H8 ANPR cameras - struggling with night capture [SOLVED]

[codlord]

I have a few of the newer H8 ANPR cameras iDS-2CD7A26G0/P-IZHSY

I have experience with the older versions of these cameras and know how to tweak exposure settings etc on those to get reliable plate capture day and night.
However, the new H8 models have very different camera sensors which seem to allow way more light in.

I have followed the HikVision H8 guide and daytime capture is no problem, but on some I am still struggling to capture at night where I would have no problem before with older cameras in the same position. This is in the UK where number plates are reflective (front plate white, rear plate yellow).

I started with very high exposure 1/2000 and over different nights reduced slowly down to current 1/200 (vehicles will be going 30mph or less).
On forwards captures where the headlights face the camera it DOES mostly capture plates.
On reverse captures where the vehicles rear lights or brake lights face the camera the plate is usually always glared out and I get an UNKNOWN read.

I did notice the "Exposure Gain" setting but the guide says to leave at 20 and does not explain what this does or what a low or high gain will do.

I don't believe this is a firmware issue so I have not listed firmwares etc.

 

[trempa92]

I did a lot of setup on H8 LPR cameras, for this speed is roughly either 1/1000 or 1/2000. Worked as spec stated 98% or higher recognition rate.

What may also be viable in detections, are angles and triggering rule. If its no secret, can you post a screenshot here?

 

[codlord]

@trempa92 thanks, I used to set my old ANPR cameras to 1/2000 to successfully capture at night but the H8 guide says:
Speed < 30km/h — Exposure Time : 1/150-1/200;
30km/h < Speed < 60km/h — Exposure Time : 1/250-1/500;
60km/h < Speed — Exposure Time : 1/500-1/1000
I guess my estimate of 30mph = nearly 50kph which in the guide would put the recommended at 1/250 - 1/500

I will post a screenshot of my angle/trigger lines when I am next at the site.

 

[codlord]

@trempa92 here are the settings for the problem H8 camera. Any advice appreciated. It's a narrow-ish country road where vehicles could be to one side of the road or could be in the middle of the road, on a bend where vehicles generally will be going fairly slow as I said before. No problems with daytime captures, only at night. I have not actually changed the 2 lane settings from the default as they seemed about right. I moved the blue crossing line a little. It's an 8-32mm lens zoomed in. Not 100% sure if it's zoomed to the max or not and I am not at the site to check.

Had an older H3 HikVision ANPR with a 2.8-12mm lens (not really enough zoom) but even that captured plates at night without problems.



Here is an example capture of a front plate - it DOES capture a plates this way a lot of the time (but not always) but plates are rarely human-readable on the photo (the one below is just about readable):



And here is an example capture of a rear plate where 99% of the time I get an "UNKNOWN" read. Even though the rear red vehicle lights or brake lights seem to exhibit less glare than headlights, the plate is always glared out:

 

[trempa92]

Your shutter speed is still too slow , if you are able to see anything else besides plate and lights.

Keep pushing shutter until result is PLATE + LIGHTS everything else is pitch black

 

[trempa92]

Something like this

 

[trempa92]

What you need to understand, ANPR cameras are not meant to be for general CCTV purpose. if you want a nice view for recording and ANPR in same time, you need 2 cameras instead of 1 with different settings.

 

[codlord]

What you need to understand, ANPR cameras are not meant to be for general CCTV purpose. if you want a nice view for recording and ANPR in same time, you need 2 cameras instead of 1 with different settings.

@trempa92 thanks and yes, I agree and I have exactly that setup - anywhere with an ANPR I have a normal camera too. With older cameras I always set to 1/2000 and no problems - black screen as you say at night but successful capture of plates. But these new H8 camera sensors just seem to let loads of light in regardless of the exposure setting.

I have already tried up to and over 1/2000, but I will try the other higher settings again over different nights which are: 1/4000, 1/10000, 1/100000

I have been using "Fixed" mode. Any thoughts on instead using one of the other modes "Generic P-Iris" or "Auto" (which has a level slider 0 to 100)?

 

[trempa92]

@trempa92 thanks and yes, I agree and I have exactly that setup - anywhere with an ANPR I have a normal camera too. With older cameras I always set to 1/2000 and no problems - black screen as you say at night but successful capture of plates. But these new H8 camera sensors just seem to let loads of light in regardless of the exposure setting.

I have already tried up to and over 1/2000, but I will try the other higher settings again over different nights which are: 1/4000, 1/10000, 1/100000

I have been using "Fixed" mode. Any thoughts on instead using one of the other modes "Generic P-Iris" or "Auto" (which has a level slider 0 to 100)?

generic P-IRIS will try to match the light to get best view, i wouldn't use that for night time at all.


Why don't you upgrade your H8 camera to latest firmware 5.8.60? it could be something buggy happens upon saving new shutter speed. Do you see a flicker in video when new shutter is applied?

 

[Phil]

Not 100% sure if it's zoomed to the max or not and I am not at the site to check.

If you can zoom-in any further then it will probably help.

 

[codlord]

@trempa92 I tested higher exposure settings (1/4000 and above) and the image gets super-grainy but the amount of light getting in still does not seem to reduce. For example, an image at 1/4000:



Although the camera DOES seem to capture more plates at 1/4000 so some success I guess.

And as I said in the other post, my other H8 camera did not seem to accept the global 5.8.60 firmware, if I can get 5.8.60 on that camera I will try on this camera... But let's leave that discussion in the other thread!

And @Phil I checked and it is max-zoomed already.

 

[codlord]

o.k. I finally got to the bottom of this with the help of direct HikVision support - I was pleasantly surprised to get responses from them.

It's all to do with the "Exposure -> Gain" setting. The H8 ANPR guide does say to set Gain to 20 BUT if the day/night switch is set to Auto then the Gain setting disappears from the Exposure section! So I had no Gain option showing (and didn't know why, I just assumed the firmware I had didn't offer this Gain setting).

SO THE SOLUTION:
1) Set "Day/Night Switch" to "Triggered by Video"
2) Set "Exposure Settings -> Gain" to "20"

For me, in the unlit scenes I have 1/2000 exposure time still seems to be the best setting for night plate capture.