License Plate capture using high-zoom low-light analog cams

[nightswatch 0]

Greetings - first post. What a wonderful and helpful community this is though!

 

I'm trying to capture license plates, for manual review, using low-light box cameras and high zoom lenses. I've got multiple cameras set up around my house catching traffic both ways. During the day, no problem. I've got plates perfectly clear using 1/500 sec shutter speeds. At night time, however, it's hard. The light levels are so low that i am usually only able to pick off partial plate numbers.

 

My setup uses two of the following:

Lg L322-BP 1/3" 620TVL 0.1Lux box camera

GVI 5-100mm variable lens.

 

I'm zoomed almost all the way to 100mm and am looking from a garage window both ways. The target area is about 20-30 degrees off the plate at a range of about 80'. The plates are big enough in my capture area, but the images are so grainy because of the low light.

 

I've disabled a lot of the DSP, WDR, AGC, etc.... I've found that these "features" end up blurring the image under low-light conditions.

 

So..... What I'm struggling with now is IR illumination. I haven't dropped $100 on big flashy illuminators yet... I've been hoping to blend in and make my own IR illuminators using 720nm and 940nm IRpass filters and placing them on or in halogen landscape lights. The red glow just simply won't work. I can't carry that high of a profile in my neighborhood. Further, the part that I don't get, is that they hardly seem to illuminate my yard and the street anyways. At night, the IR-cut filter is slid out of the way, so it seems that it *should* be working.

 

I'm using ultra low light bullet cameras (http://www.surveillance-video.com/camera-kpc-ew230nuwx.html/) for wide-range situational awareness. They also don't pick much up from my homemade IR illuminator attempts.

 

Maybe I just need to drop some serious cash on IR LED illuminators? However, even when I take my hikvision IR camera and illuminate the target area with its illuminators, I still hardly get anything on my analog cameras. I'm going to install my IR Hikvision network cameras in the back yard where I don't have to answer to anyone for the red glow. My front yard, however, simply cannot have that red glow.

 

Does anyone have any advice? I'm going crazy. I feel like i've tried just about everything.

Maybe i should play with filters more, but i have such little light to start with anyways. I'm essentially relying on the target vehicle's own license plate lights to provide my illumination.

 

Thanks in advance!

[tomcctv 190]

I'm zoomed almost all the way to 100mm and am looking from a garage window both ways. The target area is about 20-30 degrees off the plate at a range of about 80'. The plates are big enough in my capture area, but the images are so grainy because of the low light.

 

Your first problem is placing cameras behind glass it never works

 

Temp put your camera out side of window at night and see how your image is then.

 

You have not said which dvr and settings you have for recording

 

CIF or D1 Also fps

[survtech 0]

Not to mention that interlaced video does a crappy job displaying license plates anyway. And analog cameras have interlaced video.

[nightswatch 0]

Thank you for your replies. I am sorry for not responding before now.

 

I'm using a Dahua DVR-7816S-U to record, and all my analogs are set to D1.

 

I get it. Behind the glass is quite the challenge.... As if looking out 50 year old windows at 30 degrees wasn't bad enough, what I failed to mention was that the basement windows I have been peering out of also have a storm window about 3" in front of the 50-year old window panes.

 

So.... based on your input, I relocated my cameras to my garage. Angles remain the same, yet I am looking out of only fifty-year old panes. Here are the changes I made, and I must say that it is indeed better.

 

1) Looking up/down street from elevation of 10' above street level(6' above ground) instead of 4' above street level (6" above ground).

2) Now there is no extra storm window in my path

3) Camera angle to up/down street is closer to 90 degrees to the glass now; I decided to give up some of my lower angle off plate in exchange for bringing the target area closer to my camera, and therefore, increase the amount of light radiating from the plate.

 

My present experimenting includes:

a) Putting some 720nm IR-pass/visible-stop filters on a couple cameras - Those cameras are overridden to night mode so that the IR-cut filter is disengaged. During the day, they still tend to bleach out though, especially with the reflection off plates from the sunrise.

b) Leaving one camera overridden to day-mode. It's actually impressive how much better a plate looks with full spectrum color from 60' when illuminated by nothing other than the vehicle's own lighting.

c) Installing one day-mode camera upstairs in my garage to look down from an additional 8' in elevation. This particular camera needs 2lux or something and is useless at night. By looking down, I'm hoping to be able to catch a plate when the lower cameras are catching a bleached glare during the sunrise. I might also add a circular polarizer that i have to this camera to further reduce glare during sunrise. I am reluctant to put a polarizer on my night cameras since I need all the light that I can get at night.

d) I'm presently awaiting delivery of an invisible 2.5 watt 950nm IR illuminator. Hopefully it can aide with night capture.

 

Yes.... I could really benefit from an overt modern camera mounted outside but just cannot tolerate the drama that it would stir up in my neighborhood. I'm not in a home-owners association or anything, but my neighbors would be very displeased with me and I just don't want the baggage.

 

I do intend to experiment with temporarily locating a camera or two outside, but presently have been unable to given the intense rain in our region.

 

 

 

It's a lot of cameras I know. A lot to make up for the fact that I cannot have one really good camera mounted outside. It's also an ongoing experiment and I have multiple test subjects going at once.

 

My biggest challege, by far, is lack of targets. I get 4-5 cars drive by in a 4-5 hour period at night. It's near impossible to set focus therefore, as I have no targets. I review twice a day everything that they've recorded and then make adjustments and hope that I don't screw up alignment. Without traffic, my image is completely black so it's impossible to know if i've knocked the camera off of the target area. Hopefully the IR illuminator will help me to know and to set it.

 

 

Thank you for being an awesome community! Thank you for your help!