We present a new method for rendering high dynamic range images on conventional displays. Our method is conceptually simple, computationally efficient, robust, and easy to use. We manipulate the gradient field of the ...
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ISBN:
(纸本)9781581135213
We present a new method for rendering high dynamic range images on conventional displays. Our method is conceptually simple, computationally efficient, robust, and easy to use. We manipulate the gradient field of the luminance image by attenuating the magnitudes of large gradients. A new, low dynamic range image is then obtained by solving a Poisson equation on the modified gradient field. Our results demonstrate that the method is capable of drastic dynamic range compression, while preserving fine details and avoiding common artifacts, such as halos, gradient reversals, or loss of local contrast. the method is also able to significantly enhance ordinary images by bringing out detail in dark regions.
We present a new method for the animation and rendering of photorealistic water effects. Our method is designed to produce visually plausible three dimensional effects, for example the pouring of water into a glass (s...
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ISBN:
(纸本)9781581135213
We present a new method for the animation and rendering of photorealistic water effects. Our method is designed to produce visually plausible three dimensional effects, for example the pouring of water into a glass (see figure 1) and the breaking of an ocean wave, in a manner which can be used in a computer animation environment. In order to better obtain photorealism in the behavior of the simulated water surface, we introduce a new "thickened" front tracking technique to accurately represent the water surface and a new velocity extrapolation method to move the surface in a smooth, water-like manner. the velocity extrapolation method allows us to provide a degree of control to the surface motion, e.g. to generate a windblown look or to force the water to settle quickly. To ensure that the photorealism of the simulation carries over to the final images, we have integrated our method with an advanced physically based rendering system.
Placing shadows is difficult task since shadows depend on the relative positions of lights and objects in an unintuitive manner. To simplify the task of the modeler, we present a user interface for designing shadows i...
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ISBN:
(纸本)9781581135213
Placing shadows is difficult task since shadows depend on the relative positions of lights and objects in an unintuitive manner. To simplify the task of the modeler, we present a user interface for designing shadows in 3d environments. In our interface, shadows are treated as first-class modeling primitives just like objects and lights. To transform a shadow, the user can simply move, rescale or rotate the shadow as if it was a 2d object on the scene's surfaces. When the user transforms a shadow, the system moves lights or objects in the scene as required and updates the shadows in realtime during mouse movement. To facilitate interaction, the user can also specify constraints that the shadows must obey, such as never casting a shadow on the face of a character. these constraints are then verified in real-time, limiting mouse movement when necessary. We also integrate in our interface fake shadows typically used in computer animation. this allows the user to draw shadowed and non-shadowed regions directly on surfaces in the scene.
this paper introduces a new kind of mosaic, called Jigsaw Image Mosaic (JIM), where image tiles of arbitrary shape are used to compose the final picture. the generation of a Jigsaw Image Mosaic is a solution to the fo...
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ISBN:
(纸本)9781581135213
this paper introduces a new kind of mosaic, called Jigsaw Image Mosaic (JIM), where image tiles of arbitrary shape are used to compose the final picture. the generation of a Jigsaw Image Mosaic is a solution to the following problem: given an arbitrarily-shaped container image and a set of arbitrarily-shaped image tiles, fill the container as compactly as possible with tiles of similar color to the container taken from the input set while optionally deforming them slightly to achieve a more visually-pleasing effect. We approach the problem by defining a mosaic as the tile configuration that minimizes a mosaicing energy function. We introduce a general energy-based framework for mosaicing problems that extends some of the existing algorithms such as Photomosaics and Simulated Decorative Mosaics. We also present a fast algorithm to solve the mosaicing problem at an acceptable computational cost. We demonstrate the use of our method by applying it to a wide range of container images and tiles.
the proceedings contain 16 papers. the topics discussed include: a level-of-detail technique for urban physics calculations in large urban environments;procedural location of roads using desire paths;structure-preserv...
ISBN:
(纸本)9783038680932
the proceedings contain 16 papers. the topics discussed include: a level-of-detail technique for urban physics calculations in large urban environments;procedural location of roads using desire paths;structure-preserving style transfer;sensitivity analysis in shape optimization using voxel density penalization;perfect spatial hashing for point-cloud-to-mesh registration;view-dependent hierarchical rendering of massive point clouds through textured splats;a virtual reality front-end for earthquake simulation;user-reconfigurable CAD feature recognition in 1- and 2-topologies with reduction of search space via geometry filters;a voxel-based deep learning approach for point cloud semantic segmentation;visiting ancient Rome with a serious game;and multispectral registration, undistortion and tree detection for precision agriculture.
this paper presents a framework for the skeleton-driven animation of elastically deformable characters. A character is embedded in a coarse volumetric control lattice, which provides the structure needed to apply the ...
