Hello colleagues,
The image from my USB camera (fswebcam) is so overexposed that you can hardly see anything. The Brightness slider is set to the value 20. But even at 1, the image is completely overexposed.
Any ideas?
There are thousands of different USB cameras with varying software support. Have you run “fswebcam --list-controls” to see what controls are supported by your camera?
I get the following information
Trying source module v4l2...
/dev/video0 opened.
No input was specified, using the first.
Available Controls Current Value Range
------------------ ------------- -----
Error reading value of control 'User Controls'.
VIDIOC_G_CTRL: Permission denied
User Controls N/A [Unknown Control Type]
Brightness -39 (19%) -64 - 64
Contrast 0 (0%) 0 - 95
Saturation 40 (40%) 0 - 100
Hue 0 (50%) -2000 - 2000
White Balance, Automatic True True | False
Gamma 100 (15%) 64 - 300
Gain 1 1 - 8
Power Line Frequency 50 Hz Disabled | 50 Hz | 60 Hz
White Balance Temperature 4600 (48%) 2800 - 6500
Sharpness 2 1 - 7
Backlight Compensation 0 (0%) 0 - 128
Error reading value of control 'Camera Controls'.
VIDIOC_G_CTRL: Permission denied
Camera Controls N/A [Unknown Control Type]
Auto Exposure Aperture Priority Mode Manual Mode | Aperture Priority Mode
Exposure Time, Absolute 156 (23%) 10 - 626
Adjusting resolution from 384x288 to 320x240.
--- Capturing frame...
Captured frame in 0.00 seconds.
--- Processing captured image...
There are unsaved changes to the image.
Most webcams are designed to work with “normal” light levels that you would find indoors.
So assuming that you are trying to use them under super intense grow lights, it might be to much for some webcams to handle… they may not be able to automatically compensate for that much light.
If reducing the gain and brightness settings haven’t worked, then the image is overexposed and you need to reduce the exposure time by increasing the shutter speed.
If the Auto Exposure is turned on, try turning it off and manually lowering the exposure compensation or increasing the shutter speed or both.
Other than that, you may need to try a different camera or try to place a neutral-density filter over the lens to reduce the amount of light coming into the aperture.