Page 39 - Anthropometry, Apparel Sizing and Design

Anthropometric methods for apparel design: Body measurement devices and techniques 35

measurers to an allowable range when plural measurers participate in an anthropomet-
ric survey. A common understanding of locations of landmarks on the body between
measurers is most important for reducing the bias. A practical protocol for locating a
landmark helps to reduce both bias between measurers and random error within a mea-
surer. A protocol established in ISO 20685-1 (see Section 2.5) can be used for eval-
uating if the differences between measurements taken by two measurers are within an
acceptable range.

2.3 Three-dimensional anthropometry

2.3.1 Basics of 3-D measurement
Triangulation is used for obtaining the depth information in 3-D body scanners
(Fig. 2.5). In one type of body scanner, a single slit light is projected on the body
surface, which is observed by a camera from a different angle. The length between
the light source and the camera (L in Fig. 2.5) and angles between the line connecting
the light source and camera and the line connecting a point on the body surface and the
light source or the camera (α and β in Fig. 2.5) are known. Therefore the depth (D in
Fig. 2.5) can be calculated. The time required for scanning the entire body by slit light
ranges from several seconds to over 10s according to the system used.
In another type of body scanner, structured patterns are projected on the body sur-
face, which are observed by a camera from a different angle. In this method the body
can be measured within 1s, in principle. However, plural cameras and plural

Fig. 2.5 Principle of 3-D measurement.