Transform Cellphones Into a CCTV Swarm

holy_calamity writes "Swiss researchers have developed java software that has bluetooth-capable camera phones form a distributed camera network. Each phone shares information on visual events with its neighbours and can work out the spatial position of phones around it (pdf). The software will become open source sometime next year, and the creators say it could be used to make a quick and dirty surveillance system. 'The phones currently use the average speed people walk to guess the distances between themselves, based on how long people take to move from one phone's view to another's. In testing, the system determined the distances between each phone with about 95% accuracy. They were placed 4 metres apart, making it accurate to about 20 centimetres. In future, recording the speed at which objects pass by would make more accurate judgments possible.'"

scary

[facon12]

now every time i visit someones house and see a cell phone just lying somewhere im gonna wonder....

So...

[Smordnys s'regrepsA]

...now stalking my favorite celebrity can be a group event!

Open source surveillance

[PhysicsPhil]

Does the fact that this will be an open-source application compensate for the fact that this introduces yet another method of surveillance into society?

Re:

[Aladrin]

It'll depend on how instrumental it is in bringing about Skynet. Personally, I think it'll be pretty useful for it, so it goes in the 'evil' bucket. (Despite how unutterably cool it is.)

Re:

[KudyardRipling]

Human nature is finally recognized for what it is. If given the opportunity, any human being would exercise supreme authority over other human beings.

Downmodding posts is like destroying bugs; it is an admission of guilt.

Re:

[facon12]

yes, it may be used to invade privacy, violate civil rights if used by the government, and for stalking, but everyone can do it equally, and that makes it ok.

Re:

[ShieldW0lf]

Sounds like something that should be mandatory for anyone engaging in civil disobedience.

Re:

[edunbar93]

And more importantly, pervasive surveillance. Just you wait until they make public displays of affection illegal.

Re:Open source surveillance

[fm6]

Or even worse, mandatory!

Re:Open source surveillance

[jibster]

Maybe the glass is half full.

Think of a peaceful protest group using, an admittedly far superior, form of this to camera swarm the police. The perpetrator of any action, a policeman clubbing an innocent citizen for instance, might question their actions if they knew they were surrounded by this swarm.

Re:Open source surveillance

[VE3MTM]

There's a name for this: it's called "Sousveillance [wikipedia.org]".

SOMEBODY MOD THIS MAN UP

[ClioCJS]

(because I was going to say the same thing)

Other possible results

[TheLink]

I think everyone should start to grow thicker skin if it starts becoming common to be surrounded by swarms of independently controlled video cameras.

Not because you might get "clubbed", but more because you're potentially just one embarassing step/move from being the next "Youtube star".

Dig your nose in public in an unusual way or something worse, and maybe someone might sync it to music, add some sound effects. Next thing you know, you get a whole discussion on wikipedia on whether you're notable or not, w

Re:

[ackthpt]

Does the fact that this will be an open-source application compensate for the fact that this introduces yet another method of surveillance into society?

First single nanotube radios, now this. We're gonna need more than one tin-foil hat.

Be glad they are colour CCDs, the B/W CCDs are about 4 times more sensitive and will pick up more detail in lower light. Should you see a cellphone which looks like someone has operated on it and sports a thermoelectric cooling unit, you should be afraid, very afraid.

"lowlight sensitive and low noise, now just imagine a beowulf cluster of them!"
"i can't, i'm thinking how in soviet russia cell phones will be calling o

Re:

[TheCRAIGGERS]

thermoelectric cooling unit

My battery life is bad enough, thank you.

Re:

[Reality Master 101]

Clearly we all need to start wrapping tinfoil around our cell phones as well as our heads.

Re:

[davidsyes]

And, you can bet that AT&T will dip their grungy fingers into the code and obsequiously supply the alphabet soup names agencies with code to throw off the positioning far worse than GPS. They'll supply them with real-time image detection and distortion capabilities. Maybe even bluescreen/reboot the phone as a mild warning, or outright cripple the service. After all, the government HATES competition...

Re:

[KevReedUK]

RTFS!

Remind me how much you are paying for BLUETOOTH transfer of information again? I could do with a giggle!

