Accessing camera modules from the OpenCV library

In the previous section, we used a still image as a source for the OpenCV library. We can use a camera as the source of a still image. A camera generates video data, which is a collection of still images. To access camera modules from the OpenCV library, follow these steps:

1. To access a camera from OpenCV, we can use the VideoCapture object. We call read() to read a frame, which is a still of a frame.

2. For a demo, we use the camera USB drive. Just connect this device to the Raspberry Pi board through the USB drive. Then, we write the following scripts with your text editor:

   import numpy as np
   import cv2
   
   
   cap = cv2.VideoCapture(0)
   while True:
       # Capture frame-by-frame
       ret, frame = cap.read()
   
       # Display the resulting frame
       cv2.imshow('video player', frame)
       if cv2.waitKey(1) & 0xFF == ord('q'):
           break
   
   
   cap.release()
   cv2.destroyAllWindows()

3. Save these scripts into a file, called ch03_camera_player.py.

4. To run this program...