In this paper, we introduce an interactive tool for local color transfer. The new technique is based on the observation that color transfer operations are local in nature while at the same time should adhere global co...
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In this paper, we introduce an interactive tool for local color transfer. The new technique is based on the observation that color transfer operations are local in nature while at the same time should adhere global consistency. We introduce a brush by which the user specifies the source and destination image regions for color transfer. Color statistics in the source region are transferred to the destination region. A global optimization is then applied to eliminate vi- sual discontinuities that may result by the local operations. We demonstrate that our tool is easy to use yet effective in quickly generating diverse artistic effects.
We present a physically-inspired model of wax crayons, which synthesizes drawings from collections of user-specified strokes. Paper is represented by a height-field texture, and a crayon is modeled with a 2D mask that...
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We present a physically-inspired model of wax crayons, which synthesizes drawings from collections of user-specified strokes. Paper is represented by a height-field texture, and a crayon is modeled with a 2D mask that evolves as it interacts with the paper. The amount of wax deposition is computed based on the crayon contact profile, contact force, and friction. Previously deposited wax is smeared by crayon action, based on wax softness and contact information. The distributed wax is rendered using a simplified Kubelka-Monk model, which approximates light transmittance and scattering effects.
This paper introduces the geometric continuity equations of the closed planar polygons and gives the definition of a morphing with geometric continuity between two arbitrary planar polygons, including simple, non-3 an...
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ISBN:
(纸本)0769517846
This paper introduces the geometric continuity equations of the closed planar polygons and gives the definition of a morphing with geometric continuity between two arbitrary planar polygons, including simple, non-3 and even degenerated polygons. A simple morphing technique based on linear interpolation of the geometric continuity equations is proposed. The closureness of the in-between polygons is precisely achieved. Two global invariants: rotation indexes and winding numbers are introduced to describe the most general polygons. The demo shows that this technique is efficient and natural for morphing between polygons with arbitrary rotation indexes and winding numbers.
The control polygons of B-spline subdivision curves are usually refined uniformly using a technique called knot-doubling. This uniform refinement approach would perform unnecessary subdivision steps on portions alread...
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The control polygons of B-spline subdivision curves are usually refined uniformly using a technique called knot-doubling. This uniform refinement approach would perform unnecessary subdivision steps on portions already close to the limit curve enough and, consequently, cause unnecessary (exponential) increase on the number of line segments in the refined polygons. This paper overcomes this problem by proposing a local refinement technique for the control polygons of B-spline subdivision curves. Local refinement is achieved by selectively inserting new knots at midpoints of knot intervals. Efficient adaptive subdivision can be easily realized based on the new technique.
Summary form only given, as follows. Due to their simplicity, triangle meshes are often used to represent geometric surfaces. Their main drawback is the large number of triangles that are required to represent a smoot...
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Summary form only given, as follows. Due to their simplicity, triangle meshes are often used to represent geometric surfaces. Their main drawback is the large number of triangles that are required to represent a smooth surface. This problem has been addressed by a large number of mesh simplification algorithms which reduce the number of triangles and approximate the initial mesh. Hierarchical triangle mesh representations provide access to a triangle mesh at a desired resolution, without omitting any information. The article presents an infrastructure for discrete geometry processing, including algorithms for 3D reconstruction, curvature computation, reverse engineering, mesh reduction, interactive multiresolution modeling and progressive transmission of arbitrary unstructured triangle meshes.
We introduce an impostor-based visibility technique to provide approximate, average visibility for point-to-cluster and cluster-to-cluster visibility queries. Processing each object in a view-independent manner allows...
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We introduce an impostor-based visibility technique to provide approximate, average visibility for point-to-cluster and cluster-to-cluster visibility queries. Processing each object in a view-independent manner allows us to generate a mip-map-like hierarchy of approximate visibility information that can report approximate average visibility over conical shafts or conical shaft frustums. We demonstrate how these impostors can be used to approximate smooth soft shadow calculation, and improve the quality of light cuts and multidimensional light cuts. In addition, we describe how to use approximate visibility of shafts to estimate a tighter error bound for the light cuts visibility term, yielding speedup by reducing over-aggressive cut refinement.
A new approach for the generation of feature point-driven facial animation is presented. This approach is based on the construction of a hypothetical face formed by connecting face feature points into a net and repres...
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ISBN:
(纸本)0769508685
A new approach for the generation of feature point-driven facial animation is presented. This approach is based on the construction of a hypothetical face formed by connecting face feature points into a net and representing each facet of the net by a mathematically expressed surface to control the deformation of a real face model. The deformation is controlled by changing both the locations of the feature points and their tangents. The experimental results show that the hypothetical-surface-based method can generate almost identical facial expressions to a real face.
Implicit modeling is an important technique in the modeling of informal objects. However, the available automatic modeling algorithms with implicit skeletal elements are not very advanced. In this paper, we propose a ...
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ISBN:
(纸本)0769508685
Implicit modeling is an important technique in the modeling of informal objects. However, the available automatic modeling algorithms with implicit skeletal elements are not very advanced. In this paper, we propose a new skeletal element, called a metacube, and an automatic modeling technique for informal objects represented by volumetric data. The metacube has the merits of a metaball and also enhances the modeling ability of informal objects containing planar surfaces. For a 256/spl times/256/spl times/256 size of input volume, the proposed method takes a short generation time (less than ten minutes) on an SGI Indigo 2 workstation.
Realistic representation of various effects which appear in the real world paintings can be used for several applications like animation or education. To generate oriental paintings, numerous studies have focused on m...
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ISBN:
(纸本)0769517846
Realistic representation of various effects which appear in the real world paintings can be used for several applications like animation or education. To generate oriental paintings, numerous studies have focused on model-based approaches. In this paper, a new model-based approach for oriental paintings is described. To represent the diffusion effects, we propose local equilibrium model (LEM) which is a method to calculate the movement of water and ink effectively. In addition, we propose a paper model with fiber mesh structure and three layers structure on each cell. With this layer model, overlapped strokes can be well represented. A brush model proposed supports several brush effects like shading.
The appearance of computer generated plants has improved significantly due to advances in both modeling and rendering. In this paper we describe a system that further improves the appearance of CG plants by including ...
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The appearance of computer generated plants has improved significantly due to advances in both modeling and rendering. In this paper we describe a system that further improves the appearance of CG plants by including the tiny hairs that cover many plant organs. A plant skeleton is generated using an L-system and graphically interpreted using generalized cylinders. The individual hairs are then mapped onto the surfaces and boundary edges of the mesh. Hair properties are specified and adjusted according to positional information. Sample images included in the paper illustrate the impact of hairs on the appearance of rendered plants.
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