Long range plate reading, a little lens experiment.

[kamkar]

As a experiment i put a 8 mm megapixel lens on the 0806 to see how far off licence plates are readable.

I have no exact specs on the lens other then what is above, got the lens off a 1080p IP camera so i assume its a 3Mpix lens.

Here is first some pics so you can see how narrow the FOV is compared to my lukas LK 7500.

First pic is grapped off the footage from the lukas. ( please note this is right after a FW update on the lukas so it run at a lesser bitrate )

Same spot with the modified 0806.

Back to the lukas.

And same spot with the modified 0806.

The 2 videos to compare.

Lukas.

Modified 0806.

In all i dont think the FOV is too narrow, looking at the little screen on the 0806 it seem like the oncomming cars is 3 M in front of my front bumper when they pass out of view.
And there is no doubt its possible to read plates at a distance where they are just a blur on the wide lukas lens.

I am allso sure this 8 mm lens is not of the highest grade, i really wish i had a lot of good lenses to experiment with, but sadly that seem to be expensive to get a bunch as prizes are around 60 dollars and up

 

[reverend]

How's it look with HDR off in say 2560x1080 mate as that would bring stuff closer again?

 

[kamkar]

That i hope to try out tomorrow, i might even get lucky and get a little sunshine to sweeten things up.

 

[russ331]

i really wish i had a lot of good lenses to experiment with, but sadly that seem to be expensive to get a bunch as prizes are around 60 dollars and up

Not sure if this helps, but alternative lenses have been tried on a Mobius...

http://www.rcgroups.com/forums/showpost.php?p=29502009&postcount=11618

http://www.rcgroups.com/forums/showpost.php?p=29765197

I think these lenses were quite inexpensive.

 

[petepete]

This number plate is read at 50meters using optics 8x magnification....

 

[kamkar]

not that long range M8.

 

[petepete]

not that long range M8.

just paced it out and it was 46 meters... my mistake .

 

[kamkar]

According to leupold laser rangefinder 116.5 M

but not dashcam footage.

 

[kamkar]

looool the player and movie maker cant handle the +1080P resolution the 0806 made today, i kinda wasent suprised movie maker folded on the larger format, but i did expect the player to be able to play todays recordings Microsoft in a nuttshell i guess.

Guess its VLC time then, dunno what to do as to editor right now.

 

[petepete]

According to leupold laser rangefinder 116.5 M

but not dashcam footage.

#

Nice and clear, but not dashcam footage...I take it you are not convinced mine is !!

But mine is dashcam footage and you can try it for yourself as you will have something in your house to do it in minutes...

let me know when you ve worked out how and agree mine is dashcam footage !!

 

[kamkar]

well if yours is not real then i dont know what is, I have had a simmilar view many times trying to videotape thru my rifle scope and my "large" mirror telescope.
I now use a small zoom lens so i can zoom in and get full use of the frame.
I keep forgetting to make a photo myself every time its full moon.
I have my Dslr attached to my scope from my air rifle, and i want to make a 20 mpix shot of the moon with crosshairs on it.

Allmost full frame, made with cheapo dualcam dashcam and a bord cctv camer 700 TVL.
Could not zoom in for 100 % full frame picture, the adaptor i made to hold camera to scope was a little to long at this time.

This one is with a G1W fitted with a 12-22 mm optical zoom lens, the G1w isent sensetive to IR light, this is 8 M distance thru my apaprment, the low res footage above shooting is 20 M.

The other pic of the parked cars is off my ip camera 20 x optical zoom + a little digital on top of that.

 

[petepete]

I was using a cheep set of 8x kids binoculars ... not possible to get camera lens in optimal position..

having looked at monoscopes on ebay for less than £10 with a much bigger more accommodating eyepiece that will mate to a dashcam - a couple of things strike me as possible which I will be testing with a view to never missing a numberplate...

 

[Dashmellow]

I was using a cheep set of 8x kids binoculars ... not possible to get camera lens in optimal position..

having looked at monoscopes on ebay for less than £10 with a much bigger more accommodating eyepiece that will mate to a dashcam - a couple of things strike me as possible which I will be testing with a view to never missing a numberplate...

