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mmWave radar, you won't see it coming

joshhorne.com

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Re: mmWave radar, you won't see it coming

#51

Post by krasin »

samatman wrote: post #46
kjeetgill wrote: post #42

Earlier quoted context omitted.

I 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.

I 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.

By 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 https://www.mouser.com/c/?q=mmwave) and show us a demo.

Re: mmWave radar, you won't see it coming

#52

Post by krasin »

R0b0t1 wrote: post #6
krasin wrote: post #5

Earlier quoted context omitted.

I 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 y…

Temporal res can be turned into spatial res.

Theoretically: yes. Practically, there are limits to that.

Re: mmWave radar, you won't see it coming

#53

Post by ulrikrasmussen »

krasin wrote: post #5
idontwantthis wrote: post #3

> 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 m…

I 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 y…

What 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?

Re: mmWave radar, you won't see it coming

#54

Post by stingrae »

chrismorgan wrote: post #15

A technical error in one of the diagrams: Hall effect sensors are not binary, but one-dimensional, and are used so; their output voltage is directly proportional to the magnetic field strength. As for PIR sensors, fundamentally they’re certainly not binary, but I have no idea if they perhaps expose only a binary signal. A better example of a binary sensor might be an on/off switch.

analog PIR is typically a differential signal between two receivers. The receivers are placed behind a fresnel lens (where the lenses are designed to point into each of the sensors). So when an IR source (like a person) walks in front of the sensor it creates a large spike, because they are being compared against a low IR area.

There is a form of PIR sensing where it behaves like a thermal camera at a very low resolution (sometimes as low as 2x2 pixels)

Re: mmWave radar, you won't see it coming

#55

Post by hornej »

synthos wrote: post #50
hornej wrote: post #2

I've been following and building mmWave radar stuff for a little over a year now and I wanted to write an intro to help anyone get up to speed on how it works, why it's special, and what's been happening in the space.

How is the power consumption? Is it sensitive to noise or interference? The VR headset application appeals to me. If headsets could be dumb terminals they would be a lot lighter and untethered wouldn't suffer from performance loss.

Power consumption for radar can get down to around 0.5mW (edit)

But I imagine for 60GHz WiFi it's probably pretty power hungry.

At this point there's not much noise in the mmWave spectrum (it won't be competing with 2.4GHz and 5GHz anyways). And mmWave doesn't travel that far which is one of the main reasons the FCC unlicensed it in the first place.

Might be worth keeping an eye on UWB for AR/VR headsets https://www.embedded.com/wireless-transceivers-use-uwb-for-l...

Re: mmWave radar, you won't see it coming

#56

Post by krasin »

ulrikrasmussen wrote: post #53
krasin wrote: post #5

Earlier quoted context omitted.

I 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 y…

What 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?

I 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.

Re: mmWave radar, you won't see it coming

#57

Post by parsimo2010 »

transpute wrote: post #49

> Because mmWave radar doesn’t process visual light, what it sees is not personally identifiable. With machine learning improvements, identification and more are possible. From a 2021 paper on IEEE 802.11bf Wi-Fi Sensing, https://arxiv.org/pdf/2103.14918.pdf > Indeed, it has been shown that SENS-based classifiers can infer privacy-critical information such as keyboard typing, gesture recognition and activity tracking…

Right on. The whole "mm wave radar is detail rich but gives privacy" line is a contradiction. Any data that is detailed enough to be useful is detailed enough to be a privacy concern. While it might not be the same as leaking nude photos from someone's camera, radar data is something that needs to be carefully thought out. Radar data from a car can provide information about people's driving behavior even without location data- do they follow too close, do they make reckless lane changes into tight spots, do they exceed the regular flowing traffic speed, etc. Radar data from inside a building used to track people can tell when you are at your desk or somewhere else, who you congregate with in the break room, how long you spend in the bathroom, etc. If it's detailed enough to assist you, that data can also be used to monitor you.

Re: mmWave radar, you won't see it coming

#58

Post by pishpash »

idontwantthis wrote: post #3

> 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 m…

Each 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.

Re: mmWave radar, you won't see it coming

#59

Post by teraflop »

leohonexus wrote: post #33

Very dumb question: If mmWave is operating at 60GHz, how would it be possible for processors (which are operating at less than 1/10th of that clock rate) to process that sampling rate?

The same way you can receive/transmit a 5GHz wifi signal using devices running at a fraction of that clock rate: most of the critical high-frequency signal processing happens using analog electronics. The actual sample rate of the digitized signal is much lower.

Re: mmWave radar, you won't see it coming

#60

Post by smegsicle »

cj wrote: post #30
wavesquid wrote: post #9

Earlier quoted context omitted.

You 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.

(Genuinely curious) how do you know this?

i recall a comment by someone claiming to be working in an antarctic base- everyone working outside would be wearing the same suit, but you could subconsciously recognize who you were looking at, at great distances, simply by the gait.

walk without rhythm ...

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