VMV: Vision, Modeling, and Visualization

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https://diglib.eg.org/handle/10.2312/1013

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Browsing VMV: Vision, Modeling, and Visualization by Subject "Animation"

Now showing 1 - 7 of 7
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    Cloth-Fluid Contact
    (The Eurographics Association, 2013) Huber, Markus; Eberhardt, Bernhard; Weiskopf, Daniel; Michael Bronstein and Jean Favre and Kai Hormann
    We present a robust and efficient method for the two-way coupling between particle-based fluid simulations and infinitesimally thin solids represented by triangular meshes. Our approach is based on a hybrid method that combines a repulsion force approach with a continuous intersection handling to guarantee that no penetration occurs. Moreover, boundary conditions for the tangential component of the fluids velocity are implemented to model the no-slip boundary condition. The proposed method is particularly useful for dynamic surfaces, like cloth and thin shells. In addition, we demonstrate how standard fluid surface reconstruction algorithms can be modified to prevent the calculated surface from intersecting close objects. We have implemented our approach for the bidirectional interaction between liquid simulations based on Smoothed Particle Hydrodynamics (SPH) and standard mesh-based cloth simulation systems.
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    Data Driven 3D Face Tracking Based on a Facial Deformation Model
    (The Eurographics Association, 2015) Sibbing, Dominik; Kobbelt, Leif; David Bommes and Tobias Ritschel and Thomas Schultz
    We introduce a new markerless 3D face tracking approach for 2D video streams captured by a single consumer grade camera. Our approach is based on tracking 2D features in the video and matching them with the projection of the corresponding feature points of a deformable 3D model. By this we estimate the initial shape and pose of the face. To make the tracking and reconstruction more robust we add a smoothness prior for pose changes as well as for deformations of the faces. Our major contribution lies in the formulation of the smooth deformation prior which we derive from a large database of previously captured facial animations showing different (dynamic) facial expressions of a fairly large number of subjects. We split these animation sequences into snippets of fixed length which we use to predict the facial motion based on previous frames. In order to keep the deformation model compact and independent from the individual physiognomy, we represent it by deformation gradients (instead of vertex positions) and apply a principal component analysis in deformation gradient space to extract the major modes of facial deformation. Since the facial deformation is optimized during tracking, it is particularly easy to apply them to other physiognomies and thereby re-target the facial expressions. We demonstrate the effectiveness of our technique on a number of examples.
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    Kinematic ICP for Articulated Template Fitting
    (The Eurographics Association, 2012) Fechteler, Philipp; Hilsmann, Anna; Eisert, Peter; Michael Goesele and Thorsten Grosch and Holger Theisel and Klaus Toennies and Bernhard Preim
    In this paper, we present an efficient optimization method to adapt an articulated 3D template model to a full or partial 3D mesh. The well-known ICP algorithm is enhanced to fit a generic template to a target mesh. Each iteration jointly refines the parameters for global rigid alignment, uniform scale as well as the rotation parameters of all joint angles. The articulated 3D template model is based on the publicly available SCAPE data set, enhanced with automatically learned rotation centers of the joints and Linear Blend Skinning weights for each vertex. In two example applications we demonstrate the effectiveness of this computationally efficient approach: pose recovery from full meshes and pose tracking from partial depth maps.
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    Rotoscoping on Stereoscopic Images and Videos
    (The Eurographics Association, 2015) Bukenberger, Dennis R.; Schwarz, Katharina; Groh, Fabian; Lensch, Hendrik P. A.; David Bommes and Tobias Ritschel and Thomas Schultz
