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Lumotive Says It Has a Practical Solid-State Lidar

spectrum.ieee.org

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Re: Lumotive Says It Has a Practical Solid-State Lidar

#21

Post by tzs »

> The device can thus see far without having to turn up the brightness. That’s important because the sensor works at 905 nanometers, an eye-sensitive wavelength the company chose because it works with silicon. You need exotic compound semiconductors to make and detect laser light at 1550 nm, a wavelength that’s easier on the eyes

905 nm is infrared, outside the visible range for humans. If someone made a LIDAR at that wavelength, and did "turn up the brightness", what kind of damage would it do to people? Is the danger increased because it is not visible, so you don't have a clue that you are looking at something dangerously bright?

Re: Lumotive Says It Has a Practical Solid-State Lidar

#22

Post by darkpuma »

mrfusion wrote: post #20
baq wrote: post #18

Earlier quoted context omitted.

i always paste a link to Ignition! in every rocket engine thread and there are always people surprised that such a book has been written. relevant https://xkcd.com/1053/

So where’s the link?

https://archive.org/details/ignition_201612

Re: Lumotive Says It Has a Practical Solid-State Lidar

#23

Post by runin2k1 »

tzs wrote: post #21

> The device can thus see far without having to turn up the brightness. That’s important because the sensor works at 905 nanometers, an eye-sensitive wavelength the company chose because it works with silicon. You need exotic compound semiconductors to make and detect laser light at 1550 nm, a wavelength that’s easier on the eyes 905 nm is infrared, outside the visible range for humans. If someone made a LIDAR at tha…

Typically you select a class of laser safe for the environment it will be used in -- class 1 is typical of LIDAR systems for this reason which poses no eye damage risk.

Re: Lumotive Says It Has a Practical Solid-State Lidar

#24

Post by bryant »

tzs wrote: post #21

> The device can thus see far without having to turn up the brightness. That’s important because the sensor works at 905 nanometers, an eye-sensitive wavelength the company chose because it works with silicon. You need exotic compound semiconductors to make and detect laser light at 1550 nm, a wavelength that’s easier on the eyes 905 nm is infrared, outside the visible range for humans. If someone made a LIDAR at tha…

Here's a 2017 ieee spectrum piece discussing a competitor's (Luminar) use of 1550nm light for reasons involving eye safety: https://spectrum.ieee.org/cars-that-think/transportation/sel...

I'm still reading it, so I can't tl;dr it quite yet, but the answer in theory should be in here.

Re: Lumotive Says It Has a Practical Solid-State Lidar

#26

Post by Animats »

asteli wrote: post #9
Animats wrote: post #6

Continental, the big European auto parts company, has a practical solid state LIDAR.[1] It's the Advanced Scientific Concepts flash LIDAR technology, which works well but cost too much when ASC was making it by hand in Santa Barbara, CA. What they don't have is a car company ready to buy enough units to make volume production worthwhile. In the meantime, they're selling a few units to commercial drone operators.[2] […

If I hadn't seen an Animats comment here, I would have copy pasted it from your history just to beat you to it. I checked out of curiosity -- you've got at least 35 posts that directly reference Continental and their Flash LIDAR based on tech from ASC that they're going to build in volume eventually. It's a valid analysis, but why post it every time LIDAR is referenced?

I don't have any connection with Continental or ASC. I did see ASC's flash LIDAR prototype back in 2004 when it was on an optical bench. I thought back then they had the right idea. It cost too much in small quantities. It's made in an IC fab, so cost should come down with volume.

Leddar ships a flash LIDAR, but it's 16x1 pixels. Useful for near obstacle detection, but not enough to create a point cloud. Quanergy seems to have problems, but they have demoed[1] ASC has a 128x128 pixel unit, expensive but good. Those are the main flash LIDAR players.

MEMS mirror scanning looked promising. It worked for video projectors. But it has problems in the automotive environment, apparently.[2]

Liquid crystal beam steering goes back to at least 2004.[3]

The mechanical scanning people have real products, but the ones that can rapidly collect enough data for a point cloud still cost too much.

So Lumotive isn't that novel. The video on the Lumotive site is a render, not a demo.[4] If they had a price, a "buy" button, and reviews, now that would be progress. The vaporware to product ratio in this industry is far too high.

