The surveillance society

[unixronin]

A white paper published by the UK Home Office on the UK's National CCTV Strategy (PDF) discusses in depth the use of closed-circuit TV cameras for surveillance of the public.  On page 13, it cites a "best estimate" that UK government bodies now employ 4.2 million CCTV cameras¹.

Wait a minute ... "best estimate"?  You mean they don't KNOW how many cameras they're operating?

[1]  That's approximately one camera for every fifteen people in the UK.  It's unclear whether that estimate includes ANPR cameras used for traffic monitoring.  There appears to be some overlap, as there is some implication that some regular crowd surveillance cameras are being extended to track vehicle license plates as well.

Comments

[arasirsul.livejournal.com]

The thing that astounds me the most about that is what the hell does one do with the feeds from 4.2 million cameras?

That's a positively ridiculous amount of data.

[unixronin.livejournal.com]

To be fair, I understand from the paper that much — or most — of that data is not watched in real-time. A large amount of it is archived and kept for 30 days or so, and in the event of (say) a terrorist incident or a crime in a covered area, they then go to the archive and decide after the fact which camera footage to review. The paper mentions, I think, that this technique was used to back-track terrorists after the July 7 transit bombings.

[arasirsul.livejournal.com]

Exactly.

Figure we're dealing with some pretty low-end cameras and they're only shooting 320x200, and they're doing 8-bit greyscale because they don't really need color. Assume also they're only grinding fifteen frames a second, because we don't really need 24 or 30 and they're quite happy they're not stuck with NTSC over there and its 29.997.

Each camera generates 7 megabits of data every second.

Let's also assume that we can compress this stuff pretty well-- which we can in a lot of instances; if the image isn't moving and the light's not changing significantly we can get away with throwing away a lot of frames. But just to make sure I'm not picking a number that's actually feasible, let's pick a shade under 1/1000 compression (1/855) so that our 7 megabits a second comes out to one kilobyte per second per camera to give us easy numbers to work with. [0]

Now there's 4.2 million cameras generating a mere kilobyte of data every second. That's 4.2 gigabytes of data _every second_, which is

250 GB/minute
15 TB/hr
360 TB/day
10 PB/month.

Storing all that's doable; sure. I work for a company that has a few dozen petabytes on the data center floor. Note we're not recreating all of that data once a month...

Since I'm guessing on the low end for all of my figures (If you're getting 1/855 compression out of your video cameras because the image isn't changing, chances are you've got the camera pointed at something useless since there ain't no people there...), those are pretty low-ball sorts of figures, and we're still pushing 10 petabytes into it every month.

Man, I want that pipe to my house.

[unixronin.livejournal.com]

I'd love a ten-petabit pipe, as long as I don't have to pay for it. ;)

(I assume you saw that Verizon has rolled out a new FiOS service tier, offering symmetric 20Mbit service for a bit under $60/mo?)

[arasirsul.livejournal.com]

Yes, and sadly, they're not doing it here yet.

Once it's here, I'm so jumping on that...

[unixronin.livejournal.com]

Us too, assuming they roll it out in Gilford sometime this side of the second coming.

[metahacker.livejournal.com]

The thing is, the arrow of progress means we'll catch up with that data stream pretty soon...so all they have to do is archive it now, and eventually they'll be able to paw through it and extract patterns in near-real-time.

Assuming computers in 2015 still have DVD drives, that is...

BTW you should probably assume those cameras are running at 1 or 0.5Hz, not 15Hz; that seems to be typical from the feeds I've seen published. Some of this is accounted for in your obscene compression ratio, of course. ;)

[hrrunka]

My guess is frame rates are going to be down nearer one or two a second at best, but at PAL rather than NTSC resolution, judging by the sequences that make it onto the news programmes.