Examinando por Autor "Hilton, Adrian"

Mostrando 1 - 5 de 5

4D Model Flow: Precomputed Appearance Alignment for Real-time 4D Video Interpolation
(Wiley, 2015-10-15) Hilton, Adrian; Christian, Theobalt; Collomosse, John; Richardt, Christian; Casas, Dan
We introduce the concept of 4D model flow for the precomputed alignment of dynamic surface appearance across 4D video sequences of different motions reconstructed from multi-view video. Precomputed 4D model flow allows the efficient parametrization of surface appearance from the captured videos, which enables efficient real-time rendering of interpolated 4D video sequences whilst accurately reproducing visual dynamics, even when using a coarse underlying geometry. We estimate the 4D model flow using an image-based approach that is guided by available geometry proxies. We propose a novel representation in surface texture space for efficient storage and online parametric interpolation of dynamic appearance. Our 4D model flow overcomes previous requirements for computationally expensive online optical flow computation for data-driven alignment of dynamic surface appearance by precomputing the appearance alignment. This leads to an efficient rendering technique that enables the online interpolation between 4D videos in real time, from arbitrary viewpoints and with visual quality comparable to the state of the art.
4D Video Textures for Interactive Character Appearance
(Wiley, 2014-05-01) Hilton, Adrian; Collomosse, John; Volino, Marco; Casas, Dan
4D Video Textures (4DVT) introduce a novel representation for rendering video-realistic interactive character animation from a database of 4D actor performance captured in a multiple camera studio. 4D performance capture reconstructs dynamic shape and appearance over time but is limited to free-viewpoint video replay of the same motion. Interactive animation from 4D performance capture has so far been limited to surface shape only. 4DVT is the final piece in the puzzle enabling video-realistic interactive animation through two contributions: a layered view-dependent texture map representation which supports efficient storage, transmission and rendering from multiple view video capture; and a rendering approach that combines multiple 4DVT sequences in a parametric motion space, maintaining video quality rendering of dynamic surface appearance whilst allowing high-level interactive control of character motion and viewpoint. 4DVT is demonstrated for multiple characters and evaluated both quantitatively and through a user-study which confirms that the visual quality of captured video is maintained. The 4DVT representation achieves >90% reduction in size and halves the rendering cost.
Animation Control of Surface Motion Capture
(IEEE, 2013-12-06) Tejera, Margara; Casas, Dan; Hilton, Adrian
Surface motion capture (SurfCap) of actor performance from multiple view video provides reconstruction of the natural nonrigid deformation of skin and clothing. This paper introduces techniques for interactive animation control of SurfCap sequences which allow the flexibility in editing and interactive manipulation associated with existing tools for animation from skeletal motion capture (MoCap). Laplacian mesh editing is extended using a basis model learned from SurfCap sequences to constrain the surface shape to reproduce natural deformation. Three novel approaches for animation control of SurfCap sequences, which exploit the constrained Laplacian mesh editing, are introduced: 1) space-time editing for interactive sequence manipulation; 2) skeleton-driven animation to achieve natural nonrigid surface deformation; and 3) hybrid combination of skeletal MoCap driven and SurfCap sequence to extend the range of movement. These approaches are combined with high-level parametric control of SurfCap sequences in a hybrid surface and skeleton-driven animation control framework to achieve natural surface deformation with an extended range of movement by exploiting existing MoCap archives. Evaluation of each approach and the integrated animation framework are presented on real SurfCap sequences for actors performing multiple motions with a variety of clothing styles. Results demonstrate that these techniques enable flexible control for interactive animation with the natural nonrigid surface dynamics of the captured performance and provide a powerful tool to extend current SurfCap databases by incorporating new motions from MoCap sequences.
Interactive Animation of 4D Performance Capture
(IEEE, 2012-11-30) Casas, Dan; Tejera, Margara; Jean-Yves, Guillemaut; Hilton, Adrian
A 4D parametric motion graph representation is presented for interactive animation from actor performance capture in a multiple camera studio. The representation is based on a 4D model database of temporally aligned mesh sequence reconstructions for multiple motions. High-level movement controls such as speed and direction are achieved by blending multiple mesh sequences of related motions. A real-time mesh sequence blending approach is introduced, which combines the realistic deformation of previous nonlinear solutions with efficient online computation. Transitions between different parametric motion spaces are evaluated in real time based on surface shape and motion similarity. Four-dimensional parametric motion graphs allow real-time interactive character animation while preserving the natural dynamics of the captured performance.
Parametric animation of performance-captured mesh sequences
(Wiley, 2012-03-20) Casas, Dan; Tejera, Margara; Guillemaut, Jean-Yves; Hilton, Adrian
In this paper, we introduce an approach to high-level parameterisation of captured mesh sequences of actor performance for real-time interactive animation control. High-level parametric control is achieved by non-linear blending between multiple mesh sequences exhibiting variation in a particular movement. For example, walking speed is parameterised by blending fast and slow walk sequences. A hybrid non-linear mesh sequence blending approach is introduced to approxi- mate the natural deformation of non-linear interpolation techniques whilst maintaining the real-time performance of linear mesh blending. Quantitative results show that the hybrid approach gives an accurate real-time approximation of offline non-linear deformation. An evaluation of the approach shows good performance not only for entire meshes but also with specific mesh areas. Results are presented for single and multi-dimensional parametric control of walking (speed/direction), jumping (height/distance) and reaching (height) from captured mesh sequences. This approach allows continuous real-time control of high-level parameters such as speed and direction whilst maintaining the natural surface dynamics of captured movement.