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Finding Yourself With Photo Recognition
itchyfish writes "You are lost in a foreign city, you don't speak the language and you are late for your meeting. What do you do? Take out your cellphone, photograph the nearest building and press send.
For a small fee, photo recognition software on a remote server works out precisely where you are, and sends back directions that will get you to your destination.
Seems a little far fetched, but amazingly cool if it really works."
The software then looks for useful features, such as the corners of windows and doors, and extracts the colours and intensities of the pixels around them. Next, it searches the image database for matching data, using the base station the cellphone's signal came from as a guide. Finally, it uses the differences between the two images to calculate the photographer's position.
To me, it would appear that an easier solution might be to use GIS data in combination with the cell phone signal and comparisons of rough morphological features of buildings. The instructions should simply be: Point your camera at a building near you so that you can approximate its outline and then send that image. This would scale much larger than the methods referenced in the article as you would not have to store every detail of the buildings surrounding you including pixel maps of textures and color. This approach could be handled for a large city by a few commodity servers whereas the other approach would require significantly more computational resources.
Imagine how difficult it would be to capture details like that in a major city such as NYC? I don't really need directions to find my way around Cambridge city center as you could almost throw a rock from the center and hit just about every building around, but London, Washington, Houston etc... are another story and the data required from their approach would require massive computational infrastructure.
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Some problems that I can see with it. What if your in a flat area with no buildings, landmarks, etc? Or even worse, a very rocky, natural area (say something similar to the grand canyon). And even barring those problems, wouldn't GPS just plain be easier? Take the same concept, have the phone grab its GPS location, have you enter the address you want to go, and both pieces of information are sent and the phone gets its route to get you where you want to go (with associated fee). Seems cool, though.
If the photo is taken and the data on the server isn't updated very frequently, couldn't items like cars and other movable objects interfere with the location calculation, as it bases it highly off of the details of the location?
Ideally, the much sought after all in one convergence device (fone/pda/etc.) would have built-in GPS, negating the need for this otherwise functionally sound service.
I wouldn't invest to much into this technology, as I think it'll be obsoleted before it comes to fruition.
-PHiZ
Pretend I said something meaningful or insightful here.
I can just image the server's cpu goes up to 100% when I send in a photo of McDonald's.
Is this really necessary? Not everything needs to be so darned tech, you know... maybe we should just get a map and use that.
This seems like an overly complicated solution. At the moment, my phone in Japan has a feature where I logon to Vodafone's website (from the phone) and click through a couple of links and then it tells me where I am. I assume it gets this information by figuring out which cell the phone is dialing from. From the subsequent menus, there are various options like "find the last train to station X", "find the nearest place to catch a taxi", and so on. A few months ago it was only available in Japanese, but now they've introduced a bilingual version - hoochie mamma.
Why bother using the fancy-dancy image recognition software when cellular telephony has a built-in system that basically acts like a constantly-updated "user location" variable?
(Actually, the answer is simple - to make geeks foam at the mouth. Come on now people!! Excess ain't rebellion.)
--
...Whether my Maker is prepared for the great ordeal of meeting me is another matter.
Churchill
Dear All,
Wow! Thank you very much for all your comments on this mobile phone navigation system. I thought I'd throw in my 2 cents worth since I'm one of the people who invented it! Forgive the lack of structure in what follows, but I'm trying to address several different issues raised throughout this discussion...
Yes, another way of doing this is radio signal triangulation (including GPS). But actually, this method doesn't work too well in cities because of things like multipath effects and satellite visibility (BTW our system isn't designed to work outside urban environments). GPS car navigation systems rely on a combination of GPS and inertial sensors, i.e. they take a sort of average of a large number of inaccurate readings to get a good fix on position. But the simpler positioning strategies are unlikely to give good enough acccuracy to establish on which side of the street you are standing (and in any case, they don't tell you whhat direction you're looking in). GPS is also expensive: most people would not be prepared to pay more for a phone with an in-built GPS receiver - but camera phones are already selling well.
No, we're not going to build a database of every building in the world! But a good place to start would be large city centres. FYI what motivated us to invent this system was the familiar problem of getting lost outside London tube stations. Obviously I know which tube station I'm at but I don't usually know which exit I took or what direction I'm facing. Of course I can retrieve a local map via my mobile phone. But the problem is I'm missing that critical "you are here" dot that tells me where to start. This is where our system comes in: by providing the dot (well, an arrow actually because it tells you which direction you're looking in too).
In practice, builing a database is easier than you might think. Probably we could do it with nothing more than a video camera attached to a car. Granted someone will have to drive down the streets of interest but only once (and this shouldn't be too difficult in somewhere like New York).
Finally, no, movable objects don't cause too many problems. The system uses a feature based strategy that is robust to 'clutter' in the form of things like cars, pedestrians, changing shop window displays, etc. That being said, there will always be ways of confusing it, e.g. by demolishing a building. But supposing that picture messages will one day cost as little as text messages do now, a system that works almost instantaneously and gets it right 99% of the time sounds as if it might have some commercial potential at least. And what if the hypothetical tourist isn't lost but just interested? For example, the system could return information about the history of any building of interest in the middle of Venice.
Yours,
Duncan Robertson