Flashing horizontal lines on Colorvu at night

[Geordie564]

I've got the new 8mp IP turret cameras.

On two of the cameras (front) there are flashing horizontal lines only when it's dark.

I've tried changing the exposure time but still the same.

Could it be caused by the LED light I have at the front door?

 

[JB1970]

I've got the new 8mp IP turret cameras.

On two of the cameras (front) there are flashing horizontal lines only when it's dark.

I've tried changing the exposure time but still the same.

Could it be caused by the LED light I have at the front door?

It's quite possibly the LED light. I get similar - not so much flashing but scrolling through the image. Simple test - just set the exposure time at its out of the box 1/12 sec and turn the lights off to prove it one way or the other.

 

[Geordie564]

It stops when I turn the outside light off but I've tried lots of different exposure times and the lines are still there.

Do you have audio on your Colorvu cameras?

 

[JB1970]

It stops when I turn the outside light off but I've tried lots of different exposure times and the lines are still there.

Do you have audio on your Colorvu cameras?

So it is the frequency of the LED light causing it. There's something I'll check tonight that might make a difference. I'll check and report back if it does (if it doesn't I'll keep my trap shut!)

Yes I do have audio on them. To answer your next question (a guess), yes I use Environmental Noise Filter! It's not perfect but cuts down on the wind noise. It also cancels noise from traffic until passing vehicles get closer.

 

[Geordie564]

You read my mind! Thanks, I can't decide if it's better or worse with the environmental noise filter on, seems slightly more echoey.

Cheers

 

[JB1970]

You read my mind! Thanks, I can't decide if it's better or worse with the environmental noise filter on, seems slightly more echoey.

Cheers

As I say it's not perfect. We have a road outside ours that gets busy during the school run. It seems as though it almost mutes the mic completely until the noise is sufficiently loud/nearby.

I found the audio better on older models - the mic may have been repositioned causing more echo inside the casing.

 

[Geordie564]

These cameras seem to be trial and error, yes it seems to keep going silent then loud with the noise filter turned on.

 

[Geordie564]

I have LED wall lights in the back garden but they don't seem to effect the image?
The one at the front door is a different brand of light.

 

[JB1970]

I have LED wall lights in the back garden but they don't seem to effect the image?
The one at the front door is a different brand of light.

At the front I have two of the cameras about 5 metres apart directed toward one another. Beneath each is an identical light. So one side is a mirror of the other. I can see the lines on one but not the other. What will always be different is the view. One of mine has more sky visible and this makes the lines show more prominently - it's across the entire image but only perceivable in certain areas.

The other thing that makes it more visible is WDR. Switch it off and it will practically disappear (at least it will not be noticeable)

There's something I'll check tonight that might make a difference.

Tried it - it worked....

Log into the camera directly and in the image settings switch the video to NTSC 60Hz. It will lower the maximum FPS to 22 and alter the range of exposure times to match the standard.

 

[Geordie564]

Great thanks,I'll try that tomorrow
Thanks for all your help, I'll let you know if it works

 

[Geordie564]

OK, been doing lots of experiments.

Just realised when looking on the laptop with a better screen that turning the front light off makes no difference to the horizontal lines.

If I turn WDR off its very dark and I can't see anything clearly, even with the LED light turned up to 100.

I've turned the exposure all the way down to 1/25 and but the problem still persists.

I can't think what else to change, it's the only camera out of four with lines, but it's fine in the daytime, no lines at all.

 

[Geordie564]

Right ....

Been messing around today and realised the exposure times on the NVR are different to the ones when I log into the cameras IP on the laptop

NVR has a choice of 1/12 1/25 1/50 1/100 1/150 1/200 ....

Camera has 1/25 1/50 1/75 1/100 1/125 1/150 1/175 1/200

I had it set on 1/125 which showed the lines, when I changed the setting on the NVR to 1/50 ... no lines!

If I change the setting on the camera to 1/50 ... horizontal lines.

How can this be right?

 

[JB1970]

If I turn WDR off its very dark and I can't see anything clearly, even with the LED light turned up to 100.

Have you confirmed that when the LED is at 100 it's actually on? WDR is used to even out the exposure to show more detail in shadow and highlight areas but it shouldn't be used for the sake of it unless it's needed for that purpose. I wouldn't use it solely to brighten an under exposed image. Any image processing can increase noise in the image or introduce unwanted artefacts. Just dropping the contrast down by 5 will brighten the image without creating the issues that incorrect use of WDR can. When you say "it's very dark" - the LED is there to ensure sufficient light to produce a colour image. Don't expect a daylight image at night. On the other hand if you're saying you can't see anything with the LED at 100 and the exposure at 1/25 sec then I'm surprised. Maybe the LED isn't providing enough light for your camera position. The illumination distances quoted in the specifications (30/40 metres) are somewhat optimistic. Post an image so we can see what "very dark" is.

NVR has a choice of 1/12 1/25 1/50 1/100 1/150 1/200 ....

Camera has 1/25 1/50 1/75 1/100 1/125 1/150 1/175 1/200

I take it you didn't try changing the camera to 60Hz as described? If you had you would be seeing 1/30 1/60 1/120 and so on.

As has been mentioned many times before - camera settings on the NVR interface are just a means of applying a setting on the camera, they are not saved in the NVR. The reason there may be a different range is that not all camera models have the same range of speeds.