Presenter: Dr Gunther Paul Co-Author: Nathan Daniell ErgoLab: Mawson Institute University of South Australia 3D Anthropometry – From the Ergonomist’s Perspective University of South Australia

How does 3D scanning work?  A laser stripe is projected onto the body with the reflection captured by cameras  Body represented by series of XYZ data points, often referred to as “point cloud” data  Coordinates calculated by triangulation method Camera (height known) Laser (height known) β University of South Australia

Scanner Features FeatureVITUS XXL Hamamatsu Body Line Scanner Cyberware WBX Colour Scanner TC 2 NX16 Light sourceLaser White light Cameras84416 Volume (cm) H x W x D 210 x 120 x x 100 x x 50 x x 120 x 60 Scan time (s)125/10< 208 V-Resolution pitch (mm) ~32.5/522 Colour or Texture LuminanceColourNo SoftwareAnthroscanBody Line ManagerDigisize TC 2 Msr Software

2 mm ~0.5 mm Accuracy: 4.03 mm

Measurement Extraction Data Analysis Real Bodies Physical Measurements Anthropometrist Extract 1 and 2D Measurements Manual extraction Clean Scan Remove artefacts Point Cloud Scan of human Landmarked Bodies Anthropometrist Filled Scan File conversion Extract 3D measurements Manual extraction Automatic measurement extraction Scan of human, automatic extraction University of South Australia

Trips and falls The unknowns:  Limited access to scanner calibration data  Validity of gap filling function  Few studies validating segmental 3D measurements Other limitations:  High cost  Automatic landmarker identification  File formats University of South Australia

Quality assessment Automatic Landmark Function:  TC 2 (2002) compared chest and hip circumference. The bias recorded was to mm.  Mckinnon & Istook (2001) scanned a mannequin and extracted 10 measurements. The bias recorded was ± 19.3 mm. Segmental volume measurements:  Norton et al. (2002) compared segmental volume of the leg. Average difference was 0.61 %.  Wells et al. (2006) compared 5 segments using a mannequin. Average differences ranged from 0-5%.  Segmental measurements have not been validated using an object that accurately represents a human University of South Australia

ISO/FDIS three-dimensional 3-D pertaining to the use of three orthogonal scales on which the three coordinates, x, y and z, can be measured to give the precise position of any relevant anatomical point in the considered space 3-D body scanner hardware and software system that creates digital data representing a human form, or parts thereof, in three dimensions 3-D scanning methodologies for internationally compatible anthropometric databases University of South Australia

Lack of standardisation There are currently no standardized methods for using 3-D point clouds in the design process.  As a result, many users extract one-dimensional (1-D) data from 3-D point clouds.  This International Standard concerns the application of 3-D scanners to the collection of one-dimensional anthropometric data for use in design.  It does not apply to instruments that measure the location and/or motion of individual landmarks. (as defined in ISO :2008: Basic human body measurements for technological design — Part 1: Body measurement definitions and landmarks) University of South Australia

Landmarks should be  marked on the skin,  and then identified with dots or other techniques that can be seen on the displayed image  and distinguished using the available software Bilateral landmarks should be marked on both sides of the body. If landmarks (see Clause 3) are to be marked before scanning, a minimal list would be the following: (21 landmarks) ISO/FDIS University of South Australia

ISO/FDIS  There are a number of different fundamental technologies that underlie commercially available systems.  These include stereophotogrammetry, ultrasound and light (laser light, white light and infrared).  Further, the software that is available to process data from the scan varies in its methods.  Additionally, software to extract dimensions similar to traditional dimensions varies markedly in features and capabilities. As a result of differences in fundamental technology, hardware and software, extracted measurements from several different systems can be markedly different for the same individual. [The required accuracy is 1-9 mm, depending on the measurement.] University of South Australia

Anthropometric Design  Human boundary measures in space  Functional measures (Reach, Vision etc.)  Anthropometric parameters (to be considered in physiology, biomechanics etc.)  Any cross section between two volumetric objects in 3D space forms a plane  Ergonomic Design is defined in planes: inside dimensions, outside dimensions, functional space  3D for visualization only 2D University of South Australia

Anthropometric Design University of South Australia

Anthropometric Design University of South Australia

Anthropometric Design University of South Australia Female Male comparison All roads combined Female Sample size 42 Male Sample size 34 Female Male

Anthropometric Design Traditional approach  measure 1D Anthropometry  option to “enrich” the data with 2D curves or splines  create 2D/3D manikins “3D” approach  measure 3D Anthropometry  “reduce” the data with multiple filters to 2D curves or splines  “reduce” the data with multiple filters to 1D anthropometric dimensions University of South Australia

True Benefit University of South Australia  Digitised data  Ability to store and access at a later date  Less invasive  Reduces time required by subject  Allows to model real persons into 3D manikins using point cloud

Summary University of South Australia  Quality issues not solved  Precision not conform with ISO  Combining data from 1D and 3D scans remains difficult  Economic benefits  Not required for ergonomic, anthropometric design  Main advantage is visualization