7 ms·
> Because mmWave radar doesn’t process visual light, what it sees is not personally identifiable. This makes it an ideal choice for monitoring where a camera wo
by idontwantthis 5y ago
> Because mmWave radar doesn’t process visual light, what it sees is not personally identifiable. This makes it an ideal choice for monitoring where a camera would not be appropriate.
Is 5mm resolution not enough to identify a face?
What’s the difference between a 3d model of a person constructed from high res radar and a black and white photo?
The radar sounds even more identifiable.
Edit: Couldn’t you construct a mosaic and have much higher resolution?
And also remove their clothes?
- krasin 5y agoI worked with mmWave radars previously, but not professionally. In my opinion, it would be quite challenging to extract enough features from the current generation of mmWave radars, such as TI IWR1642 ([1]) which have around 4 receivers and 2-3 transmitters, because the incoming data, while having a lot of temporal resolution is very limited in spatial resolution. With greater number of antennas something like what you describe is theoretically possible, but becomes cost prohibitive. By limiting the number of transmitters / receivers, we can have an almost perfect privacy monitoring. For example, it would be possible to detect a attack / a fight in a public bathroom, while not exposing anyone. 1. https://www.mouser.ec/datasheet/2/405/1/swru521c-1954464.pdf https://www.mouser.ec/datasheet/2/405/1/swru521c-1954464.pdf
- R0b0t1 5y agoTemporal res can be turned into spatial res.
- krasin 5y agoTheoretically: yes. Practically, there are limits to that.
- jcims 5y agoTo an extent, but depending on the sampling rate and frequency and your ability to control the area being observed, there is still a lot of information available for modeling and biometric identification. In the extreme you can detect things like heartbeat, rate of breathing, etc. For example, I have a CDM324 24Ghz radar module here on my desk. I set it up to 'watch' me type this comment from across the keyboard. This is an extremely simple module that I have powered by a bench power supply and the IF routed directly to the audio input on my desktop. It was sampled with audacity and amplified a bit to help with visibility. Towards the end of the recording I'm expecting a flat spot followed by regular motion followed by 'noise' as I pause motionless for ~10 seconds or so, then take about 5-6 exaggerated breaths, then resume typing. This is with zero design, the wrong frequency for the job, and next to zero signal conditioning. (post: i've included a zoomed in image of the 'motion demonstration' to show still/breathing/typing, then zoomed in on typing to show the detail, then a spectrogram and waveform of me reaching up to scratch my ear.) https://imgur.com/a/0JmENYu https://imgur.com/a/0JmENYu Bonus: yo check out my soundcloud - This is what the doppler signal actually sounds like: Scratching my ear - https://soundcloud.com/buckrunner2/scratch https://soundcloud.com/buckrunner2/scratch Talking directly at the module - https://soundcloud.com/buckrunner2/talking https://soundcloud.com/buckrunner2/talking
- AdamH12113 5y ago“Privacy” seems to be a marketing term here; what they really mean is that you can’t take naked pictures with it.
- samatman 5y agoWhich is also nonsense of course, the pornotron of TSA fame is mm wave radar.
- krasin 5y agoThe difference is the number of transmitters / receivers. TSA uses an array of them (from top to bottom) with narrow beams and they also rotate them and ask you to not move, so that effectively their number is considerably higher (ten of thousands), when reconstructing the image. Additionally, they use a higher frequency (160-400GHz), which additionally helps with resolution. See [1] and [2]. If we limit the number of transmitters / receivers to 3/4, the image reconstruction becomes impossible, similar how you would not really make a real photo from a few color sensors stationary looking at a scene, while a linear array of them that moves around an object would make a perfect scanner. It's a non-ideal analogy, but the best I can offer. 1. http://mt-fedfiles.blogspot.com/p/tsa-frequency-updates.html http://mt-fedfiles.blogspot.com/p/tsa-frequency-updates.html 2. https://www.3dbodyscanning.org/cap/papers/2017/17263mcmakin.pdf https://www.3dbodyscanning.org/cap/papers/2017/17263mcmakin....
- visarga 5y agoYou can reconstruct the images with neural networks even if you have little signal to guide.
- akimball 5y agoThis is true in the sense that NNs offer a convenient way to estimate a distribution of hidden values conditionalized upon visible values. That is an approximation of what is usually understood by "a reconstruction". I would argue that a reconstruction per se would only include parts for which the credible interval could be systematically bounded within a suitable tolerance threshold.
- samatman 5y agoSorry, don't buy it. Gait analysis is excellent at identifying people, and that's projecting from a 2D image at a distance. Anything which can draw a moving voxel cloud around a human is going to figure out who that human is eventually.
- kjeetgill 5y agoI don't disagree but I think this version of privacy is reductive. Plenty of real world privacy exists on a spectrum. My family knowing I'm in the bathroom is a far cry form them pointing a camera at me. If stores track you "anonymously" with this ... Who cares? It's less invasive than the ubiquitous security cameras they have pointed at you.
- samatman 5y agoI have no opinion on your reply, I was discussing technical feasibility in response to someone claiming it was infeasible. The normative claims aren't germane or particularly interesting to me.
