Open CV无法从Raspberry Pi上的USB相机读取帧

Question

I have a Logitech c270 usb webcam connected to my Raspberry Pi 3, running on a Jessie image. I have tried to capture frames with this simple tutorial code on

http://www.pyimagesearch.com/2016/02/22/writing-to-video-with-opencv/

Whenever I try to read frames in the while loop, it gives out this error:

NoneType object has no attribute 'shape'

I have printed out the vs.read() function and it also returns None object.

What can I do to resolve this problem? NOTE: When I executed cmake to build the binaries for Open CV 3.1 on Raspberry Pi, I havent specified OpenCV to use V4L. Could this be a problem?

Thanks in advance.

Answer 1

It's Because your video stream object does not get attached with the camera. Hence no image is displayed. If you are using Pi Camera, then make sure to type --picamera 1 as an argument while running the script. else your camera is not connected to your Pi correctly.