Holy privacy violations Batman!

[edunbar93]

it could be used to make a quick and dirty surveillance system

Emphasis on "dirty". People take those things into their homes and leave them on their bedroom end-tables you know.

Re:

[zaffir]

I don't do that, but I think I'll start once this software is out there :D

The real question at hand here.

[blhack]

But does it run skullbocks?

F&TF3: Tokyo Drift

[OctoberSky]

Is this basically the last drive sequence of F&TF3: Tokyo Drift?

Where all the kids are viewing/filming the race down the mountain as it goes by?

I thought that technology (well, that CGI) was rediculous but maybe it's not that far away?

(NOTE: Give me Karma, I admitted to watching that movie, that's gotta count for something).

Umm.....and the purpose?

[Seakip18]

I can see this being advantageous for single system, but for people in general? This just reeks of being impractical.

For one, no one I KNOW walks with their cameras out in front of them, so the cameras would have setup such a way such that there is a single camera dedicated to capture the event. How do you know a camera is going to capture an event in the first place? Seriously, phones are for talking, not being your peeping-tom from afar.

Now for virii spreading purposes, this sounds awesome. Just set a pho

Re:

[LinEagle]

Now for virii spreading purposes should be... Now for virus spreading purposes

There, fixed it for you.

Re:

[Troed]

Seriously, phones are for talking

You must be a USian. The rest of the world moved on a long time ago. The "phone" is the mobile Internet and media companion in your pocket - the digital "you".

Re:

[Seakip18]

Actually, I use my phone for streaming media, checking email and goggle maps. The point I'm making here is that if you want a surveillance camera, your phone is a poor substitute for one. Just like it is a poor substitute for a web browser, video playback or a folded map(or does the digital age eschew all things dead tree based?). It'll get the job done, but not necessarily the best. What your does better than those previous devices, is handle phone calls.

And sorry about the virii slipup. Damn flu shot I go

Re:

[Torvaun]

You must be thinking of my PDA, not my phone.

Re:

[Troed]

The number of people willingly carrying around several devices so closely matched in size and features are so low that they're not an interesting share of the market.

Q: Why did Apple make the iPhone?
A: They knew mobiles (Sony Ericsson Walkman amongst others) would take over their iPod business

Re:

[ShieldW0lf]

I can see this being advantageous for single system, but for people in general? This just reeks of being impractical.

For one, no one I KNOW walks with their cameras out in front of them, so the cameras would have setup such a way such that there is a single camera dedicated to capture the event. How do you know a camera is going to capture an event in the first place? Seriously, phones are for talking, not being your peeping-tom from afar.

It would be pretty easy to strap a cell phone to your vest, wou

Re:

[geekoid]

"Seriously, phones are for talking, not being your peeping-tom from afar."

Thanks for the thought, gramps.

Seriously though, when something that does happen people want to record, there will be several people recording it. That is when it is useful.

The bigger the event, the more people will be recording it. Most of the time, the bigger the event the more important it is.

Re:

[zero_offset]

For one, no one I KNOW walks with their cameras out in front of them, so the cameras would have setup such a way such that there is a single camera dedicated to capture the event. How do you know a camera is going to capture an event in the first place?

RTFA. The positions of the phones are assumed to be static. They use the motion of people around them to work out a few basic things about their relative positions, and that's really about it. The slash blurb makes it sound a lot more interesting than it real

I predict

[Buelldozer]

That the police are going to really dislike this.

Re:

[poetmatt]

I always knew 360 degree camera porn was coming

Re:

[Maxo-Texas]

Oh my.

Bullet-time, swoop around come shots?

Actually, in slow mo- people's bodies look disturbingly ripply.

Re:

[poetmatt]

Somehow I didn't exactly think my plan through that far. Definitely not. Something about "gettin jiggy with it" I have a hard time visualizing in this case, it seems more like T-Rex from Orgasmo.

Re:

[mpe]

That the police are going to really dislike this.

