1,947 research outputs found
A survey of real-time crowd rendering
In this survey we review, classify and compare existing approaches for real-time crowd rendering. We first overview character animation techniques, as they are highly tied to crowd rendering performance, and then we analyze the state of the art in crowd rendering. We discuss different representations for level-of-detail (LoD) rendering of animated characters, including polygon-based, point-based, and image-based techniques, and review different criteria for runtime LoD selection. Besides LoD approaches, we review classic acceleration schemes, such as frustum culling and occlusion culling, and describe how they can be adapted to handle crowds of animated characters. We also discuss specific acceleration techniques for crowd rendering, such as primitive pseudo-instancing, palette skinning, and dynamic key-pose caching, which benefit from current graphics hardware. We also address other factors affecting performance and realism of crowds such as lighting, shadowing, clothing and variability. Finally we provide an exhaustive comparison of the most relevant approaches in the field.Peer ReviewedPostprint (author's final draft
A multimedia package for patient understanding and rehabilitation of non-contact anterior cruciate ligament injuries
Non-contact anterior cruciate ligament (ACL) injury is one of the most common ligament injuries in the body. Many patients’ receive graft surgery to repair the damage, but have to undertake an extensive period of rehabilitation. However, non-compliance and lack of understanding of the injury, healing process and rehabilitation means patient’s return to activities before effective structural integrity of the graft has been reached. When clinicians educate the patient, to encourage compliance with treatment and rehabilitation, the only tools that are currently widely in use are static plastic models, line diagrams and pamphlets. As modern technology grows in use in anatomical education, we have developed a unique educational and training package for patient’s to use in gaining a better understanding of their injury and treatment plan. We have combined cadaveric dissections of the knee (and captured with high resolution digital images) with reconstructed 3D modules from the Visible Human dataset, computer generated animations, and images to produce a multimedia package, which can be used to educate the patient in their knee anatomy, the injury, the healing process and their rehabilitation, and how this links into key stages of improving graft integrity. It is hoped that this will improve patient compliance with their rehabilitation programme, and better long-term prognosis in returning to normal or near-normal activities. Feedback from healthcare professionals about this package has been positive and encouraging for its long-term use
3D mesh processing using GAMer 2 to enable reaction-diffusion simulations in realistic cellular geometries
Recent advances in electron microscopy have enabled the imaging of single
cells in 3D at nanometer length scale resolutions. An uncharted frontier for in
silico biology is the ability to simulate cellular processes using these
observed geometries. Enabling such simulations requires watertight meshing of
electron micrograph images into 3D volume meshes, which can then form the basis
of computer simulations of such processes using numerical techniques such as
the Finite Element Method. In this paper, we describe the use of our recently
rewritten mesh processing software, GAMer 2, to bridge the gap between poorly
conditioned meshes generated from segmented micrographs and boundary marked
tetrahedral meshes which are compatible with simulation. We demonstrate the
application of a workflow using GAMer 2 to a series of electron micrographs of
neuronal dendrite morphology explored at three different length scales and show
that the resulting meshes are suitable for finite element simulations. This
work is an important step towards making physical simulations of biological
processes in realistic geometries routine. Innovations in algorithms to
reconstruct and simulate cellular length scale phenomena based on emerging
structural data will enable realistic physical models and advance discovery at
the interface of geometry and cellular processes. We posit that a new frontier
at the intersection of computational technologies and single cell biology is
now open.Comment: 39 pages, 14 figures. High resolution figures and supplemental movies
available upon reques
Three-dimensional isotropic perfect lens based on LC-loaded transmission lines
An isotropic three-dimentional perfect lens based on cubic meshes of
interconnected transmission lines and bulk loads is proposed. The lens is
formed by a slab of a loaded mesh placed in between two similar unloaded
meshes. The dispersion equations and the characteristic impedances of the
eigenwaves in the meshes are derived analytically, with an emphasis on
generality. This allows designing of transmission-line meshes with desired
dispersion properties. The required backward-wave mode of operation in the lens
is realized with simple inductive and capacitive loads. An analytical
expression for the transmission through the lens is derived and the
amplification of evanescent waves is demonstrated. Factors that influence
enhancement of evanescent waves in the lens are studied and the corresponding
design criteria are established. A possible realization of the structure is
outlined.Comment: 22 pages, 15 figure
Capture, Learning, and Synthesis of 3D Speaking Styles
Audio-driven 3D facial animation has been widely explored, but achieving
realistic, human-like performance is still unsolved. This is due to the lack of
available 3D datasets, models, and standard evaluation metrics. To address
this, we introduce a unique 4D face dataset with about 29 minutes of 4D scans
captured at 60 fps and synchronized audio from 12 speakers. We then train a
neural network on our dataset that factors identity from facial motion. The
learned model, VOCA (Voice Operated Character Animation) takes any speech
signal as input - even speech in languages other than English - and
realistically animates a wide range of adult faces. Conditioning on subject
labels during training allows the model to learn a variety of realistic
speaking styles. VOCA also provides animator controls to alter speaking style,
identity-dependent facial shape, and pose (i.e. head, jaw, and eyeball
rotations) during animation. To our knowledge, VOCA is the only realistic 3D
facial animation model that is readily applicable to unseen subjects without
retargeting. This makes VOCA suitable for tasks like in-game video, virtual
reality avatars, or any scenario in which the speaker, speech, or language is
not known in advance. We make the dataset and model available for research
purposes at http://voca.is.tue.mpg.de.Comment: To appear in CVPR 201
Hyperparameter-free losses for model-based monocular reconstruction
This work proposes novel hyperparameter-free losses for single view 3D reconstruction with morphable models (3DMM). We dispense with the hyperparameters used in other works by exploiting geometry, so that the shape of the object and the camera pose are jointly optimized in a sole term expression. This simplification reduces the optimization time and its complexity. Moreover, we propose a novel implicit regularization technique based on random virtual projections that does not require additional 2D or 3D annotations. Our experiments suggest that minimizing a shape reprojection error together with the proposed implicit regularization is especially suitable for applications that require precise alignment between geometry and image spaces, such as augmented reality. We evaluate our losses on a large scale dataset with 3D ground truth and publish our implementations to facilitate reproducibility and public benchmarking in this field.Peer ReviewedPostprint (author's final draft
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