A full 3D body scan takes under a minute and uses light, with no ionizing radiation, according to a 2018 review of the technology.
A 3D body scan is a digital copy of the surface of a person's body, made with cameras or depth sensors in place of a tape measure. A 2018 review in the European Journal of Clinical Nutrition calls the method optical: the scanner works with light and, unlike CT or DXA, uses no ionizing radiation.
How a 3D body scanner records a body
A 3D body scanner records a body in 1 of 4 ways, according to the review: structured light, time of flight, several fixed cameras, or a platform that turns the person through 360 degrees. With structured light, the scanner projects a pattern and reads depth from how the pattern bends over the body.
Each method produces frames of depth data. Software turns the frames into a cloud of points, lines the points up, merges them and builds a mesh. A full scan takes under a minute.
What a 3D body scan measures
A 3D body scan returns 4 kinds of numbers: circumferences, widths, lengths and volumes. Volume can be given for the whole body or for a region such as the trunk. The review adds that shape models can estimate body composition from a scan.
| What the scan returns | Compared with | What the review found |
|---|---|---|
| Waist and hip circumference | A flexible tape | The values correlate well |
| Total body volume | Air displacement plethysmography | The values correlate well |
| Any dimension | Existing reference data | Systematic differences remain |
Where a 3D body scan falls short
The review names 4 limits of a 3D body scan. Posture changes between scans add variation to regional volumes. Bony landmarks cannot be felt on a digital body, and a high BMI can hide them. Areas the cameras cannot see, such as the top of the head, the underarms and the space between the legs, leave holes that software has to repair. Sensors can interfere with each other, and time of flight sensors have lower resolution.
The review concludes that systematic differences between 3D optical and standard measurements are evident. Scan data therefore cannot yet be compared directly with older tape data. An ISO standard, ISO 20685-1, sets out how to evaluate body dimensions taken from 3-D scans for anthropometric databases.
The first large 3D body scan survey
The CAESAR project was the first anthropometric survey to provide 3-D human models, according to a 2003 paper by Robinette and Daanen. The survey measured 4,431 people in North America, the Netherlands and Italy and produced over 13,000 3-D scans.
A 1998 report in Federal Computer Week gives the aim of the US Air Force: body data for uniforms, helmets and cockpits. The report names a full-color 3-D laser scanner made by Cyberware.
Who offers 3D body scans
Fit3D and Styku are 2 makers of body scanning systems. Both makers list gyms, clinics and wellness businesses as their customers. Styku's site lists body composition, circumferences and side by side 3D images over time among its reports.
3D body scan or 3D body visualizer
A 3D body scan needs the person and a scanner. A 3D body visualizer needs numbers only.
| Question | 3D body scan | 3D body visualizer |
|---|---|---|
| What it starts from | A real body | Height, weight and tape measurements |
| What it needs | Cameras or depth sensors | A web browser |
| Whose body it shows | The person scanned | A likely body for the numbers |
The 3D body visualizer draws a figure from a height and a weight, and holds any tape measurement typed in. To see tape numbers on the figure, open the figure with its tape lines on. The guide on how to take body measurements at home gives the tape position for each one, and the guide on where the body visualizer came from follows the research that turned scans into body models.