Especially if there is no easy way to cause it to malfunction. As often appears to be the case with publically accessiable webcams near the site of any kind of demonstration. Even more so if the resolution is high enough to clearly see police officers faces and/or read their badges.

concert-recording on the cheap

[smellsofbikes]

I've spent some time designing and programming (but will never finish) something similar to this, just using cellphones' audio capabilities. Imagine getting twenty random people at a concert to call into a server and leave their cellphones running, recording the concert from twenty different points. From the overall stream, you should be able to derive an excellent, local-noise-removed bootleg, and from a bit of playing with signal intensities you should be able to figure out where the individual recorders were and do some nice sound balancing.

We're all carrying these great little computers: we should start doing networked or collaborative stuff with them.

Re:

[NeoSkandranon]

That seems really interesting but (Warning: non audio engineer question ahead) How would you deal with the distortion the audio goes through between transmission and general crappy quality input (ie microphones) on the phones themselves?

I guess the little dinky mic may not be so different from a typical bootleg though...Still, neat idea. It makes sense that you could do that kind of manipulation, but I'd never really considered it (Signals *really* is not my forte)

Re:

[smellsofbikes]

Yeah, it'd be crap. My hope is that by using multiple microphones and relying on the fact that they're bad in different ways, you'd be able to derive a fair amount of quality. Obviously, information that none pick up is lost. But oversampling to partially compensate for poor signal/noise is done with a lot of other noisy signals.
Signals isn't my forte either, by a long shot. It's just an idea I thought was interesting, so I started playing with using some dsp software mixers.

Re:concert-recording on the cheap

[Jherek Carnelian]

This might be true with a 44- or 48kHz sampling rate, but "phone quality" 8kHz sampling will give you something that sounds worse than a cassette recorder stuck inside a coffee can.

Not so fast there. If it is possible to algorithmically combine a handful of low-resolution (i.e. low sample rate) images of the same scene to get a high resolution version, it ought to be possible to algorithmically combine a handful of low-resolution recordings of the same audio to get a high resolution version.

Re:

[Anonymous Coward]

If it is possible to [apples], it ought to be possible to [oranges].

Sorry, but speaking as someone with a degree in electrical engineering who spent the better part of a decade studying this stuff, it just doesn't work like that. You can use padding tricks increase the [false] resolution of the spectrum you're dealing with, but you can't recover signal that you failed to record in the first place. See also: Nyquist-Shannon sampling theorem [wikipedia.org].

For a simpler analogy, it's like using 16-bit registers to recor

Re:

[account_deleted]

Comment removed based on user account deletion

Re:

[matfud]

Yes that true, but only for one source. If you have multiple 8khz signals whose sample points are not synchronized then you can combine them to improve the overall frequency range obtainable. However this would increase the final achivable frequency in proportion to the log of the number of sampling devices (under ideal situations) so you would need a fair few sources (If I remeber correctly). Mobile phones would probably be quite far from this ideal as they
a) would be physically seperated so you'd have to

Re:

[evanbd]

The problem with this approach is that audio ADCs have an analog antialiasing filter in front of them. It's not just that you can't see the high frequencies because you don't have enough samples; they're actually *removed* from the analog signal before it's digitized. If they weren't, you could recover them with enough microphones, but you'd also get weird aliasing artifacts. As it is, they're gone, never to return.

Re:

[smellsofbikes]

Well, that just sucks. So they've got, basically, a low-pass filter with a rolloff so that their sampler never sees anything above 8khz? Phoo.
My oscilloscope dithers the clock rate so even though it's 350 MHz, it acts cleaner because it moves back and forth across a signal, to evade aliasing artifacts. My thought was that multiple data streams from different cellphones would act similarly, but if the data's shorted to ground before it ever sees the ADC's front end, well, just phoo.

Re:

[evanbd]

Well, 4kHz, because that's the Nyquist frequency for 8kHz sample rate. Unfortuntaley, if you're intending to use the data without doing the dithering work, you need to get rid of the aliasing artifacts -- which, uncoincidentally, are the exact data that would allow the dithering to function.

Re:

[Agripa]

My oscilloscope dithers the clock rate so even though it's 350 MHz, it acts cleaner because it moves back and forth across a signal, to evade aliasing artifacts.

