Dedicated License Plate Cam project

[nayr]

fyi the big black face dahua ptz can actually look about 10-15 degrees above its horizon; extremely useful.

cam235's trying for an extremely difficult setup; I am shooting at almost half his distance and only get good results because of a great angle/fov.. getting results at that distance is going to be a trick.

commercial setups shoot at much closer distances for a good reason; its alot easier to achieve.

 

[blake]

Thanks Nayr! I'm going to have to order one for testing.

 

[cam235]

Nayr speaks the truth... 250-300 feet is a real challenge. Right now, using the 4MP Dahua with 40 mm lens I actually get legible-by-eye plates to about 250 ft at night. Not quite good enough image quality for reliable ALPR at this time. For example, below image is a 2x digital zoom of a car around 250 ft.

My long-range illuminator is homebrew, a single 850nm LED (one of 3 taken from an "IR Cannon") running just under 2 watts, with a car-headlight type lens. The big lens gives me a 1.9 degree beam which is 1/3 the spread of the cannon. Other things equal that would be 9x more intensity, but I have only 1 LED so my spot is just 3x brighter than the cannon at peak focus... if you can get the spot on the target, that is! With black foil wrapped around it, looks like a small theatrical lighting fixture.

 

[blake]

Thanks everybody. I'm looking at maybe 100ft-150 ft max.

 

[blake]

LTS just introduced their LPR Bullet Cam

 

[steve457]

LTS just introduced their LPR Bullet Cam

Oh nice. I may have to give it a try. I assume that the camera itself still cannot auto-detect plates, however, and that OpenLPR or similar would still need to be run?

 

[nayr]

correct, Hikvision/LTS charges nearly $2k for the ANPR software on the server side..

that camera just has white LED's instead of IR so it can run in color mode (lighting is going to be visible); and a nice deep varifocal lens that you dont find on typical cameras..

you could piece together equivalent capabilities with a bullet-box camera, except for the motorized zoom.

 

[blake]

So Nayr, do you think it's worth a try to purchase?

 

[nayr]

havent seen the cost; but in my experience commercial solutions and residential solutions are vastly different.. for nearly all commercial applications the intent is to install it low and close on industrial grade mounting structures.. like on a post at a electronic gate/parking lot entrance where functionality beats form.. no compromises are made in using the correct install location.

for those of us doing this at home; rarely can you ignore form over function.. the best spot to do the job is compromised by city easements, aesthetics, landscaping, trees, road parking, etc.. hanging a metal terrace over the public road with cameras and lights hanging off it is not what anyone will accept at home.. unless your very rural w/out neighbors, or code enforcement, or anything like that to worry about.

I could setup OpenALPR with a generic box camera and a couple spotlights in commercial environments all day long and never run into big issues; because I'd tell em this is where the camera has to go and I would not compromise a bit, if they wont let me put a camera there then the ANPR is removed from the bid and they can find someone else to do all the dicking about trying to find a solution.. I also would not care if the cost of the camera was absurd; I'd be charing an absurd amount for such a gig.

Residential ALPR/ANPR is a whole different beast thats going to take a metric ton of planning, testing, adjusting, testing, adjusting, researching, learning, then repeating.. Every environment is going to be different, some lucky people will find an easy solution.. many others will find they have no good options at all, and most are going to have to be willing to compromise on some level or another.

 

[blake]

Everything I've been doing is residential, but looking at future commercial possible project that may need LPR.

 

[j4co]

Would the new IPC-HF5231E box starlight 2MP be a good unit for lpr camera ?
IPC-HF5231E | Dahua Technology

If you can add a lens that brings you close enough to do enough pixels for reliable results, does the 2 MP matter ?
I bought a light cannot already, but need to wait for new house built, but i could prepare cable runs now in the planning phase.

I will have garage/carport near the fence which will be at about 250 cm high.
That looks at an angle on the road which is the entry to the street where the houses are on.

This is a very rough drawing (copyd house outline into the environment drawing) but it shows the environment pretty well.

Number 1 is the road.
The area marked 3 are car parking positions.
Number 6 is walking path in between bushes or lawn (short type of grass or lower plants) and higher bushes (will grown in time, but has all kind of trees.
The trees/bushes are listed as:
Prunus spinosa (1½ tot 3 metres)
Cornus mas (5 en 6 metres)
Ligustrum vulgare (5 metrer)
Crataegus monogyna (5–14 metres)
Rosa canina (1 tot 3 metres)
Viburnum opulus (1.80 - 3 metres)
Euonymus europeaus (4 to 5 metres)

Some of them will grow beyond the camera height so I should stay away from that area.

Could move the camera to green position on the carport roof also, so angle would be less, but distance somewhat longer.
Distance of the area where we built on is like 25 meter deep. So the orange lines are under 20 meter lenght.

Perhaps I could install it lower at just above 2 meter height so it would look direct over the fence wall I intend to install. I will have a Pole for the perimeter units, and could make a bird house on top of it.

The arrow points North, so there will not be any sunlight into this lens.
Only issue might be the * sign with yellow circle round it, in the drawing, which are public lamp posts and they tend to be on when it is dark throughout the night.

I see one other issue, it is max 30 kmh speed there, but people tend to drive faster. Will that be an issue for LPR ?

 

[nayr]

The light sensitivity of starlight is not needed for LPR but I suppose it wont hurt, and at the shutter speeds needed people's driving speeds wont matter much.. The extra WDR might help though in the daytime.

