LPR on a Incline

[c hris527]

Hi All,
Well as time progresses, the rural neighborhood is slowly getting infected with weird things happening, Crime is on a uptick here. I had always wanted a LPR to cover my street but laziness and time always got in the way.
My driveway is almost dead balls in the middle of hill. Any LPR captures would be from the bottom up, I did some rough testing and have a very clear shot about at 165' and the grade difference from the camera to the area I want to cover
is about 20 feet . I know I have read tons here about positioning the lpr looking down on the street but has anybody captured on a incline where the Camera is facing up hill?
Thanks in advance
Chris

 

[Timokreon]

First thing I'd look into is the position of the sun and any exterior lights that may cause issues with the camera.

 

[wittaj]

I don't think it would be an issue. Mine is 30 feet above and I don't see how it would make as big of a difference whether it is above or below, especially at 165 feet out.

 

[c hris527]

First thing I'd look into is the position of the sun and any exterior lights that may cause issues with the camera.

I should be OK in that Department as far as the sun, My street is North south, very little light from any neighbors but I will run out and check.

 

[samplenhold]

Test it out BEFORE you install. That is the only real way to tell.

Got a DSLR camera? Get out there and zoom in a little and take some pics. But I don't think that shooting uphill will matter.

 

[tangent]

The main problem I think you might encounter is IR reflection off the ground / hill, but as long as the camera isn't too close to the ground it probably wont be too much of an issue. Worst case you can potentially use an external IR illuminator closer to the street.

 

[wittaj]

The main problem I think you might encounter is IR reflection off the ground / hill, but as long as the camera isn't too close to the ground it probably wont be too much of an issue. Worst case you can potentially use an external IR illuminator closer to the street.

The problem with an external illuminator though as it applies to plates is that the way the reflective property is of plates and it reflecting back to the light source, the IR has to be as close as possible to the camera. Someone did a test here once and after about 24 inches separation between the camera and the external, the external IR was useless.

Plus at the speed we run the shutters, the IR reflection off the ground shouldn't be an issue. The bigger issue is does enough of the IR get to the plate.

 

[Parley]

Plus at the speed we run the shutters, the IR reflection off the ground shouldn't be an issue. The bigger issue is does enough of the IR get to the plate.

Exactly. From my experimentation I would use the most powerful external IR illuminator I can find. Also, I would not run one with over a 60 degree angle for license plates. With good reflective plates you should be OK. The problem that I am finding is those plates that are put out by the states with very little reflection and those plates that have been sprayed by a non-reflective coating and those that are dirty and those worn by age. I am going to be going to two external IR illuminators on my LPR cameras to help those situations. One external IR illuminator and LPR camera is around 25 feet from the traffic and is doing the job. My longest ones are around 75' and are not reading those plates well at all and where I will be experimenting with the two external IR illuminators.

Edit: I just ran across this one which looks to be twice as powerful as the one I am currently using. I will order one from B&H Photo today.

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