Your oscilloscope uses random repetitive sampling to reconstruct repetitive waveforms which general audio is not. There is a trigger circuit which serves to align the sampling clock with the presumed start of the waveform so that new samples are placed into the correct place. This technique allows full reconstruction of a high bandwidth repetitive

Re:

[EMH_Mark3]

That's assuming the ADC actually only samples at 8khz. It's entirely possible that the phone records audio with a sample rate and resamples it before encoding and transmitting.

Re:

[evanbd]

If it's doing that, then there's a digital AA filter before the resampling for the same purpose as the analog AA filter. It would have the same effect.

Re:

[matfud]

Yup, you're probably correct.

However even with low pass filters the values at the offset sampling points will be different and could still be used to enhance the frequency range. Whether you could with mobile phones or not is engineering not theory :)

Another point is that most modern sampling systems do not have particularly effective low pass filtering prior to sampling. Analog filters take a fair bit of space even if they are surface mount or integrated into chips. Most devices rely on the filters in fron

Re:

[matfud]

But yes, I don't really think it would work. It only works marginally well in ideal situations without low pass filters (that log(n) thing again). With low pass I doubt it would work at all. Although there is more information there. It depends on how much additional information that is and how it interacts with the log(n) limit. There is some information but not much.

matfud

Re:

[DamnStupidElf]

a) would be physically seperated so you'd have to perform some correlation first to remove the arbitrary time delays from the audio source to the phones and this would remove some of the resolution

Couldn't you synchronize the samples using the phase of a common high amplitude frequency component? Say the first drum beat of the song, which would provide a good synchronization point as well as phase information.

Re:

[snooo53]

It seems like a high sharp, drumbeat (or any other like sound) would be useful although I think one would have to look at an actual waveform to see what happens in the 1.25ms nearby, to see if it would be useful for phase synchronization at that level of precision. I suppose if planned ahead of time, someone could generate a loud pulse of sound lasting a discrete amount of time, say .625ms or less to see what other microphones pick it up and use that to determine an offset for any given mic.

One thing I am

Re:

[Jherek Carnelian]

You can use padding tricks increase the [false] resolution of the spectrum you're dealing with, but you can't recover signal that you failed to record in the first place.

For a simpler analogy, it's like using 16-bit registers to record 32 bit integers. No matter how many 16 bit registers you use or how you combine them, you're not going to recover the upper 16 bits -- they're lost because you didn't record them.

I'm not sure what you mean by "padding tricks" but I have to disagree and your analogy is what makes it clear. By using two 16-bit registers you can fully represent a 32-bit value.

Similarly an 8KHz sampling rate means that a measurement is taken 8,000 times per second or once every 1.25 milliseconds. If you have two 8KHz recordings that are offset by exactly half of the sampling period (0.625 milliseconds) from each other then you can combine the two into a single recording with a sampling period of 0.62

Re:

[FishWithAHammer]

I'm not sure what you mean by "padding tricks" but I have to disagree and your analogy is what makes it clear. By using two 16-bit registers you can fully represent a 32-bit value.

Correct, but this is like storing the same (or very similar) 32-bit integer in two 16-bit registers (the same integer, put in both places). The top data is sliced off both of them.

Re:

[snooo53]

Isn't that the whole point though of using multiple offset signals, so that one can obtain the data at some point in between the original waveform, thereby essentially doubling the effective sampling rate? What precisely is being sliced off the signals?

Re:

[FishWithAHammer]

Can you do that with cell phone recorders?

Re:

[Seakip18]

I think I am wrong on this, but couldn't the swarm instead just assign certain thresholds? IE-one phone records a the highs, allowing it capture more of that range whereas another phone captures the low, bass,etc. That way, you combine your captures and get a full pitch, each phone contributing their range.

Re:

[fenodyree]

That comparison is flawed.
To use a car analogy: You can construct a complete working car from a junkyard provided that the cars in the junkyard have different problems and conversely different working parts.
As the way multiple low resolution images of the same seen create a higher resolution is primarily based upon the (usually accurate) assumption that the images will be lit differently such that where information is lacking in one image, it _is_ in another, and vise versa.