The technique of attaching some sort of magnification optic to an existing dash cam lens can indeed work but is not really practical for the primary reason that the more optical elements you put in front of an existing lens, the less light is transmitted to the sensor. Doing this will not only make it more difficult to capture well exposed images in anything but the brightest conditions it will also degrade the sharpness of the images that are captured. It would also likely to be difficult to impossible to mount a monocular to a dash cam lens accurately enough to achieve true optical alignment and sharpness. Another issue is that if you use a telephoto magnification that is too strong for this purpose the images captured while driving will be so shaky (similarly to the sample video you posted, but more-so) that they would probably be unusable. @kamkar1's approach of replacing the existing lens with a longer focal length M12 x.05 lens designed to fit the existing mount is the better way to go about long range plate reading in my view.

 

[kamkar]

Indeed, even the best polished glass stop some ammount of light, using the G1W on my rifle scope the picture allmost go completely dark when i use the full zoom on the scope.
Doing the same with the much more light sensetive bord camera is no problem, if my memory serve me right i think the above clip with me shooting at night on cardbord is at full zoom on my scope.

Digiscoping is a cheap way to get started shoting things at a distance, but to really enjoy the hobby of photography its better still to use dedicated long range equipment.

I have allways wished i had one of those huge lenses one can see at the sideline of ballgames, the kind where the camera is mounted on the lens and not the usioal way where the lens is mounted on the camera.
BUT ! those carry a astronomical prize

 

[petepete]

The technique of attaching some sort of magnification optic to an existing dash cam lens can indeed work but is not really practical for the primary reason that the more optical elements you put in front of an existing lens, the less light is transmitted to the sensor. Doing this will not only make it more difficult to capture well exposed images in anything but the brightest conditions it will also degrade the sharpness of the images that are captured. It would also likely to be difficult to impossible to mount a monocular to a dash cam lens accurately enough to achieve true optical alignment and sharpness. Another issue is that if you use a telephoto magnification that is too strong for this purpose the images captured while driving will be so shaky (similarly to the sample video you posted, but more-so) that they would probably be unusable. @kamkar1's approach of replacing the existing lens with a longer focal length M12 x.05 lens designed to fit the existing mount is the better way to go about long range plate reading in my view.

problem with the m12 lens is I have not found any suitable that come with the ir filter for a reasonable price .. ( need one 5x magnification if you can tell me how many mm that is )

in the mean time...

I solved the problem of mounting the camera and on this dull low light day, the footage lacks no loss of light were the camera not viewing through additional lens....

The van is 75 meters from the camera. the blue car 45 with the focus not changed - both at 8x magnification but maybe 6x or less is all that is needed ( better field of view, less shaky ! ) to read passing/rear approaching number plates in the distance using this as a rear set up.

 

[kamkar]

Yeah finding lenses with IR filter, and beeing magapixel isent easy.

I an not sure what 5x would adde up to in mm lens, but i would guess on somthing like 30 mm.

I found some charts regarding cctv lenses.

The zoom lens in my ip camera is 94 mm at 20X optical zoom, so i assume 10x zoom is 47 mm, and so 5x zoom is 23.5 mm.

If you want to pete i have a non magapixel lens lying i can sent you to try out, it dont have ir filter, but it can maybe give you a idea as to what you might need in regard to zoom.
Its a 15 mm pinhole lens for use on 1/3 cmos chips

Its just some grams so no problem sending it to you in a padded envelope.

• Focal Length: 15mm
• F.O.V: 18 degrees (1/3 CCD)
• Aperture: 2.0

 

[petepete]

Thanks for the offer but i am looking into finding out exactly whats needed....

Having looked at your pictures and done some more research - the 8mm lens you have used with success is actually giving just less than 2x magnification determined by the change in image from the original lens that was easily measured.

Knowing that and having driven my car on digital 4x - probably all that's needed is a genuine optical 3 times magnification for nice steady capture.

