Reconstructing 3D Objects With A Tiny Distance Sensor

February 20, 2025 by Lewin Day 6 Comments

There are a whole bunch of different ways to create 3D scans of objects these days. Researchers at the [UW Graphics Lab] have demonstrated how to use a small, cheap time-of-flight sensor to generate scans effectively.

Not yet perfect, but the technique does work…

The key is in how time-of-flight sensors work. They shoot out a distinct pulse of light, and then determine how long that pulse takes to bounce back. This allows them to perform a simple ranging calculation to determine how far they are from a surface or object.

However, in truth, these sensors aren’t measuring distance to a single point. They’re measuring the intensity of the received return pulse over time, called the “transient histogram”, and then processing it. If you use the full mathematical information in the histogram, rather than just the range figures, it’s possible to recreate 3D geometry as seen by the sensor, through the use of some neat mathematics and a neural network. It’s all explained in great detail in the research paper.

The technique isn’t perfect; there are some inconsistencies with what it captures and the true geometry of the objects its looking at. Still, the technique is young, and more work could refine its outputs further.

If you don’t mind getting messy, there are other neat scanning techniques out there—like using a camera and some milk.

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Watch A 3D Scan Become A Car Body Model

December 20, 2024 by Donald Papp 1 Comment

Not all 3D scanning is alike, and the right workflow can depend on the object involved. [Ding Dong Drift] demonstrates this in his 3D scan of a project car. His goal is to design custom attachments, and designing parts gets a lot easier with an accurate 3D model of the surface you want to stick them on. But it’s not as simple as just scanning the whole vehicle. His advice? Don’t try to use or edit the 3D scan directly as a model. Use it as a reference instead.

Rather than manipulate the 3D scan directly, a better approach is sometimes to use it as a modeling reference to fine-tune dimensions.

To do this, [Ding Dong Drift] scans the car’s back end and uses it as a reference for further CAD work. The 3D scan is essentially a big point cloud and the resulting model has a very high number of polygons. While it is dimensionally accurate, it’s also fragmented (the scanner only captures what it can see, after all) and not easy to work with in terms of part design.

In [Ding Dong Drift]’s case, he already has a 3D model of this particular car. He uses the 3D scan to fine-tune the model so that he can ensure it matches his actual car where it counts. That way, he’s confident that any parts he designs will fit perfectly.

3D scanning has a lot of value when parts have to fit other parts closely and there isn’t a flat surface or a right angle to be found. We saw how useful it was when photogrammetry was used to scan the interior of a van to help convert it to an off-grid camper. Things have gotten better since then, and handheld scanners that make dimensionally accurate scans are even more useful.

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VR Headset With Custom Face Fitting Gets Even More Custom

September 28, 2024 by Donald Papp 7 Comments

The Bigscreen Beyond is a small and lightweight VR headset that in part achieves its small size and weight by requiring custom fitting based on a facial scan. [Val’s Virtuals] managed to improve fitment even more by redesigning a facial interface and using a 3D scan of one’s own head to fine-tune the result even further. The new designs distribute weight more evenly while also providing an optional flip-up connection.

It may be true that only a minority of people own a Bigscreen Beyond headset, and even fewer of them are willing to DIY their own custom facial interface. But [Val]’s workflow and directions for using Blender to combine a 3D scan of one’s face with his redesigned parts to create a custom-fitted, foam-lined facial interface is good reading, and worth keeping in mind for anyone who designs wearables that could benefit from custom fitting. It’s all spelled out in the project’s documentation — look for the .txt file among the 3D models.

We’ve seen a variety of DIY approaches to VR hardware, from nearly scratch-built headsets to lens experiments, and one thing that’s clear is that better comfort is always an improvement. With newer iPhones able to do 3D scanning and 1:1 scale scanning in general becoming more accessible, we have a feeling we’re going to see more of this DIY approach to ultra-customization.

3D Imaging For Natural Science — For Free

March 11, 2024 by Al Williams 4 Comments

It isn’t that unusual for a home lab to have a microscope, but wouldn’t it be cool to have a CT scanner? Well, you probably won’t anytime soon, but if you are interested in scans of vertebrates — you know, animals with backbones — a group of museums have you covered.

The oVert project is scanning 20,000 specimens and making the results available to everyone. This should be a boon to educators and might even be useful for 3D printing animal forms. Check out the video about the project below.

