License Plate Camera VS Regular IP MP

[ak357 0]

If the words Washington were same size letters then it would

quote]

 

Show me, prove me wrong. Then why can I see the registration stickers on the plate, but not the larger WASHINGTON?

Have a look at my few posts

viewtopic.php?f=15&t=23765

[buellwinkle 0]

Nice IR image of an Alberta red number plate from your post ak357. The problem I'm having with one LPR camera, the Avigilon dome is the sun shining on the plate sort of washes out the plate number, enough so the software can't make out the plate number during the late afternoons.

 

[ak357 0]

Nice IR image of an Alberta red number plate from your post ak357. The problem I'm having with one LPR camera, the Avigilon dome is the sun shining on the plate sort of washes out the plate number, enough so the software can't make out the plate number during the late afternoons.

 

Which VMS are u using ?

[buellwinkle 0]

Milestone XProtect Express with LPR.

[msecure 0]

It gets pretty expensive with LPR and you are typically charged per lane and while their software is one of the least expensive LPR solutions out there at about $800/camera, it's far from the best.

 

My cameras is set at 1/200 second exposure, I'm pretty sure I can capture a car going much faster. Certainly fast enough to get a plate going in/out of a parking lot. The only reason we do LPR is to activate a gate automatically based on a plate match. From a security standpoint, not sure you would benefit from LPR as you just want to see a plate in a video.

 

I get good capture of moving vehicle plates at night if I set 1/200 second on my SDI too, but when daytime come it is all whitewashed. Your IPC without this problem?

[buellwinkle 0]

Not familiar with SDI, but with the Hikvision it's easy because I can set separate day & night image settings, so I set 1/30 max exposure during the day and 1/200 at night. Same with WDR, I set it on during the day, off at night. The only PITA is that with Hikvision, I have to set a fixed schedule for this to happen, so every few months I have to change the start/end times. What I wanted to do was either write a program on my NVR PC to set the start/end times using a calendar, or maybe write it into a Raspberry PI. This setting on the camera is independent of the IR cut filter day/night setting.

[dvarapala 0]

[Geovision] IS ALSO 1 of 4 companies which can be licensed to use national vehicle data bases.

 

 

So you're saying that if I license their software it will do real-time lookups in the DMV database? What information will I get? Registered owner name and address? Make/model/color of the vehicle? Will they do it for anyone with the $$$, or only for "authorized" agencies?

 

[dvarapala 0]

Currently we have no cameras in our front parking lot so I need some advice on what kind of camera to put there. My confusion is over License plate camera vs standard outdoor IP MP camera.

 

The main differences between a regular IP camera and one marketed for license plate capture is usually the lens and a special filter that blocks most visible light while allowing infrared wavelengths to pass. I'm using a regular IP box camera, a 25mm lens, and a threaded filter that screws onto the end of the lens, all mounted inside a standard outdoor camera housing. The illuminator is a RayMax RM100C, the "covert" version which emits 940nm light and is less noticeable to the naked eye than the standard 850nm illuminators. This setup produces excellent results as long as the plates are retro-reflective (e.g. California). Some states (e.g. Nevada) are using a different type of plate which appears completely blank using this type of setup. I would love to know what equipment ALPR companies sell for use in Nevada and other non-reflective-plate states.

[cglaeser 0]

I would love to know what equipment ALPR companies sell for use in Nevada and other non-reflective-plate states.

 

My guess is ALPR for non retro-reflective plates is limited to daytime use and is very iffy for nighttime use. If the vehicle has an evenly and well-lit plate and there are a sufficient number of pixels on the plate, then they might be able to pull the plate. But if the vehicle's license plate light is burned out or is very bright on one side and is not evenly lit, I doubt an ALPR can pull the plate. We have a lot of vehicles in our city with dealer (the owners never bothered to attach registered license plates after purchasing the vehicle). The dealer plates are not retro-reflective. Sometimes I get lucky and can read the dealer plate at night on either an Avigilon 5 MP or a Messoa LPR camera, but more often than not it's a miss. Of course, if the vehicle is driving through a well-lit parking garage or similar, then it's easy to read the plates, but the white lights essentially create a daytime scenario.

