Realistic Speech Animation of Synthetic Faces

Transcription

1 Relistic Speech Aimtio of Sythetic Fces Brış Uz Uǧur Güdükby Bület Özgüç Bilket Uiversity Deprtmet of Computer Egieerig d Iformtio Sciece Bilket, Akr, Turkey E-mil: fbris, [email protected], [email protected] Abstrct I this study, we combied physiclly-bsed modelig d prmeteriztio to geerte relistic speech imtio o sythetic fces. We used physiclly-bsed modelig for muscles. Muscles re modeled s forces deformig the mesh of polygos. Prmeteriztio techique is used for geertig mouth shpes for speech imtio. Ech meigful prt of text,which is letter i our cse,correspods to specific mouth shpe d the mouth shpe is geerted by settig set of prmeters used for represetig the muscles d jw rottio. We lso developed mechism to geerte d sychroize fcil expressios while spekig. Some tgs specifyig the fcil expressios re iserted ito the iput text together with the degree of the expressio. I this wy, the fcil expressio with the specified degree is geerted d sychroized with speech imtio. Key words: fcil imtio, speech imtio, musclebsed, physiclly-bsed, fcil expressio. 1. Itroductio Fcil imtio hs ttrcted my reserchers durig the lst decde sice the fce is very importt for idetifyig people d hs very complex structure. Reserchers worked extesively o the relistic imtio of fces. Aimtig fce is geerlly uderstood s modelig speech s well s the fcil expressios, such s fer, ger, surprise, disgust, hppiess d sdess. It is very difficult to defie d costruct model cpble of performig relistic fce motios. It is eve more complicted to costruct model which is both relistic d efficiet eough to ru t iterctive rtes. This difficulty is mily cused by the complexity of the fcil tomy. I this study, we developed system for relistic imtio of speech o sythetic fce ccordig to give text. For this purpose, we modified the fcil imtio softwre developed by Wters [9]. He modeled the fce muscles s the forces deformig group of vertices of the fce model s polygo mesh. We dded some pseudomuscles to emulte the bsic muscle ctios for the mouth [9]. These ctios re essetilly due to the cotrctios of the orbiculris oris. To icrese relism, we dded teeth d eyes to the model. We developed mechism to geerte fcil expressios while spekig. Tgs specifyig the fcil expressios relted to word or setece re iserted to the iput text together with the degree of the expressio. I this wy, the fcil expressio with specified degree is geerted d sychroized with speech imtio. 2. Previous Work Sice speech imtio is prt of fcil imtio, the techiques used for fcil modelig d imtio provide bsis for speech imtio Fcil Aimtio Previous studies for fcil modelig d imtio strted with the semil work of Prke [6]. He used keyfrmig techiques to imte the fce. Sice ech key frme must be completely specified to imte the fce, simple keyfrmig cot be esily used for three-dimesiol (3D) fcil imtio. Prmetric systems hve emerged s result of this [8]. A prmetric fcil imtio system defies set of prmeters for the fce. These re mily the expressio prmeters for differet prts of the fce, such s mouth d eyes d the coformtio prmeters tht pply globlly to the whole fce. The mjor prmeters for the mouth re jw rottio (for mouth opeig), width of the mouth, etc. The mjor prmeters for the eyes re pupil diltio, eyelid opeig, eyebrow positio d shpe. The coformtio prmeters re ski color, spect rtio of the fce, etc. Ech expressio prmeter effects set of vertices of the fce model. I this wy, key frmes of imtio c be defied esily. A fcil stte c be creted by /98 $ IEEE 111

2 lterig the expressio prmeters tht move the vertices to desired ew positios. The disdvtge of the prmetric systems is tht they cot esily bled fcil expressios sice ech prmeter effects disjoit set of vertices i the fce model. This limittio led to the developmet of structure bsed fcil models which re bsed o the tomy of the fce [11]. However, ll these models do ot tke ito ccout the fct tht the fce is ot oly geometric model but complex biomechicl system. Physiclly-bsed fce models hve emerged to overcome these limittios. Terzopoulos d Wters model the fce i lyered fshio d icorporte tomiclly bsed muscle model with physiclly bsed lyered tissue model. They used trilyer