Text OCR is the cannonical neural nets challenge (MNIST) so it seems natural to extend it to be something practical like LPR, without the insane difficulty of other real world shape recognition problems.
The easy ubiquity of LPR is essentially the death knell of privacy of movement. We'd have to move to encrypted transponders that only respond to queries with the right codes, but of course the police would still be able to know where you were whenever they liked. Rolling QR code digital number plates would work. But it won't happen.
Yes, what I found interesting the growth in articles discussing the technology and even open-source projects for LPRs. It's like vehicle facial recognition. Because of this, I've always been intrigued by subversive/defense techniques that fit into the realm of ML - like adversarial patches. Essentially, surveillance in some form is becoming ubiquitous, and private companies especially in the US will probably lead the way. It seems necessary to keep these systems in check at the citizen/individual level because political systems are out-paced by the rate of technological developments.
I like the "Rolling QR code digital number plates" concept; are you aware of rolling QR codes used elsewhere?
Recognizing individual vehicles is actually really difficult from a distance, because all the features are small -- scratches and dints at the 0.1-50mm scale, mm scale paint irregularities visible in other wavelenghts, misalignment of panels, window stickers etc. So licence plates are a huge reduction in privacy.
Other digital transponders, either for tolling or just your devices broadcasting their Wifi/Bluetooth addresses, certainly cause problems but they are within your scope to control.
It would be interesting to see if you could design an adversarial LPR jammer, that would not look to a cop like a licence plate.
When I wrote 'rolling code' I was being a bit off the cuff.
A PKI based system might be something like: {nonce,E(rego_pub,(nonce,car ID, date, hour)),S(car_priv,(nonce,car ID, date, hour))}, where rego_pub is the public key of the local authority, car_priv is the private key of the car, E is encrypt, S is sign.
This is already quite complicated, requires central PKI etc. And unfortunately QR codes themselves are not a great fit, because you need to be close to read them, but you could have a variant designed for shorter strings.
Another possibility might be to use a (prefix, TOTP code). With a fixed prefix indexed on car model/year (which is already visible from looking at it), the set of all TOTP codes from that fleet at that time could easily be searched by the registration authority to identify which vehicle it was. So, e.g., all blue Toyota Camry 2018s would have prefix 'P9J' and then a 10 minute changing code, like 'Y3KE'.
So if a cop needs to look up a car the LPR reads P9JY3KE. The local terminal says it should be a blue Camry, and then sends the string to the validator, which computes the TOTP for all vehicles in the class (like, 2000 in a group) and see if any of them match. If none match, pull them over.
There are a few problems with this still, e.g. replay attacks. But possibly solved by using IFF techniques, i.e. the police car can send a signed query forcing the named plate to show more digits of the TOTP code.
Criminals just steal the plates off another vehicle (of the same model/color if they are smarter), so maybe they can just steal the whole digital licence plate computer module? Unless the smart licence plate is part of the vehicle security system, on the car bus, it is still going to happen.
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The whole IOV (Internet of Vehicles), V2V (Vehicle to Vehicle) space is going to have to deal with these problems, and there is no shortage of protocols but I don't think it is remotely solved. Lots of companies pushing 5G approaches for this, but I wonder if transponders like for aircraft (ADS-B) or ships (AIS) won't be a simpler (and much cheaper) way, even if they are still using mm wave radios.
The easy ubiquity of LPR is essentially the death knell of privacy of movement. We'd have to move to encrypted transponders that only respond to queries with the right codes, but of course the police would still be able to know where you were whenever they liked. Rolling QR code digital number plates would work. But it won't happen.