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ISBN:
(纸本)9781581135213
this paper presents a framework for the skeleton-driven animation of elastically deformable characters. A character is embedded in a coarse volumetric control lattice, which provides the structure needed to apply the finite element method. To incorporate skeletal controls, we introduce line constraints along the bones of simple skeletons. the bones are made to coincide with edges of the control lattice, which enables us to apply the constraints efficiently using algebraic methods. To accelerate computation, we associate regions of the volumetric mesh with particular bones and perform locally linearized simulations, which are blended at each time step. We define a hierarchical basis on the control lattice, so for detailed interactions the simulation can adapt the level of detail. We demonstrate the ability to animate complex models using simple skeletons and coarse volumetric meshes in a manner that simulates secondary motions at interactive rates.
In this paper, we describe a method for realistically animating ductile fracture in common solid materials such as plastics and metals. the effects that characterize ductile fracture occur due to interaction between p...
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ISBN:
(纸本)9781581135213
In this paper, we describe a method for realistically animating ductile fracture in common solid materials such as plastics and metals. the effects that characterize ductile fracture occur due to interaction between plastic yielding and the fracture process. By modeling this interaction, our ductile fracture method can generate realistic motion for a much wider range of materials than could be realized with a purely brittle model. this method directly extends our prior work on brittle fracture [O'Brien and Hodgins, SIGGRAPH 99]. We show that adapting that method to ductile as well as brittle materials requires only a simple to implement modification that is computationally inexpensive. this paper describes this modification and presents results demonstrating some of the effects that may be realized with it.
there are many applications that demand large quantities of natural looking motion. It is difficult to synthesize motion that looks natural, particularly when it is people who must move. In this paper, we present a fr...
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ISBN:
(纸本)9781581135213
there are many applications that demand large quantities of natural looking motion. It is difficult to synthesize motion that looks natural, particularly when it is people who must move. In this paper, we present a framework that generates human motions by cutting and pasting motion capture data. Selecting a collection of clips that yields an acceptable motion is a combinatorial problem that we manage as a randomized search of a hierarchy of graphs. this approach can generate motion sequences that satisfy a variety of constraints automatically. the motions are smooth and human-looking. they are generated in real time so that we can author complex motions interactively. the algorithm generates multiple motions that satisfy a given set of constraints, allowing a variety of choices for the animator. It can easily synthesize multiple motions that interact with each other using constraints. this framework allows the extensive re-use of motion capture data for new purposes.
this paper describing a new framework for video matting, the process of pulling a high-quality alpha matte and foreground from a video sequence. the framework builds upon techniques in natural image matting, optical f...
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ISBN:
(纸本)9781581135213
this paper describing a new framework for video matting, the process of pulling a high-quality alpha matte and foreground from a video sequence. the framework builds upon techniques in natural image matting, optical flow computation, and background estimation. User interaction is comprised of garbage matte specification if background estimation is needed, and hand-drawn keyframe segmentations into "foreground," "background," and "unknown". the segmentations, called trimaps, are interpolated across the video volume using forward and backward optical flow. Competing flow estimates are combined based on information about where flow is likely to be accurate. A Bayesian matting technique uses the flowed trimaps to yield high-quality mattes of moving foreground elements with complex boundaries filmed by a moving camera. A novel technique for smoke matte extraction is also demonstrated.
作者：
Kim, Tae-YongNeumann, UlrichCGITL
Integrated Media Systems Center University of Southern California Los Angeles CA United States
Human hair modeling is a difficult task. this paper presents a constructive hair modeling system with which users can sculpt a wide variety of hairstyles. Our Multiresolution Hair Modeling (MHM) system is based on the...
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ISBN:
(纸本)9781581135213
Human hair modeling is a difficult task. this paper presents a constructive hair modeling system with which users can sculpt a wide variety of hairstyles. Our Multiresolution Hair Modeling (MHM) system is based on the observed tendency of adjacent hair strands to form clusters at multiple scales due to static attraction. In our system, initial hair designs are quickly created with a small set of hair clusters. Refinements at finer levels are achieved by subdividing these initial hair clusters. Users can edit an evolving model at any level of detail, down to a single hair strand. High level editing tools support curling, scaling, and copy/paste, enabling users to rapidly create widely varying hairstyles. Editing ease and model realism are enhanced by efficient hair rendering, shading, antialiasing, and shadowing algorithms.
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