Y. Lee, D. Terzopoulos, and K. Waters. Realistic face modeling for animation. In SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 55--62. ACM SIGGRAPH, Addison Wesley, Aug. 1995. 10  Home/Search   Document Not in Database   Summary   Related Articles   Check

....surgery and therefore concentrated on cutting and stretching of skin and epidermis rather than on repositioning bones. Further, his model lacked the resolution required for a reliable simulation of very subtle changes in the appearance of a face and did not provide a C surface. Lee et al. [12] presented a promising approach to facial animation where they introduced a layered tissue model based on masses and springs connected to form prism shaped elements. The facial model is adapted from a template face, takes into account various anatomical aspects and aims at facial animation. Koch ....

Y.Lee, D.Terzopoulos, and K.Waters. "Realistic face modeling for animation." In R.Cook, editor, SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 55--62. ACM SIGGRAPH, Addison Wesley, Aug. 1995.

....constant volume basically requires adding radial forces or displacements, as shown by Promayon et al. 14] To simply ensure volume preservation, we propose a volume force formulation adapted to tetrahedral volume element. It is loosely related to soft volume preservation constraint of Lee et al. [8]. Let us define xB the position of the barycenter of the tetrahedral element, with xB = where x i is the position of the ith vertex. Then, we define the force applied on the jth vertex as f j = Gammak s kx i Gamma xBk Gamma kx i Gamma xBk t=0 # x j Gamma kx j Gamma xBk ....

....geometry, we use a slightly different expression for volume preservation forces, while keeping the idea of employing a set of forces that act in radial directions with respect to the volume element. This formulation is also loosely related to soft volume preservation constraint of Lee et al. [8]. Let us define xB as the position of the barycenter of the hexaedral element, with = 8 7 where x i is the position of the ith vertex. Then, we define the force applied on the jth vertex as f j = Gamma k s (klk Gamma klk t=0 ) k d l Delta l l ; l = x j Gamma ; l = ....

Y. Lee, D. Terzopoulos, and K. Waters. Realistic face modeling for animation. In SIGGRAPH '95 Conference Proceedings, pages 55--62. Addison Wesley, Aug. 1995.

....based on marching cubes techniques can be found in the algorithms of [17] and [16] whose visual quality is amazing. In most approaches, force feedback devices are utilized to implement the interface to the user. The Eurographics Association and Blackwell Publishers 1999. Furthermore, [13] for instance, developed a soft tissue model for facial animation and [14] used mass spring and particle systems for the representation of human muscles. Other interesting work can be found in [21] who devised an efficient collision detection method for cloth simulation. Lately, 1] optimized ....

Y. Lee, D. Terzopoulos, and K. Waters. "Realistic face modeling for animation." In R. Cook, editor, SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 55--62. ACM SIGGRAPH, Addison Wesley, Aug. 1995.

....muscles within a person specific mesh have been reported. Other deformation methods include spline models [19, 20] and free form deformations [21, 22] See [9] for an excellent survey of these and other methods. Skin wrinkles and creases can be modeled by physically based mass spring system [16, 17]. These methods produce geometry deformations with static skin texture. Tuning these to produce a particular person s skin behavior is difficult. Textures provide an alternative to geometry for representing skin appearance. Guenter et al. 37] represents texture variations as a compressed data ....

Y. C. Lee, D. Terzopoulos, K. Waters. Realistic face modeling for animation. Proc. Siggraph, 1995, pp. 55-62

....to the facial expressions and body language of the people they are talking to. And that s how they know what s going on inside a person s head by condensing fact from the vapor of nuance. Attention control is being studied by Chopra [16] Extensive literature on facial animation exists: [44, 39, 2, 46, 47, 45, 35]. Efforts on other gestural communication include [40, 11, 10, 38, 15, 33] 2.7. Facial Expressions, Emotion, and Personality Facial expressions seem to be particularly important, and again can be classified as either explicit or affective. Explicit expressions include: fluttering eyelashes, ....

Y. Lee, D. Terzopoulos, and K. Waters. Realistic face modeling for animation. In SIGGRAPH '95 Proceedings, pages 55--62, Aug. 1995.

