Adding a comment here with some info on LIDAR human safety, since many are asking.
There are two wavelengths of interest used:
a) 905 nm/940 nm (roof and bumpers): 70–100 µJ per pulse max, regulated by IEC 60825 since this WL is focused on the retina
b) 1550 nm systems (the Laser Bear Honeycomb): 8–12 mJ per pulse allowed (100x more photons since this WL stays the cornea)
The failure mode of these LIDARs can be akin to a weapon. A stuck mirror or frozen phased array turns into a continuous-wave pencil beam.
A 1550 nm LIDAR leaking 1W continuous will raise corneal temperature >5C in 100ms. The threshold for cataract creation is only 4C rise in temp.
A 905 nm Class 1 system stuck in one pixel gives 10 mW continuous on retina, capable of creating a lesion in 250ms or less.
20 cars at an intersection = 20 overlapping scanners, meaning even if each meets single-device Class 1, linear addition could offer your retina a 20x dose enough to push into Class 3B territory. The current regs (IEC 60825-1:2014) assume single-source exposure. There is no standard for multi-source, multi-axis, moving-platform overlay.
Additionally, no LIDAR manufacturer publishes beam-failure shutoff latency. Most are >50ms, which can be long enough for permanent injury
The article talks about eye safety a bit in section 4.
> a stuck mirror
This is one of the advantages of using an array of low power lasers rather than steering a single high power laser. The array physically doesn't have a failure mode where the power gets concentrated in a single direction. Anyway, theoretically, you would hope that class 1 eye-safe lidars should be eye safe even at point blank range, meaning that even if the beam gets stuck pointing into your eye, it would still be more or less safe.
> 20 cars at an intersection = 20 overlapping scanners, meaning even if each meets single-device Class 1, linear addition could offer your retina a 20x dose enough to push into Class 3B territory.
In the article, I point out a small nuance: If you have many lidars around, the beams from each 905 nm lidar will be focused to a different spot on your retina, and you are no worse off than if there was a single lidar. But if there are many 1550 nm lidars around, their beams will have a cumulative effect at heating up your cornea, potentially exceeding the safety threshold.
Also, if a lidar is eye-safe at point blank range, when you have multiple cars tens of meters away, laser beam divergence already starts to reduce the intensity, not to mention that when the lidars are scanning properly, the probability of all of them pointing in the same spot is almost impossible.
By the way, the Waymo Laser Bear Honeycomb is the bumper lidar (940 nm iirc) and not the big 1550 nm unit that was on the Chrysler Pacificas. The newer Jaguar I-Pace cars don't have the 1550 nm lidar at all but have a much bigger and higher performance spinning lidar.
Beamforming with a phased array is talked about in the article, but you are conflating two very different types of arrays. You can't form beams with the types of macroscopic arrays I was referring to, since they consist of macroscopic array elements whose phase cannot be controlled, and reside behind a fixed lens that ensures that they all point in different directions.
Pressure switches, flow sensors, mechanical flame detectors, power supply monitoring, watchdog timers, and XX years of Honeywell or whoever knowing what they are doing.
So yes, a mirror trip reset is probably a good start. But would I trust someone's vision to this alone?
> Pressure switches, flow sensors, mechanical flame detectors, power supply monitoring, watchdog timers, and XX years of Honeywell or whoever knowing what they are doing.
Nope, nothing as complicated as that. You're close with the watchdog timer.
The solenoid is driven by a charge pump, which is capacitively coupled to the output of the controller. The controller toggles the gas grant output on and off a couple of times a second, and it doesn't matter if it sticks high or low - if there's no pulses the charge pump with "go flat" after about a second and drop the solenoid out.
Do the same thing. If a sensor at the edge of the LIDAR's scan misses a scan, kill the beam.
Same way we used to do for electron beam scanning.
>> if there's no pulses the charge pump with "go flat" after about a second and drop the solenoid out.
>> Do the same thing. If a sensor at the edge of the LIDAR's scan misses a scan, kill the beam.
Sounds like a great plan, but I question the "about a second" timing; the GP post calculates that "about a second" is between 4X and 10X the time required to cause damage. So, how fast do these things scan/cycle across their field of view? Could this be solved by speeding up the cycle, or would that overly compromise the image? Change the scan pattern, or insert more check-points in the pattern?
