Image flickering when WDR is turned on

XuWHuK

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When turned on in the WDR settings and subsequently under certain lighting conditions, a flicker appears on the camera image, as in the attached video. Tell me the camera settings to remove this problem.

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XuWHuK

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I tried decreasing it, but values less than 45 just turns off the WDR
 

bigredfish

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I wonder if that’s DWDR like on some low end budget models? That never has worked well.

Do you have an SSA backlight setting?
 
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bigredfish

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Hmmm.. what is your exposure and Gain settings? Can you try a manual range setting of like 2-3 and limit the range it can use?
 

bigredfish

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Yes that's what i was referring to, a Manual shutter range. In theory it should limit what WDR can do with the exposure

Still thats very high on the max end. Try 0 - 8.33
 

wittaj

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Remember that we are not going for a photography ribbon at the County Fair and a nice bright static image means nothing.

A 20ms shutter will result in motion blur.

In terms of getting the most out of the camera, here is my "standard" post that many use as a start for dialing in day and night that helps get the clean captures and help the camera recognize people and cars.

Start with:

H264
8192 bitrate
CBR
15FPS
15 iframes

Every field of view is different, but I have found you need contrast to usually be 6-8 higher than the brightness number at night.

We want the ability to freeze frame capture a clean image from the video at night, and that is only done with a shutter of 1/60 or faster. At night, default/auto may be on 1/12s shutter or worse to make the image bright.

In my opinion, shutter (exposure) and gain are the two most important parameters and then base the others off of it. Shutter is more important than FPS. It is the shutter speed that prevents motion blur, not FPS. 15 FPS is more than enough for surveillance cameras as we are not producing Hollywood movies. Match iframes to FPS. 15FPS is all that is usually needed.

Many people do not realize there is manual shutter that lets you adjust shutter and gain and a shutter priority that only lets you adjust shutter speed but not gain. The higher the gain, the bigger the noise and see-through ghosting start to appear because the noise is amplified. Most people select shutter priority and run a faster shutter than they should because it is likely being done at 100 gain, so it is actually defeating their purpose of a faster shutter.

Go into shutter settings and change to manual shutter and start with custom shutter as ms and change to 0-8.3ms and gain 0-50 (night) and 0-4ms exposure and 0-30 gain (day)for starters. Auto could have a shutter speed of 100ms or more with a gain at 100 and shutter priority could result in gain up at 100 which will contribute to significant ghosting and that blinding white you will get from the infrared or white light.

Now what you will notice immediately at night is that your image gets A LOT darker. That faster the shutter, the more light that is needed. But it is a balance. The nice bright night static image results in Casper blur and ghost during motion LOL. What do we want, a nice static image or a clean image when there is motion introduced to the scene?

In the daytime, if it is still too bright, then drop the 4ms down to 3ms then 2ms, etc. You have to play with it for your field of view.

Then at night, if it is too dark, then start adding ms to the time. Go to 10ms, 12ms, etc. until you find what you feel is acceptable as an image. Then have someone walk around and see if you can get a clean shot. Try not to go above 16.67ms (but certainly not above 30ms) as that tends to be the point where blur starts to occur. Conversely, if it is still bright, then drop down in time to get a faster shutter.

You can also adjust brightness and contrast to improve the image. But try not to go above 70 for anything and try to have contrast be at least 7-10 digits higher than brightness.

You can also add some gain to brighten the image - but the higher the gain, the more ghosting you get. Some cameras can go to 70 or so before it is an issue and some can't go over 50.

But adjusting those two settings will have the biggest impact. The next one is noise reduction. Want to keep that as low as possible. Depending on the amount of light you have, you might be able to get down to 40 or so at night (again camera dependent) and 20-30 during the day, but take it as low as you can before it gets too noisy. Again this one is a balance as well. Too smooth and no noise can result in soft images and contribute to blur.

Do not use backlight features until you have exhausted every other parameter setting. And if you do have to use backlight, take it down as low as possible.

After every setting adjustment, have someone walk around outside and see if you can freeze-frame to get a clean image. If not, keep changing until you do. Clean motion pictures are what we are after, not a clean static image.
 

XuWHuK

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Unfortunately, no settings helped, with WDR turned on and the suggested settings, flickering still appears.
 

bigredfish

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You said with an exposure range it stopped.?
Try 0-16 this is the slowest you can go with minimal motion blur. As I mentioned 0-8.33 would be even better

And dont use WDR at night
 

XuWHuK

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Yes, it stops, but it appears again in different light conditions.
 

CCTVCam

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Gain is now too high at 80. You should never exceed 50. You will get lots of noise and probably ghosting. If you're needing WDR + Gain at 80 to get an acceptable picture then your camera is in all probability a model that's on a small sensor and poor at night vision.

If this is in B&W and not colour, then the camera may be really poor. If it's B&W, make sure you turn IR on and that it's working. Your other alternative is to add light from eg a bulkhead light that's on all night or a flood light on a sensor if using colour, or if your camera uses IR, an IR floodlight thats on dusk to dawn.

Beyond that post your camera specs as it maybe the camera you're using is not suitable for your low light application.
 
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