New to LPR? Considerations Before You Begin

[DLONG2]

https://www.bhphotovideo.com/c/product/1395702-REG/axton_at_11e_s_11es3810_megapixel_series_at_11e_s_poe.html

This made a significant difference for my Z12’s

97JeepXJ, did you integrate the pulse mode with your Z12? The 850nm light reaching 540 feet, and ideally the camera shutter would allow a quick pulse from a trigger event, so as to not disturb the neighbors, seeing a big red eye all the time.

 

[97JeepXJ]

97JeepXJ, did you integrate the pulse mode with your Z12? The 850nm light reaching 540 feet, and ideally the camera shutter would allow a quick pulse from a trigger event, so as to not disturb the neighbors, seeing a big red eye all the time.

I have not tried pulse mode and I’m not sure if the Z12 is capable of utilizing it. The light is noticeable if you’re directly in front of it but not too bad when out of the viewing angle. We’re just talking about a small red glow on the side of the house, I don’t see it disturbing the neighbors.

 

[pbc]

Ok, so you have one cam for two lanes at 100-120 feet. When you say two lanes, are you talking about a normal suburban neighborhood street? Like 24 feet wide? Similar to the map view below?

View attachment 151101

If so, then your LPR setup is comparable to mine. Show a daytime shot so we can see what the situation looks like.

Below. My cameras are where the white circle is.





One issue is that I'm capturing cars coming dead on, so at night, full blown headlights. Been using HLC of 50, but wonder if I should ramp that up to 70?

Day capture:


Night capture (at 1/500, if I go to 1/1000 things start to get too dark, and more plates seem to get lost due to headlights, lack of IR?):

 

[DLONG2]

You have a great view of the street. I would suggest zooming as much as possible so as to still capture both lanes. Go out to 200-250 feet, and don't worry about the gutters. You just need the plates, and the two plates ought not be more than 15' apart from each other.

 

[wittaj]

Yeah that is a big wide spread to try to catch with one camera.

This is where having that perfect straight angle is a disadvantage.

@samplenhold example is at an angle, so he is able to get the lanes.

You have to decide what is more important - capturing a large number of plates with one camera, or getting two cameras and being able to zoom in more to capture a higher percentage.

Even the focused external IR being talked about is so focused of a light beam that it probably wouldn't illuminate all 3 lanes. And those specialty IR units cost more than another Z12E

And depending on what state you are in, if they go to the new 3M printed plate, you will be screwed at that wide angle trying to get 3 lanes as tests here by myself and others are showing you need to be as close to the plate as possible with the plate as large as possible.

 

[pbc]

Yeah that is a big wide spread to try to catch with one camera.

This is where having that perfect straight angle is a disadvantage.

@samplenhold example is at an angle, so he is able to get the lanes.

You have to decide what is more important - capturing a large number of plates with one camera, or getting two cameras and being able to zoom in more to capture a higher percentage.

Even the focused external IR being talked about is so focused of a light beam that it probably wouldn't illuminate all 3 lanes. And those specialty IR units cost more than another Z12E

And depending on what state you are in, if they go to the new 3M printed plate, you will be screwed at that wide angle trying to get 3 lanes as tests here by myself and others are showing you need to be as close to the plate as possible with the plate as large as possible.

Biggest problem seems to be the oncoming headlights which can sometimes “black out” the plate. Or a plate that just doesn’t seem to get an IR boost.

I’m getting most plates, but trying to see if there are things I can adjust to get a bit better without losing the ability to see the 3 lanes.

In Canada so not sure if or when we’re adopting the new plates.

 

[pbc]

Hmm...just went out and did a night time focus on my own plate.

One thing I just realized, when I'm viewing the camera feed directly from the camera web GUI, it looks much sharper than what I am getting off of BI? Both are set to the same fps (30).

Anything else I should be checking?

 

[wittaj]

Hmm...just went out and did a night time focus on my own plate.

One thing I just realized, when I'm viewing the camera feed directly from the camera web GUI, it looks much sharper than what I am getting off of BI?

Is BI using the substream when you see it?