....a human figure. In this paper, we will concentrate on deformations required for facial animation. We develop methods for deforming a given 3D model to create facial expressions and mouth shapes. The creation of person specific models is a separate sub problem and example approaches can be found in [5, 6, 15, 20, 26]. We briefly survey common facial animation techniques in the following subsection. 1.1 Background Pighin et al. 20] combine 2D morphing with 3D transformations of a geometric model to produce facial animation. The success of their animation depends on how realistically a collection of facial ....

....typically a stress strain relationship. When external forces are applied, the displacements of the nodes are computed to minimize local stresses and strains imposed onto the nodes. Layered skin models based on mass spring systems mimic the anatomical structure and dynamics of the human face [15]. The mesh consists of three layers corresponding to skin, fatty tissue, and muscles tied to bones. Elastic spring elements connect each mesh node and each layer. Muscle forces propagate through the mesh to create deformations. The computational cost for such spring systems can be very high. Kalra ....

Y. C. Lee, D. Terzopoulos, K. Waters. Realistic face modeling for animation. Siggraph proceedings, 1995, 55-62

....systems to create animation. This model achieves great realism, however, simulating volumetric deformations with three dimensional lattices requires extensive computation. A simplified mesh system reduces the computation time while still maintaining visual realism (Wu. et al. [135] Lee et al. [61] presented models of physics based synthetic skin and muscle layers based on earlier work [122] The face model consists of three components: a biological tissue layer with nonlinear deformation properties, a muscle layer knit together under the skin, and an impenetrable skull structure beneath ....

....is implicit in the fitting process. Person specific modeling and fitting processes use various approaches such as scattered data interpolations [103, 124] anthropometry techniques [27, 59] and projections onto the cylindrical coordinates incorporated with a positive Laplacian field function [61]. Some methods attempt an automated fitting process, but most require significant manual intervention. Figure 9 depicts the general fitting process. 10.1. Bilinear interpolation Parke [90] uses bilinear interpolation to create various facial shapes. His assumption is that a large variety of ....

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Y. C. Lee, D. Terzopoulos, K. Waters. Realistic face modeling for animation. Siggraph proceedings, 1995, pp. 55-62

....computing requirements. In achieving the above goals, facial animation synthesis often takes two approaches: 3D mesh based geometry deformations and 2D image manipulations. In a typical 3D mesh approach, a person specific model is prepared by deforming a generic mesh in a preprocessing step [8][15][18] 24] The generic mesh contains all the animation parameters necessary for the subsequent person specific animations. The model is animated by mesh node displacements based on motion rules specified by deformation engine such as vector muscles [25] 26] spring muscles [15] 19] free form ....

....preprocessing step [8] 15] 18] 24] The generic mesh contains all the animation parameters necessary for the subsequent person specific animations. The model is animated by mesh node displacements based on motion rules specified by deformation engine such as vector muscles [25] 26] spring muscles [15][19] free form deformations [13] volume morphing [10] or simple interpolation [18] Texture mapping [10] 15] 18] is employed to improve realism with characteristics such as skin wrinkles that are hard to achieve by geometric deformations alone. Such 3D approaches hold promise for realistic ....

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Y. C. Lee, D. Terzopoulos, K. Waters. Realistic face modeling for animation. Siggraph proceedings, 1995, pp. 55-62

....Deformations, Facial animation, Morphing, Neural Nets 1 Introduction Facial animation aims at producing expressive and plausible animations of a 3D face model. Some approaches model the anatomy of the face, deriving facial animations from the physical behaviors of the bone and muscle structures [16, 24, 30, 31]. Others focus only on the surface of the face, using smooth surface deformation mechanisms to create facial expressions [11, 12, 23] In general, these approaches make little use of existing data for animating a new model. Each time a new model is created for animation, a method specific tuning ....

....only when the involved models are equipped with properly positioned muscles. Even then, problems still arise when muscle structures or surface shapes are inherently different between two models, e.g. a human and a cat face. A three layer mass spring muscle system requires extensive computation [16] and the final computed parameters are only useful for one model. Free form deformation manipulates control points to create facial expressions [12] but there is no automatic method for mapping the control points from one model to another. Expression synthesis from photographs can capture ....

