3-D or Not 3D? That Is The Question December 2005

Transcription

1 3-D or Not 3D? That Is The Question December 2005 Kathleen M. Robinette, Ph.D. Principal Research Anthropologist Human Effectiveness Directorate Air Force Research Laboratory

2 3-D or Not 3-D? Did you know? Some 3-D anthropometric surveys don't provide 3-D data! Some 3-D scanners don't provide 3-D data! Why? Privacy concerns Buyers didn t have 3-D mindset Used what they knew Example of 1-D measure If there is only one number then it is 1-D 2

3 Overview Why 1-D measurement is a poor use of 3-D scanning Example CAESAR: A Truly 3-D Survey Why YOU should use 3-D data! Summary 1 st Trimester 3 rd Trimester Preferred Waist 1 st Trimester Preferred Waist 3 rd Trimester Preferred Waist 3 rd Trimester 1-D is Blind No location No shape Different locations over time 3

4 3-D Encourages Truth 1-D Percentiles Are Not Additive! 3-D Models from 1-D Measures Add Undetected Error! Sum of 5th %ile Parts= cm 5th %ile Height= cm Difference= cm Sum of 95th %ile Parts= cm 95th %ile Height= cm Difference= cm % iles SAMPLE SIZE=3235 *From Robinette and McConville

5 3-D Encourages Truth in Modeling Subject 1 x y z Subject Subject 2 2 Average 2 Subject Subject Average Subject 3 3 Average is Different From Everyone! Average Person Does Not Exist! (Daniels 1952) Mythical Person from 1-D Measurements is Believable Mythical Person from 3-D Images is NOT Attempt at 95 th %ile Man from 1-D Measures 5

6 Internet Size Selection: Is It 3-D? Example: Lands End Scanned People and Created Their Virtual Model on the WWW Only 1-D Measurements Used and Model Was Built Using Artistic Interpretation of 1-D Measurements 6

7 Reviews of Land's End 3-D Model Several Reviews of the Land's End Process (Wall Street Journal, New York Times, and others) Conclusions of Reviewers: Measurements Were Wrong, Model Didn't Look Like Them, All Sizes Looked The Same on the Model One Reviewer Had a Tailor Measure Her and the Hip Circumference Was 4 Inches Smaller Land's End Spokesperson Said They Knew It Did Not Work Well But Wanted to Be The First A True 3-D Virtual Model is in The Works Bottom Line: 1-D measurements make poor 3-D models 7

8 Civilian American and European Surface Anthropometry Resource First 3-D Surface Anthropometry of NATO First Survey to Provide 3-D Models of Subjects as The Product Represent anthropometric variability age (18-65), both genders, ethnicity 4,431 subjects U.S. (most people) Netherlands (tallest) Italy (among shortest) 8

9 3-D Poses Captured Complete 3-D Figures 3-D Landmarks Landmarks are visible in the color file of the 3D scan Software is used to extract landmarks location in 3D 9

10 Data Collection Process Times CAESAR Process: 3 Stations & 5 Team Members Demographics (1 Member) Traditional Measurement (2 Members) Scanning (2 Members) Station 3 Station 1 Station 2 Greeting & Demographics Change Tradit ional Measurem ent Apply Targets 3D Scans Data Handling * * Change Leave Minut es Non-measurement subject time: 25 minutes 3D Digitizer Rate: 0.5 Megabytes/second Process Rate: 7.7 Kilobytes/second (1.5%) Station 3: Scanning with 73 Landmarks Took Less Time than Station 2: 40 Traditional Measurements! 10

11 CAESAR Data Processing 3-D Scan Stitching: Combines views from multiple cameras to create one 3-D model Cyberware Scanner: Automated with standard calibration matrix Vitronic Scanner: Automated without standard calibration matrix using Polyworks 3-D Landmark ID*: semi-automated 99.8% correctly identified Just over 10 minutes of operator time per subject Burnsides et. al., (2001), 3-D Landmark Detection and Identification in the CAESAR Project, in Proceedings of the 3DIM

12 CAESAR Precision Study* Highly reproducible Most Mean Absolute Differences (MADs) < 5 mm 93% significantly smaller than ANSUR allowable error** Sample MADs Axilla Height, Left Axilla Height, Right Biacromial Breadth Bustpoint-Bustpoint Cervicale Height Chest Height Allowable Error ** CAESAR US Team 4.3* 3.7* 5.0* 2.4* 2.4* 4.5* CAESAR Dutch Team 5.7* 5.3* 6.0* 3.0* 2.9* 4.7* * Robinette and Daanen 2006 ** Gordon et al

13 3-D Provides Difference/ Change Visualization Size 6 Size 16 13

14 3-D Size Grade You can see and measure the exact change and its location DISTANCE Negative < 20 mm mm mm mm mm >100mm COLOR Pink Blue Green Slate Gray Orange Blue Green Differences are not same everywhere Bust difference is twice waist difference Front & back difference are not the same 14

15 Traditional 1-D Size Grade Body Measurements (in) Size 6 Size 10 Size 16 Height 5' 6 1/2" 5' 6 1/2" 5' 6 1/2" Bust Waist High 4" from natural waist 33 1/2 35 1/2 40 1/2 Low 8" from natural waist 36 1/4 38 1/4 42 5/8 Low Fullest 10" from natural waist 38 1/4 40 1/4 44 5/8 Shoulder Width: Bone to Bone /4 16 3/8 Total Rise 26 1/4 27 1/2 30 1/2 Fullest 21 3/ /4 Arm Length from CB with Arm Bent to wrist Crotch to Floor (Inseam) Less Information + Harder to Understand = Easier to Make Mistake 15

16 3-D Provides 3-D Electronic Models for Concept Visualization 3-D Electronic Models for 3-D Computer Aided Design 3-D Solid Models for Rapid Prototyping Numerically Controlled Milling Old Form StereoLithography Scintering New Form* Deposition Modeling The Ability to Measure the 3-D Geometry of Fit * Sharpdummies 16

17 3-D Adds Visualization and Fit Geometry Measurement Capability Fit of a Ballistically Protective Helmet Outside of Helmet Inside of Helmet Subject within Helmet Head areas too close to helmet CAD Simulation Indicated Helmet Did Not Have This Problem! (from Meunier, 2000) 17

18 Summary 1-D Sometimes Disguised as 3-D: Don t be Fooled 3-D Encourages Truth 3-D Makes Best 3-D Models Real 3-D Brings Many New and Better Measuring and Engineering Capabilities Sometimes 3-D Is the Only Tool Capable of Doing The Job 3-D can be easier to use than 1-D Time to Start Using It! 18