Very cool tech, and as a fan of Hyperion I think the company name is very cool as well.
For those who don't know the reference :)
https://en.wikipedia.org/wiki/Hyperion_Cantos
Ouster's new digital Lidar – 128 beams, ultra-wide view
101–110 of 122 posts
Re: Ouster's new digital Lidar – 128 beams, ultra-wide view
#102Earlier quoted context omitted.
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.
Unfortunately the gain falls as function of temperature so you also get a lot less light and you have to pump harder (more current). So while it’s possible to somewhat compensate somewhat with the mirrors the device still has this behavior at high temperatures as the device self heats. This behavior is widely documented in the literature.
VCSELs have a smaller current aperture and the current density is higher than in an edge emitting laser. As the reliability is a function of the junction temperature and the current density, VCSELs operating at high temperatures have significantly reduced lifetime compared to an edge emitting device due to the high current density.
See for example slide 5 which shows how lifetime scales as a function of temperature and current density. For high reliability your devices need to have low current density.
http://www.ieee802.org/3/NGAUTO/public/adhoc/Kropp_NGAUTO_03...
Re: Ouster's new digital Lidar – 128 beams, ultra-wide view
#103Earlier quoted context omitted.
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.
It’s just a relatively simple calculation of (amount of energy/amount of space) * time You could have a 100w laser pointed at your eye, but if it only operates for a femtosecond it would have no effect. The light isn’t worse or better than any other form of light.
Re: Ouster's new digital Lidar – 128 beams, ultra-wide view
#104Earlier quoted context omitted.
> Also there is a significant delay of 10 to 100ms I'm curious why there is such an apparently long delay?
It really depends on the type of RADAR being used. If it's an FMCW radar, typically you will get a beat signal whose frequency corresponds to the target range. That frequency will vary with range, and in order to be well resolved you have to observe it for something like 1/period. So that puts a fundamental lower bound on how long you have to integrate. There are lots of tricks to improve things, and there are lots o…
That doesn't explain 100ms delays though. Speed of light times 100ms round trip is 15,000 km.
Re: Ouster's new digital Lidar – 128 beams, ultra-wide view
#105Earlier quoted context omitted.
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.
This doesn't invalidate your point, but the watt comparison you're making isn't correct. 100W is the power of the electricity input to the lightbulb, while the laser wattage is the power of the light output. The actual comparison would be more like 10W to 50 mW (which of course still means that the concentration of energy is required to explain the difference in eye danger).
Re: Ouster's new digital Lidar – 128 beams, ultra-wide view
#106Does 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.
At 865 nm, laser eye damage is due to the laser being focused by your eyeball into a small spot on your retina. This is in contrast to other wavelengths, like 1550 nm, which do not get focused, but can instead damage the surface or your eyeball at much higher powers.
However, when there are many 865 nm lidars around, each one gets focused to a different spot in your retina, so it is not any more likely to cause damage than a single lidar. Thanks to the low power of the Ouster lidar, it is Class 1 eye-safe at any distance.
If there were a hundred high-power 1550 nm lidars all pointed at the surface of your eyeball, however, I wonder if it would be more likely to cause damage?
Re: Ouster's new digital Lidar – 128 beams, ultra-wide view
#107Earlier quoted context omitted.
Imagine every car has a FMCW LIDAR. The chance of interference is very high. Additionally if those receivers are using SE PDs, then these sensors will also be “blinded” (TIAs and or PDs will saturate) when a nearby Lidar system shines its laser into the detector.
I suppose it will be a good while before we can approach an empirical proof for this sort of thing, since FMCW lidars are still very scarce, even more so than pulsed lidars right now. However, even if every car does have an FMCW lidar, the conditions required to get them to interfere with each other is are: a) Have identical laser wavelength. Not just '905nm' or '1550nm', but _precisely_ the same wavelength. This is…
Unfortunately FMCW lidar is sweeping the lasers across the same band. You don’t need the exact frequency just a beat frequency that’s within your detection Bw.
Also balanced detectors have something called common mode rejection. This is not infinite. In high volume applications it’s difficult for this to be >25dB but you can buy some devices >35dB.
Given that Lidar dynamic range is ~100dB you will definitely see the DC. I’ve not thought about this too much but it seems like an issue for the AGC as your demodulator won’t be bothered by it.
Re: Ouster's new digital Lidar – 128 beams, ultra-wide view
#108Am surprised no one yet cited Elon saying "this is fool's errand" because of price, complexity, etc. I think LIDAR will improve significantly the safety of vehicles (autonomous or not) because it can definitely see better and deeper, even in damning weather conditions (rain, fog, haze). Alas, the price of these devices has to come down at least one order of magnitude. Maybe even two. Still, I am really thankful that…
Lidar is solidly worse than the human eye in dust, rain etc. Waymo has struggled w/ dust devils in AZ. Cruise has struggled w/ steam vents in SF. I work at a John Deere subsidiary and we are quite interested in dust performance for field work. From our tests Lidar is low on the list for seeing through small particles. Lots of things could fix this, less beam divergence, custom signals processing on multiple returns.…
I work at an industrial plant we use microwave radar based imaging can get quite detailed surface profiles in very poor conditions including inside reactors etc where dust is big issue. I'm not expert in this field I think systems used are continuous wave based.
For vehicle applications specifically probably worth looking into what they use on autonomous vehicles at mine sites imagine that tech probably useful in agriculture. For example Pilbara here in Australia large autonomous fleets in very dusty conditions.
Re: Ouster's new digital Lidar – 128 beams, ultra-wide view
#109Earlier quoted context omitted.
Lidar is solidly worse than the human eye in dust, rain etc. Waymo has struggled w/ dust devils in AZ. Cruise has struggled w/ steam vents in SF. I work at a John Deere subsidiary and we are quite interested in dust performance for field work. From our tests Lidar is low on the list for seeing through small particles. Lots of things could fix this, less beam divergence, custom signals processing on multiple returns.…
I work at an industrial plant we use microwave radar based imaging can get quite detailed surface profiles in very poor conditions including inside reactors etc where dust is big issue. I'm not expert in this field I think systems used are continuous wave based. For vehicle applications specifically probably worth looking into what they use on autonomous vehicles at mine sites imagine that tech probably useful in agr…
Hi, I've previously been to a company that makes the hardware for autonomous mining vehicles. They rely mainly on DGPS systems for positioning and a combination of simple camera vision and radar for obstacle detection. Keep in mind they don't drive that fast (around 25 mph), are supposed to be in clear unobstructed (unless they're in a queue to load or unload) and just stop when they detect a vehicle or a person.
Re: Ouster's new digital Lidar – 128 beams, ultra-wide view
#110Anyone have a LIDAR (or similar) product suggestion? I'm getting ready to start a hobby project that involves scanning the interior surfaces of a house. Ideally the accuracy would be at least 1/16" (1.5mm), including any scan-stitching required because the sensor had to be moved around. I've seen a few promising products, but none stands out as a perfect match.
Take a look at Leica RTC 360. It's a survey grade terrestrial lidar scanner.
Angular accuracy 18” Range accuracy 1.0 mm + 10 ppm 3D point accuracy 1.9 mm @ 10 m 2.9 mm @ 20 m 5.3 mm @ 40 m
(disclaimer: I work for Leica)