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Ouster's new digital Lidar – 128 beams, ultra-wide view

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Re: Ouster's new digital Lidar – 128 beams, ultra-wide view

#91

Post by apacala »

agoodthrowaway wrote: post #53
derek_frome wrote: post #35

Earlier quoted context omitted.

This is the spec for a cold start. If you give it a warm start, you can operate it much lower than -20C! For instance, it's being used in underground mines in Scandinavia without issue.

The issue will not be at cold but at high temperature. VCSELs have very poor efficiency at high temperature and it’s possible to operate them where increasing current reduces light output. In a vehicle application the temperatures are very high and humidity can also be very high and condensing.

Ouster CEO here.

This couldn't be further from the truth. You can design the VCSEL cavity and top and bottom mirrors for peak efficiency at any temp, including very high temps. I wonder what we did...

Compared to the side emitter diode lasers used in legacy spinning lidar, VCSELS are cheaper, more efficient, more reliable, longer life, and better quality light sources to boot.

Re: Ouster's new digital Lidar – 128 beams, ultra-wide view

#92

Post by apacala »

max_res wrote: post #86
randyrand wrote: post #32

Only temperature rated to -4F degrees. I hope they can get that lower. Up to ~25 days a year are <0F in Chicago for instance.

TL;DR: the operating temperature range of these sensors is small, nowhere near automotive spec, and a real problem at high temperatures. Also, watch the fine print on Ouster's thermal specs. The bigger issue is hot weather; electronics and lasers work well (often more efficiently) at cold temps, and the electrical power running through them self-heats the components. The problem arises when the environment is already…

Ouster CEO here.

We didn't claim these were auto rated parts... that being said, our temp spec is in line with the industry, and we're dead set* on reaching auto temp spec in a future iteration of the product.

Our shock, vibe and ingress specs are far better than the competition and pass most auto specs already though. Ruggedness like this was unheard of in spinning lidar even two years ago.

*I believe our internal thermal design group is "cultofthelavapeople at ouster dot io".

Re: Ouster's new digital Lidar – 128 beams, ultra-wide view

#93

Post by nabla9 »

entangledqubit wrote: post #37

Does anyone know whether eye safety is de facto maintained when your eye is being continuously bombarded by the 100+ scanning lasers being emitted from each of the 100 cars in the vicinity of an intersection? I'm on board with the case with a handful of lasers scanning by quickly but the energy may really start to add up in certain plausible future scenarios.

Near/Bright thermal heater range is 780 nm – 1.4 μm.

Unless those heat lamps that also produce visible light damage the eye, I don't see how 865nm lidar could do it if the power is low.

Re: Ouster's new digital Lidar – 128 beams, ultra-wide view

#95

Post by DaniFong »

lmilcin wrote: post #75
runin2k1 wrote: post #54

Earlier quoted context omitted.

It doesn't matter if it is IR, UV, or visible. Only the power and duration matter. Lidar uses very short pulses and very low power and is very safe even en masse.

This is actually more complex than that. Due to optical aberration wavelengths outside of visible range don't get focused the same way as visible light. This means that the energy is spread over larger area. Also, both UV and IR light is absorbed in a different way. UV tends to be absorbed much faster than visible light so that little of it reaches the retina while for IR opposite is true, the eye is more translucent…

Love these kind of analyses on HN (still where you can find them!) where someone will describe how the details matter.

Thank you to all involved.

If anyone can point me to the generalized best studies for safety margins and laser energy, please post links -- it's pretty relevant to a lot of AR designs to use laser projectors, and it is of course relevant to the lidar self driving cars at question.

Re: Ouster's new digital Lidar – 128 beams, ultra-wide view

#96

Post by jdsully »

nabla9 wrote: post #93
entangledqubit wrote: post #37

Does anyone know whether eye safety is de facto maintained when your eye is being continuously bombarded by the 100+ scanning lasers being emitted from each of the 100 cars in the vicinity of an intersection? I'm on board with the case with a handful of lasers scanning by quickly but the energy may really start to add up in certain plausible future scenarios.

Near/Bright thermal heater range is 780 nm – 1.4 μm. Unless those heat lamps that also produce visible light damage the eye, I don't see how 865nm lidar could do it if the power is low.

Laser light is much worse for the eyes because the energy is concentrated. It’s why you can buy 100W light bulbs but a 50mW laser needs a warning label.

Re: Ouster's new digital Lidar – 128 beams, ultra-wide view

#98

Post by DaniFong »

utopian3 wrote: post #3

> The OS0 lidar sensor: an ultra-wide field of view sensor with 128 lines of resolution > The OS2 lidar sensor: a long-range sensor with up to 128 lines of resolution > Two new 32 channel sensors: both an OS0 and OS2 version > Price: Starts at $16,000 with volume discounts available I would LOVE to get my hands on this tech. Maybe in 5-10 years when the price comes down to commodity level for hackers to play around w…

has someone explored what the state of the art is if you just use two 1080p LG laser projectors and 2+ cameras and clever software

https://www.bhphotovideo.com/c/product/1453431-REG/lg_hf80la...

it's 1080p of resolution in lighting from two angles at 60 fps for like ~100-200 W. if you had some good cameras and some clever and fast software you could use this thing to illuminate anything you need to know about -- a high frequency light probe. i don't think you need coherent light at all or phase control, you'd just like timing control so you can strobe between left and right lights and use the variation to better characterize objects.

whole system seems doable in budgets of ~$8k hardware (total guess...)

Re: Ouster's new digital Lidar – 128 beams, ultra-wide view

#100

Post by Animats »

dllu wrote: post #12
scotty79 wrote: post #4

I wonder how well this works if 20 such devices shine on the same object.

Lidars can interfere but somewhat less than other types of active sensors. First of all, the detector only needs to be on for a microsecond or two, and it's unlikely for two sensors to be scanning at the same microsecond. Second, laser spots are fairly small and unlikely to overlap. Finally, there are techniques to further get rid of crosstalk, such as coded random pulses with a matched filter.

LIDARs for volume use should add a few microseconds of random (not pseudorandom) jitter to the outgoing pulse time. That will prevent multiple interfering scans from different units from all synchronizing. You may still get blinded on one scan, but not all of them.
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