A quick note about units -- you correctly quote the limits as an energy-per-pulse limit. The theory behind this is that pulses are short enough that rotation during a pulse is negligible, so they tend to hit a single point (on the retina, at focusable frequencies; the cornea itself for longer wave lengths), and the absorption of that energy is what causes damage. But LiDAR range is determined not by energy per pulse, but by power. This drives a desire for minimum-time pulses, often < 10 ns -- if you can halve your pulse length, you can increase your range substantially while still being eye-safe. GaNFETs are one of the enabling technologies for pulsed lidar, since they're really the only way out there to steer tens of amps in single-digit nanoseconds. Even once you've solved generating short pulses, though, you still need to interpret short responses. Which drives either a need for very fast ADCs (gigasample+), or TDCs, which are themselves fascinating components.
I live in town, and walk past countless stopped and moving cars every day.
I also know how the tech industry makes decisions about safety and responsibility (hahaha...). And I have seen some of the recent changes that automakers have somehow slipped past safety regulators. So it seems foolish to trust any of them on this safety issue.
Do we all have to move to rural areas, if we want to be able to go outside without wearing laser safety goggles?
If you find anything, please let me know. The least obtrusive option I've found is this Zeiss lens coating ("Thermo Force") which claims to block 90% of IR "between 780 and 2000 nm", which covers the NIR used in both types of lidar. It only seems to be available as part of sunglasses though.
Laser safety glasses are off-the-shelf, but are usually tuned for a single band stop. There are at least three frequencies of near IR LiDAR in use in the wild.
Hm the ones I can find have a heavy green reflex and their optical density seems about twice or thrice what you'd need for a 1W CW laser. Maybe it's unavoidable given the closeness of near IR and deep red, but I wonder if there exists glasses with a cutoff sharp enough and reduced OD so as to not result in noticeable color shift.
We always used Thorlabs' [0]. If you want to block Waymo (900 - 940 nm), but not Ouster (840 nm), the LG11s may work and are quite transmissive and neutral, but I've never used them. The LG20s are the standard NIR blockers that I'm familiar with.
I was thinking more "one could create a business" vibe. The requirements for making everyday protections from errant lasers is different from what you'd need for lab safety working with lasers.
You know, I was just thinking a headset like Oculus would be pretty great for night driving if it was sensitive enough; my night vision is getting really bad and coupled with most new cars having annoyingly bright LED lamps with auto-high beams it's getting super uncomfortable to drive in the dark. Then that would automatically shield eyes from lasers!
One could go further, and have an integrated system where the headset shows video feed from cameras around the car. You could almost get a 3rd person view of your own car like in video games.
I was always curious about this, it's impossible to find any safety certifications or details about the lidars used by e.g. Waymo. Are we supposed to just trust that they didn't cut corners, especially given the financial incentives to convince people that lidar is necessary (because there's a notable competitor that doesn't use it).
To date most class-1 lasers have also been hidden/enclosed I think (and there is class 1M for limited medical use), so I'm not convinced that the limits for long-term daily exposure have been properly studied.
Until I see 3rd party studies otherwise, I plan to treat vehicle lidar no different than laser pointers and avoid looking directly at them. If/when cars become common enough that this is too hard to do, maybe I'll purchase NIR blocking glasses (though most ones I found have an ugly green tint, I wonder if it's possible to make the frequency cutoff sharp enough that it doesn't filter out visible reds).
Every day dozens of Waymos are in close proximity to the people cleaning them and plugging them in, and they are maneuvering in tight spaces amongst other Waymos. That's not a peer reviewed study, but it seems to work.
The visual system can patch over tiny defects (see: blindspot) and visual field tests have not been part of standard yearly eye exams I've been to. And possible longer-term risks (say increased risk of cataracts) would be harder to conclusively show. And the sample size involved would skew heavily towards young healthy adults instead of people with pre-existing eye conditions.
I realize it's not easily possible to prove the negative, but when you're exposing the public the burden must be on the company to be transparent and rigorous. And from what I see it's difficult to even find certification documents for the lidars used in commercial self-driving vehicles, possibly because everything is proprietary and trade secret.
“…Every day dozens of cigarettes are smoked in close proximity to other people… that’s not a peer reviewed study, but it seems to work…”
- someone probably, sometime in the 1950s
OK, I did some digging. Automotive lidar passes tests to be classified as a class 1 laser device. Are you regularly around class 2 laser devices? Chances are good. I'll let you guess where. Hint: you never saw a warning sign either.