Y.C. Lee, D. Terzopoulos, K. Waters, Realistic Face Modeling for Animation. SIGGRAPH 95 Proceedings, 1995, 55-62

....muscles within a person specific mesh have been reported. Other deformation methods include spline models [19, 20] and free form deformations [21, 22] See [9] for an excellent survey of these and other methods. Skin wrinkles and creases can be modeled by physically based mass spring system [16, 17]. These methods produce geometry deformations with static skin texture. Tuning these to produce a particular person s skin behavior is difficult. Textures provide an alternative to geometry for representing skin appearance. Guenter et al. 37] represents texture variations as a compressed data ....

Y. C. Lee, D. Terzopoulos, K. Waters. Realistic face modeling for animation. Proc. Siggraph, 1995, pp. 55-62

....when cutting some surface elements. This can be very expensive since BEM matrices are usually not sparse. In order to make 3D soft tissue modeling real time, different strategies have been proposed. 6] for instance, develops surface based snakes to represent human organs. Furthermore, [17] developed a soft tissue model for facial animation and [18] used mass spring and particle systems for the representation of human muscles. Appeared in Proceedings of Pacific Graphics 2000, IEEE Computer Society Press, pp. 116 125 Another interesting approach is the 3D ChainMail, as introduced ....

Y. Lee, D. Terzopoulos, and K. Waters. "Realistic face modeling for animation." In R. Cook, editor, SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 55--62. ACM SIGGRAPH, Addison Wesley, Aug. 1995.

....background Human face animation is a complex task requiring modeling and rendering not only of face geometry, but also of distinctive facial features (such as skin, hair, and tongue) and their motions. Most research in face modeling in computer graphics has addressed these latter problems [LTK95, MTMdAT89, Par82, PW96] Research on human geometry itself falls into two camps, both crucially dependent (in different ways) on human participation. The first approach is to extract geometry automatically from the measurement of a live subject. Lee, et al. LTK95] use a range scan of a subject, ....

....addressed these latter problems [LTK95, MTMdAT89, Par82, PW96] Research on human geometry itself falls into two camps, both crucially dependent (in different ways) on human participation. The first approach is to extract geometry automatically from the measurement of a live subject. Lee, et al. LTK95] use a range scan of a subject, and produce a physics based model capable of animation. Akimoto, et al. ASR93] use front and profile images of a subject to produce a model. The second approach is to facilitate manual specification of new face geometry by a user. A certain facility is offered ....

[Article contains additional citation context not shown here]

Y. Lee, D. Terzopoulos, and K.Waters. Realistic face modeling for animation. In Proceedings SIGGRAPH '95, pages 55--62, 1995.

....of soft tissues or other highly nonlinear materials. 2. 1 Modeling Deformation Linear elastic models have been successfully used in real time applications where only small deformations and strains occur [BNC96, JP99] Mass spring systems have been widely used to model deformation (e.g. Mil88, LTW95, BW98] due to their simplicity. However, they are notorious for their difficulty in determining the stiffness parameter and modeling incompressibility. Finite element methods (FEM) have been regarded as a versatile, effective and more accurate technique for discretization of continuum models. ....

Yuencheng Lee, Demetri Terzopoulos, and Keith Waters. Realistic face modeling for animation. SIGGRAPH 95 Conference Proceedings, pages 55--62, 1995.

....grids are reported in [19] Pure geometric and topological manipulations based on marching cubes techniques can be found in the algorithms of [16] and [15] whose visual quality is amazing. In most approaches, force feedback devices are utilized to implement the interface to the user. Furthermore, [12] for instance, developed a soft tissue model for facial animation and [13] used mass spring and particle systems for the representation of human muscles. Other interesting work can be found in [20] who devised an efficient collision detection method for cloth simulation. Lately, 1] optimized ....

Y. Lee, D. Terzopoulos, and K. Waters. "Realistic face modeling for animation." In R. Cook, editor, SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 55--62. ACM SIGGRAPH, Addison Wesley, Aug. 1995.

