STAGE 3 : Sizing system
3.4 Planning a national anthropometric survey for clothing
3.4.2 Preparation
The key issues to be dealt with may include the preparation of logistics software, sub-ject registration, a life style questionnaire, an anthropometric measurement set, benchmarking and the purchase of equipment, statistics, a model for a data collection center, a proofing study, and the selection of survey staff and their training.
3.4.2.1 Logistics software
A comprehensive set of software is needed for subject registration, subject selection, the life style questionnaire, and uploading of the body scan and other data collected and tracking statistics (seeFig. 3.2).
3.4.2.2 Subject registration
One of the aims of encouraging online registration is that subject details can be processed and their details checked against the recruitment frame. This check enables the acceptance or rejection of a subject according to the numbers required for each age/gender/region (see example inTable 3.3). If a subject is accepted, a bar code could be issued and appointments for visits to venues agreed well in advance of the data collection program (i.e., details needed for recruitment selection—age; gender; eth-nicity; key measurements—height, weight, chest/bust, waist, and hip; location; and contact details). In addition, information for subjects related to the project (ethical papers, confidentiality agreement, a comprehensive description of 3-D body scanning, data collection process, and preparation for scanning) could all be accessed and, where necessary, processed prior to appointment.
3.4.2.3 Life style questionnaire
Life style questionnaires would normally be designed and tested in conjunction with the marketing departments of the commercial partners. They also tend to be gender-specific (and, in the case of children’s study, age-gender-specific). A questionnaire would Fig. 3.2 Screenshot showing a recent example of a logistics software package. It shows a
“Home/Welcome” page.
Source: University College London.
normally include subject clothing preferences; size and fit issues; shopping habits (both in-store and online); and personal details related to body measurements, health and income, etc (seeFig. 3.3).
3.4.2.4 Anthropometric measurement set and postures
The selection of measurements and postures will depend on the objectives of the sur-vey. If the data required are to be intergenerational (i.e., all adults and/or all children) to include a full range of shapes, sizes, and postures and the majority of clothing prod-uct types, then it will be necessary to
l identify the body postures to be scanned (e.g., ISO 8559-1:2017);
l assess the measurements listed inISO 8559-1:2017and, should the ISO measurements not be sufficient to meet the requirements of inclusive design and the development of the major-ity of clothing product types, then there may be a need to include additional measurements;
l create a survey-specific measurement set.
(The latter two proposals would need to include relevant body landmarks, body loca-tions, images, and an estimation of allowable errors.)
Such an assessment would be required in order to evaluate available measurement extraction software offered during scanner benchmarking. The majority of scanner providers currently offer measurements listed in ISO 8559 and ISO 7250 (recently updated) for clothing and technological design. However, if there is incompatibility (between the survey-specific set and software offered), then it may be possible for a scanner manufacturer to extend their current measurement provision, for example, the development of TC2 software for SizeUK measurement set. In addition, if
Fig. 3.3 Screenshot of a recent lifestyle questionnaire incorporated into logistics software, discussed above.
Source: University College London.
intergenerational adult studies (18–100years) were undertaken, a means of addressing life-span morphological changes would be required (e.g., spinal posture—see Ashdown and Na, 2008).
It is important to note that both of these standards (ISO 8559 and ISO 7250) were revised in 2017, and although there are a few basic measurements, common to both standards, there is now a much clearer distinction between the amount and type of landmarks, measurements, and postures required for clothing as opposed to techno-logical design.
3.4.2.5 Equipment benchmarking, selection, and purchase
All subjects need to register with the survey and would ideally, complete an online life style questionnaire before selection (see discussion earlier). However, in order not to exclude any potential volunteers, an additional set of PCs and paper copies of ques-tionnaires would need to be made available at each data collection center.
To maximize national benefit, it may be necessary to supplement 3-D body scan-ners with head or foot scanscan-ners and include a height gauge and a body composition monitor to automatically record subject height and weight. Depending on the objec-tives of the study and the 3-D scanner selected, it may also be necessary to include traditional anthropometric equipment, underwear/scan wear, head covers, and mate-rials for the hygienic maintenance of equipment.
