Biomechanical Simulation and Control of the Face, Neck and Body. Demetri Terzopoulos

Transcription

1 Bomechancal Smulaton and Control of the Face, Neck and Body Demetr Terzopoulos Computer Scence Department Unversty of Calforna, Los Angeles Overvew The Face Bomechancal facal modelng Capturng facal models from data Effcent facal tssue smulaton The Neck Bomechancal modelng of the neck-head complex Neuromuscular control The Body Modelng body musculature Bomechancal smulaton of the upper body 1

2 Realstc Facal Modelng Square Pctures USA (2001) Realstc Facal Modelng 2

3 Facal Moton Capture Vrtual Celebrty Productons, LLC Bomechancal Facal Modelng Muscle Model Skn Model Epderms Derms Muscle Layer 3

4 Real-Tme Bomechancal Facal Smulaton Functonal Facal Models Scanned Data Synthetc Faces Range Image Texture Image Cyberware Data Cyberware Scanner Syntheszed Expressons 4

5 Raw Input Dataset ( Hed ) From CyberWare 3D Color Dgtzer Range Image RGB Texture Image Generc Facal Mesh 5

6 Fttng the Generc Mesh Feature-based mage matchng algorthm localzes facal features n: Processed range mage RGB texture mage Samplng Facal Shape Ftted mesh nodes sample range data 6

7 Textured 3D Geometrc Model Texture map coordnates Postons of ftted mesh nodes n RGB texture mage Auxlary Geometrc Models Eyeld Texture Interpolaton 7

8 Complete Geometrc Model Neutral expresson s estmated Facal Anatomy The face: a complex bomechancal structure 8

9 Facal Hstology A complex, multlayer structure Bomechancal Skn Model Deformable tssue element Epderms Derms Muscle Layer Sngle Element 9

10 Bomechancal Skn Model Vscoelastc unaxal prmtve Epderms Derms mass m poston x (t) velocty v (t) acceleraton a (t) Muscle Layer rest length stffness c dampng γ l Sngle Element j Vogt Vscoelastc Model Bomechancal Skn Model Element dynamcs r = x j x Span Epderms Derms e f = ( c e + γ e& ) e = r l r r Deformaton Vscoelastc Force Muscle Layer Stress Bphasc Elastcty c2 Sngle Element c1 Stran 10

11 Emprcal vs Idealzed Stress-Stran Curve Langer s Lnes Non-sotropc stress-stran stran characterstcs 11

12 Bomechancal Skn Model Element dynamcs r = x j x Span Epderms Derms e f = ( c e + γ e& ) e = r l r r Deformaton Vscoelastc Force Muscle Layer Sngle Element Dfferental Equatons of Moton m d x dt f j N e = f m Muscle Forces Bomechancal Skn Model Element dynamcs Epderms Derms m d x dt f j N e = f m + f v + f c Volume Preservaton Constrant Muscle Layer Non-Interpenetraton Constrant 12

13 Bomechancal Skn Model Deformable tssue element and patch Epderms Derms Muscle Layer Muscle Sngle Element Skn Patch Explct Euler Method Effcent near-stablty lmt for moderately deformable bomechancal skn model x& x t + dt t + dt = x& = x 1 e m v c ( f + f + f f j N t a = + m t t + dt a + dt x& t t + dt ) 13

14 Facal Subdvson Surface Subdvson Surface wth Tssue Model 14

15 Facal Subdvson Surface Incson on Facal Mesh 15

16 Retrangulaton Around Incson Facal Musculature 16

17 Muscles & Insertons Facal Muscle Model Structure 35 Muscles Levator Ocul Corrugators Naso-Labal Zygomatcs Obculars Ors plus Artculate Jaw Eyes/Eyelds 17

18 Muscle-Actuated Expressons Muscle-Actuated Expressons 18

19 Muscle-Actuated Expressons Muscle-Actuated Expressons 19

20 Expresson Analyss and Resynthess Capture expresson n vdeo Transfer t to a synthetc facal model Analyss Resynthess NN Estmaton of Muscle Actons Traned neural network muscle control Inner Major Outer Inner Major Outer Left Rght Left Rght Left Frontals Rght Frontals Zygomatcus Levator Lab Jaw Rotaton Image Feature Input Traned Neural Network Transducer Muscle Acton Output 20

21 Expresson Analyss and Resynthess Herarchcal Facal Model Structure From expresson control to mages Expresson Control Actuators Bomechancs Geometry -> Images 21

22 Functonal Model of George The Neck 22

23 Anatomcal Structure of the Neck Skeleton Model 7 cervcal vertebrae and a skull coupled by 3-DOF 3 jonts Lgaments/dsks passve jont sprngs Equatons of moton mass M(q) q& && + b(q,q) & = P(q)f 0 (q,q,a) & gravty, Corols, passve elastc forces c moment arm matrx neural nput actve muscle force 23

24 Bomechancal Neck Model Total of 72 anatomcally-based Hll-type muscle actuators n 3 layers 48 deep muscles (16 longus coll,, 16 erector, 16 rotator) 6 muscles n each jont ncrease controllablty 12 ntermedate muscles (scalerus: : 4 anteror, 4 posteror, 4 capts) 12 superfcal muscles (2 sternomastod,, 2 cledooccptal,, 8 trapezus) Challenge s actuaton and control Bomechancal Neck Modelng 24

25 What Would Leonardo da Vnc Thnk of Ths? Bomechancal Smulaton of the Neck-Head-Face Complex Neuromusculoskeletal model proproceptve feedback (pose, velocty of head) muscle feedback (stran/stran rate) voluntary controller feedfwd sgnal setpont sgnal reflex controller muscle actvaton levels muscles muscle contracton forces skeletal system head pose Traned Neural Networks sst t fft t ut t s tt+ t t envronment gravty, appled force bomechancal face 25

26 Tenson Control Tenson Control 26

27 Neck-Head-Face-Eye Behavor Autonomous Mult-Head Interacton 27

28 Artfcal Lfe Comprehensve computatonal model of humans The ALfe Modelng Pyramd Cognton Learnng Behavor Percepton Bomechancs Physcs George n Bureaucrat Too 28

29 Muscles n the Spne Posteror Muscles n the Deep Layers Modelng all the major muscles partcpatng n spnal posture 29

30 Full Upper-Body Musculature 3D Muscle Geometry 30

31 Sknned Model A prelmnary smulaton demo flexng_sold.av flexng_transparent.av 31

32 Acknowledgements Collaborators: Sung-Hee Lee Eftychos Sfaks Yuencheng Lee Keth Waters Shgeo Morshma UCLA (neck model) UCLA (body tssue smulaton) UofT (face model) Orange Labs, Boston Waseda Unversty, Tokyo Addtonal nfo: deformable.com Thank You! 32