Access numpy array in openCV

Question

Using the documentation here here, the code

import time import picamera import picamera.array import cv2 with picamera.PiCamera() as camera: camera.start_preview() time.sleep(2) with picamera.array.PiRGBArray(camera) as stream: camera.capture(stream, format='bgr') # At this point the image is available as stream.array image = stream.array 

As i understand it, this returns a numpy array to be read in openCV correct? My question is, how do I then open/access it to perform image processing on it in openCV?

Answer 1

On the last line of that script, image is a numpy array with shape (rows, cols, color-plane) with the color planes in BGR order - which is precisely how OpenCV represents image data. In other words, you can just pass that array straight to OpenCV functions:

import time import picamera import picamera.array import cv2 with picamera.PiCamera() as camera: time.sleep(2) with picamera.array.PiRGBArray(camera) as stream: camera.capture(stream, format='bgr') # At this point the image is available as stream.array image = stream.array image = cv2.dilate(image, None) image = cv2.erode(image, None) image = cv2.cvtColor(image, cv2.cv.CV_BGR2GRAY) r, image = cv2.threshold(image, 127, 255, 1) cv2.namedWindow('win') cv2.imshow('win', image) cv2.waitKey(0)