License Plate Capture Help

[Tim2255]

Can any one give some suggestions for setting up cameras for License plate capture (not recognition)?

My company recently started selling camera systems and we are looking to get into license plate capture.

The cameras I have in place are Axis Q1765-LE-PT

I have no problem getting good pictures during the day, however I have not been able to get any usable images at night.

The cameras are aimed to capture only the lane of cars driving away from the camera to avoid headlight glare.

Are there any suggestions for adjusting settings for better night time images? Do I need additional lighting?

 

[fenderman]

Can any one give some suggestions for setting up cameras for License plate capture (not recognition)?

My company recently started selling camera systems and we are looking to get into license plate capture.

The cameras I have in place are Axis Q1765-LE-PT

I have no problem getting good pictures during the day, however I have not been able to get any usable images at night.

The cameras are aimed to capture only the lane of cars driving away from the camera to avoid headlight glare.

Are there any suggestions for adjusting settings for better night time images? Do I need additional lighting?

See the lpr section of the forum

 

[pozzello]

- lots of IR at or very near the camera (license plates are retro-reflective)
- shorten the max exposure to 1/500 or even 1/1000. this will be fine in the daytime,
and you'll get plates at night, but ONLY plates and headlights/taillights - that's the trade-off...

 

[Valiant]

I've used this camera in the past. Good night (LPR) shots are achievable. Make sure that autofocus is disabled because the focus will likely shift at night.

 

[Tim2255]

Thanks, I had it set to 1/17000 last night and that looked way too dark. I just set it to 1/500 and disabled auto focus, I will have to wait for dark to test it. I also purchased an IR spotlight. The camera is about 200 feet from the road.

 

[bigredfish]

Please do post some day/night captures for us..

 

[Tim2255]

Here are my most recent captures at 1/500 exposure and auto focus disabled.

This is the best night capture I have had so far, but it is not near usable yet.

 

[Tim2255]

Should I try making adjustments to the gain? it is currently set to auto.

 

[bigredfish]

Try 1/1000

On Gain on my Dahua's I have it set at 10-40 and Iris at about 40

Have you stepped off the actual distance to the plates? Are you by chance using Digital zoom to reach out?

 

[kevkmartin]

You need more IR, and less gain / shorter exposure. Night captures will show little more than the plate and headlights / taillights.

 

[Tim2255]

Try 1/1000

On Gain on my Dahua's I have it set at 10-40 and Iris at about 40

Have you stepped off the actual distance to the plates? Are you by chance using Digital zoom to reach out?

It is using optical zoom. For the gain I can only choose a single db value ranging from 0 to 52.

 

[bigredfish]

Oh wow, I see a 84.6mm lens

I'd see what 1/1000 and say 1/2 way on gain gets you.. then adjust from there. More IR wouldnt hurt...Maybe back off on Sharpness a bit..

 

[Tim2255]

Ok I just set it to 27 of a possible 52 gain. I also lowered the sharpness to 30 (was at 50). Speed is 1/1000.

I ordered an IR spotlight that should be here in a few days.

 

[pozzello]

more IR. also, your day shot is over-exposed, so your cam may be strictly enforcing your 1/500 rather than using that as a max exposure.
in that case, you'll need separate configs for day & night...

 

[Tim2255]

Hey everyone, I finally got some IR lights mounted and I have gotten a few good captures. I now have an issue with the camera being out of focus most of the time. I have heard that auto focus should be turned off for night time operation. Is this true? My camera also has the option for scheduled refocus events.

 

[pozzello]

Have you got an old license plate lying around? mount it on a stand at about 18" from the ground and put it out there (hopefully where/when some bozo won't run over it!) for tuning. does your cam have presets that include a manual focus setting? [ like my Huisun's ] I have preset 1 and preset 2 set to the same field of view (same location and zoom settings) but they differ only in the focus at that preset. Preset 1 was set up during the day, preset 2 is slightly different focus for night-time with IR. I use BI's scheduled events per cam to switch from day to night focus and back at sunset/sunrise... If your cam doesn't have focus as part of presets, you may still be able to automate focus changes (it's usually just one or two clicks in one direction or the other) somehow, assuming your cam does allow totally manual focusing. If the cam will always auto-focus, then try to put something out on the street about as far away as captured plates for the cam to focus on, like a piece of reflective tape, i guess. that may not always work, tho... On the plus side, you're getting closer! that first shot is great - possibly a still bit high on the gain...

 

[Tim2255]

Yes, I can program just about anything in this Axis camera. I will give that a try and see what happens. I currently have a different shutter speed profile for day and night so I can just add the focus along side it.

 

[Valiant]

Another thing you may want to try is using MJPEG rather than H.264, See if you get better results.