e-Toll Gantries: How they work

[shogun]

The OCR device and transceiver will work in tune, so the no-gooder will have to copy the plates as well.

The whole point of the tag is to get a better read rate because OCR is not the optimal solution. Why else would they need it? OCR alone is going to give them major headaches. Computer vision of number plates is very tricky (even with infrared / UV filters and the like), and is unlikely to be 100%. In fact I would imagine the read rates are pretty bad actually, with a number of false reads. If the OCR was without problems they wouldn't even bother with e-tags. If I was in JHB, I'd be staying well clear of e-tags for a long while, and would first determine just how effective their OCR is. Having played around with OCR on number plates, I imagine they would have to have quite a contingent of manual human backup in place to deal with untagged vehicles.

Oops, was that a little mud splattered on parts of the numberplate? My bad.

 

[creeper]

The whole point of the tag is to get a better read rate because OCR is not the optimal solution. Why else would they need it? OCR alone is going to give them major headaches. Computer vision of number plates is very tricky (even with infrared / UV filters and the like), and is unlikely to be 100%. In fact I would imagine the read rates are pretty bad actually, with a number of false reads. If the OCR was without problems they wouldn't even bother with e-tags. If I was in JHB, I'd be staying well clear of e-tags for a long while, and would first determine just how effective their OCR is. Having played around with OCR on number plates, I imagine they would have to have quite a contingent of manual human backup in place to deal with untagged vehicles.

Oops, was that a little mud splattered on parts of the numberplate? My bad.

I'm selling spray on mud if anyone is interested

 

[Messugga]

I wondered about this....

The gantry scans your tag as you pass under it, this info moves from the gantry to a server located where and how is the info moved?

The info is stored locally and transmitted to one of several sites where it is processed further. This includes all video feeds and tag information.

 

[Messugga]

I wondered about this....

The gantry scans your tag as you pass under it, this info moves from the gantry to a server located where and how is the info moved?

Fibre network provided by Neotel with multiple VPNs to keep everything separate. Fail overs are in place.

 

[Messugga]

Another one, where does the gantry source it's power from? Is there a backup power source? , just in case somebody steals the cable?

City power provides the juice. There is a UPS and generator at each site so they can run indefinitely provided the generator fuel is filled up when it gets low.

 

[froot]

The whole point of the tag is to get a better read rate because OCR is not the optimal solution. Why else would they need it? OCR alone is going to give them major headaches. Computer vision of number plates is very tricky (even with infrared / UV filters and the like), and is unlikely to be 100%. In fact I would imagine the read rates are pretty bad actually, with a number of false reads. If the OCR was without problems they wouldn't even bother with e-tags. If I was in JHB, I'd be staying well clear of e-tags for a long while, and would first determine just how effective their OCR is. Having played around with OCR on number plates, I imagine they would have to have quite a contingent of manual human backup in place to deal with untagged vehicles.

Oops, was that a little mud splattered on parts of the numberplate? My bad.

This is a very serious problem for any license plate recognition system - the systems are, assuming the specific plate type exists in its system, it has the ability to have an accuracy of 99.5% (the 0.5% inaccuracy is due to old or weathered plates). Now splatter some mud on certain parts of the plates so that letters can be misread as either or - ie O->C, B->D, I -> I, etc. Changing one letter on a plate will really screw up the ability for a LPR system to recognise the plate.

 

[Kelerei]

This is a very serious problem for any license plate recognition system - the systems are, assuming the specific plate type exists in its system, it has the ability to have an accuracy of 99.5% (the 0.5% inaccuracy is due to old or weathered plates). Now splatter some mud on certain parts of the plates so that letters can be misread as either or - ie O->C, B->D, I -> I, etc. Changing one letter on a plate will really screw up the ability for a LPR system to recognise the plate.

The FE-Schrift typeface (which is used on South African license plates) is specifically designed to mitigate this problem. From Wikipedia:

The motivation for the creation of the typeface was spun in the late 1970s in the light of Red Army Faction terrorism when it was discovered that with the then-standard font for vehicle registration plates—the DIN 1451 font—it was particularly easy to modify letters by applying a small amount of black paint or tape. For example, it was easy to change a "P" to an "R" or "B", a "3" to an "8", or an "L" or "F" to an "E". Modifications to FE-font plates are somewhat more difficult, as they also require the use of white paint, which is easily distinguished at a distance from the retroreflective white background of the plate, in particular at night.

The original design for the FE-Schrift typeface has been created by Karlgeorg Hoefer who was working for the Bundesanstalt für Straßenwesen (Federal Highway Research Institute of Germany) at the time. The typeface was slightly modified according to the results of tests that lasted from 1978 to 1980 at the University of Giessen (Dept. of Physiology and Cybernetic Psychology).[3] Whilst the DIN typeface was using a proportional font, the FE-Schrift is a monospaced font (with different spacing for letters and numbers) for improved machine readability. Faked FE-Schrift letters (e.g., "P" to "R") appear conspicuously disproportionate.

The biggest issue will likely be the quality of the OCR software.

 

[koeksGHT]

They are a joke.

