Feb 8, 2016 | By Benedict

Nowadays, in what could be considered a Golden Age of customization and specificity, knowing your measurements can be extremely valuable. Whether you’re a professional athlete looking for the perfect-fitting sportswear and equipment, or a patient requiring an artificial limb, the one-size-fits-all culture of past generations is surely behind us.

One piece of technology doing its best to assist made-to-measure services in a range of fields is the 3D scanner, which can capture 3D images of a body or body part. Unfortunately though, taking accurate 3D scans of humans and their various body parts can be tricky, since people are liable to move around, whether they want to or not, causing inaccurate data—a problem not associated with other, more stationary 3D scanning subjects.

Pieter Smakman, an Industrial Design Engineering and Integrated Product Design student at the Delft University of Technology, recognized this deficiency in 3D scanners and wanted to fix it, focusing particularly on 3D scans of the human hand—measurements of which can inform custom-made tennis rackets, steering wheels, prosthetic fingers, wrist fracture braces, and much more. The student thus set about designing Curatio: a dedicated 3D hand scanner.

“Good 3D scanners already exist, but they’re really only suitable for stationary objects,” Smakman explained. “They are not good enough for scanning the human body. If someone with their hand in the air has to stand on a rotating disc during a scan, the person can’t help but move. So a scan like this isn’t very accurate.”

Once Smakman had the idea for his project, he had to make a number of important design decisions. Via what method would his device capture the images? From what materials would he build the body of the scanner? What hardware would he use?  After a thorough analysis phase, the student decided upon a photogrammetry scanner, for its flexibility, speed, and affordability.

The engineer decided he would build a “ring” of many cameras, between which a subject could place their stationary hand, with each camera firing at the exact same moment to eliminate movement problems. The designer built a PMMA frame using a laser cutter, using aluminum profiles to create two camera rings.

To obtain the perfect camera placement, Smakman used a mannequin arm and set up a single Raspberry Pi camera in a number of different positions. “They are affordable printed circuit boards the size of a packet of cigarettes with the functionality of a fully-fledged computer,” Smakman said of the Raspberry Pi, which provided the brains of Curatio.

After over 100 scans, the designer found the perfect arrangement, which would require 32 Raspberry Pi cameras. He had initially been taking 48 photos for a single scan, but realized that fewer were required: “On the computer I discarded 1 photograph from each series, through which I discovered that 32 images were sufficient for producing a good 3D scan.”

The challenge facing Smakman now was figuring out how to operate those 32 cameras in perfect unison, in order to produce a flawless 3D scan of a human hand. He tested the mini computers by having them photograph a stopwatch simultaneously. Each photograph showed the exact same time to a hundredth of a second.

However, Smakman still had a problem when trying to send the images down the line to a main computer: the wireless network was overburdened. The quick-thinking student overcame this problem by incorporating a send delay into each Raspberry Pi. The code modification did the trick, and his 3D hand scanner was complete. “What I then felt... It’s truly wonderful when it all works,” the Curatio designer said. “Especially because no one has done this before.”

The prototype Curatio was able to produce hand scans with a maximum deviation of 1.5mm from the subject. Smakman envisions the 3D hand scanner being used as the starting point of a 3D printed wrist brace service called “Carpifix”. In the Carpifix business model, a patient could have their hand 3D scanned, after which medical professionals could use the 3D images to produce a custom-fit, 3D printed brace for that patient.

Smakman’s creation was first showcased at Dutch Design Week 2015 in Eindhoven, Netherlands.

 

 

Posted in 3D Scanning

 

 

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Bill Rodriguez wrote at 7/21/2016 3:34:06 PM:

This is very interesting! Do you have you code posted on github?

Kamrenae wrote at 2/14/2016 10:38:38 PM:

I'm looking to start an after school program for makerspace, but need to know where to begin?!?! Any help on this would be fabulous!! Thanks!!



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