Your gonna need a lens to go with it, probably a 50mm or 60mm.. those box cameras dont come w/lenses

 

[j4co]

I did understand I would need a lens to go along with that. I could use the often referenced calculator and see what it does at 2MP and 20 meters (with different lenses)

edit:
With 35 mm lens (on 1/2.8 sensor) I will have 5.12 meter wide scene (about size road) and 375 ppm on 22 meter distance.

Would it make sense to try to take recordings near the lamp post, so I have that light also to use in night time ? So slightly move it down ?

 

[nayr]

street lighting wont do squat for you; your going to need fairly bright external light source at the camera's location to activate the retroreflectors on the plates.. more than a few degrees of separation and it wont flare up the plate.. yeh gotta get the plate as bright as the headlamps to be seen at 1-3ms shutter speeds.

lenses for these will be varifocal, I doubt you'll run em at full zoom but you'll want something about those sizes to give you the range needed.. I suspect you'll land between 35-40mm in actuality.. a 50-60mm varifocal should give you some headroom to play with install locations.. ie moving it further away to get a better angle.

You'll also need an external script to refocus the camera twice a day via backfocus; the focal point for IR light at that distance is enough to present problems when you switch between day/night.. either that or very expensive lenses are nessicary to correct for this.. my lens is supposedly IR corrected but still needed to be refocused; was not corrected enough or really at all but it was cheap.

 

[j4co]

Thx, i have a ir canon already, 20% off on the ali 11-11 sale.
Since i like your birdhouse, that will be my example. So boxed camera with varivocal lens and ir cannon at same position

 

[mauzer]

Thx, i have a ir canon already, 20% off on the ali 11-11 sale.
Since i like your birdhouse, that will be my example. So boxed camera with varivocal lens and ir cannon at same position

Could you share the link of IR canon, please?

 

[j4co]

CCTV 850nm IR Array Led IR Light (5 90 degree IR) DC12V Night vision IR Infrared Illuminator For IR AHD SDI HD CAM-in CCTV Accessories from Security & Protection on Aliexpress.com | Alibaba Group
5-50 meter 3.6 watts

Not the same as nayr has i think.
They have video on there that shows something like hot spotting on maximal zoom. No idea if this will be an issue. I will need it at 25 meter max, so hope it will do.

Nayr seems to have this type:
CCTV 850nm WideAngle 10 90 Degree 3pcs High Power Adjustment Focusing LED Array 80M IR Illuminator Lighting for Camera IR-in CCTV Accessories from Security & Protection on Aliexpress.com | Alibaba Group

10-80 meters, 7.2 watts.

The video or at least the effect on full zoom seems the same. It is sort of showing the Number and pattern of the diodes there. But i assume you use it just before that setting.

 

[j4co]

I even found a lens with starlight in the name

F1.4 elctrical iris 5-60 mm with CS mount. $60

Super HD 3.0Megapixel Auto Iris Varifocal 5 50mm IR CCTV HD Lens Starlight CS Mount For Road Bank Supermarket Monitor F1.4-in CCTV Lenses from Security & Protection on Aliexpress.com | Alibaba Group

Is not listed for camera though.

This one is: ricom 5-50 F1.4 $38
Free shipping 5 50mm CCTV camera lens F1.4 1/3", auto iris manual zoom lens, vga cctv cs mount lens-in CCTV Lenses from Security & Protection on Aliexpress.com | Alibaba Group

How much that F1.4 is true i doubt a bit though..

And the lens nayr seems to have: 6-60 mm F1.6 $40
Free shipping cctv lens 6 60mm F1.6 1/3" DC Driven Auto Iris Vari Focal, CS mount lens for security cameras. VGA lens-in CCTV Lenses from Security & Protection on Aliexpress.com | Alibaba Group


10-120 F1.6 $70
10 120mm Auto iris 1/3" F1.6 cs mount cctv lens for box cameras, 1.3 mp ip camera lens-in CCTV Lenses from Security & Protection on Aliexpress.com | Alibaba Group

Again, so much zoom and than for whole range F1.6 ?


And those number raise a question..

If a lens is stated to be for a 1/3" sensor, and you use it for 1/2.8" sensor, the mm notation does not match anymore i assume, but that is less important.
However if the light path is like 1/3" it is smaller than a 1/2.8".

Would this lens for a 1/1.8" be working for example ?

Aliexpress.com : Buy 3 megapixel lens 12 50mm vari auto iris 1/1.8" F1.4, camera lens, cs mount cctv lens for ip cameras from Reliable lens webcam suppliers on Wellcam Lens

This is than F1.4/1.5 and 10-50 mm. should perhaps have better optics for the larger light path ?
It is more expensige with $74

 

[nayr]

You can use a larger lens on a smaller sensor, so a 1/2.8 will work on a 1/3rd or 1/4th but if you put a 1/4th on a 1/3rd or a 1/2.8 you'll see the lens in the image and it'll create a barrel effect.

for the 1080p starlight camera you'll want a 1/2.8 specific more than likely.

 

[j4co]

i just read up on it, and was posting it but the stupid ipad window refreshed.

The sort of describe it here: Camera Lenses for Machine Vision
So to small a lens it is called vignetting, and to large a lens it would be cropping, and that is less an issue.

It seems if i would add a 1/1.8" lens to a 1/2.8" sensor the 50 mm would become a 1.4 x big as 70 mm sort of. Info from the link in this post.

A 8mm lens for 1" lens on a 1/2" sensor

And the same 8 mm 1" lens on a 2/3" sensor

So less pixels because of the smaller sensor, but field of view is like zoomed in, if i understand it.

It is the field of view that changes i think.

That linked site is a bit off with the info i think..

1/1.8" sensor = 9 mm diagonal, but other sites: 9.17 mm.
1/2.0" sensor = 8 mm diagonal, other site: 8.25 mm