[buellwinkle 0]

What if you throw a good amount of light on it so it balances out glare from other lights at night.

[cglaeser 0]

What if you throw a good amount of light on it so it balances out glare from other lights at night.

 

Most surfaces are to some degree reflective, not retro-reflective. Some of the light will scatter, and much of the light will bounce off at an equal but opposite angle. Keep in mind that LPR cameras are typically at an angle so you can read multiple plates if the cars are moving closely together. The amount of white light required to scatter back to the camera from a reflective plate and sufficiently mask the headlights or taillights would likely distract the driver. That is one of the benefits of IR; it does not distract the driver. The benefit of retro-reflective plates is that much of the light bounces back in the same direction as the light source.

[MaxIcon 0]

Not familiar with SDI, but with the Hikvision it's easy because I can set separate day & night image settings, so I set 1/30 max exposure during the day and 1/200 at night. Same with WDR, I set it on during the day, off at night. The only PITA is that with Hikvision, I have to set a fixed schedule for this to happen, so every few months I have to change the start/end times. What I wanted to do was either write a program on my NVR PC to set the start/end times using a calendar, or maybe write it into a Raspberry PI. This setting on the camera is independent of the IR cut filter day/night setting.

The other consideration with the Hik is that it doesn't set a fixed exposure, just a maximum exposure, so if things are too bright, it still can run shorter exposures to compensate.

 

If your SDI is setting a fixed exposure, you don't have that option, but if you can set the max exposure and leave the minimum exposure much faster, it should take care of it.

[buellwinkle 0]

I don't think blinding drivers is a concern here in California because the tolll road authority implemented LPR for toll collection and they use 2 flash, one to capture you front, one to capture the rear. At night, it looks like a lightning storm from a distance with the flashes going off for each lane in both directions every second or so. I have to close my eyes when I drive through.

 

 

What if you throw a good amount of light on it so it balances out glare from other lights at night.

 

Most surfaces are to some degree reflective, not retro-reflective. Some of the light will scatter, and much of the light will bounce off at an equal but opposite angle. Keep in mind that LPR cameras are typically at an angle so you can read multiple plates if the cars are moving closely together. The amount of white light required to scatter back to the camera from a reflective plate and sufficiently mask the headlights or taillights would likely distract the driver. That is one of the benefits of IR; it does not distract the driver. The benefit of retro-reflective plates is that much of the light bounces back in the same direction as the light source.

[cglaeser 0]

I don't think blinding drivers is a concern here in California because the tolll road authority implemented LPR for toll collection and they use 2 flash,

 

I was referring to a continuous white light. Using a strobe requires the addition of a vehicle detection or ranging device.

[MaxIcon 0]

The other option I've seen people use for choke-point LPR is using IR with an IR-only filter on the camera; that is, a filter that only passes IR light. This lets you expose for just the IR reflection without worrying about the white light exposure changes.

 

Whether ambient daytime IR is a problem would depend on the strength of the IR illuminator and distance to the plates. I've never tried it myself.

 

Not so common, and requires either a lens threaded for a filter or a box with the filter built in, but it helps with the variable exposure issues.

[cglaeser 0]

The other option I've seen people use for choke-point LPR is using IR with an IR-only filter on the camera; that is, a filter that only passes IR light. This lets you expose for just the IR reflection without worrying about the white light exposure changes.

 

Whether ambient daytime IR is a problem would depend on the strength of the IR illuminator and distance to the plates. I've never tried it myself.

 

Not so common, and requires either a lens threaded for a filter or a box with the filter built in, but it helps with the variable exposure issues.

 

I purchased IR bandpass filters and tried this. I never got it to work.

