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How do I set exposure time of Logitech C922 webcam on OpenCV?

asked 2017-08-13 09:33:11 -0500

Hello

I am writing a code for a project, and it requires some color segmentation which seems to be quite sensitive to the camera settings. I can get the frame size, brightness, autofocus, contrast and etc to set to a certain value, but I can't seem to set the exposure. My webcam always changes to auto exposure, and I prefer to have a set manual exposure. I tried the code below:

import cv2 import numpy as np cap = cv2.VideoCapture(1) cap.set(cv2.CAP_PROP_FRAME_WIDTH, 864) cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 480) cap.set(cv2.CAP_PROP_BRIGHTNESS, 0.7) cap.set(cv2.CAP_PROP_AUTOFOCUS,0) cap.set(cv2.CAP_PROP_EXPOSURE,0.5)

but as I stated before, it will not change the exposure. Does anyone have any experience with c922 webcams, or have any suggestions?

Thanks

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Try using webcam driver if it works in C++, import your function to python.

Ziri gravatar imageZiri ( 2017-08-14 00:01:34 -0500 )edit

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answered 2019-01-04 01:55:19 -0500

pjoe gravatar image

I can set manual exposure like this (on windows):

cap.set(cv2.CAP_PROP_AUTO_EXPOSURE, 0)
cap.set(cv2.CAP_PROP_EXPOSURE, -6)

I believe the values are negative power of 2, e.g. -4 would be 1/16

I do however have issues turning on auto exposure. When getting the property value it always return -1

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answered 2017-08-15 03:40:02 -0500

supra56 gravatar image
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please do not post link-only answers

(this also does not answer the question)

berak gravatar imageberak ( 2017-08-19 00:54:41 -0500 )edit
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Asked: 2017-08-13 09:33:11 -0500

Seen: 2,442 times

Last updated: Aug 15 '17