The exposure control methods of the USB camera module mainly include manual setting and automatic adjustment. The following is a detailed introduction:
Set the exposure parameters manually
Control via Python and the OpenCV library: Connect the USB camera using the cv2.VideoCapture object in the OpenCV library and set the exposure parameters through the Set method. For example, cap.set(cv2.CAP_PROP_EXPOSURE, -4) can set the exposure value (the specific value needs to be adjusted according to the camera model).
Controlled by the v4l2-ctl tool: In the Linux system, the exposure parameters can be directly set using the command-line tool v4l2-ctl, such as v4l2-ctl –set-ctrl=exposure_absolute=200.
Control via the camera app: On Android devices, find “Exposure Time” or a similar option through the Settings options of the camera app, and adjust the exposure time by dragging the slider or entering a specific value.
Automatically adjust the exposure parameters
Auto Exposure Control (AEC) : Most USB cameras support the auto exposure function, which can automatically adjust the exposure time according to the ambient light without the need for manual Settings. For example, by setting the exposure_auto parameter to the automatic mode (such as cap.set(cv2.CAP_PROP_AUTO_EXPOSURE, 0.25), where 0.25 is the identification value for the automatic mode in some drivers).
Automatic exposure reference value setting: In the automatic exposure mode, users can adjust the reference value of the automatic brightness by setting parameters such as backlight contrast, enabling the camera to automatically maintain the brightness set by the user.