However, with the phones, the

Re:

[gurps_npc]

Not entirely. There will be some overlap of frequency ranges. Also high resolution does not consist entirely of greater frequency ranges. It also consists of more samplings. I.E. it may have a restricted frequency range, but the number of sounds per second sampled (equivelent to DPI) will be MUCH higher than from just one microphone.

Re:

[sootman]

Hmm... it might take a lot. I made these images* [pixelcity.com] by combining many still images and it reduced the noise but it would be a stretch to really increase the effective resolution. I suppose an array of phone recordings would sound better than stock but it would take a lot to get the quality up to anything reasonable, and I think even a hundred combined signals wouldn't be enough for anyone to mistake the result for a 48k studio piece.

* those pics were taken during a lunar eclipse with my DV camera (25x optical

Re:

[Lumpy]

From the overall stream, you should be able to derive an excellent, local-noise-removed bootleg,

Great idea. you are forgetting one small tidbit. Audio quality will suck because of 2 things you fail to consider. Microphone quality in cellphones is below dismal. Think lower than toy quality. Secondly the audio processing aspects of callphones is just as dismal. Unless you can get an open hardware platform to scab on decent microphones and decent audio circuits and encoders it will not sound any better th

Re:

[mpe]

Great idea. you are forgetting one small tidbit. Audio quality will suck because of 2 things you fail to consider. Microphone quality in cellphones is below dismal. Think lower than toy quality. Secondly the audio processing aspects of callphones is just as dismal.

Actually they are both quite good for the intended purpose. Which is to pick up speach from within a few cm of the microphone.

Unless you can get an open hardware platform to scab on decent microphones and decent audio circuits and encoders it

Re:

[Lumpy]

Actuayy it's a bootlegging hat. iRiver recording mp3 player and a set of binuaral microphones placed carefully in them so the audio hole is unobscured on each microphone. works exceptionally well. except when you turn your head so you need to be trained not to turn your head during songs.

I get recordings that are typically far better than the live albums you can buy. adding a 9V battery box increases the dynamic range even better. if you are at outdoor loud events, adding some attenuation also works wo

Not exactly....

[denzacar]

It would still measure the distance from you to the other phones.

No (useful) image from you, but it still might be useful sonar data.

Until someone starts putting bluetooth phones into the walls and burying them into the ground just to screw with people.

Re:

[HTH NE1]

I keep my cell phone in my back pocket

Is that why so many Europeans keep losing their phones in the toilet?

Little Brother?

[Anonymous Coward]

So if you have a huge surveillance system that isn't controlled by anyone, is that the opposite of Big Brother?

Re:

[davidsyes]

As in "Little Sister"?

Re:

[dlr03]

I wouldn't be against ubiquitous safety, ala Diamond Age (Neil Stephenson) / Hominids (Robert J. Sawyer)

Labware

[Zebra_X]

It works in a lab but the real question is how well does this perform in the real world...

The team also found that ...

[Van Cutter Romney]

The Swiss team also found a unique characteristic of the network that it used to swarm around one of the nodes more often than not. Later they pinned it on the only hot blonde in the team.

Telescope Array

[darkshadow]

How about combining everyones cellphone cameras into a large Telescope Array, or at least a very detailed camera?

Huh ?

[ant-1]

A CCTV system from BT cellphones ? Why, oh why ? Because boffins have time and my money to lose ?
Somebody please explain the use of such a... discovery ?

Ah.

Surveillance.
I get it now. The T word is about to be spoken, again. Great. I'm looking forward to BT-holding surveillance militia roaming the streets.

Terrifying

[wattrlz]

So now someone could be watching all those cell phone cameras everybody is so afraid of. If the phones could somehow figure out where they're pointing and stich the images together.. *shudder*

Re:

[HTH NE1]

So now someone could be watching all those cell phone cameras everybody is so afraid of. If the phones could somehow figure out where they're pointing and stitch the images together.. *shudder*

No need for Google Street View?

Power use? Data Costs?