fcil tissue cocept which is modeled s trilyer mesh of vertices coected by sprigs [12]. The trilyer mesh propgtes the tissue deformtios from the iermost lyer (muscle ctutors iserted ito the iermost lter) to the fce ski with the help of sprigs coectig the vertices. Atomiclly bsed muscle models re first used by Wters [13] to imte mjor fcil expressios Speech Aimtio Speech imtio hs two prts: first, the imtio of sythetic fce ccordig to give text, d secod, sychroizig speech with fcil imtio. Geertig Spekig Fce Models To geerte covicig spekig fce model oe hs to model vriety of mouth d lip postures d iterpolte these postures i relistic wy. The first ttempt to geerte speech imtio of sythetic fces is by Prke [7]. Perce et l. [10] used prmetric pproch to imte speech. There re lso imge-bsed pproches for speech imtio. Wtso et l. [16] developed morphig lgorithm for iterpoltig phoeme imges to simulte speech. Wters d Frisbie [14] described coordited muscle model to model complex muscle iterctios roud the mouth. I this wy, they produce turl-lookig speech o fcil imge but their muscle model is two-dimesiol. Bsu [1] developed 3D model of hum lips d frmework for triig it from rel dt. Although his work is mily for recostructio of lip shpes from rel dt, it c lso be used for lip shpe sythesis for speech imtio. Sychroizig Speech with Fcil Aimtio Aimtig sythetic fce sychroized with give udio requires lip sychroiztio. Keyfrmed, prmetric d muscle-bsed systems re used with o-utomted techiques to chieve lip-sychroiztio. This process requires the specifictio of keyfrmes, essetilly jw d lip positios together with the timig iformtio. Prke used prmetric pproch to demostrte this sychroiztio [7]. Perce et l. [10] used rule-bsed speech sythesizer to icorporte speech prmeters for 3D fcil model. They record the speech sequece geerted to the udio chel d the frmes of movig fce model geerted usig the speech prmeters to the video chel. They ply the sequece to imte the fce. However, the o-utomted process of lip sychroiztio is ot flexible sice chgig the udio requires the whole process to be repeted [15]. DecFce is utomtic lip-sychroiztio lgorithm for sythetic fces [15]. DecFce hs the bilityto geerte speech d grphics t rel-time rtes, where the udio d the grphics re tightly coupled to geerte expressive fcil chrcters. It sychroizes the sythesized speech smples geerted from give text d the motio of the fce model. To chieve this, it computes mouth shpe for ech phoeme d iterpoltes the mouth shpes usig cosie iterpoltio techiques. The phoemes re determied by queryig the udio server for ech phoeme so tht the correct mouth shpe is computed sychroously for ech phoeme. Aother importt problem is the geertio of fcil expressios due to emotios. Klr et l. [4] developed fcil imtio system bsed o lyered bstrctios. They decompose the problem ito five lyers. The higher lyers re more bstrct d specify wht to do d the lower lyers describe how to do it. The highest lyer llows bstrct mipultio of the imted etities. Durig this process, speech is sychroized with the eye motio d emotios by usig geerl d extesible sychroiztio mechism provided by high-level lguge they developed. At the lowest level, they use bstrct muscle ctio procedures [5], which is pseudomuscle-bsed techique tht develops models with few cotrol prmeters emultig the bsic fcil muscle ctios. Cssell et l. [2] lso developed system for utomticlly geertig d imtig coverstios betwee multiple hum-like gets with pproprite d sychroized speech, itotio, fcil expressios d hd gestures. They derive fcil expressio, hed d eye motio from spoke iput utomticlly. 3. Overview of Fcil Muscle Atomy There re three types of muscles i fce [13]: 1. Sphicter, like the oe roud the mouth (squeezig). 2. Lier, like the oe used while smilig (pullig). 3. Sheet, like the oe used whe risig the eyebrow. The musculture of the lower fce differs from the musculture of the other prts of the hum body. Most of the 112