A camera CMOS dies at 1–2 µJ pulse, this same pulse energy reaches the cornea. If a sensor has fried, that means the dose to your eye is already in the zone of cataract creation. Human corneal endothelial cells do not regenerate. If the endothelium is damaged, stromal fluid accumulates and opacity can progressively over months/a year from one hit. You might never know what caused it.
Yep. Reminds me of the arguments in favour of leaded petrol.
Thomas Midgley even organised an event for reporters where he poured pure tetraethyl lead on his hands and inhale its fumes for around a minute to show how safe it was. "I could do this every day without getting any health problems", he claimed. Once the reporters left, he needed a lay-down to recover.
There's a history of things like this: pfas, tobacco, asbestos, BPA, which are later found to cause issues. Generally regulation seems to be under the principle of "no concern until dangerous side-effects found" when it should obviously be the other way around (assumed dangerous until sufficiently rigorous trials show no adverse effects).
That's a possibility. Google appears to be contracting out depot work to car rental companies because a Waymo depot is basically a car rental lot. They need three shifts for each depot. So there's probably a couple hundred people who would otherwise be cleaning out rental cars working the depots. At some point injuries would get hard to sweep under the rug.
Ouster uses (or at least used to use, not sure if they still do) 840 nm. Much higher quantum efficiency for standard silicon receivers, without having to play games with stressed silicon and stuff; but also much better focusing by the retina, so lower power permitted.
The incredible irony that reduced injury and death from collisions is how these things are sold to registers and cities, but no one mentioned that in a city full of millions of poorly maintained lidars, they just might slowly make everyone blind instead.
Enormous complexity, safety risks, and completely unnecessary for successful level 4 FSD - the hurdle to full autonomous driving was basically jumped by Tesla this year. I don't see why lidar is even allowed in public at this point, it seems dangerous enough that you'd want it effectively restricted to highly regulated and licensed uses, like military or academic scanning, with all sorts of deliberate safeguards and liability checks.
Social media is full of little clips of lidar systems burning out camera pixels, and I'm sure big proponents of the tech have paid people off over eye injuries at this point. There've probably been a ton of injuries that just got written off as random environmental hazards, "must have looked at the sun" etc.
the hurdle to full autonomous driving was basically jumped by Tesla this year.
Tesla doesn't have driverless operations anywhere, and their Austin fleet consists of <30 vehicles with full time safety drivers that have a far worse safety record than Waymo vehicles.
It's not nothing, but it's a long way from being a complete system (let alone the obviously superior one).
I really do not understand comments like this. Waymo cars are actually autonomous. They can drive around empty for thousands of miles with no issues. No Tesla has ever driven empty for any significant length of time.
IIRC, Tesla's safety record is about 30% worse than Waymo. The gap has been closing rapidly. It's not that long time ago Tesla made an order of magnitude more mistakes than Waymo.
That's with safety drivers, a small fleet, and literally only the most recent data (since it wasn't broken out before). My experience with AV deployments is that your incident rate is significantly different once you remove humans, and small fleet sizes/deployment areas hide a lot of long tail issues.
Waymo is operating at a much larger scale across a huge range of conditions with hardware that's generations behind their latest and still performing better.
No need to wait. It's got the same reliability as FSD. If people were sitting in the backseat while FSD is driving and taking a nap, I'd believe it's comparable to Waymo.
There are two wavelengths of interest used:
The failure mode of these LIDARs can be akin to a weapon. A stuck mirror or frozen phased array turns into a continuous-wave pencil beam. A 1550 nm LIDAR leaking 1W continuous will raise corneal temperature >5C in 100ms. The threshold for cataract creation is only 4C rise in temp. A 905 nm Class 1 system stuck in one pixel gives 10 mW continuous on retina, capable of creating a lesion in 250ms or less.20 cars at an intersection = 20 overlapping scanners, meaning even if each meets single-device Class 1, linear addition could offer your retina a 20x dose enough to push into Class 3B territory. The current regs (IEC 60825-1:2014) assume single-source exposure. There is no standard for multi-source, multi-axis, moving-platform overlay.
Additionally, no LIDAR manufacturer publishes beam-failure shutoff latency. Most are >50ms, which can be long enough for permanent injury