
The cost of LIDAR is coming down - edward
https://www.washingtonpost.com/news/innovations/wp/2015/12/04/the-75000-problem-for-self-driving-cars-is-going-away/
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Dwolb
LIDAR is pretty cool because you don't have to do object recognition on the
point cloud to know what you shouldn't be bumping into - since the data comes
back "already 3D" you have distance and size information and just need to
calculate speed. Another benefit LIDAR has is its high resolution as compared
to RADAR.

Where LIDAR typically falls down is in adverse conditions (rain, snow, low
sunlight in the horizon). There's a group at my university, MDAR, who is
prototyping a tech to better overcome the adverse weather issues through a
better laser sensing technique.

Here's an article with a little more technical information [1].

Disclaimer: I've done some part time work on market research for MDAR.

[1] [http://articles.sae.org/13899/](http://articles.sae.org/13899/)

~~~
AndrewKemendo
_you don 't have to do object recognition on the point cloud to know what you
shouldn't be bumping into - since the data comes back "already 3D"_

This is true of any pointcloud system though. No system returns density
though, so you still have to make assumptions about what is worth running into
at what resolution. So if a leaf falls in front of your car, you don't
immediately slam on the brakes.

I don't know of any vision systems that do object recognition immediately, in
fact I'm not even sure that is possible - or desirable. I guess if you baked
segmentation into the firmware it would serve as a fast classifier, but AFAIK
nobody is even talking about doing that as you would need a very well trained
vision library and classifier to deploy to FPGA.

I make the distinction because we build fairly dense pointclouds with
monocular RGB cameras and VSLAM. LIDAR isn't required anymore. LIDAR is faster
with lower error tolerances today, but nowhere near as cheap or portable. I
suspect monocular SLAM will overtake LIDAR in the next couple of years as it's
getting faster and more accurate everyday.

~~~
dimatura
I agree VSLAM is good and getting better everyday, but I don't necessarily
agree it'll displace LiDAR for autonomous vehicles. The first generations will
probably have both. Sure, LiDAR is more expensive, but we're talking about
avoiding collisions here -- I believe the extra safety is worth it. I don't
think portability is not a big issue for cars (though it is a bigger concern
for smaller aerial vehicles). LiDAR will still work in the dark, and
potentially with much more range than cameras can. Having worked with vehicles
using both technologies, I'd feel far better on the LiDAR-equipped one.

~~~
AndrewKemendo
100% agree currently. Your point about dark I was totally overlooking, so I
think that's the big difference that makes LiDAR better long term until
something better comes along.

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deftnerd
I'm more excited by the possibility of a small light-weight LIDAR device that
can be attached to drones for terrain mapping.

My wife is an archaeologist and we've seen lots of discoveries of buried
historical sites found by flying over areas with airplanes and expensive (and
large) LIDAR systems. It would be great to be able to disrupt that with
prosumer equipment.

~~~
bsenftner
Imagine this as a consumer technology: 3d scan your home, car, yard and I'm
sure game developers will create titles that "take place" at your home.

~~~
spyder
It's already possible to do it with any drone that can take good quality
photos:
[http://www.makerbot.com/blog/tag/uav](http://www.makerbot.com/blog/tag/uav)
The resolution depends on the quality of the pictures and the number of them.

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hokkos
LIDAR is not the only way for visual odometry as shown with the kitti
challenge, stero camera show similar accuracy than LIDAR :
[http://www.cvlibs.net/datasets/kitti/eval_odometry.php](http://www.cvlibs.net/datasets/kitti/eval_odometry.php)

The same is true for object detection :
[http://www.cvlibs.net/datasets/kitti/eval_object.php](http://www.cvlibs.net/datasets/kitti/eval_object.php)

And tracking :
[http://www.cvlibs.net/datasets/kitti/eval_tracking.php](http://www.cvlibs.net/datasets/kitti/eval_tracking.php)

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melted
Since there are so many experts on the thread, say these are deployed in every
car on the road. How will one tell its own laser reflection from everybody
else's, if there's a hundred lidars per city block scanning simultaneously?

~~~
owenversteeg
Light travels really fast. As each pulse has an extremely short length, and
there aren't that many scans per second comparative to the lengths of the
pulses, collisions should be rare. When you do have a collision, it will look
completely different from the pulses around it, so you can easily discard it.

~~~
melted
Are you guessing or do you know this for a fact? I know that in radars for
example this is dealt with using matched filters (i.e. filters tuned to
extract known, but delayed signal through correlation), but that requires
continuous, modulated signal.

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TYPE_FASTER
Fewer laser elements means cheaper, but also means lower resolution. I agree
that a combination of video and radar works well for current active driver
aids in cars. LIDAR isn't necessary.

~~~
brianwawok
True but what resolution do we need? The smallest object a car would need to
stop for would be what, a cat or racoon? We don't need snowflake resolution.

~~~
TYPE_FASTER
32 elements might be able to detect objects that small. It depends on how far
away they are.

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supermatt
Does anyone know of any examples of a "solid state" lidar as mentioned in the
article? Im unable to visualise how such a thing would actually work, and its
got me excited!

~~~
huuu
Maybe they use a digital micromirror device also used in dlp projectors. By
using a fish eye lens you could use the mirror array to look around and
calculate the traveling distance of light pulses.

