Member Discussion

LPR At Vehicle 500' Away?

Hi John, I have a special case where the camera has to me mounted about 500 ft away for the scene for LPR. When I was at Ifsec exhibition in London, I came across a camera from chinese company Uniview. Their PTZ camera uses "laser" to get light to appox. 820 ft.Do you know more about this.

I have tried to find out more of this technologi, but the specs are unclear. I have worked a little with the SWIR (1550nm technologi) but this is very expensive and probably not the technology in the case.

The camera can be mounted very stabile to avoid vibrations.

NOTICE: This comment was moved from an existing IPVM course discussion.

I suppose the camera lenses is zoomed in to target only the license plate?

Here's feedback from Genetec:

"Our AutoVu Sharp line uses high-resolution sensors for LPR capture, and can read plates at distances up to 100 feet. Beyond that distance, a combination of illumination efficiency and pixel per foot decrease capture and read capabilities. A 500 feet capture range is not a scenario we’ve encountered before. We do see situations where access to power or network is challenging, but these can usually be handled while keeping the LPR camera within a 100 feet capture range."

I think it's worth asking other LPR specialists about this (and if any are reading this, please comment).

However, I suspect 500' is pushing it. Just to get a 20' wide (or less) FoV to be narrow enough to read the plate, you will need a ~100mm lens. You may have depth of field problems at that point, etc.

Shouldn't any decent IP ptz do the job? Even our 2mp with 20x zoom is able to clearly see the tag from the top of our office building as shown in this YouTube video.

EPN4220_Demo_Video_2 - YouTube

Jesper is asking for LPR, not LPC. Also, that marketing sample is an ideal daytime shot.

Having a camera automatically recognize license plates, at night, with moving vehicles that far away is a challenge.

The LPR developer / manufacturer needs to verify / commit to being able to do that.

All LPR starts with good LPC.

The only requirement given by Jesper was "500 ft away for the scene."

We need to know the full requirement and not make any assumptions.

The point is that LPC is much easier to do than LPR.

LPR requires far more demanding image quality than LPC. That's why I am objecting to your simplistic recommendation of using a PTZ.

Given the distance, I would think you'd need some sort of lighting out there pointing at the target area. If there is power for the light, then there would be power for a camera and wireless bridge out there and I think that would be the better route to go.

If there is no hope of power out there, then I'd look for a long range white light or IR light. But it'd have to have enough intensity to be able to use a fast shutter speed, with enough finagling of the settings to eliminate motion blur.

500 feet during the daytime is possible but I would not recommend it. Any kind of sway in the mount can throw off your observation window to the point that you won't see vehicles. Aiming also becomes critical as your distance increases - just like shooting a rifle, a small change in angle makes a big difference in what's covered. Calibrating on a 10-15 foot wide, 5 foot tall, precisely from 500 feet can be a tedious process. Illumination at night, assuming you are using infrared, would be a huge challenge.

The farthest I have personally performed daytime LPR was at about 160-170 feet with PTZ IP cameras. In my opinion you would be better off pulling wire, power and mounts to get the LPR camera closer to the street in question.

Can the target area be flooded with IR just to increase the camera performance?

Theoretically, I think adding IR near the target will help. In principle, for a camera that is IR sensitive it should be the same as adding a streetlight over the car / vehicle checkpoint / driveway. That said, I have never attempted anything like that so don't know for sure.

Hi Kevin, I suppose you could do that, but if you are in a position to get power for infrared close to your target, you're also in a position to get the camera there!

BTW I work for PlateSmart and we've tested dozens of cameras and scenarios over the past 3-4 years, but nothing to the extent of your use case.

I haven't heard yet if the plates to be read are reflector or not. Flooding a reflector plate with IR and using a conventional imager can also cause issues.