Post a comparison pic. Most do not see a difference between the two.

 

[pbc]

Is BI using the substream when you see it?

Post a comparison pic. Most do not see a difference between the two.

Not sure, where do I check if it is using a substream? Seems to say mainstream in the General window (can't snip it as when I use Snipping tool what's in the status window dissappears):

 

[wittaj]

Nope your subs are not being used. But I think you can drop the FPS, especially on that straight shot. If you went with 15FPS and 8192 bitrate CBR you might get some better results. Spreading your bitrate over 15FPS instead of 30FPS allows more bitrate per frame.

I do 8FPS and don't miss any and I am at an angle and the car is in my field of view for a lot less than yours.

 

[pbc]

Nope your subs are not being used. But I think you can drop the FPS, especially on that straight shot. If you went with 15FPS and 8192 bitrate CBR you might get some better results. Spreading your bitrate over 15FPS instead of 30FPS allows more bitrate per frame.

I do 8FPS and don't miss any and I am at an angle and the car is in my field of view for a lot less than yours.

So change to 15fps on the cam (as well as I Frame Interval) and on BI?

 

[wittaj]

Yeah, try 15FPS and 15iframe in the camera. BI will take care of it automatically (the FPS you can set in BI is only for USB cams).

 

[David L]

You have a great view of the street. I would suggest zooming as much as possible so as to still capture both lanes. Go out to 200-250 feet, and don't worry about the gutters. You just need the plates, and the two plates ought not be more than 15' apart from each other.

Going out too far, couldn't Traffic possibly block capturing LPs, obviously depending on camera angle?

 

[97JeepXJ]

That looks pretty wide for the light I linked to but it does great at max zoom with this camera. As @wittaj said it’s more than the camera itself but it’ll light the plates up.

 

[samplenhold]

Your FOV is really three lanes wide. So that is really 36 feet wide. As @DLONG2 stated, get closer and not worry about the gutters. No plates will be in that area.

 

[pbc]

Your FOV is really three lanes wide. So that is really 36 feet wide. As @DLONG2 stated, get closer and not worry about the gutters. No plates will be in that area.

That will have to wait until winter is done so I can repoint the camera.

What does “not worry about the gutters” mean?

 

[wittaj]

That will have to wait until winter is done so I can repoint the camera.

What does “not worry about the gutters” mean?

The curbs LOL. Tighten the FOV to within the actual driving range vehicles would go. Someone would have to be up on the curb to get a plate out that far LOL.

 

[pbc]

The curbs LOL. Tighten the FOV to within the actual driving range vehicles would go. Someone would have to be up on the curb to get a plate out that far LOL.

Yeah figured it out minutes after I posted. Heading to London this weekend so should have put on my English hat.

Isn’t the IR much less effective at say 200 feet than 100 feet?

 

[pbc]

Going out too far, couldn't Traffic possibly block capturing LPs, obviously depending on camera angle?

No worries about traffic. It’s a stub street into the subdivision so rarely busy, certainly not at the times I’d be concerned with (between midnight and 5 sort of thing).

 

[wittaj]

LOL. I figured it was a country jargon barrier.

Yes, the further out you go, the less effective the IR is. I can get 175 feet out of my Z12E in an area with no streetlights and no other ambient light, while others have only been able to get 100ish or so out of it.

I think the most I saw someone here was 230ish feet with just Z12E IR.

But plates and other things factor into it. Some have just more highly reflective plates and great contrast.

I have seen though that my camera that could get all but the dirtiest or rusty or temp plates of the old stamped plates at 175 feet out cannot get the new 3M printed plates at all.

Here is a representative sample of the stamped plates I get at night with a 1/2,000 shutter and 8 FPS of vehicles traveling about 45MPH at 175 feet from my Z12E that is on the 2nd story soffit, Camera is 35 feet above street at this location with no street lights or house lights on, just the infrared from the camera:

The new 3M process of printed plates results in poor contrast of a certain blue with infrared.

Here is a sample of a new plate with my Z12E at 175 feet away:

As you can see, the plate is washed out. I have tried everything and just cannot get a consistent plate with new printed plate.