(graydiff, 50,255,cv2.THRESH_BINARY) 
  
      mask = cv2.dilate(mask, None, 18)
      mask = cv2.erode(mask, None, 10) 
  
      contours = cv2.findContours(mask, cv2.RETR_LIST, cv2.CHAIN_APPROX_NONE) #not right
  
      while contours:
          vertices = cv2.boundingRect(list(contours))
          interest = vertices
  
          point1 = (interest[0], interest[1])
  
          point2 = (interest[0] + interest[2], interest[1] + interest[3])
          cv2.rectangle(f, point1, point2, cv2.RGB(255,0,0), 1)
          cv2.rectangle(mask, point1, point2, cv2.RGB(255,255,255), 1)
  
          contours = contours.h_next()
  
      cv2.imshow('mask',mask)
  
      cv2.imshow('img',f)
      cv2.imshow('avg1',res1)
  
      k = cv2.waitKey(20)
  
      if k == 27:
          break
  
  cv2.destroyAllWindows()
  c.release()
  </code></pre>
  
  <p>How do i solve this? Thanks.</p>