For hardware accelerated rendering, photon mapping is especially useful for simulating caustic lighting effects on non-Lambertian surfaces. However, an efficient hardware algorithm for the computation of the k nearest...
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For hardware accelerated rendering, photon mapping is especially useful for simulating caustic lighting effects on non-Lambertian surfaces. However, an efficient hardware algorithm for the computation of the k nearest neighbours to a sample point is required. Existing algorithms are often based on recursive spatial subdivision techniques, such as kd-trees. However, hardware implementation of a tree-based algorithm would have a high latency, or would require a large cache to avoid this latency on average. We present a neighbourhood-preserving hashing algorithm that is low-latency and has sub-linear access time. This algorithm is more amenable to fine-scale parallelism than tree-based recursive spatial subdivision, and maps well onto coherent block-oriented pipelined memory access. These properties make the algorithm suitable for implementation using future programmable fragment shaders with only one stage of dependent texturing.
A method is presented for the modelling and animation of generalized cylinders with variable radius offset space curves. The boundary surface of a generalized cylinder is constructed: either as a translational sweep o...
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The Core and GKS computergraphics standards are reviewed with respect to their data entry facilities and a historical survey of interactive devices is given. A new and more fundamental model for data entry from logic...
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The Core and GKS computergraphics standards are reviewed with respect to their data entry facilities and a historical survey of interactive devices is given. A new and more fundamental model for data entry from logical input devices is presented. Two classes of signals or events are defined external to the computer: continuous and discrete. The devices which report these signals are categorized in one of these two classes according to the type of signal they report. These classes are at the lowest level in the system and serve as primitives which may be used to implement any of the existing standards. As such, they assist in developing both device and machine independent code, since only the primitives must be altered for transportability to other systems.
作者：
Jortner, J.N.Brewer III, J.A.Louisiana State Univ
Computer Graphics Research & Applications Lab Baton Rouge LA USA Louisiana State Univ Computer Graphics Research & Applications Lab Baton Rouge LA USA
The objective of this work is to develop an interpolating curve capable of supporting a broad range of analytical needs while still being amenable to a natural user-interface. A specific analytical goal is to allow th...
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The objective of this work is to develop an interpolating curve capable of supporting a broad range of analytical needs while still being amenable to a natural user-interface. A specific analytical goal is to allow the definition of conic sections as well as free-form shapes. Rational parametric curves meet these needs and are the focus of this work.
This paper introduces a new kind of mosaic, called the Decorative PixMosaic, where photo tiles of square shapes are used to compose the final image. We can express the resulting image with a similar color distribution...
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作者：
Thompson, D.E.Brewer III, J.A.Louisiana State Univ
Computer Graphics Research & Applications Lab Baton Rouge LA USA Louisiana State Univ Computer Graphics Research & Applications Lab Baton Rouge LA USA
The design and implementation of a high-speed network are described. This network fills the many roles needed in a research environment while maintaining both high speed and functionality. This is achieved using Ether...
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The design and implementation of a high-speed network are described. This network fills the many roles needed in a research environment while maintaining both high speed and functionality. This is achieved using Ethernet and five Digital Equipment Corporation VAX 11/750 computers configured as a master processor with four satellite processors. The use of the VMS operating system allows the full use of DECnet software services while the interprocessor, intertask communications speeds achieved under Ethernet approach 10Mbits/second. This research, while directly applicable to CAD, is also important in robotics, automated systems, and workstations of many different kinds.
There are many algorithms in non-photorealistic rendering for representing an image as a composition of small objects. In this paper, we focus on the specific case where the objects to be assembled into a composition ...
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ISBN:
(纸本)1568813376
There are many algorithms in non-photorealistic rendering for representing an image as a composition of small objects. In this paper, we focus on the specific case where the objects to be assembled into a composition are letters rather than images or abstract geometric forms. We develop a solution to the "calligraphic packing" problem based on dividing up a target region into pieces and warping a letter into each piece. We define an energy function that chooses a warp that best represents the original letter. We discuss variations in rendering style and show results produced by our system.
Inspired by recent advances in high-quality mesh parameterization, I present a technique for decorating surfaces with seamless ornamental patterns. The patterns are transferred from planar drawings with wallpaper symm...
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In this paper, we present an image watermarking scheme based on discrete wavelet transform and singular value decomposition (SVD) for color Images. This scheme embeds the watermark into the luminance (Y) channel of YC...
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ISBN:
(纸本)9780889869264
In this paper, we present an image watermarking scheme based on discrete wavelet transform and singular value decomposition (SVD) for color Images. This scheme embeds the watermark into the luminance (Y) channel of YC bCR color space of the host image. The luminance image is decomposed up to four DWT levels. SVD is applied on the HL1-4 and LH1-4sub-bands of each level and pseudo random number (PRN) sequence is added to the singular values of their coefficients to produce what we call modified singular values. To obtain the modified HL and LH coefficients, we take the inverse of the SVD of the modified SVs. Finally, we perform the IDWT on the modified HL & LH coefficients as well as HH and LL coefficients to produce the watermarked Y channel image. Then, the modified luminance, Cb and Cr are combined to get the watermarked color image. Simulation results show that our watermark is robust against high JPEG compression, filtering, Gaussian-noise, resizing and other image processing attacks. In addition, this watermark is not susceptible to any false positive or detection of false reference watermark.
This paper presents an approach to collision detection and response for dynamically deforming pointbased objects. Both the volume of an object and its surface are represented by point sets. In case of a collision, res...
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ISBN:
(纸本)3898380580
This paper presents an approach to collision detection and response for dynamically deforming pointbased objects. Both the volume of an object and its surface are represented by point sets. In case of a collision, response forces are computed for penetrating surface points and distributed to volume points which are used for simulating the object dynamics. The decoupling of collision handling and deformation allows for a very stable collision response while maintaining interactive update rates of the dynamic simulation for environments with moderate complexity. Simulation results are presented for elastically and plastically deforming objects with changing topology.
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