[SyconsciousAu 0]

One caveat, as I've said before with plates with IR cameras, including the Geovision LPR is that you can not capture plates with red characters, for example Illinois license plates. If you are not sure, ask the manufacturer if their cameras can capture Illinois plate number at night (Alberta if you are in or near Canada).

 

Your issue with plate capture appears to be linked to the design of the plates in your local area. I don't have the same issue.

 

 

 

That is a capture of a black plate with red letters under IR.

[cglaeser 0]

One caveat, as I've said before with plates with IR cameras, including the Geovision LPR is that you can not capture plates with red characters, for example Illinois license plates. If you are not sure, ask the manufacturer if their cameras can capture Illinois plate number at night (Alberta if you are in or near Canada).

 

Your issue with plate capture appears to be linked to the design of the plates in your local area. I don't have the same issue.

 

[attachment=0]red on black at night.jpg[/attachment]

 

That is a capture of a black plate with red letters under IR.

 

That looks pretty bad. A human can read it, but not automated recognition.

[SyconsciousAu 0]

One caveat, as I've said before with plates with IR cameras, including the Geovision LPR is that you can not capture plates with red characters, for example Illinois license plates. If you are not sure, ask the manufacturer if their cameras can capture Illinois plate number at night (Alberta if you are in or near Canada).

 

Your issue with plate capture appears to be linked to the design of the plates in your local area. I don't have the same issue.

 

[attachment=0]red on black at night.jpg[/attachment]

 

That is a capture of a black plate with red letters under IR.

 

That looks pretty bad. A human can read it, but not automated recognition.

 

It was never set up for automated recognition. Field of view is way to large.

[cglaeser 0]

It was never set up for automated recognition. Field of view is way to large.

 

Understood. It's still pretty bad. I have been using LPR cameras for several years. In both tactical situations (i.e. a burglary in progress) and evidence collection for detectives and the DA, clean crisp black and white plates are preferred and much less tedious.

[MaxIcon 0]

With the increase of LPR use by law enforcement, I wouldn't be surprised if better IR capture properties are rolled into the license plate specs in many areas.

[cglaeser 0]

With the increase of LPR use by law enforcement, I wouldn't be surprised if better IR capture properties are rolled into the license plate specs in many areas.

 

Common sense would dictate plates should be designed for easy reading, but many states in the US add all sorts of crap to the plates that make them difficult to read. Of course, state mottos and slogans don't affect the retroreflective properties needed for IR capture, but given how incredibly difficult they make it for humans to read plates, I don't have much faith states will use common sense going forward.

[SyconsciousAu 0]

It was never set up for automated recognition. Field of view is way to large.

 

Understood. It's still pretty bad.

 

There is still some tweaking to be done but I'm fairly happy where it is at at this stage given that I'm using an illuminator that cost less than $50 and a camera that wasn't designed for plate capture.

 

Those particular plates are also the hardest to capture (of the local plates) with numbers that are only 50mm high.

[SyconsciousAu 0]

My cameras is set at 1/200 second exposure, I'm pretty sure I can capture a car going much faster. Certainly fast enough to get a plate going in/out of a parking lot. The only reason we do LPR is to activate a gate automatically based on a plate match. From a security standpoint, not sure you would benefit from LPR as you just want to see a plate in a video.

 

I've been doing some testing and tweaking today and I don't think that 1/200 sec exposure would give clear images over about 20kph, especially if there is any sort of offset between the camera and the moving vehicle.

 

I've found that even with a 1/500 second exposure there is noticeable motion blur as the speeds increase.

 

This is a capture of a vehicle doing about 20km/h

 

 

This guy was doing 60-70 km/h

 

 

 

A human can still read the plate but number plate recognition would be fairly tough I think.

[vlkc 0]

Number plate recognition depends on two components. 1 - good camera, 2 - good software. In our case we use IP cemera SIGNA TIP 5200IR and have no problems at night. See yourself.