    Creating an animation based on video footage (rotoscoping) often requires significant manual work. For monoscopic videos diverse publications already feature (semi-)automatic techniques to apply non-photorealistic image abstraction (NPR) to videos. This paper addresses abstraction of 3D stereo content minimizing stereoscopic discomfort in images and videos. We introduce a completely autonomous framework that enhances stereo and temporal consistency. Stereoscopic coherence with consistent textures for both eyes is produced by warping the left and right images into a central disparity domain followed by mapping them back to the left and right view. Smooth movements with reduced flickering are achieved by considering optical flow in the propagation of abstract features between frames. The results show significant improvements of stereo consistency without discomforting artifacts in the depth perception. We extend existing stroke based rendering (SBR) for higher accuracy at strong image gradients. Furthermore, we demonstrate that our stereo framework is easily applicable to other point-based abstraction styles. Finally, we evaluate the stereo consistency of our results in a small user study and show that the comfort of the visual appearance is maintained.
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    Tongue S(t)imulator - A Comprehensive Parametrized Pose Model for Speech Therapy
    (The Eurographics Association, 2015) Haraké, Laura; Bełtkiewicz, Dorota; Lochmann, Gerrit; David Bommes and Tobias Ritschel and Thomas Schultz
    Recent digital applications in speech therapy address patients to train auditive speech comprehension, reading or semantics, in a playful way. Virtual tutors consist of three-dimensional head models for assisting the patient with conversational exercises. However, speech therapists also have to give pronunciation instructions and motility training of the tongue very often, but only have two-dimensional drawings or their own mouths for demonstration. In this paper we propose a comprehensive application for speech therapy as a therapeutical tool, simulating the articulation of German phones including color-coded expiration flows and the deglutition process (swallowing). A three-dimensional visualization of anatomical models of pharyngo-laryngeal area can be used in an interactive way. For examining the benefits of our tool over common conventional therapy media, our approach considers iteratively the demands of speech therapists. A final expert interview was conducted to assess how the application could be involved in treatment and the application’'s limits.
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    Video-Driven Animation of Neural Head Avatars
    (The Eurographics Association, 2023) Paier, Wolfgang; Hinzer, Paul; Hilsmann, Anna; Eisert, Peter; Guthe, Michael; Grosch, Thorsten
    We present a new approach for video-driven animation of high-quality neural 3D head models, addressing the challenge of person-independent animation from video input. Typically, high-quality generative models are learned for specific individuals from multi-view video footage, resulting in person-specific latent representations that drive the generation process. In order to achieve person-independent animation from video input, we introduce an LSTM-based animation network capable of translating person-independent expression features into personalized animation parameters of person-specific 3D head models. Our approach combines the advantages of personalized head models (high quality and realism) with the convenience of video-driven animation employing multi-person facial performance capture.We demonstrate the effectiveness of our approach on synthesized animations with high quality based on different source videos as well as an ablation study.
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    Weighted Laplacian Smoothing for Surface Reconstruction of Particle-based Fluids
    (The Eurographics Association, 2023) Löschner, Fabian; Böttcher, Timna; Rhys Jeske, Stefan; Bender, Jan; Guthe, Michael; Grosch, Thorsten
    In physically-based animation, producing detailed and realistic surface reconstructions for rendering is an important part of a simulation pipeline for particle-based fluids. In this paper we propose a post-processing approach to obtain smooth surfaces from ''blobby'' marching cubes triangulations without visual volume loss or shrinkage of drops and splashes. In contrast to other state-of-the-art methods that often require changes to the entire reconstruction pipeline our approach is easy to implement and less computationally expensive. The main component is Laplacian mesh smoothing with our proposed feature weights that dampen the smoothing in regions of the mesh with splashes and isolated particles without reducing effectiveness in regions that are supposed to be flat. In addition, we suggest a specialized decimation procedure to avoid artifacts due to low-quality triangle configurations generated by marching cubes and a normal smoothing pass to further increase quality when visualizing the mesh with physically-based rendering. For improved computational efficiency of the method, we outline the option of integrating computation of our weights into an existing reconstruction pipeline as most involved quantities are already known during reconstruction. Finally, we evaluate our post-processing implementation on high-resolution smoothed particle hydrodynamics (SPH) simulations.