Somebody needs to get this right so we can have vehicle anticollision systems that profile the ground and don't plow into stationary objects.

[1] https://www.bloomberg.com/news/features/2018-08-13/how-a-bil...

[2] https://precisionlaserscanning.com/2017/12/mems-mirrors-vs-p...

[3] https://aip.scitation.org/doi/10.1063/1.1765211

[4] https://www.lumotive.com/

Re: Lumotive Says It Has a Practical Solid-State Lidar

#27

Post by Animats »

deepnotderp wrote: post #19
Animats wrote: post #6

Continental, the big European auto parts company, has a practical solid state LIDAR.[1] It's the Advanced Scientific Concepts flash LIDAR technology, which works well but cost too much when ASC was making it by hand in Santa Barbara, CA. What they don't have is a car company ready to buy enough units to make volume production worthwhile. In the meantime, they're selling a few units to commercial drone operators.[2] […

No they don't. Flash LIDAR suffers from too little range, if you have an angular resolution for the LIDAR of say 0.01 degrees, you're looking at 36 million points! This means that you need 36 million times as much energy to match the same SNR as normal LIDAR. Even with 1550nm light and single photon avalanche diodes (SPADs), this is clearly infeasible. Even Princeton Lightwave (now bought by Ford/Argo), arguably the…

128x128 is as far as ASC got. There's a tradeoff between range and beam width for flash LIDAR. The idea is to get the price down, so you can have multiple wide-angle short range ones around the perimeter of the vehicle, and a narrow beam long range one pointed ahead.

Re: Lumotive Says It Has a Practical Solid-State Lidar

#28

Post by theoh »

greglindahl wrote: post #16
asteli wrote: post #9

Earlier quoted context omitted.

If I hadn't seen an Animats comment here, I would have copy pasted it from your history just to beat you to it. I checked out of curiosity -- you've got at least 35 posts that directly reference Continental and their Flash LIDAR based on tech from ASC that they're going to build in volume eventually. It's a valid analysis, but why post it every time LIDAR is referenced?

He also posts a negative comment about Tesla in every Tesla thread -- I guess this is his hobby or something.

Can you not see the tragic dimension of this?

Re: Lumotive Says It Has a Practical Solid-State Lidar

#29

Post by Animats »

forgotmysn wrote: post #7
Animats wrote: post #6

Continental, the big European auto parts company, has a practical solid state LIDAR.[1] It's the Advanced Scientific Concepts flash LIDAR technology, which works well but cost too much when ASC was making it by hand in Santa Barbara, CA. What they don't have is a car company ready to buy enough units to make volume production worthwhile. In the meantime, they're selling a few units to commercial drone operators.[2] […

I can't speak to profitability of competitors like velodyne and their existing lidar tech but isn't it possible that the risk of waiting for sales volume to reach a certain threshold, thereby creating opportunities for other companies to bring their tech up to the same standard, outweighs the risk of selling the units below cost to capture marketshare in the short term?

If more of these companies had real products, I'd expect them to at least be selling development kits. There are lots of industrial applications at the $1000 price point.

Re: Lumotive Says It Has a Practical Solid-State Lidar

#30

Post by tzs »

bryant wrote: post #24
tzs wrote: post #21

> The device can thus see far without having to turn up the brightness. That’s important because the sensor works at 905 nanometers, an eye-sensitive wavelength the company chose because it works with silicon. You need exotic compound semiconductors to make and detect laser light at 1550 nm, a wavelength that’s easier on the eyes 905 nm is infrared, outside the visible range for humans. If someone made a LIDAR at tha…

Here's a 2017 ieee spectrum piece discussing a competitor's (Luminar) use of 1550nm light for reasons involving eye safety: https://spectrum.ieee.org/cars-that-think/transportation/sel... I'm still reading it, so I can't tl;dr it quite yet, but the answer in theory should be in here.

That seems to settle it:

> The retina does not respond to the 905-nm infrared light used in current car lidars, so we can’t see it. But the eye transmits 905 nm to the retina, so it’s subject to the same restrictions as visible light. In fact, it’s even more hazardous because the eye cannot automatically turn away from a bright source that the retina can’t sense.

The eye is opaque to 1550 nm light, and so even if you are looking right at it none of it makes it to the retina.

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