Best dedicsted LPR camera $1k or under

[achalmersman]

Ok. So calling @bigredfish and other guys that have lots of LPR experience. We've all used the Dahua 5231 / 5241 Z12s etc and we all know they will work with all the nuances but....

Let's discuss purpose built LPRs. $1k ish or less. What's out there? Only limitation is they cannot strobe flash like a toll both or red light. I may be willing to consider white light LED not sure (some of my deployments point on the road). My states plates are extremely challenging to capture especially if dirty.

Any conversation appreciated.

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[biggen]

What is it that the ones you mentioned can't do that you need? I guess I'm confused on what you need done better than the ones that are popular here. You actually want the LED built into the camera? Is that the requirement?

 

[achalmersman]

The ones mentioned I have used. I have 4 deployed. They have inherent focus issues. The 2nd thing is that they don't produce the best images. On dirty Delaware plates the results are completely unreadable plates. Some plates are perfectly exposed, some under exposed, and some over exposed. The short amount of reading I've done out of Dahua world shows that there are some cameras with pulsed IR, some with white light, etc. Im asking if anybody has experience with more expensive purpose built LPR cameras that produce better results than the defacto standard we use here.

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[bigredfish]

Something like this?

https://www.dahuasecurity.com/products/All-Products/Mobile--Traffic/Traffic-Enforcement-Products/All-in-One-Enforcement-Cameras/ITC952-RU2D-IRL8

If you can get @EMPIRETECANDY to donate one I'll take one for the team and test it

Honestly Im not sure there are many options under $1000. I think HiK makes an ANPR camera and Dahua has a few others priced more moderately but their pages are blank for some reason now?

https://www.dahuasecurity.com/products/All-Products/Mobile--Traffic/Entrance--Exit-Control-Products/Access-ANPR-Cameras/ITC215-PW6M-(IR)LZF

Most though are fully automated systems and much higher end with super fast shutters, big bitrates and internal databse/whitelist fucntionality.

Bosch has the Dinion line with full ANPR- (though I can no longer find a link to them???)

As does Axis
License plate recognition | Axis Communications

 

[achalmersman]

Here is an example of plates I get and the challenge my ststes plates are. I've tried everything I can to get the non textures gold letters to contrast against the blue tag but this is the best I can get. Tags that appear perfectly readable in the daytime can have dust on them and be completely unreadable at night. One of the attached images is an example.

Yea I guess I'm coming to realize you can spend $250-300 or $3,000-5,000. Nothing in between.

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[bigredfish]

Worth trying to tweak that.

Maybe add more contrast (I run 70-80), add more HLC (70 at least), and then play with Iris a bit. Keep Gain at 50 or less and of course DNR at 45 or less but I dont really see any blur.

 

[achalmersman]

Worth trying to tweak that.

Maybe add more contrast (I run 70-80), add more HLC (70 at least), and then play with Iris a bit. Keep Gain at 50 or less and of course DNR at 45 or less but I dont really see any blur.

I'll check the settings against your recommendations next time I'm out there. I dont have remote access to that site. I spent weeks dialing them in about a year and a half ago to read the majority of plates acceptably. Maryland plates for example look like a million bucks. Its the Delaware plates especially when dusty that give me problems. The IR light and road grims dust make these plates completely unreadable. I proved it one day by taking a plate that looks perfect to the human eye and wiping it with windex. As soon as I did that the plate was readable at nighttime again. This is one of the reasons I'm thinking about trying a camera with white light LEDs. Not sure how obtrusive they will be on a roadside though. The camera in the above examples could use it though as thats just the end of a driveway.

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[EMPIRETECANDY]

Can use IPC-HFW7442H-Z4, this one can work at distance below 70feet, and add a NVR4216-16P-I AI NVR.
Cost will be within 1000USD and you also can add more cams in the system too.

IPC-HFW7442H-Z4

IPC-HFW7442H-Z4

www.dahuasecurity.com

 

[wittaj]

I think you may still have the same issue with those problem plates regardless of camera. LED off one of these cameras I do not think would be bright enough at the location of the plate.

If the issue is the nighttime plates and B/W with IR, you probably need enough light at the street to run in color.