 

[Dashmellow]

problem with the m12 lens is I have not found any suitable that come with the ir filter for a reasonable price .. ( need one 5x magnification if you can tell me how many mm that is )

in the mean time...

I solved the problem of mounting the camera and on this dull low light day, the footage lacks no loss of light were the camera not viewing through additional lens....

The van is 75 meters from the camera. the blue car 45 with the focus not changed - both at 8x magnification but maybe 6x or less is all that is needed ( better field of view, less shaky ! ) to read passing/rear approaching number plates in the distance using this as a rear set up.

I still believe you are going to run into various problems, but hey, what the hell.

Here is a dynamic lens calculator that might help you determine what focal length lens to purchase.

http://www.videologyinc.com/lens focal length calculator.htm

It is difficult to find M12 lenses that come with a pre-installed IR filter; you need to purchase an IR cut filter separately and install it yourself.
Here are a few of sources for filters and lenses:

http://www.m12lenses.com/IR-Cut-Filters-s/59.htm (good source for M12 lenses you won't likely find on eBay)

http://stores.ebay.com/rjcameraaccessorystore/cokin-filter-adapter-/_i.html?_fsub=19 (great resource for photography buffs)

http://www.surveilzone.com/cctv-lens/mtv-lens?zenid=1v0ogm4qgv45qev7j3bt8l3b62
another good selection of M12 lenses (free ww shipping)

 

[boilers]

As a experiment i put a 8 mm megapixel lens on the 0806 to see how far off licence plates are readable.

I have no exact specs on the lens other then what is above, got the lens off a 1080p IP camera so i assume its a 3Mpix lens.

Here is first some pics so you can see how narrow the FOV is compared to my lukas LK 7500.

First pic is grapped off the footage from the lukas. ( please note this is right after a FW update on the lukas so it run at a lesser bitrate )



Same spot with the modified 0806.




Back to the lukas.



And same spot with the modified 0806.



The 2 videos to compare.

Lukas.

Modified 0806.

In all i dont think the FOV is too narrow, looking at the little screen on the 0806 it seem like the oncomming cars is 3 M in front of my front bumper when they pass out of view.
And there is no doubt its possible to read plates at a distance where they are just a blur on the wide lukas lens.

I am allso sure this 8 mm lens is not of the highest grade, i really wish i had a lot of good lenses to experiment with, but sadly that seem to be expensive to get a bunch as prizes are around 60 dollars and up

I desire a lens that points rearward to capture faces. I get far more threats and those that are behind me are harder to perceive as my eyes are in the front of my head.
I would like to video the face and eyes of rear oncoming traffic, for moments before any issues (accidents, etc) to better ascertain the driver's focus and attention.
I had a semi truck driver rear end me. I think it was on purpose. He claimed accident. A lens pointing at his face would have given me evidence that would more than likely allow me to make the determination. If it was on purpose, he basically threatened my family's well being when he decided to see how close he could come to my rear bumper.

 

[kamkar]

I use to run the above mentioned 15 mm pinhole lens on a rear camera ( in my old 4 channel cctv setup )

The problem using a lens with this narrow FOV, it was good for me as ppl in line behind me was captured fine, but if i was a little to the right in the lane and they was a little to the left the driver would be out of frame.
And a semi driver or for that matter a van driver would disappear out of frame as he get closer to your car.

You can see the problem youself in this video where a guy not paying attencion and driving too fast allmost rearend me as i stop for yellow light as i am supposed to do.
As you can see i have a good shot at the drivers face allthough there is a lot of reflections of the sky in his windscreen.

Another video with footage from the rear camera, offcourse only low resolution recordings, but the level of reflections in the windscreen of the car behind make it problematic to capture faces, and i am not sure if a CPL filter would help on that.
you can see the diffference in reflections as he pass under the overpass, in that second its easy to see the driver.

Sadly i have no collection of megapixel lenses or i would have made a lot of experiments regarding these questions, but i think its safe to say that for front or rear cameras there is no viable single lens solution, so if one is demanding i see no other solution than to run with more cameras covering 1 angle.