3 other muscles of the hum body origite d isert ito the boe, but muscles i the lower fce origite d isert ito other muscles. The pricipl muscles roud the mouth re the orbiculris oris, the buccitor, the levtor lbii superioris leque si, the levtor lbii superioris, the zygomticus mjor d mior, the levtor guli oris, the guli oris, the depressor lbii iferioris, the risorius, d the metlis. The muscles closig the lips re the orbiculris oris d the icisive muscles. The muscles opeig the lips re kow s rdil muscles, which re divided ito the rdil muscles of upper d lower lips, superficil d deep. The shpe of the lips is mostly determied by the orbiculris oris d ffected by some of the other muscles roud the mouth. The orbiculris oris cosists i prt of muscle fibers derived from the other fcil muscles tht coverge to the mouth. For exmple, the buccitor forms the deep lyer of the orbiculris oris. A detiled expltio of the fcil muscles d their ctios c be foud i [9]. 4. Modelig Our sythetic fce is bsed o the model developed by Wters [9]. We modified this fce model to imte speech i relistic mer. The modifictios re explied below Fce Model The fce model cosists of 888 trigles d is symmetric bout the verticl ple cuttig through the ceter of the fce (sgittl ple). The vertices of the upper lip re duplicted to distiguish lower lip vertices from upper lip vertices. The model cosists of oly oe lyer which is eough for speech imtio. Sice bsic im is to crete relistic speech imtio, we did ot elborte o relistic modelig of fce ski d tissue, such s modelig wrikles roud the mouth, ose d bove the ose d eye. Our muscles d ski re i the sme lyer, lthough some of the muscles re goig towrds the outside of the ski. Durig speech imtio, we eed bstrctio o the fce. Speech mily occurs i the lower fce. Our model cotis 240 polygos i the lower fce d 610 polygos i the upper fce. Remiig polygosbelogto the itermedite regio tht coects upper d lower regios s see i Figure 1. As result, whe the lower fce is deformed, or the jw is rotted, these polygos provide the cotiuity of the fce. Rther th clssifyig polygos s lower or upper, we clssified their vertices s lower d upper. Upper d lower fce re ffected by muscle ctios. I dditio, lower fce is ffected by jw rottio. Our muscles my hve the tgs UPPER, LOWER or BOTH, which mes tht the muscle ctio ffects the upper fce vertices, lower fce vertices, or both, respectively. We lso hve dditiol motio type JAWROT, which ffects Upper regio Itermedite regio Lower regio Figure 1. Regios of fce. lower fce d lower teeth. Ech vertex lso hs tg specifyig the muscle ctios d motios ffectig the vertex. If this tg is NONE, the vertex is ot ffected by y muscle ctio d motio (for the upper teeth). The reltioship betwee muscles (d jw rottio) d the fce vertices is giveitble1. Motio or Vertex Tg Muscle Tg UPPER LOWER BOTH NONE JAWROT UPPER LOWER BOTH JAWROT Tble 1. Reltioship betwee muscle (motio) d vertex Fcil Muscles Types of Fcil Muscles I our model, there re 34 muscles. We used four lier muscles to represet the orbiculris oris d the other muscles re represeted s pirs of muscles which hve left d right compoets. The fcil muscle structure is show i Figure 2. The mjor muscles tht ffect the speech re explied i the sequel. 1. Orbiculris oris: This muscle hs the most sigifict role i composig the shpe of the mouth durig 113

4 Frotlis Mjor Frotlis Ier Lterl Corrigtor Frotlis Outer Ier Lbi Nsi Lbi Nsi Zygomtic Mjor Risorius Agulr Depressor Lbii Iferioris Depressor Oris Mjor Secodry Frotlis Levtor Lbii Superioris Aleque Nsi Zygomtic Mior Buccitor Orbiculris Oris Metlis Figure 2. Fcil muscles i our model. speech. Especilly, whe we sy O or (h), the orbiculris oris determies the shpe of the mouth. It hs lso very importt positio sice the orbiculris oris is where ll of the other muscles roud the mouth merge ito. 2. Metlis, buccitor, depressor guli oris mjor, depressor lbii iferioris: These muscles re plced i the lower fce. They cotrol lower lip d lower fce. These muscles ply gret role i speech together with the orbiculris oris d jw rottio. 3. Zygomtic mior, levtor lbii superioris leque si, levtor lbii superioris: These muscles re plced i the upper fce regio. They re rrely used d ctivted durig speech. 