a 3D scanner for the hand
Curatio (a 3D scanner)

3D scans of a person's hand provide detailed measurements useful in design and medical treatments. They can also be used to personalise products, like a 3D-printed plastic cast that fits perfectly, is water-resistant and is reusable. However, most 3D scanners have trouble scanning hands.

Curatio is a 3D scanner designed specifically to produce high quality scans of the human hand. The project builds on an earlier proof of concept scanner design and user experience concept. Unlike most other scanners it can handle the hand's difficult shape and texture. That means it can obtain accurate measurements of virtually anyone's hand. Also of people with an impairment. And the intuitive interface means basically anyone can do it.

With its low-cost components, Curatio can commoditise the use of accurate 3D scanning. Enabling improved hand therapy and a new world of design opportunities for personalised products like braces.

Flexible multi-component audio system Ultimaker 3D printer Hololens

The vision for Curatio was commoditising the use of accurate 3D scanning to enable improvements to hand therapy and product design. I envisioned the use of a flexible architecture with off-the-shelve components, it providing the required result without effort, and creating a comfortably high-tech experience that provides a feeling of attention.

Developing a robust 3D scanning system using 53 Raspberry Pi’s

To enable instantaneous scans pictures are taken from all around the hand simultaneously using 52 Raspberry Pi's with cameras. These are processed into a 3D model afterwards. The system is designed to be flexible: a single coordinator Raspberry Pi automatically finds all the cameras on the network and coordinates scans. This means adding & removing cameras, or trying a different arrangement is as simple as (un)plugging a Pi and clicking the scan button.

Early scanner prototype Late-stage scanner prototype
Partial UMD diagram of scanner software

24 major design iterations to achieve accurate scanning without calibration

3D scanning using photogrammetry, the technique used by Curatio, is complex and involves dozens of variables. That makes it incredibly difficult to find the best hardware and software setup. To overcome this I used a highly iterative approach, trying various changes in each iteration and continuing with the best. To make this proces quicker and simpler I started out with only a partial scanner and slowly made it more complete as experiments got closer to the final result.

Scan results of various iterations of the 3D scanner

On-screen UIs to support complex interactions involving two devices and two people

To enable anyone to get accurate results, Curatio's interface was designed to guide both operator and subject through the process. It's a matter of selecting the scanning protocol and following the instructions. The scanner shows the correct hand postures, ensuring reproducible results.

Entering and reviewing information, and selecting protocols happens on an external computer because the small touch-screen isn't suitable when scanning more than a few hands. The status bar is a key element: it provide continuous feedback about the state of the current scan and the scanner.

Operator application status bar states Operator application screen
Situation with scanner, computer, operator and patient Situation with scanner, computer, operator and patient
Pre-scan screen of scanner showing posture Scanning screen of scanner showing live view of hand

Interesting opportunities for hand therapy and anthropometry

Just getting 3D scans isn't very useful. What's actually interesting is using them for personalising products or automatically retrieving measurements from them. That's why operator application is designed to show measurement results for scans and not just the 3D scans themselves.

For personalised products this can be taken even further. The application can function as a marketplace: the operator would select the product, do the preconfigured scans and several days later the product would be delivered to the customer or patient. This would be of great value to users and an interesting business opportunity.

Scan selection list showing product options