You would be better off with spot lights with a high power lumen bulb like these:

https://www.amazon.com/Non-Dimmable-Floodlight-Warehouse-Supermarket-SANSI/dp/B07DL99ZXZ/ref=sr_1_4?dchild=1&keywords=nightchaser+led&qid=1600053655&sr=8-4

https://www.amazon.com/SYLVANIA-Equivalent-Replacement-Dimmable-Daylight/dp/B07DPZ8DZC/ref=sr_1_6?dchild=1&keywords=nightchaser+led&qid=1600053856&sr=8-6

But then you may have mad neighbors if it is shining in their bedroom LOL.

Not my LPR camera, but my PTZ autotracking has picked up plates at night with color with these things...shocked me as the shutter is not as fast as my LPR by a long shot.

 

[bigredfish]

Can use IPC-HFW7442H-Z4, this one can work at distance below 70feet, and add a NVR4216-16P-I AI NVR.
Cost will be within 1000USD and you also can add more cams in the system too.

IPC-HFW7442H-Z4

IPC-HFW7442H-Z4

www.dahuasecurity.com

I hadn’t thought of that . It would do the job, though with shorter distances as Andy said.

Still similar issues with dirty plates as would any camera, but I think you can further enhance it with some tweaks. White light/color would be an option as you mention.

 

[cjowers]

I agree to check the settings - make it way darker / adjust HLC, increase contrast

Another thought - Is your IR light source strong enough / or is the visible light (streetlight / LP bulb) overpowering you IR? I think most camera sensors collect a mix of visible and IR light. To test, just see whether it makes any difference if you're closer / farther away? A (cheap) seperate flood light might give you more control here.

But regardless, dust probably reflects IR well, so you just can't differentiate the numbers from the plate background (it's all dust!). Or maybe the Delaware paint colors just don't differentiate well under IR? In either case, a visible (or colored) light source could help in theory, but may not be practical at the intensity levels needed.

Just some thoughts that this situation might not really be improved by an expensive camera.

----------------------------------------
And the following is probably not helpful to you, but might be interesting to someone...
if this were normal visible light (not IR light source) you would just add a colored filter to block the one color (and create contrast), ur use a colored light source. This is very common for monochrome imaging, which struggles to differentiate two colors if they have the same 'levels', like your plates. Not sure if that works the same in the IR spectrum (itll be two IR freq. not visible colors).... but you kinda see what i'm saying below. A different frequency of IR source or filter on the lens might help your situation dramatically, but I don't know enough to say for sure. (note: specific camera sensor brands are optimized for specific IR frequency ranges, so this needs to match your IR light source / some cameras brands might be better suited)

visible colors

monochrome (low contrast)

with filter on lens (blocks red, higher contrast)


various light source colors can reduce or improve contrast (for visible light) - you'd use the red light source in 'c' for better contrast of blue/yellow combos


images borrowed from A Practical Guide to Machine Vision Lighting

 

[achalmersman]

I agree to check the settings - make it way darker / adjust HLC, increase contrast

Another thought - Is your IR light source strong enough / or is the visible light (streetlight / LP bulb) overpowering you IR? I think most camera sensors collect a mix of visible and IR light. To test, just see whether it makes any difference if you're closer / farther away? A (cheap) seperate flood light might give you more control here.

But regardless, dust probably reflects IR well, so you just can't differentiate the numbers from the plate background (it's all dust!). Or maybe the Delaware paint colors just don't differentiate well under IR? In either case, a visible (or colored) light source could help in theory, but may not be practical at the intensity levels needed.

Just some thoughts that this situation might not really be improved by an expensive camera.

----------------------------------------
And the following is probably not helpful to you, but might be interesting to someone...
if this were normal visible light (not IR light source) you would just add a colored filter to block the one color (and create contrast), ur use a colored light source. This is very common for monochrome imaging, which struggles to differentiate two colors if they have the same 'levels', like your plates. Not sure if that works the same in the IR spectrum (itll be two IR freq. not visible colors).... but you kinda see what i'm saying below. A different frequency of IR source or filter on the lens might help your situation dramatically, but I don't know enough to say for sure. (note: specific camera sensor brands are optimized for specific IR frequency ranges, so this needs to match your IR light source / some cameras brands might be better suited)

visible colors
View attachment 70504
monochrome (low contrast)
View attachment 70505
with filter on lens (blocks red, higher contrast)
View attachment 70506

various light source colors can reduce or improve contrast (for visible light) - you'd use the red light source in 'c' for better contrast of blue/yellow combos
View attachment 70507

images borrowed from A Practical Guide to Machine Vision Lighting

Very very interesting. You are correct about one of the biggest issues being gold on blue in my state has little contrast. Contrast adjustment in the camera has had little to no effect. I will read into this filtering you reference thanks!

