Three-Dimensional (3-D) Photonic Scanning: A New Approach to Anthropometry

Abstract

Anthropometric measurements, such as body mass index (BMI) and body girths have long been used to assess nutritional status in all age groups. Although most such measurements are merely one-dimensional (1-D), they are often used to index body shape. Examples include BMI, waist–hip ratio or waist–height ratio, each of which acts as a proxy for whole-body or regional-body shape. Recently, whole-body photonic scanners developed by the clothing industry have appeared, and offer a new approach to body shape assessment. Although a variety of technologies have been developed, all photonic scanners project light onto the surface of the body, and record the surface topography. Initial data capture provides a ‘point-cloud’, which is then processed using computer algorithms to extract the skin surface topography. Automatic landmark identification then allows an ‘e-tape measure’ to be applied, extracting multiple girths, distances, diameters and two-dimensional (2-D) cross-sectional areas. Current software allows around 200 such measurements to be extracted, making the technique ideal for large anthropometric surveys. However, the major potential of the technique lies in its ability to go beyond 1-D measurements and extract more complex topographical and shape outcomes. The technology offers numerous benefits over traditional approaches, with the digital data facilitating rapid processing and archiving, the application of diverse analytical software programmes, and repeat scans allowing change in shape to be quantified. 3-D scanning has recently been applied in several large National Sizing Surveys, allowing exploration of the associations of age, gender and nutritional status with body dimensions. Validation studies against manual measurements indicate high consistency in ranking individuals compared with manual measurements, but systematic differences in average values, due to differences in the way that the data is obtained. 3-D photonic scanning is easy, quick and cheap to apply, as well as being non-invasive and well-accepted by the majority of adults. The technology offers a novel approach to anthropometry and is likely to be adopted increasingly in large surveys of size, growth, nutritional status and health.