Page 159 - Anthropometry, Apparel Sizing and Design

154 Anthropometry, Apparel Sizing and Design

if the process were slowed down. However, current resolutions are appropriate for
most anthropometric uses. The exceptions are scans of hands, feet, and faces, for
the design of gloves, of shoes, and of facemasks. Foot scanners optimized to scan feet
are marketed separately from body scanners and are available from many providers.
Scanning hands and faces is another issue, and few scanners have been developed spe-
cifically for this purpose. A low-scan volume, high-resolution scanner developed for
head scans by Human Solutions provides good hand data for glove design and face and
head data for facemask and helmet design.

6.4.3 Posture, scanning apparel, and hair issues in scanning
Posture is a critical issue in scanning. For most measurement purposes a relaxed, nat-
ural posture is desirable in which the person’s position is as close to bilaterally sym-
metrical as possible (weight equally distributed on both feet, shoulders, and hips
square and balanced). The anthropometric position (head in the Frankfort horizontal
plane, shoulders relaxed, arms at the sides, hands relaxed and facing forward, and feet
with heels together and toes at a 60-degree angle) is ideal both to provide the most
reliable measurement data and to maintain comparability with manually performed
anthropometric studies from the past (see Fig. 6.7). However, this position will
obscure sensors from parts of the body such as the underarm, inner thighs, and crotch,
particularly for overweight or obese subjects. Therefore most scanners require that the
subject being scanned stand with their feet, shoulder width apart (or further if needed
to separate thighs), and with their arms abducted from the body.
Scanning a participant in the most common scan position may result in variation in
stature and height measurements, and if care is not taken to coach the scanee into a
relaxed position, he/she may brace his/her shoulders back, raise his/her shoulders,
and/or lock his/her knees and elbows, all of which postures can affect the validity
of the body measurements extracted from the scan. Defining and maintaining a stan-
dard position is important to conduct a study that is internally reliable. If it is important
that the study be consistent with other anthropometric studies or if height measures are
important, it may be necessary to take two scans of each subject, one optimized for
circumferential measurements with arms and legs abducted and a second one opti-
mized for height measurements, taken in the anthropometric position. In any case,
it is important to coach the subject to assume a relaxed posture. The ISO standard
on scanning metrics for anthropometrics specifies one anthropometric standing posi-
tion and one standing position with limbs abducted. Also included in this standard is a
standing pose with one arm extended forward and the other arm bent at a 90 degree at
the elbow and a seated position (ISO International Standard, 2010).
If stature and crotch height are important measurements for the study, it may be
preferable to take these two measurements manually. Scanners generally do not cap-
ture the top of the head well. Light sources can be scattered in hair, impacting the scan
quality, and cameras are generally not aimed in a direction that will capture the top of
the head. Also, even with the legs abducted, few scanners can actually capture the
exact position of the crotch.