Helmdar: 3D Scanning Brooklyn on Rollerblades

https://owentrueblood.com/blog/2025/05/04/helmdar/

143•todsacerdoti•9mo ago

Comments

fshafique•9mo ago

You should post this on /r/Photogrammetry on Reddit: https://www.reddit.com/r/photogrammetry/

condensedcrab•9mo ago

Very impressive! LiDAR and point clouds seem very promising, but the challenge of denoising point clouds and artifacts keep the skill bar very high/time intensive.

timzaman•9mo ago

Just install polycam and walk around :)

amelius•9mo ago

Wouldn't this be cheaper with a stereo pair of cameras + software reconstruction instead?

fake-name•9mo ago

That would need WAY more compute.

pj_mukh•9mo ago

Also a lot less robust depending on baseline.

amelius•9mo ago

There are also advantages, such as that you now also have a map of RGB information corresponding to the depth map.

SequoiaHope•9mo ago

Actually a single camera is all you need. I think it’s fair to say that the only thing stereo gets you is scale. But both cameras and lidar have their place in sensing systems, and getting more experience with either is useful.

If you’re interested in reconstruction from images check out Meshroom and Nerf Studio

https://alicevision.org/

https://docs.nerf.studio/

taneq•9mo ago

Scale is the one thing stereo doesn't get you compared with sequential mono images, unless you have some fancy lens model that lets you derive scale from nonlinearities in the lens. Is that something we do now? I always wanted to try out monocular SLAM with a fisheye lens.

Jyaif•9mo ago

With 2 mono images you can figure out that an object is twice as big as an other, but you can't tell the size of any objects (= you don't know the scale).

With a stereo image you know the distance between the lenses, which allows you to know the size of the objects (= you know the scale).

pj_mukh•9mo ago

So cool! I wonder how the Lidar and ARCore poses were cross-calibrated?

Just to avoid this, I would just use a LiDAR equipped iPhone Pro, with industrial grade cross-calibration and still have all the visualization fun.

dllu•9mo ago

I once put an Ouster OS1 on a hat and walked around with it. Pic of me here: [1]

[1] https://x.com/ddetone/status/1141785696224477184?s=46

weinzierl•9mo ago

Very cool. When was this? If you would repeat it, which LIDAR would you use? Is there anything on a generous hobby budget nowadays?

mkarklins•9mo ago

On cheaper side there's MID360

dllu•9mo ago

It was at CVPR 2019, a computer vision conference. I may be biased since I used to work at Ouster, but cost notwithstanding, I would definitely pick the OS1 again for its unparalleled number of points per second combined with low weight and decent accuracy.

plun9•9mo ago

dllu is a serial astroturfer! He commented “Looks like Ouster just announced their security system” on Reddit.

maeln•9mo ago

A slight tangent but rollerblades is a case of proprietary eponym : Rollerblade is a brand of inline skates (often call skates - plural - for short) that became so famous people started to use it to describe all inline skates, no matter the brand. Just like vaccum cleaner and hoover :)

techn00•9mo ago

and xerox

ioma8•9mo ago

and roomba

taneq•9mo ago

Thanks, I'll hoover up these examples for later use.

ghaff•9mo ago

As another tangent, it's a great example of an activity that became very popular for a time and then almost completely faded away for no obvious reason. (If anything, paved rail trails--which are often a great place to inline skate--are much more common today than they were during skating's heyday.)

BLKNSLVR•9mo ago

I should attempt to trademark myself as The Rollerbalder.

(I haven't checked but I'm sure someone else has already used this on all the popular socials)

voidUpdate•9mo ago

I've thought about trying to do 3d scanning with a LIDAR module, but they all seem really expensive. Does anyone have a recommendation for a spinning LIDAR module that can be interfaced with by an arduino-style device, rather than USB, that doesn't cost me an arm and a kidney?

coder543•9mo ago

I've never actually tried them, but if you google "RPLIDAR", there seem to be some budget-friendly options out there.

mlsu•9mo ago

slamtec RPlidar points come in on UART. They are 2D, not 3D.

You won't be able to do much with the raw data on something with the compute power of an arduino. SLAM takes a lot of compute and memory and compute scales with resolution quickly.

iugtmkbdfil834•9mo ago

While it does feel like we are slowly approaching weird mix of "Snowcrash" and "Fringe", I can't help but marvel at how eerily beautiful those scans are. And the worst part is now I wanna try something similar. Is this what normal people call social proof?

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