4. Risorius, zygomtic mjor: These muscles re locted roud the cheeks. They ply importt role i simultig expressios, rther th speech. Modelig of Fcil Muscles The ski is iterpreted s elstic mteril. Muscles re modeled s forces deformig the ski. The ski is similr to other elstic mterils i tht it is deformed uder force. However, it is ot perfectly elstic sice fter tesio its visco elstic behvior prevets the ski from deformig y more. The ski is thought s mesh of sprigs d it is deformed uder tesio of muscle. There re two mi types of muscles i our fce model. 1. Lier, like the oe used while smilig (pullig). 2. Sphicter, like the oe roud the mouth (squeezig). A lier muscle deforms the mesh like force. We c model lier muscle with the followig prmeters: Ifluece zoe: Ech muscle hs ifluece zoe i which the vertices re mostly ffected. This vries from oe muscle to the other d it is typiclly betwee 35 d 65 degrees. Ifluece strt (fll strt): Ech muscle s ifluece will pper fter tesio. Ifluece ed (fll ed): Ech muscle hs limit to be tesioed. After this limit, ski resists deformtio. Cotrctio vlue: Muscle tesio. Chgig these prmeters lter the effect of muscle ctio. We used the formultio i [13] to model muscles. Sice lier muscle is modeled s force, its directio is lso importt d is defied by the directio of muscle vector. Strtig poit of the vector is ever repositioed d it is the origitig poit of the muscle. A muscle pulls or pushes the vertices log this muscle vector (Figure 3). D I Figure 3, V1 P1 θ θ P4 P α P Rs Rf P2 Figure 3. Prmeters of muscle. P is poit i the mesh, P3 V2 P 0 is its ew positio fter the muscle is pulled log the V 1 V 2, R s d R f represets muscle fll strt d fll fiish rdii, respectively, represets the mximum zoe of ifluece, typiclly betwee 35 d 65 degrees, D is the distce of P from muscle hed d is the gulr displcemet. 114

5 Note tht V 1 d V 2 re ot ecessrily plced s ode of mesh becuse muscles re thought s forces which c be ywhere i the spce. This muscle represettio is for 2D but it c esily be dpted to 3D by pplyig the sme rules to the third dimesio. If P is i the regio of V 1 P 3 P 4, ew positio P 0 = P + kr PV1,where kpv 1k k is the muscle sprig costt, = cos() d r = ( cos(( 1,D cos(( D,Rs R s ) ) 2 if P i (V 1P 1 P 2 ) R f,r s ) ) 2 if P i (P 1P 2 P 3 P 4 ) This holds for lier muscle but ot for sphicter muscle. However, the orbiculris oris is sphicter muscle tht is ellipticl. We represeted the orbiculris oris s group of 4 lier muscles. Verticl prts hve 140 degrees of ifluece zoe where horizotl oes hve 40 degrees (Figure 4). This cretes the desired ellipticeffect together with the other fcil muscles d is very prcticl to implemet. Rel plcemet of Orbiculris Oris Our bstrctio for Orbiculris Oris Figure 4. Abstrctio of orbiculris oris Jw Rottio I fcil modelig d imtio, it is very importt to rotte jw, which mkes the imtio covicig. Hum jw is composed of two prts: upper d lower jw. The movble prt is the lower jw. This motio is essetilly rottio roud xis coectig the two eds of the jw boes [3]. I our model, the jw cotis the vertices with tg LOWER d JAWROT (lower teeth). Sice the lower teeth re lso ttched to the lower jw, they will be ffected by jw rottio Eyes ed Teeth The eyes d teeth of our model re lso defied s meshes of polygos. A eye c rotte bout x, xis, y, xis or both. It is ot possible for eye to rotte bout z, xis. Oe eye cot rotte idepedet from the other. Two eyes cot be lookig t differet directios. Teeth re pure polygos d ffected oly by jw rottio. Upper teeth re ot ffected by ctio. However, lower teeth move with the lower jw. 5. Speech Aimtio Turkish is syllble bsed lguge. The vowels i word determie the lip motios d lip shpe chges. I Turkish, the vowels re clssified s show i Tble 2. Low High No-roud e ıi Roud oö uü Tble 2. Clssifictio of vowels i Turkish. Although Turkish is syllble-bsed lguge, we modeled speech bsed o letters. The mouth d lip shpes re determied ccordig to letters sice ech letter is ssocited with soud. To do this, ech letter is ssocited with mouth shpe by defiig the prmeter vlues for muscles roud the mouth d jw rottio. For exmple, de d do syllbles hve differet lip shpes, due to the chrcteristics of letters e d o. For do, mouth is roud, but for de, mouth is flt. So, it is meigful to defie d, e d o souds idividully d the we c compose syllble, like de, esily. By usig the clssifictio i Tble 2, the vowels c be grouped ito four sice the pirs d e, o d ö, ı d i, d u d ü hve similr mouth shpes. I dditio, some