It is advisable to benchmark all equipment to be used during the survey. This includes scanners, height, weight, and any other manual measuring equipment (see 8559-1 2017). Types of technology used to capture the 3-D surface shape of the body include lasers; projected light; and, latterly, millimetric radio waves and smart phone capture (Ballester et al., 2017) (although the latter maybe useful for size prediction, its suitability for accurate anthropometric clothing-specific studies is not yet clear). Each has its advantages (resolution, cost, automatic measurement extraction, etc.), but new, extended, or enhanced systems are being offered (e.g., 3dMD System-4D). Guidance is also available via conference publications (e.g.,Hometrica Consulting, 2018) and in some ISO standards (e.g., ISO 20685 Parts 1 and 2). It is, however, advisable to con-duct a benchmarking exercise—especially if it is planned to
l scan subjects with differing heights, sizes, skin shades, and ages;
Table 3.3 The recruitment of subjects participating in the SizeUK survey. Figures for seven age bands recruited for each of three regional centers (total populations in each region were matched for accurate representation)
Age group 16–25 26–35 36–45 46–55 56–65 66–75 76 + Sum
Region 1 188 188 188 188 188 188 188 1316
Region 2 188 188 188 188 188 188 188 1316
Region 3 188 188 188 188 188 188 188 1316
Totals 564 564 564 564 564 564 564 3948
Allen et al. (2003).
l use a range of underwear/scan wear—this will depend on the objectives of the study, the requirements of commercial partners, cultural variations in a population, and the selected scanner;
l scan subjects who may not be able to remain still for longer than 8–10s;
l use survey-specific measurement sets that do not include dimensions that are listed in ISO standards (e.g., ISO 8559-1).
(SeeAllen et al., 2003, for an example of benchmarking.)
A key issue raised by the need for benchmarking is an assessment of the accuracy of 3-D scan capture, landmarking, and measurement extraction. ISO 20685 Parts 1 and 2 give guidance for reducing error in 3-D scanning and for establishing accuracy of body dimensions by comparing traditional manual measurements with those extracted from scanners. In addition, although such comparisons are still the subject of debate, it is acknowledged that some scanners have now reached a stage of development where they can automatically extract measurements from subjects with a higher accuracy and consistency than those taken by trained anthropometrists. Notwithstanding these advances and debates, what is perhaps as important is the need to agree definitions and measurement positions. As can be seen in earlier work, where waist definitions ofISO 8559:1989(now reissued as ISO 8559-1) are compared with those of a preferred waist taken during the CAESAR study (Veitch, 2012) and where acceptable upper and lower limits of the waist are compared to define the true height of the waist (Gill et al., 2014).
3.4.2.6 Statistics
The determination of a statistical sample of earlier clothing-specific surveys (e.g., SizeUK) was based on the pioneering work of US military studies (Gordon et al., 1989), and as can be seen inTable 3.3. I., the SizeUK study took place in three geographical regions (the total population within each region was approximately equal to obtain statistical relevant results), and each region was divided into seven age bands.
However, an ISO standard (ISO 15535 General requirements for establishing anthropometric databases) introduced in 2006 and revised in 2012 sets out options for desired levels of relative accuracy and confidence—for stature, chest circumfer-ence, and shoulder breadth—with proposed numbers of subjects for the achievement of each level. How those numbers are distributed will depend on the number of regions selected and their relative populations. Account needs to be taken of the homogeneity of the population (e.g., age distribution, ethnicity, and socioeconomic status); a coun-try, for example, that has a homogeneous population might be treated as a single region. A further difference in the ISO standard is the age bands. For example, in the case of the SizeUK survey, the lower adult age band was determined by the (then) UK school leaving age of 16 years, as those subjects could be included in a socioeco-nomic category. It is suggested inISO 15535:2012that adult population data should be collected from those aged over 20 years of age and that young adults should be con-sidered as single-year bands. No upper age limit is proposed, and as can be seen in recent studies (Tables 3.1 and 3.2), there is a wide range of upper ages, but with an
ageing global population and the fastest growing group being those 80 years and above (UN 2017Revision), future anthropometric studies for clothing will need to address these intergenerational clothing requirements. For example, SizeUK had an upper age group of 75 plus (eldest person was 93 years), but future studies will need to include data for centenarians if they are to meet an inclusive design and sustainable strategy for RTW clothing, that is, to provide a choice of garment shape, size, and fit for all members of a population that meets the required sustainable process.
