3D Body Scanning has Suitable Reliability: An Anthropometric Investigation for Garment Construction

3D Body Scanning has Suitable
Reliability?
Dr Christopher J, Parker

@UserGenDesignPaper: 3D Body Scanning has Suitable Reliability
1. 3DBS is Reliable?

Reliability of Measurements
99.73% 95.46% 68.26%

Key Points
1. 3D Body Scanners do not have one reliability score, they have many.
2. Users need to determine their allowable errors.
3. Manufacturers need to communicate the reliability of each measurement.
4. Users need to critically consider if the scanner will deliver required
reliability.

2. The Problem

The Problem
• The global fashion industry > $212 Billion
• 3D Body Scanning promises a data driven revolution in fashion
• Virtual Tailoring has been an ongoing industry goal
• BUT is 3D Body Scanning reliable enough?
• To drive further integration of Body Scanning in industry, the technologies’
reliability must be fully understood and communicable.

–Every Body Scanner User
“We expect 3D Body Scanning measurements to match the
accuracy and reliability of manual methods used by experts”

Research Aim
• To establish a method of communicating reliability in 3D Body Scanning
• To provide benchmarks for allowable error and reliability
• To offer guidance on where 3D Body Scanning may be the most and least
reliable

3. Theory Background

Previous Literature
• Previous research has not been specific about methods to make scanning
comparable
• Limited knowledge on variability of manual measurement variation in the
clothing industry.
• 3D Body Scanning is ‘reliable’ [8], [11], [12], [16], usually meaning less
variation between practitioners.
• Other research has provided a single reliability figure [27]
• Earlier research said 3D Body Scanning is comparable to manual methods [4],
[12], [15]

Engineering: Three Important Terms
• Appropriateness
• Are we taking the right measurement
• Accuracy
• The closeness of the measurement taken to it’s ‘True’ value
• Reliability
• Confidence that variation in measurements is within allowable error

Allowable Error
• You design and manufacture to
specific dimensions
• An engine needs a rod that
needs to be a precise length and
diameter
• It can be smaller or larger by Set
limits (allowable error)
• If the reliability of the
manufacturing it LESS than the
allowable error, everything is
good

Normal Distribution
• Theory
• Communicate reliability as 3 SD (e.g. +-
5mm)
• 99.73% of the sample occurs in this area
• 9 in 2,500 are outside this reliability
• Application
• You can measure the RIGHT body part
• But if your reliability is GREATER than
Allowable error, you loose confidence.
• Reliability is communicated in 3 SD of
variance

4. Methods

Methods
• 27 Participants
• Size Stream 14 Body Scanner
• Established scan protocol (see paper)
• 5 Repeat Body Scans
• 90 Body Measurements Taken
• Average standard deviation taken for each
measurement
• Data analysed with SPSS 23

Reliability Calculation
• Each person’s standard deviation
calculated for each measurement
• Average Standard deviation calculated
for each measurement
• Average standard deviation per
measurement multiplied by 3
• Reflects 99.73% of the average
variance in measurements

Descriptives
• Gender (n=27)
• 15 Male, 12 Female
• Age
• 19-60 (M=31, SD = 10.3)
• Ethnicity
• White (N=22)
• Height to Waist ratio had no significant
association with reliability
• 12,150 total measurements

5. Results

FINDINGS
• Less that half (49%) of measurements were within the allowable error of the
best manual method benchmarks
• Note: Industry has no strict guidelines (many people measure very
differently) and thus tighter universal definitions are needed.
• Reliability is not universal, it is measurement dependant

Reliability of Measurements (excluding heights)
99.73% 95.46% 68.26%

99.73% Reliability
• Min Lower Leg Girth (Right)
• Under Knee Height (Right)
• Calf Circumference (Right)
• Bicep Circumference (Left)
• Under Knee Height (Left)
• Back Neck to Shoulder Blade Tape
Measure
• Seat Fold Height
• Across Chest Arm to Arm Length
• Under Knee Circumference (Left)
• Forearm Circumference (Left)
• Chin Height
• Under Knee Circumference (Right)
• Side Neck to Bust length (Right)
• Side Neck to Bust length (Left)
• Thigh Circumference (Right)
• Abdomen Circumference
• Forearm Circumference (Right)
• Thigh Circumference (Left)

95.46% Reliability
• Opt Small of Back Waist
• Outer Arm Hole Circumference (Left)
• Elbow Height Waist
• Arm Hole Circumference (Right)
• Elbow Height Waist
• Outer Arm Hole Circumference (Right)
• Arm Hole Circumference (Left)
• Collar Circumference
• Back Vertical Rise
• Opt Small Waist Back Height
• Opt Small Waist Front Height
• Opt Small Waist Left Height
• Elbow Circumference Tape Measure
(Right)
• Opt Small Waist Right Height
• Half Back Centre
• Outside Leg Length (Right)
• Actual Ankle Circumference (Right)
• Outside Leg Length (Right)
• Actual Ankle Circumference (Right)
• Elbow Circumference (Left)
• Outside Leg Length (Left)
• Across Back
• Actual Ankle Circumference (Left)
• Low Hip to Small Of Back Optimised Waist

68.26% Reliability
• Actual Mid-Thigh Circumference (Right)
• Actual Mid-Thigh Circumference Left
• Stomach Circumference
• Shoulder Length (Right)
• Wrist Circumference (Left)
• Min lower leg Height (Left)
• Front Hip
• Sleeve Length (Right)
• Back Neck to Back Chest Contour Length
• Arm Length (Right)
• Arm Under Length (Right)
• Abdomen Rise
• Back Shoulder Width Horizontal
• Shoulder Length (Left)
• Abdomen Height
• Min lower leg Height (Right)
• Front Waist
• Wrist Circumference (Right)

Unreliable (<68.26%)
• Actual Knee Circumference (Right)
• Sleeve Length (Left)
• Arm Under Length (Left)

Outcome
• Many key 3D Body Scan measurements are suitably reliable for garment
construction….But many are not
• Therefore no Manufacturer, Scientist, or Engineer should consider a 3D
Body Scanner as having a single reference of reliability
• Instead, each measurement needs to be proved reliable
• This contradicts many earlier and less thorough research publications.

6. Conclusion

Implications
• Reliability of 3D Body Scanners needs to be communicated at the
Measurement level to 3 Standard Deviations (99.73% confidence).
• Practitioners need to ascertain their allowable error before adopting any 3D
Body Scanning
• Researchers need to collect multiple scans (5) as part of their protocol in
order to tests their equipment and communicate it as suitably reliable.

Limitations
• Only used one scanner (SizeStream 14)
• Complimentary studies within ADE suggest this varied reliability is not
specific to SizeStream (i.e. TC2 et al. too)
• Comparable to current technologies on show today.
• Small sample size
• 27 participants = 12,150 measurements
• Good for statistics, but needs greater numbers for generalisability

Further Research
• Calculate influence of human body in reliability
• Comparison of multiple scanners
• Partner with YOU
• Repeat scans with your equipment
• Develop new protocols for scanning
• Develop new software for virtual tailoring, lifestyle advice, and virtual fit

3D Body Scanning has Suitable Reliability: An Anthropometric Investigation for Garment Construction

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