

Laser Scans of London Are a New Way to See the World - astrange
http://www.wired.com/2015/04/laser-scans-london-new-way-see-world/

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Robadob
I did a bit of work with point-cloud/lidar data during a placement with an
engineering company. They were actually driving down highways with LIDAR
apparatus attached to a vehicle to build a point clouds of roads/similar. The
sheer detail (points per inch/similar) in the point clouds whilst beneficial
also requires ridiculous amounts of RAM to do any form of processing. If
rendered as points, it's only useful at a distance, as you zoom in it becomes
a void with sparse points.

I tried using PCL[1] to convert a point-cloud into a mesh and I seem to recall
it using upwards of 6 times the amount of memory of the stored points (before
I ran out of memory). I was only there a short time so I never did get round
to making it work.

[1][http://pointclouds.org/](http://pointclouds.org/)

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CountHackulus
There's a few innovative approaches to this, some of the done in real time.
The "histopyramid" approach is used in the demoscene, and it's explained in
the Fairlight rendering secrets talk:
[https://www.youtube.com/watch?v=ZiPGd3DDfMU](https://www.youtube.com/watch?v=ZiPGd3DDfMU)

It's maybe not suited to billions of points, but it's a decent start.

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mentos
"The project required 223 laser scans, collected over four days in December.
Each scan takes 10 minutes to half an hour to complete. ScanLab also takes
photographs, which it uses later to map color onto the point cloud (newer
scanners can capture color automatically, but ScanLab prefers its techniques;
the vivid color of the group’s scans is part of its uncanny magic). Once the
field work is done, software compiles individual scans into a pointcloud. The
Mail Rail scan is comprised of more than 11 billion points, consuming over a
terabyte of storage. (When the ScanLab guys talk numbers with companies that
specialize in data storage and backup solutions, the experts often assume
ScanLab is an architecture studio of 150 employees. It has in fact
expanded—it’s now a team of six.)"

I wonder if they use AgiSoft's 'PhotoScan' software to bring their photos and
laser scans together into one model?

edit: Looks like they probably use the following scanner:
[http://www.faro.com/en-us/products/3d-surveying](http://www.faro.com/en-
us/products/3d-surveying) Still curious to know what their process is to bring
their own photos and the 3d point cloud data to life

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ignoramous
Something like this will have huge ramifications on the ecommerce, travel
industry and esp online video, and with a tech like this, they are going to
absoultey crush their non-digital counterparts.

Imagine buying a dress using a VR which lets you explore the dress with pin
point accuracy and detail. This is the kind of stuff that would help save a
tonne of money in returned products for fashion bases e-tailers. It won't be
surprising to see these companies being acquired by Amazon, Google, or
Facebook to be integrated with their ecommerce, gaming businesses.

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grondilu
> The Mail Rail scan is comprised of more than 11 billion points, consuming
> over a terabyte of storage.

That's about 90 bytes per point. Seems a lot.

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kefka
When I devised my format for laser scanning, I used X, Y, Z, R, G, B where X,
Y, and Z are 4 bytes. RGB was 1 byte each, total of 3 bytes.

That's 15 bytes. So.... I'm 600% more optimized than Faro? I think someone's
off on their numbers.

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pbhjpbhj
Is it the difference between raw data and processed? The scan could have
things like [I'm guessing] corrected baseline direction of the laserbeam
(3-axes: theta, phi, psi??), time of pulse initiation in ns(?), time of pulse
reception, colourific data, CRC. Then you process that to create the point
cloud?

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kefka
I made mine using a line laser and a webcam. Its slow, but I can scan decently
well, and in color. Of course, the more lasers and cameras, the faster I can
scan.

~~~
pbhjpbhj
Do you have more details somewhere about how you made it?

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calgoo
This really reminds me of level editors for games :) I wonder if this could be
imported and used in something like counterstrike or unreal.

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madaxe_again
Not certain what engine they're using, but they're working to open London's
museums up to the world as rift/gear VR experiences - so probably unity or
UE4.

The other thing that the article doesn't mention which is really neat is that
the Shipping Galleries that they picture at the Science Museum are sadly no
more - so their work has preserved those galleries in virtual form, and allows
them to live on, even when the physical space has been repurposed.

Edit: here's a nice video of the pointcloud of said gallery.

[https://www.youtube.com/watch?v=gDTbFhFZl9I](https://www.youtube.com/watch?v=gDTbFhFZl9I)

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darkmighty
Really cool, I hope they open the data for improved visualizations. Rendering
raw colored points leaves to be desired, some kind of geometry extractor would
much improve the display.

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shubb
Anyone else in the uk doing work like this? Can I help?