Public acceptance of an EVR solution: Due to the
authority related focus of the main applications, public
acceptance may be an issue. The acceptance can be raised
through direct benefits for road users (e.g. user focussed
services) or road user oriented applications (e.g. parking
and payment solutions, offering efficient and convenient
ways to pay for services).

 

[bboy]

So.. 1 x pellet gun and a stroll down the road = no more cameras/sensors/uv lights working?
Then we just need a jammer to overload the frequency on the tags.

 

[spiderz]

http://www.wikihow.com/Build-an-EMP-Generator

 

[b_crazy]

What's stopping Sanral from forcing newly registered cars to buy e-tags, as part of new vehicle registration?

The next obvious question is how long before people are forced to buy e-tags at their car's next license renewal?

 

[creeper]

What's stopping Sanral from forcing newly registered cars to buy e-tags, as part of new vehicle registration?

The next obvious question is how long before people are forced to buy e-tags at their car's next license renewal?

To my understanding, they will need to changethe RTA and Etoll act to do this. Remember. Etag buy is not mandatory

 

[The_Unbeliever]

I'll "charge" my etag with 10 minutes on full in the microwave prior to use should they start to force us to buy these ****.

Besides, forcing people to buy etags will be unconstitutional, and will open a whole can of whoop-ass worms.

 

[Bismuth]

I'll "charge" my etag with 10 minutes on full in the microwave prior to use should they start to force us to buy these ****.

Besides, forcing people to buy etags will be unconstitutional, and will open a whole can of whoop-ass worms.

Indeed, if I am forced to get one, then I will also charge it in the microwave. I hear that is the latest trend in wireless charging!

B

 

[b_crazy]

Indeed, if I am forced to get one, then I will also charge it in the microwave. I hear that is the latest trend in wireless charging!

B

Will that work on my phone?

 

[Lukcydog]

I used to work in this field so I can give a basic idea. The tag is based on RFID technology, so in theory when you drive through the gate, the RFID is triggered to pulse its information to the gantry. This is the easy solution for e-tolling.

You will see that there are the black lights and cameras posted next to each other. The white area of a car's number plate is designed/painted to reflect black light which are then picked up by the cameras as a black and white image. You will also see that there are paint markings on the road under the gantry that are used as trigger points. The trigger points initiate the taking of pictures as well as determining the class of vehicle currently passing the gantry. They then have a server/s that process the images to retrieve the number plate, length of vehicle. They also take a picture of the vehicle as part of the record in case of a dispute from clients. The problem with number plate recognition is the fact that typical accuracy is 94% (to reach 98% accuracy starts costing so much its not feasible), which leaves a massive margin of undetectable plates. So if a plate can't be recognised automatically, they have to manually annotate the "toll" which will be at cost to them. I don't know what camera's they are using but we used to use ARHungary's product (currently running at ACSA aiports when you go into the parking area where you pull your ticket) which is incredibly fast, very accurate, but very very expensive. The one used for e-toll look like a cheaper solution. So SANRAL want you to use tags, because it makes they life very very easy in terms of maintenance and effort.

I hope someone finds this interesting.

 

[Duan]

@Luckydog Wow, very informative! Thank you for sharing!

When I have some time I will review the thread to date and enhance the first posts in the thread!

 

[b_crazy]

So, according to Lukcydog, if, say, half of a license plate is white, but doesn't reflect the black light back to the camera.... and you don't have an e-tag.... The manual overhead required to physically annotate each car (which will cost them) is massive. Interesting.

 

[czc]

So what if you paint your number plates with invisible paint. Will the black light pick it up and give them a blank number plate?

 

[Messugga]

I used to work in this field so I can give a basic idea. The tag is based on RFID technology, so in theory when you drive through the gate, the RFID is triggered to pulse its information to the gantry. This is the easy solution for e-tolling.

You will see that there are the black lights and cameras posted next to each other. The white area of a car's number plate is designed/painted to reflect black light which are then picked up by the cameras as a black and white image. You will also see that there are paint markings on the road under the gantry that are used as trigger points. The trigger points initiate the taking of pictures as well as determining the class of vehicle currently passing the gantry. They then have a server/s that process the images to retrieve the number plate, length of vehicle. They also take a picture of the vehicle as part of the record in case of a dispute from clients. The problem with number plate recognition is the fact that typical accuracy is 94% (to reach 98% accuracy starts costing so much its not feasible), which leaves a massive margin of undetectable plates. So if a plate can't be recognised automatically, they have to manually annotate the "toll" which will be at cost to them. I don't know what camera's they are using but we used to use ARHungary's product (currently running at ACSA aiports when you go into the parking area where you pull your ticket) which is incredibly fast, very accurate, but very very expensive. The one used for e-toll look like a cheaper solution. So SANRAL want you to use tags, because it makes they life very very easy in terms of maintenance and effort.

I hope someone finds this interesting.

I can't speak about accuracy, but having discussed their capabilities with one of the senior techs, these cameras seem to be very, very fast. I have a couple of ideas in mind on how to bypass the camera's with great success, it's just quite illegal, so I would need to think of how to approach this correctly, if I were inclined to proceed with bypassing their tolling.

My car is pretty rare on the roads, so if they were waiting for me to pass, I'd be screwed. If I drove a white Polo or something equally frequent on the roads, I'd be golden.