title: FindContours supports only CV_8UC1 images
body: <p>I've converted my image file to grayscale, then blurred it and used canny, the result is in uint8 but still I'm getting the error. Please help!</p>
  <pre><code>    shapes= cv2.imread('E:\Photos\shapes.jpg')
      shapes= cv2.resize(shapes, (640,360))
      shapes_gray= cv2.cvtColor(shapes, cv2.COLOR_BGR2GRAY)
      shapes_blur= cv2.GaussianBlur(shapes_gray, (5, 5), 1)
      shapes_edges= cv2.Canny(shapes_blur, 50, 50)
      blank= np.zeros_like(shapes)
      
      def getContours(img):
          contours, hierarchy= cv2.findContours(shapes, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
          for i in contours:
              area= cv2.contourArea(i)
              print(area)
  
      print(getContours(shapes_edges))
  </code></pre>