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[cjowers]

I will read into this filtering you reference thanks!
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I wouldn't look too deep as I'm not sure how well it translates to IR LPR usage.
but it could maybe help if you decide to try a colored visible light source or a filter. If the main issue is due to dirt, you may still struggle to filter out the 'dirt' you want from 'the other dirt'. But thinking more, Polarizing filters can change the way reflected light appears, maybe the dirt would be less pronounced? those are at least cheap.

If the issue is not just dirt, but the plate reflects IR the same for letters/background, might be worth looking into.

Which of your images is of a definitely clean plate?


Have you taken the image wayyy darker? so only the plate is lit (still not saturated). it should work 2 fold: will appear more contrasted (humans see low blacks well), and it may actual have more accurate blacks. in general, i think oversaturation can cause added noise (electrons from adjacent pixels, delayed pixel recovery)

 

[achalmersman]

I wouldn't look too deep as I'm not sure how well it translates to IR LPR usage.
but it could maybe help if you decide to try a colored visible light source or a filter. If the main issue is due to dirt, you may still struggle to filter out the 'dirt' you want from 'the other dirt'. But thinking more, Polarizing filters can change the way reflected light appears, maybe the dirt would be less pronounced? those are at least cheap.

If the issue is not just dirt, but the plate reflects IR the same for letters/background, might be worth looking into.

Which of your images is of a definitely clean plate?


Have you taken the image wayyy darker? so only the plate is lit (still not saturated). it should work 2 fold: will appear more contrasted (humans see low blacks well), and it may actual have more accurate blacks. in general, i think oversaturation can cause added noise (electrons from adjacent pixels, delayed pixel recovery)

I cant go much darker or some plates won't appear at all. There was still some ambient light out when I took those which may contribute to it looking brighter than it should for a true night time plate read. Those were just examples of some plates I snapped a pic of with my cell phone in the 5 minutes before I left to give an example of the low contrast plate. I would say most of those plates are clean, the last example image is probably a dirty plate that looks clean to the human eye. I know for sure that last plate does not have any kind of cover or anything over it. If I wipes it with a damp paper towel it would probably be readable.

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[achalmersman]

Example of another install with same or extremely similar exposure settings. We also have black non reflective plates in this state. This is an example of why I can't go much darker. Luckily although these aren't reflective they are white letters on black background so contrast is good.

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[cjowers]

ah, ok. i got nothing for you then...

I was just reading some stuff from another frequent user on here, who uses gigE cameras (to have IR strobe control and exposure bracketing) to get both reflective and non-reflective plates. it takes say 3 rapid shots at different exposures, or uses a rapidly strobing IR source in sync with camera trigger i believe. only 1 of the 3 images will look good, and you just use that. it wouldn't work well with BI or whatever else your using, but thought I'd mention that there are solutions being worked on for exactly this.

Maybe you could have 2 cheap cams at the same location? with 2 different exposure settings / IR intensity light setups. 1 for reflective (and or dirty) plates, and 1 for non-reflective plates

 

[achalmersman]

ah, ok. i got nothing for you then...

I was just reading some stuff from another frequent user on here, who uses gigE cameras (to have IR strobe control and exposure bracketing) to get both reflective and non-reflective plates. it takes say 3 rapid shots at different exposures, or uses a rapidly strobing IR source in sync with camera trigger i believe. only 1 of the 3 images will look good, and you just use that. it wouldn't work well with BI or whatever else your using, but thought I'd mention that there are solutions being worked on for exactly this.

Maybe you could have 2 cheap cams at the same location? with 2 different exposure settings / IR intensity light setups. 1 for reflective (and or dirty) plates, and 1 for non-reflective plates

I've thought of that an although not ideal it would probably work pretty well. Interested in the bracketed exposure cam but yea you're probably right about it working with BI. I have my LPRs recording constantly because I dont trust the trigger hit activate on every car / lighting scenario.

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