I am also thinking about a 3d camera. Maybe those are getting good enought to
measure distance.

~~~
oofoe
Another possibility might be to use multiple solid state laser
transmitter/receiver pairs located close together, kind of like ink-jet
printer nozzles. Because they're discreet, you would lose some resolution
compared to a continuous scan system, but it might be OK for the purpose of
staying in a road.

And, since the vehicle is moving (most of the time) anyway, maybe multiple
returns can be integrated something like a synthetic aperture radar system to
form a more complete picture.

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tomohawk
What happens after one of these things fails on a 10 year old car? Given the
track record of most electronics on cars, this doesn't seem to be that
unlikely.

Given these kinds of liability concerns, it might be that reducing the cost of
the tech won't reduce the cost of the product much.

~~~
tim333
I guess the computer will tell you to get the sensor replaced? "By 2018, they
are expecting to have a third-generation system in place which will be the
size of a postage stamp and will sell for under $100."
[http://blog.lidarnews.com/postage-stamp-sized-
lidar/#sthash....](http://blog.lidarnews.com/postage-stamp-sized-
lidar/#sthash.delhMrNV.gbpl)

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Animats
Finally. I was pushing for this back in 2003, but the volume wasn't there.

There are quite good eye-safe flash LIDAR units.[1] Advanced Scientific
Concepts in Santa Barbara makes some.[1] A pulsed laser sends out a flash, and
the receiver has a 128x128 pixel chip with time of flight counters for each
pixel. Range in hundreds of meters, in sunlight. No moving parts except a fan.
Cost is about $100K, because they are hand-made using custom ICs produced in
tiny volumes. Space-X uses one on the Dragon spacecraft to dock with the space
station.

Back in 2003, when we were preparing for the DARPA Grand Challenge, I went
down to Santa Monica to see the thing. But the demo was of components on an
optical bench, aimed out a garage door into a parking lot. The technology
wasn't ready to use yet, but it was clearly the right idea, something that
would become cheap in volume. They were working more on making the device more
sensitive than on making it cheaper, because they were getting DoD funding.
Some of their units even have a photomultiplier tube stage, like an image
intensifier. The photoelectric effect is at the atomic level, and so fast you
can use it in front of a time of flight device.

So we ended up using the SICK LMS scanner, like everybody else.

There's a tradeoff between field of view and range with flash LIDAR, because
there's a limited amount of illumination power. A single one of these devices
won't give a full circle of scan, like the Velodyne rotating devices.

There's a cheaper, but less precise, approach, used in the Kinect 360. That's
the ZCam technology. See p. 13 of this paper [2] for how it works. It's a
phase-shift type LIDAR; the outgoing beam is modulated with an RF signal, and
the phase shift of the RF carrier is measured on return. That's also all solid
state, but not as good at rejecting interfering illumination. It doesn't have
digital counters for each pixel; the timing system is analog. So they don't
need counters running at tens of GHz behind every pixel.

Once someone is ready to order > 100,000 flash LIDARs, they'll get cheap. The
technology is not inherently that expensive.

The main reason for having a LIDAR is not to see obstacles. It's to profile
the terrain ahead. You can detect potholes and drop-offs. Since we were
driving off-road for the DARPA Grand Challenge, that was absolutely essential.
Automatic driving systems for on-road use can sleaze by without doing that.
Most of the time. Until they encounter a big pothole, or are misled by road
markings into a ditch. That's why Google has that LIDAR up on top.

[1]
[http://www.advancedscientificconcepts.com/](http://www.advancedscientificconcepts.com/)
[2]
[http://tesi.cab.unipd.it/47172/1/Tesi_1057035.pdf](http://tesi.cab.unipd.it/47172/1/Tesi_1057035.pdf)

~~~
jonah
I have a friend who worked at ASC and got to play with their "Portable 3D
Flash LIDAR Camera Kit"[1] a few years after you saw the tech on an optical
bench. Paired with a optical video camera, you get a full-color 3d scene in
realtime 30fps. Pretty neat.

Their stuff is much smaller and more advanced now and they're pushing the OEM
angle pretty hard[2].

[1] [http://www.advancedscientificconcepts.com/products/older-
pro...](http://www.advancedscientificconcepts.com/products/older-
products/portable.html)

[2]
[http://www.advancedscientificconcepts.com/applications/autom...](http://www.advancedscientificconcepts.com/applications/automotive.htm)

~~~
Animats
They've made a lot of progress. But their site says "The ASCar website is not
providing product or company details at this time. The company will begin
promoting its products in 2015." Getting the price down by three orders of
magnitude is tough for a small startup, especially since the technology pushes
the limits of the technology at the high price point.

~~~
jonah
(They're still small, but have been around since 1987.)

My office is right next door to ASCar's. I won't say much because it's
probably privileged information but let's just say things seem to be coming
along quite nicely.

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peloton
Not mentioned in article but bodes well for drones, aerial mapping, etc.

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wycx
What wavelengths are typically used for LIDAR?

~~~
dljsjr
Infrared.

~~~
tomkinstinch
Infrared is a wide band though, 0.7µm-1mm.

It looks like LIDAR products typically operate in the near-infrared, with two
products I picked at random operating at 905nm[1] and 850nm[2]. They'd want to
pick bands that are invisible to humans, ones where laser diodes exist that
can be modulated, and ideally bands that suffer minimal attenuation from
environmental factors like water. NIR meets those criteria pretty well.

1\.
[http://velodynelidar.com/docs/datasheet/63-9229_VLP16_Datash...](http://velodynelidar.com/docs/datasheet/63-9229_VLP16_Datasheet_Rev-
A_Web.pdf)

2\. [https://sick-
virginia.data.continum.net/media/dox/6/16/516/P...](https://sick-
virginia.data.continum.net/media/dox/6/16/516/Product_information_TIM_Series_Incrediby_good_at_detection_absolutely_accurate_at_measuring_en_IM0042516.PDF)