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Hackaday Links: May 28, 2023

May 28, 2023 by Dan Maloney 20 Comments

The Great Automotive AM Radio War of 2023 rages on, with the news this week that Ford has capitulated, at least for now. You’ll recall that the opening salvo came when the US automaker declared that AM radio was unusable in their EV offerings thanks to interference generated by the motor controller. Rather than fixing the root problem, Ford decided to delete the AM option from their EV infotainment systems, while letting their rolling EMI generators just keep blasting out interference for everyone to enjoy. Lawmakers began rattling their sabers in response, threatening legislation to include AM radio in every vehicle as a matter of public safety. Ford saw the writing on the wall and reversed course, saying that AM is back for at least the 2024 model year, and that vehicles already delivered without it will get a fix via software update.

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Hackaday Links: November 15, 2020

November 15, 2020 by Dan Maloney 13 Comments

Now that we drive around cars that are more like mobile data centers than simple transportation, there’s a wealth of data to be harvested when the inevitable crashes occur. After a recent Tesla crash on a California highway, a security researcher got a hold of the car’s “black box” and extracted some terrifying insights into just how bad a car crash can be. The interesting bit is the view of the crash from the Tesla’s forward-facing cameras with object detection overlays. Putting aside the fact that the driver of this car was accelerating up to the moment it rear-ended the hapless Honda with a closing speed of 63 MPH (101 km/h), the update speeds on the bounding boxes and lane sensing are incredible. The author of the article uses this as an object lesson in why Level 2 self-driving is a bad idea, and while I agree with that premise, the fact that self-driving had been disabled 40 seconds before the driver plowed into the Honda seems to make that argument moot. Tech or not, someone this unskilled or impaired was going to have an accident eventually, and it was just bad luck for the other driver.

Last week I shared a link to Scan the World, an effort to 3D-scan and preserve culturally significant artifacts and create a virtual museum. Shortly after the article ran we got an email from Elisa at Scan the World announcing their “Unlocking Lockdown” competition, which encourages people to scan cultural artifacts and treasures directly from their home. You may not have a Ming Dynasty vase or a Grecian urn on display in your parlor, but you’ve probably got family heirlooms, knick-knacks, and other tchotchkes that should be preserved. Take a look around and scan something for posterity. And I want to thank Elisa for the link to the Pompeiian bread that I mentioned.

The Defense Advanced Research Projects Agency (DARPA)has been running an interesting challenge for the last couple of years: The Subterranean (SubT) Challenge. The goal is to discover new ways to operate autonomously below the surface of the Earth, whether for mining, search and rescue, or warfare applications. They’ve been running different circuits to simulate various underground environments, with the most recent circuit being a cave course back in October. On Tuesday November 17, DARPA will webcast the competition, which features 16 teams and their autonomous search for artifacts in a virtual cave. It could make for interesting viewing.

If underground adventures don’t do it for you, how about going upstairs? LeoLabs, a California-based company that specializes in providing information about satellites, has a fascinating visualization of the planet’s satellite constellation. It’s sort of Google Earth but with the details focused on low-earth orbit. You can fly around the planet and watch the satellites whiz by or even pick out the hundreds of spent upper-stage rockets still up there. You can lock onto a specific satellite, watch for near-misses, or even turn on a layer for space debris, which honestly just turns the display into a purple miasma of orbiting junk. The best bit, though, is the easily discerned samba-lines of newly launched Starlink satellites.

A doorbell used to be a pretty simple device, but like many things, they’ve taken on added complexity. And danger, it appears, as Amazon Ring doorbell users are reporting their new gadgets going up in flame upon installation. The problem stems from installers confusing the screws supplied with the unit. The longer wood screws are intended to mount the device to the wall, while a shorter security screw secures the battery cover. Mix the two up for whatever reason, and the sharp point of the mounting screw can find the LiPo battery within, with predictable results.

And finally, it may be the shittiest of shitty robots: a monstrous robotic wolf intended to scare away wild bears. It seems the Japanese town of Takikawa has been having a problem with bears lately, so they deployed a pair of these improbable looking creatures to protect themselves. It’s hard to say what’s the best feature: the flashing LED eyes, the strobe light tail, the fact that the whole thing floats in the air atop a pole. Whatever it is, it seems to work on bears, which is probably good enough. Take a look in the video below the break.

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3D Print Your 3D Scanner

February 19, 2020 by Al Williams 15 Comments

[QLRO] wanted a 3D scanner, but didn’t like any of the existing designs. Some were too complex. Some were simple but required you to do things by hand. That led to him designing his own that he calls AAScan. You can see the thing operating in the video below.

In general, you can move the camera around the object or you can move the object around while the camera stays fixed. This design chooses the latter. You’ll need a stepper motor with a driver board and an Arduino to make the turntable rotate. You also need a computer running Python and Meshroom. The phone also has to run Python and [QLRO] used QPython on an Android device.

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