....et al. developed a surface based Finite Element approach which yielded very promising results both in the field of surgery simulation [15] and facial animation [14] They approximated the volumetric behavior through a spring mesh connecting the thin plate spline surface to the skull. Lee et al. [17] presented a realistic model for facial animation which was based on prism elements combining the facial surface with a layered synthetic tissue model. Both, Koch and Lee, took into account anatomy and implemented an elaborate model of facial skin layers. Although both models have proved very ....

Y. Lee, D. Terzopoulos, and K. Waters. "Realistic face modeling for animation." In R. Cook, editor, SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 55--62. ACM SIGGRAPH, Addison Wesley, Aug. 1995. held in Los Angeles, California, 06-11 August 1995.

....area on the facial surface. During the editing procedure the user defines only the central fibres. The following section addresses the generation of the entire muscular system from the central muscle fibres and from the facial and skull geometry. Here, we follow the approaches from Lee e.a. [12]. On contraction facial regions close to the skin attachment point of a muscle are affected. The muscular influence decreases with both the distance perpendicular to the muscle vector r ji and with the distance from the muscle attachment point in direction to the muscle origin w ji . The following ....

Y. Lee, D. Terzopoulos, and K. Waters. "Realistic face modeling for animation." In R. Cook, editor, SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 55--62. ACM SIGGRAPH, Addison Wesley, Aug. 1995. held in Los Angeles, California, 06-11 August 1995.

....and is relatively close to the underlying simulated muscles or bone. The springs are generated by locating one (or several in [KGC 96] points close to the mesh vertices on the underlying structure. In [WV97] a parameterization of the muscles is used to create such attachment points. In [LTW95] a scanned facial model is animated via a spring network which includes an estimated underlying skull, and a layer of springs representing simulated muscles. A method for more precise modeling of muscles connected to an anatomically correct skeleton has been shown in [SPCM97] In [GTT89] finite ....

Yuencheng Lee, Demetri Terzopoulos, and Keith Waters. Realistic face modeling for animation. In Robert Cook, editor, SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 55--62. ACM SIGGRAPH, Addison Wesley, August 1995. held in Los Angeles, California, 06-11 August 1995.

....et al. developed a surface based Finite Element approach which yielded very promising results both in the field of surgery simulation [15] and facial animation [14] They approximated the volumetric behavior through a spring mesh connecting the thin plate spline surface to the skull. Lee et al. [17] presented a realistic model for facial animation which was based on prism elements combining the facial surface with a layered synthetic tissue model. Both, Koch and Lee, took into account anatomy and implemented an elaborate model of facial skin layers. Although both models have proved very ....

Y. Lee, D. Terzopoulos, and K. Waters. "Realistic face modeling for animation." In R. Cook, editor, SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 55--62. ACM SIGGRAPH, Addison Wesley, Aug. 1995. held in Los Angeles, California, 06-11 August 1995.

....realistic facial models based on mass spring systems feature a linear approximation of the facial surface. The particle based approach is also used to govern control vertices of parametric B spline models and thus provides continuous shape descriptions. In particular, the works of Terzopoulos e.a. [10, 16] extend the prior approaches in many significant ways: Anatomy is incorporated and an elaborate model of facial skin layers and muscles is proposed which is essential to compute realistic facial appearance. In facial animation, computational complexity is a fundamental constraint, and real time ....

....ffl The elastomechanics of the surface is only approximated by spring mass systems which can be considered linear and hence C 0 continuous finite elements. ffl Unsatisfactory approximations of the patient s skull surface were used which are essential for surgical applications. ffl Although [10] proposes a very elaborate and elegant model, the underlying facial tissue is still template based and does not account for individual variations of the different layers and tissue types. Our Approach In the following paper we present a human facial model that enables prediction of facial ....

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LEE, Y., TERZOPOULOS, D., AND WATERS, K. Realistic face modeling for animation. In Computer Graphics (SIGGRAPH '95 Proceedings) (Aug. 1995), ACM SIGGRAPH, R. Cook, Ed., vol. 29, pp. 55--62.

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Y. Lee, D. Terzopoulos, and K. Waters. Realistic face modeling for animation. In SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 55--62. ACM SIGGRAPH, Addison Wesley, Aug. 1995. 10

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