There are several options for subject recruitment, but if software is designed to con-stantly monitor registration, subjects can be selected in two stages: first, to meet the recruitment strategy (gender, age, and geodemographics), and, second, to ensure other national statistics (ethnicity and socioeconomic grouping) before being invited to a center to be scanned.
3.4.2.7 Model data collection center
A model venue for the collection of data, setting out the orientation of equipment for easy team measurement operations and subject processing, needs to be arranged and tested before any necessary training. A data collection center, whether a static venue or a mobile unit, is likely to comprise
l a reception desk with a PC;
l additional registration facilities;
l an auto height gauge;
l an auto weight scale (e.g., a body composition monitor);
l a set of traditional anthropometric tools;
l a foot, hand, and/or head scanner;
l a whole-body scanner, with dedicated PC and integral changing space;
l storage facilities (e.g., underwear/scan wear, cleaning equipment, and materials).
3.4.2.8 Proofing survey
Crucial to the efficient operation of a survey and to its overall cost is the number of subjects that can be processed per day in a given data collection center or unit. Issues that could arise to affect the operation of a collection center might include the selected equipment, the data collection team, subject ages, the location of the data collection center, and the recruitment of a steady stream of subjects for measurement. To test the process of the layout and efficiency of the equipment and to provide an estimate of the daily subject throughput, it is important to conduct a proofing survey of at least 40 sub-jects (ISO 20685). Subject recruitment needs to be in accordance with the objectives of the study and in the proportions indicated in current national census for gender, age, and ethnicity.
If a survey isnot to be conducted using a mobile unit (Fig. 3.4), then the identifi-cation and inspection of all venues in selected cities would ideally be completed before the selection and/or training of a team or teams.
3.4.2.9 Selection of data collection team and training
Collection of data may be either one team of experts that travel to each venue or sev-eral individual teams recruited and trained for each venue (e.g., university/industry partner venue and team). If the latter course is taken, then the selection of a team and the method of training could be influenced by the selected scanner. For example, in addition to a scanner operative, measurement extraction systems
l may require prior manual landmarking;
l have automatic measurement extraction but with the need for some supplementary manual measurements;
l offer fully automatic landmarking and measurement extraction.
Most scanner systems have training manuals, but if training is required for the collec-tion of manual anthropometric data, courses are available (e.g., ISAK) as well as pub-lications, for example,Marfell-Jones, 2006;Stewart et al., 2011; and ISO standards ISO 8559-1:2017andISO 7250-1:2017. If a survey is to be designed for its data to be internationally compatible, guidance can be found in ISO/DIS 20685-1:2018, ISO/20685-2:2015. Whichever scanner system, if training were required, it would be necessary to assemble an appropriate team, prepare a training manual for the selected scanner system, and assemble a set of training materials.
A team of trainers could comprise a computer scientist responsible for logistic soft-ware, scanner operatives, and expert anthropometrists. Male and female models that represent the proposed population could be recruited to act as subjects, though it is advisable for all team members to experience the subject measuring sequence.
Proposed training materials could include information related to:
Fig. 3.4 Mobile scanning unit: University College of London and Sizemic Ltd.
l data collection center—health and safety issues for subjects and team;
l subject registration—questionnaire and measurement briefing papers, preparation for scan-ning procedures, and processing sequence;
l physical training—team presentations, instructions for logistic software and manual mea-surement, equipment and scanning system procedures, videos of subject processing, and care and maintenance.
The number of teams and selected scanner would determine the number of days required for training, although the aim would be to ensure that all team members would be multiskilled and hence able to:
l prepare, maintain, and derig a venue;
l welcome, brief, and guide subjects through each stage of a measuring process;
l ensure subjects prepared for measuring process;
l use and maintain all measuring equipment;
l evaluate the capture and accuracy of all manual measurements (i.e., intra- and inter-validation, where necessary);
l assess accuracy of 3-D scan images and the extracted measurements;
l record and store data in accordance with chosen system;
l prepare for the next session and/or derig the venue.