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Augmented reality, enforced locality, geometric hashing

I had discussion with Lester Madden at linkedin MAR group. The thing we discussed was the concept of the locality in the AR. That is, each AR object should be attached to specific location and accessible only from that location.
I’ll try explain it more in depth here.
Augmented graffiti, augmented reality mail/drop boxes and billboards, user-built reality overlays – all of those should be attached to specific location. This locality could be enforced – only local data would be available (filtered into) in the specific location. This locality of data prevent user from sinking in the augmented noise, generated all other the world, and reduce possibility of spam.
For example you can have neighborhood billboard, leave note for the friends in the park and so on. All those AR objects data could be accessed only locally for both read and write – to read billboard and to post a message on it you would have to go to it.
The user should get the data/content only if he is physically present at the specific location. The same way poster/producer of the data or AR object should physically visit each location where it placed.
If locality is enforced, to place note for your friend in the park you have to visit park, and there is no way around it.
Locality could be enforced with location-based encryption. I think this encryption could be made with use of geometric hashing. User scan environment and make 3d registration with his mobile or wearable device. Encryption key is generated by mobile device from the scanned 3d model of the environment.
If user want to get data attached to the location, he access the server, retrieve local data and decrypt them with that key.
In the opposite direction, if user want to attach some object or data to location, mobile device encrypt data with part of the hash key and send other part of the key to server. Before storing data the server do uniqueness check. Nearby data already stored on the server are checked, and the new data allowed in only if there is some distance from new key to keys of all the other stored data. After that new data encrypted with the second part of the key by server and stored.
Each object encrypted by two keys, one of which is server side. Server have no access to content of the data, but have access to the part of the location hash key. That way no two objects or data attached to exactly the same location. Clattering of AR objects could be reduced. More importantly if poster have to physically visit location where he want to place AR object, he should have at least some relation to that location, and he is not some spammer from the other end of the world.
If spammer forge location key without actually visiting the place, that will most probably be non-existing location, and no one will be hit by his data.
That all is of cause is a rough outline of how could enforced locality works. Building robust algorithm for extracting geometric hash could be non-trivial.


1, May, 2009 - Posted by | Augmented Reality | , , , ,


  1. An interesting approach to spam/clutter reduction. But to me it seems overly restrictive. What if you wanted to leave a note for a friend/relative in say, another country? Why not just go down the user account road, i.e., to post on an AR channel you have to have login credentials.

    Comment by David Beaney | 2, May, 2009

  2. Sure you can do it, but that would be a general channel/overlay, available to everyone, not different form any net forum, twitter etc. or just some generic overlay, produced by trusted manufacturer. IMO general non-trusted overlays shouldn’t be turned on permanently. You can turn it on in some specific situation, or in specific places, like worldwide billboard. I think by default only local overlay should be on.

    Comment by mirror2image | 2, May, 2009

  3. I have just found this AR game, http://bit.ly/bVAa2 – it would not be possible at all with this approach.

    Any way, what you describe is trivial to do for any AR-enabled mobile device with GPS.

    Comment by makc3d | 15, May, 2009

  4. I was talking about global AR network for devices with permanent data connection. It is not directly related to games, it’s a general concept for data localization. Anyway GPS is not useful for enforcing locality. Enforced locality is a method of data encryption by using environment as the key. GPS coordinate is just a number. You can use it as a password, but it wouldn’t be better then any other password.

    Comment by mirror2image | 15, May, 2009

  5. хорошо, а чем видеовход, а точнее, извлекаемые из него данные, отличается от числа в данном контексте? предъявите алгоритму на вход видеозапись вместо реалтайма – и имеете гарантированный false positive. какой, собсно, смысл тут бороться с хакерами? если юзерю выгодно видеть данную информацию именно в данном месте, он будет именно так и поступать, а если выгодно в каком-либо другом – у вас ничего не получится.

    Comment by makc | 15, May, 2009

  6. на английском, чтобы не повторять если снова будет тот же вопрос:
    Video input – one-time asymmetric key. With minimal distance defined by some geometric metric it can not be modified for repeated use. To put it simple to use the same place second time you have to see it the from different side. This is enforced by server, but server have no access to data itself.
    Why to do it – to make data “tangible”, to give it some properties of the physical object, make it scarce. It could be used for community information, social networks, political actions, games, non-intrusive advertising. It of cause could be hacked with enough efforts, as could everything, but it couldn’t be reliably hacked.

    Comment by mirror2image | 15, May, 2009

  7. I like the general idea, but some parts may be unenforcable. I think the idea of different layers of AR would be appropriate. There could be a commerical layer of information, a physical one (shows structure like x-ray), general information, then you could have private layers like IRC channels.

    Viewing the information would be like pealing away the layers of an onion. Potentially, the layers could be very thick in areas that needed lots of information (like major cities).

    Also, I have an AR blog and would like to contact you with a few questions, but I could not find an email addy on your site. If you are interested, can you send me an email.

    Comment by Thomas K Carpenter | 9, June, 2009

  8. Comment by mirror2image | 9, June, 2009

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