[Joe The Dragon]

Bluetooth is a big power draw as well as the camera. Also cell phone data costs alot as well.

battery life

[Ichelo]

sounds like it wouldn't run very long given battery life in phones, sounds more like just a neat idea that won't go anywhere...

Analyze the average quantity of pocket lint?

[kevmatic]

Most people I know don't keep their cell phones in some snap-off carrier on their belt like a modern-geek pocket protector. They stay in pockets, where they can't see. And women keep them in purses. So only a few phones are actually going to be able to see without their owners holding them out on purpose.

What's the point of this, again?

Re:

[T-Bone-T]

That is exactly what I was thinking. How is this going to be effective if most of the cameras can't see anything?

Re:

[geekoid]

Becasue if there is something worth seeing, more people will take there cameras out of their pockets.

You are also overlooking the fact that if Gollum had one, he would have know what was in Bilbo's pocketess

Re:

[T-Bone-T]

that's a good point. But wouldn't most of them be pointing 90 degrees away?

Can you see me now?

[r_jensen11]

Good!

Off topic .. well tangential

[Maxo-Texas]

I think soon, the last thing most of the public cameras need to see is a paintball or the business end of a spraycan. Just remember to wear a mask, hat and cloak while doing it- since you are going to be surveilled by multiple cameras as you take them out. For irony, I suggest a "V" mask.

Re:

[superwiz]

There has got to be a Natalie Portman joke sitting somewhere in this comment.

Re:

[geekoid]

Cameras in everybody's hand is a good thing. It levels the playing field.

Re:

[Maxo-Texas]

Not if the government can monitor it and enforce arbitrary morality and political laws based on it.

Only privacy protects that. Privacy comes with it's own risks and abuses but carries some ability to redress abuses.

Re:

[geekoid]

If everyone does it, it minimizes abuse of power.

In '1984' monitoring was bad because the people couldn't monitor the 'government', and if they could they had no recourse.

In the US, people actually do have recourse, and in fact have protection that help them.
Do people try to over ride those laws for there own agenda? From time to time, yes. Inevitably they get slapped down.
We also have the advantage of being able to remove someone from office.

Plus your appearance on a public area is not private information.

Re:

[Maxo-Texas]

I really think you don't get blue laws, the great enlightenment, the communist scare in the 50's, the popularity of slavery, killing people for committing adultery, or sharia islamic law.

We need protection FROM the majority. For some seriously extended periods of history a majority of the population can get really weird. Sometimes only a tiny secret flickering flame of liberty remains.

Closed-circuit?

[jpfed]

Correct me if I'm wrong, but doesn't CCTV mean "closed-circuit television"? As in, the camera is connected with a solid conductor to the display? If that's the case, then wouldn't a system that transmitted video over the air (at least, without displaying it locally first) be something other than CCTV?

Sounds like Crichton

[wickedpixie]

Anyone else read Prey by Michael Crichton? It deals with swarms of miniature cameras and the havoc that ensues. Hopefully these people will be more responsible than the ones in the book. And hopefully the stuff won't go berserk on us and start killing us.

Re:

[KlaymenDK]

Granted, it's been a while since I read Prey, but I recall nothing about cameras. Swarms, yes. Miniature, yes: nanoscale. But cameras? Hmm.

Scary book nonetheless, though.

The Bandwidth

[kcbanner]

This is alot of broadcasting for something that is slightly useful to the average person. What about those with phones in their pockets, now spamming your crotch with useless radiation.

another project along the same lines

[mrbobjoe]

A professor of mine is working on using swarms of cell phones as a distributed self organizing sensor and computing network. Part of the project involved a new programming language to specifically deal with the spatial distribution of the phones.
Here's his page on the project: http://www.research.rutgers.edu/~uli/Sarana/ [rutgers.edu] (summary PDF at the bottom)

What they should do...

[Wobble-U]

What someone should do is get mobile phones with cameras and bluetooth and when they're in a group surrounding some event, they make a 3d model that can be later downloaded onto the computer, so the viewer can change angle whenever they want. Much more interesting than surveillance!

Bad good?

[PK077295]

This technology of providing cheap way to monitor environment present more harm than good. It's highly abusive especially in the hands of teenagers...