cosots hve similr mouth shpe chrcteristics. We c, for exmple, use the sme mouth shpe for letters b, m d p cosots. Cosequetly, we c defie thousds of words by usig pproximtely 20 soud defiitios. As result, we use souds to compose syllbles d syllbles to mke words, s i Turkish Keyfrmig Bsed o Prmeteriztio To geerte imtio of spekig fce model, we use keyfrmig bsed o prmeters of the muscles roud the mouth d jw rottio. Ech keyfrme of imtio sequece icludes properly positioed mouth d fce shpe ccordig to the curret settigs of theexpressio d the letter to be spoke. I Turkish, words re proouced by strict rules. The writte form dicttes the proucitio d there re o exceptios. Hece, the dtbse for mouth shpes c esily be bsed o letters. Ech etry i the dtbse will coti the followig: 1. Letter whose prmeters will be defied. This is the key field of etry i the dtbse. 2. Muscle cotrctio vlues to determie which muscles re ctive while prooucig tht letter. 3. Jw rottio gle, ecessry for some letters. The system ccepts the text to be spokes iput. The, it cretes ecessry keyfrmes for ech letter. It uses cosie 115

6 iterpoltio scheme to geerte i-betwees. The frmework for the imtio system is show i Figure 5. Iput Text Prser Expressio Letter Figure 5. The imtio system Cosie Iterpoltio Fcil Aimtio System Cosie iterpoltio is suitble for pproximtig the viscoelstic behvior of the ski [9]. A cosie fuctio is used to clculte the time of displyig ibetwee. This scheme is lso kow s ccelertio d fits well to the fcil imtio. The disply time for ibetwee frme i is give by the formul where tb i = = t 1 + t(1, cos()) i 2( + 1) ; 0 << 2 ; d i = 1; 2; 3;:::;: 6 Sychroizig Speech with Expressios Sice we re iterested i cretig relistic speech imtio, we should be ble to geerte sequece of expressios produced durig speech d sychroize them with speech. Fcil expressios cused by the emotios c be determied from the text i two wys: Guessig from the Text By usig puctutio, postfixes d keywords, we could guess some iformtio bout the expressios. However, this ever gives uique result s i the followig exmple. Both seteces fiish with! but feeligs re differet: Come here! ger Oh, it s very ice to see you! surprise Similrly, keywords do ot give y cler ide bout the setece: Whe will he come? A questio, voice will rise I do t kow whe he will come. A egtive setece, with questio word It is eve more difficult, if ot impossible, to determie the differet meigs of sigle word which my cuse differet expressios to be geerted. Hece, it is better to isert the iformtio ecessry to determie the fcil expressios ito the text mully. By Isertig Tgs ito the Text To guide the geertio of fcil expressios durig speech, some tgs could be iserted ito the iput text specifyig the expressios, which is wht we did. Expressio itesities d the durtio of expressio re lso specified by ddig the ecessry prmeters to the tgs. Sice the itesities of the fcil expressios re ot costt durig speech, we defie miimum d mximum itesity levels for ech fcil expressio d lierly iterpolte betwee these two vlues for the itermedite itesity levels. The tgs for the fcil expressios hve the followig formt: \b{expr level} strts expressio expr of degree level. If this expressio is set before, level is used to icrese the degree of the expressio. \e{expr level} eds or decreses the degree of expressio by level. Iflevel is -1, expressio is removed from the fce. We c lso bled fcil expressios. For exmple, ssume tht iput text cotis tgs of two expressios for setece, oe for risig eyebrows d oe for smilig. These two expressios re combied together to give the combied fcil expressio of smilig d surprise. The followig iput text geertes this effect. The Turkish letter ı is deoted by I. \b{smile 3} merhb, silsi? \e{smile 1} \b{eyebrow 4} yei rb sil? \e{smile -1} I this exmple, there re 3 prts: 1. SMILE 3: Sets the fce usig expressio SMILE with degree 3. merhb, silsi is sid with this expressio. 2. SMILE 1: Decreses the degree of SMILE by 1. EYEBROW 4: Sets the fce usig expressio EYEBROW with degree 4. Now, the fce is both smilig d the eyebrow is rised to degree of 4. yei rb sil is sid with this expressio. 3. SMILE -1: Removes the SMILE expressio. At the ed of the tlk, eyebrows re left rised. SMILE expressio is completely removed from the fce. The lgorithm for speech imtio is give i Figure 6. Stillfrmes from imtio sequece d the timigs of the fcil expressios re show i Figure

