Ligthing question for camera with zoom lens

[Scruit 0]

I have a 9ch home system, and one of the camera has a 75mm zoom lens and looks down a 150' driveway. Any car that drives down my driveway will have it's license plate captured. Well, that's the plan.

 

The biggest problem I'm having is to do with lighting at night.

 

- Car facing towards or away from the camera with headlights off = too dark to see

- Car facing the camera with headlights on = blinds the camera

- Car facing away fro the camera with headlights on = license plate lit up just fine.

 

I have tried all of these configurations while shining a maglight at the license plate and it's readable on the camera. The reflective surface helps a lot.

 

 

So, what I need is to light up side of the car facing the camera. Best I can think of right now is using low-voltage landscaping lights, and to install a spotlight in the grass beside the driveway and point it down the driveway. At night the spotlight comes on. If a car comes down the driveway then the plate is lit up.

 

Can anyone else suggest anything better / cheaper?

[Rooney 0]

The spotlight idea should work well. Another option is to buy an infrared illuminator. The cctv cameras see the illumination fine and it should also light up the license plate good. One that would light up an area of 50 feet runs about $75. You can buy them online.

[Scruit 0]

The license plate camera is a regular color BNC camera with 75mm zoom lens and reads plates on cars that are ~100' away.

 

If i was to get an IR-pass filter (blocks visible light, allows IR light) AND an IR illuminator that is rated for 120', AND make sure the filter and illuminator are both rated at the same wavelength... Then that should help, right?

 

Woudl it be better to switch to a BW camera? OR is the color camera able to see IR just as well?

 

 

I did a test right now. Using visible light, headlights dazzle the camera. My hope is that by using an IR filter and illuminator that the camera will pick up the license plate withotu being dazzled by the headlights.

[Rooney 0]

Color will still see it but B/W will give you a better picture using IR. I think the way you said will work fine. Let me know how it works out.

[kensplace 0]

Most decent colour cameras have very poor infrared ability, b&w can also have poor infra red ability but usually b&w is ok, it depends on the ccd and what filters are used in the camera. Check the camera specs for the camera, it should tell you what wavelenghts the cam can see.

 

If its up in the 900nm range it can see the invisible IR used by covert ir illuminators, if its around 730ish its the ir lights that glow red that it will be able to see. If its higher than 1000 then its a very expensive ir optimised camera

[Scruit 0]

Most decent colour cameras have very poor infrared ability, b&w can also have poor infra red ability but usually b&w is ok, it depends on the ccd and what filters are used in the camera. Check the camera specs for the camera, it should tell you what wavelenghts the cam can see.

 

If its up in the 900nm range it can see the invisible IR used by covert ir illuminators, if its around 730ish its the ir lights that glow red that it will be able to see. If its higher than 1000 then its a very expensive ir optimised camera

 

Thanks for the advice for checking the camera's sensitivity range - I wouldn't have thoguht of that.

 

When I get home tonight I'll get the make/model and pull the specs. I'd rather use 900-950nm so the illuminator doesn't glow red and tip off the bad guy.

[Scruit 0]

I'm getting a replacement B&W camera with 0.01 lux and 480 tv lines instead of 330. This will allow for more precise license plate recognition at night, especially with the ir-pass filter and illuminator.

 

I'll post before/after pics when I get it set up.

[cctv_down_under 0]

Adjust your gain settings, bright light in low light will cause the gain to rise making the reflective plate too bright, you need a cam that dynamically can change modes and shutter speeds, adjust the level then the gain then adjust the shutter spead, if your cam supports peak level adjust this too, mnake sure you hae an appropriate shutter speed, the bosch cams can dynamically adjust shutter speed and can have hartd wired triggered modes which can help...failing that a cam with inversion will help, the black on th plate..IE the numbers will be bright but the reflective will be dark and the headlights also dark