title: Low FPS with Python, OpenCV on Raspberry Pi
body: <p>I'm trying to do some image processing on a Raspberry Pi with Python and OpenCV. It works well so far except a low FPS rate. Even without any image processing and just with the code below I get only 10 FPS with 640x480 resolution.
  Is there a faster way to capture the video stream? Do I something wrong here?</p>
  
  <pre><code>import numpy as np
  import cv2
  import time
  from picamera.array import PiRGBArray
  from picamera import PiCamera
  
  # initialize the camera and grab a reference to the raw camera capture
  camera = PiCamera()
  camera.resolution = (640, 480)
  camera.framerate = 32
  rawCapture = PiRGBArray(camera, size=(640, 480))
  # allow the camera to warmup
  time.sleep(0.1)
  start = time.time()
  
  for img in camera.capture_continuous(rawCapture, format="bgr", use_video_port=True):
  
      frame = img.array
      rawCapture.truncate(0)
      end = time.time()
      print 'fps:', int(round(1 / (end - start)))
      start = time.time()
  </code></pre>
  
  <p>Thank you so far.</p>
  
  <p>regards</p>