Using OpenCV on Linux, if you have a video device that interfaces a V4L2 device such as a USB webcam:
camera = cv2.VideoCapture(0)
in order to set the manual white balance temperature, you first need to disable automatic white balancing using CAP_PROP_AUTO_WB. See our previous post How to enable/disable manual white balance in OpenCV (Python) for more details on how you can do this, here’s only the short version that works with most cameras.
After that, you can set the white balance temperature using CAP_PROP_WB_TEMPERATURE:
camera.set(cv2.CAP_PROP_AUTO_WB, 0.0) # Disable automatic white balance camera.set(cv2.CAP_PROP_WB_TEMPERATURE, 4200) # Set manual white balance temperature to 4200K
For V4L2 cameras, as you can see in our previous post on mapping of OpenCV parameters to V4L2 parameters, CAP_PROP_WB_TEMPERATURE is mapped to V4L2_CID_WHITE_BALANCE_TEMPERATURE which is shown in v4l2-ctl -d /dev/video0 --all as white_balance_temperature
. Therefore, you can easily verify if, for example, disabling the auto white balance worked for your V4L2 camera such as any USB camera by looking at the white_balance_temperature section of v4l2-ctl -d /dev/video0 --all:
white_balance_temperature 0x0098091a (int) : min=2800 max=6500 step=1 default=4600 value=4200