How to make USB camera work with OpenCV?

问题

I copied code from https://stackoverflow.com/a/34588758/210342 and used with default (built-in) camera, it worked. Then I attached USB camera, tested it with VLC and changed the code to open camera 1:

cam = cv2.VideoCapture(1)

I check whether the camera is open cam.isOpened() -- it is -- but the camera is not enabled (its hardware indicator, LED, is off) and indeed all I see on the screen is black frame.

Is there some extra special code to add in order to enable USB camera?

回答1:

Are you sure the usb camera is camera 1, i've done this before and had to use cv2.VideoCapture(0)

回答2:

You can also refer this link here

https://devtalk.nvidia.com/default/topic/1027250/how-to-use-usb-webcam-in-jetson-tx2-with-python-and-opencv-/

Here he changes the line below to

cap = cv2.VideoCapture("/dev/video1") # check this

Before plugging in the camera, go to your terminal home

1. Type cd /dev
2. Type ls video and then press tab, if you find only result as video0, that means only webcam is present.
3. Now repeat 1 to 2 with USB webcam plugged in. You should find video1 or video2 when you repeat the steps.

来源：https://stackoverflow.com/questions/52029233/how-to-make-usb-camera-work-with-opencv