7 While ot ll of the text is processed { Red chrcter If tg is begiig { /* "\" is red */ Red tg /* me d degree of expressio */ If degree is -1, Remove expressio from the fce else Set fce ccordig to expressio with specified degree } If vlid chrcter { /* letter or puctutio mrk */ If this is the first chrcter to sy Set fce usig curret expressio d letter settigs Disply fce else for ech i-betwee Clculte vertex coordites usig cosie iterpoltio Disply fce Store vertex coords for future referece } } Figure 6. The lgorithm for speech imtio. 7. Coclusios d Future Work I this work, we focused o relistic imtio of speech o sythetic fce ccordig to give text. Our work is bsed o Turkish. I Turkish, we spek wht we wrote. Ech letter correspods to specific mouth posture. So, we eed mouth posture for ech of the 29 letters i Turkish. This is ot the cse i Eglish. Eglish is bsed o smll structures, clled phoemes. I Eglish, we eed 45 phoemes to proouce ll of the words. There re 18 visully distict mouth postures for Eglish d some of them re ot used for Turkish, like the oe for phoeme th. We lso developed mechism for geertig fcil expressios cused by the emotios durig speech imtio. This is doe by isertig some tgs specifyig the types d degrees of the fcil expressios ito the iput text. This work c be exteded by ddig the followig: i. Texture mppig could be implemeted to icrese relism of imtios. ii. Togue could be dded to the fce model. It hs importt role whe syig letters d, l, d t. iii. Hir could be dded by usig texture mppig. Ackowledgmet We thk Keith Wters for givig permissio to use his fcil softwre without which this reserch cot be doe. Refereces [1] Bsu, S, A Three Dimesiol Model of Hum Lip Motio, M.Sc. Thesis, Dept. of Electricl Eg. d Computer Sciece, Msschusetts Istitute of Techology,1997. [2] Cssell, J., Pelchud,C., Bdler, N., Steedm, M., Achor, B., Becket, T., Douville, B., Prevost, S., Stoe, M., Aimted Coverstio: Rule-Bsed Geertio of Fcil Expressio Gesture d Spoke Itotio for Multiple Coverstiol Agets, ACM Computer Grphics (Proc. SIG- GRAPH), pp , July [3] Güdükby, U., A Movble Jw Model for the Hum Fce, Computers & Grphics, Vol. 21, No. 5, pp , [4] Klr, P., Mgili, A., Mget-Thlm, N., Thlm, D., SMILE: A Multilyered Fcil Aimtio System, IFIP WG 5.10, pp , Tokyo, [5] Mget-Thlm, N., Primeu, N. E., Thlm, D., Abstrct Muscle Actio Procedures for Hum Fce Aimtio, Visul Computer, Vol. 3, No. 5, ,1998. [6] Prke, F.I., Computer Geerted Aimtio of Fces, Proc. of ACM Ntiol Coferece, Vol. 1, pp , [7] Prke, F.I., A Model for Hum Fces tht Allows Speech Sychroized Aimtio, Computers & Grphics, Vol.1, No. 1, pp. 1-4, [8] Prke, F.I., Prmeterized Models for Fcil Aimtio, IEEE CG & A, Vol. 2, No. 9, pp , November [9] Prke, F.I., d Wters, K., Computer Fcil Aimtio, A. K. Peters, Wellesley, MA, [10] Perce, A., Wyvill, B., Wyvill, G., Hill, D., Speech d Expressio: A Computer Solutio to Fce Aimtio, Proc. Grphics Iterfce 86, pp , [11] Pltt, S.M., A Structurl Model of the Hum Fce, Ph.D. Thesis, Uiversity of Pesylvi, Dept. of Computer d Iformtio Sciece, [12] Terzopoulos, D., Wters, K., Physiclly-bsed Fcil Modelig, Alysis, d Aimtio,The Jourl of Visuliztio d Computer Aimtio, Vol. 1, pp , [13] Wters, K., A Muscle Model for Aimtig Three- Dimesiol Fcil Expressio, ACM Computer Grphics (Proc. SIGGRAPH), Vol. 21, o. 4, pp , July [14] Wters, K., Frisbie, J., A Coordited Muscle Model for Speech Aimtio, Proc. Grphics Iterfce 95, pp , My [15] Wters, K., Levergood, T.M., DECfce: A Automtic Lip- Sychroiztio Algorithm for Sythetic Fces, Tech. Report, CRL 93/4, DEC Cmbridge Reserch Lb., [16] Wtso, S.H., Wright, J.R., Scott, K.C., Kgels, D.S., Fred D., Hussey K. J., A Advced Morphig Algorithm for Iterpoltig Phoeme Imges to Simulte Speech, Tech. Report, Jet Propulsio Lb., Clifori Istitute of Techology,

8 m e r h b s I l s I y e i \b{smile 3} SMILE EYEBROW \e{smile 1} Level \b{eyebrow 4} r b s I l \e{smile -1} Fces with expressios Fces without expressios Text Figure 7. Still frmes from imtio d the timigs of expressios. 118