- krasin 5y agoBy not exposing anyone I meant reconstructing an image. Identification is a different story and there are multiple ways on how to achieve that (heartbeat classification is an obvious one). If you have ideas how to reconstruct an image with 4 receivers / 2-3 transmitters, please, buy a dev kit from TI (they cost <$200, https://www.mouser.com/c/?q=mmwave https://www.mouser.com/c/?q=mmwave) and show us a demo.
- ulrikrasmussen 5y agoWhat about correlation? If you have other information that can tell you who is alone in the bathroom (common area CCTV, log of RFID key usage, etc) and your radar can infer that something very private is taking place there because the person thinks they are alone, then isn't that still a huge breach of privacy?
- krasin 5y agoI really must have phrased my message more clearly. I meant reconstructing images, not identifying who is inside. The latter is quite feasible, and you're correct that extra data helps with that as well. Just like with browser pinning, we have a variety of signals, which combined together give a very high rate of correct identification.
- ulrikrasmussen 5y agoGot it, I think I read your message as defending the idea more than it was.
- yjftsjthsd-h 5y ago...so what I'm hearing is "hard today so probably trivial in 5 years"? Or is this an exception to the usual march of technological progress?
- wavesquid 5y agoYou don't need to identify a face; you can identify people by Gait. If you can resolve something as big as a leg you've got enough, as long as you have it over 10 seconds or so.
- astrange 5y agoIt's odd that people care so much about technology "identifying them" when they have cell phones in their pocket and license plates on their car. There's not much of your daily life left after that, but I suppose it makes them feel good to imagine they're important enough to be tracked.
- kortilla 5y agoI opt into carrying a cell phone and it’s when I want. I don’t opt in to my neighbor’s Alexa tracking my comings and goings by scanning through my walls.
- astrange 5y agoYou can do that by sniffing wifi packets even if you can't decrypt them, I think? Could be a good opportunity for home Faraday cages.
- deadmutex 5y agotl;dr is that the technology is very very different than a phone camera. So it's not the same as an IR photo. E.g. Google Pixel 4 has a radar chip AND IR dot projector+camera for face unlock. Presumably, if you could do face identification with Pixel 4's radar sensor only they would not have needed the IR tech. Disclaimer: Work at Google, but not on Pixel 4.
- hornej 5y agoA couple examples to show what the mmWave data looks (bathroom, living room, etc) Intelligent fall detection using TI mmWave radar sensors https://www.youtube.com/watch?v=lsIo_HIk4GY&t=93s https://www.youtube.com/watch?v=lsIo_HIk4GY&t=93s 3D Occupancy Sensing For Home and Office https://www.youtube.com/watch?v=9EDhJQbLNyo&t=83s https://www.youtube.com/watch?v=9EDhJQbLNyo&t=83s As you can see the radar doesn't reveal too much, while still being able to discern a lot of what is going on in each scene.
- Schroedingersat 5y ago> As you can see the radar doesn't reveal too much, while still being able to discern a lot of what is going on in each scene. No, you can't see that, because it's a video of a specific visualisation of the data from one specific sensor. If it can see through walls and measure biometrics like heart rate, mass and body type, build a 3d point cloud of limb positions and measure vibration, then it's more privacy invasjve than a camera, not less.
- chrismorgan 5y agoThe visual signal there is utterly meaningless for assessing how much is exposed. For analogy, take https://en.wikipedia.org/wiki/RANDU https://en.wikipedia.org/wiki/RANDU: it was very popular in its day, and its distribution looked good to the naked eye, but plot it in more than two dimensions and you see that it’s actually extremely terrible, failing spectral tests badly. The information has been captured; the fact that one visualisation of it doesn’t expose that information is irrelevant and gravely misleading (as in: I don’t want someone that hasn’t already realised this working on this kind of stuff, because they’re dangerously ignorant and/or naive; I would rather they stop, and go and learn about the risks in detail before continuing).
- hornej 5y agoall sensors/technology are invasive to a degree, but I would argue radar fairs well in usefulness and anonymity in comparison to other sensors. if the data were leaked, would you rather have some of your vitals and point cloud data exposed, or a video of you taking a shower?
- fy20 5y agoIn terms of an IoT device or phone sensor form factor, not yet, but in the future I expect it will be possible. Airport body scanners use millimeter wave radar, and they use software to mask the image so it isn't personally identifiable. There are even passive versions that just use background radio waves in a compact form factor: https://www.qinetiq.com/en/what-we-do/services-and-products/stand-off-threat-detection https://www.qinetiq.com/en/what-we-do/services-and-products/...
- pishpash 5y agoEach time something comes up like this, I call for jammers. If someone wishes to exploit the shared physics of the environment, I'll have no qualms to do the same.
- transpute 5y agoThere's some research, but more funding is urgently needed, https://ans.unibs.it/assets/documents/COMCOM-ext-WONS_Preprint.pdf https://ans.unibs.it/assets/documents/COMCOM-ext-WONS_Prepri... (Dec 2021 paper) > This work explores the possibility of countering CSI based localization with an active device that, instead of jamming signals to avoid that a malicious receiver exploits CSI information to locate a person, superimpose on frames a copy of the same frame signal whose goal is not destroying reception as in jamming, but only obfuscate the location-relevant information carried by the CSI. A prototype implementation and early results look promising;