The synchronization problems involved in mixing computergraphics with a video signal are outlined, and it is shown how two components solve them. The components, a video encoder and a genlocking digitizer facilitate ...
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The synchronization problems involved in mixing computergraphics with a video signal are outlined, and it is shown how two components solve them. The components, a video encoder and a genlocking digitizer facilitate overlays of digital computergraphics and/or text data onto a standard analog NTSC (National Television System Committee) or PAL baseband television signal. The mapping of the clock and subcarrier recovery algorithm and the video encoding procedure into the architectures of the two chips is discussed.< >
This paper presents a divide-and-conquer ray-traced volume rendering algorithm and a parallel image compositing method, along with their implementation and performance on the Connection Machine CM-5, and networked wor...
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This paper presents a divide-and-conquer ray-traced volume rendering algorithm and a parallel image compositing method, along with their implementation and performance on the Connection Machine CM-5, and networked workstations. This algorithm distributes both the data and the computations to individual processing units to achieve fast, high-quality rendering of high-resolution data. The volume data, once distributed, is left intact. The processing nodes perform local raytracing of their subvolume concurrently. No communication between processing units is needed during this locally ray-tracing process. A subimage is generated by each processing unit and the final image is obtained by compositing subimages in the proper order, which can be determined a priori. Test results on the CM-5 and a group of networked workstations demonstrate the practicality of our rendering algorithm and compositing method.
This paper presents a graphics renderer which incorporates new partitioning methodologies of memory and work for efficient execution on a parallel computer. The task adaptive domain decomposition scheme is an image sp...
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This paper presents a graphics renderer which incorporates new partitioning methodologies of memory and work for efficient execution on a parallel computer. The task adaptive domain decomposition scheme is an image space method involving dynamic partitioning of rectangular pixel area tasks. We show that this method requires little overhead, allows coherence within a parallel context, handles worst case scenarios with reasonable speedup, executes efficiently, and requires minimal processor synchronization. The implementation analysis indicates that load imbalance is the major cause of performance degradation at the higher processor counts. Even so, on a variety of test scenes, an average rendering speedup of 79 was achieved utilizing 96 processors on the BBN TC2000 multiprocessor with processor efficiency ranging from 66% to 94%.
We present a parallel rendering algorithm targeted to MIMD distributed-memory message-passing architectures. For maximum performance, the algorithm exploits both object-level and image level parallelism. The behavior ...
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We present a parallel rendering algorithm targeted to MIMD distributed-memory message-passing architectures. For maximum performance, the algorithm exploits both object-level and image level parallelism. The behavior of the algorithm is examined both analytically and experimentally. The results show that the choice of message size has a significant impact on performance. Scalability to large numbers of processors is found to be limited primarily by communication overheads. An experimental implementation for the Intel iPSC/860 confirms the analytical results and demonstrates increasing performance from 1 to 128 processors across a wide range of scene complexities.
This paper describes a multiresolution approach to the visualization of surface data. The algorithms discussed allow the generation of arbitrary views of 3-dimensional surfaces. imageprocessing and texture mapping te...
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This paper describes a multiresolution approach to the visualization of surface data. The algorithms discussed allow the generation of arbitrary views of 3-dimensional surfaces. imageprocessing and texture mapping techniques are combined in a new 3-pass scanline algorithm to achieve smooth and continuous translations, rotations, and scale changes of large data sets. The implementation of the algorithms on a massively parallel SIMD video supercomputer, the Princeton Engine, allows the scenes to be generated interactively at video rates.
The ability to generate visual representations of data, and the ability to enhance data into a suitable form for the purpose of visual representation, form two key components in a scientific visualization system. By a...
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The ability to generate visual representations of data, and the ability to enhance data into a suitable form for the purpose of visual representation, form two key components in a scientific visualization system. By a visual representation we mean the ability to render the data, using visual cues, such that the important features are readily perceived by the user. By the ability to enhance data we mean the ability to apply transformations to the data so that salient features embedded in the data become discernible and quantifiable. The rendering of data, computergraphics, and the enhancement of data, imageprocessing, have emerged over the last twenty years into separate scientific disciplines. However, in scientific visualization and other applications of empirical data interpretation, we are increasingly confronted with the need to combine both data rendering and data transformation capabilities under one system framework. This paper describes the design issues and implementation of a program for visualizing and enhancing volume data on distributed memory architectures. Our design is motivated by the desire to interactively view, transform, and interpret volume data acquired using seismic imaging techniques. Experimental results derived from an implementation on the Connection Machine CM-5 are described.
An image understanding system (IUS) was developed for the processing of aerial photographs into cartographic images. The system makes use of both a bottom-up (data driven) and a top-down (object driven) analysis schem...
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An image understanding system (IUS) was developed for the processing of aerial photographs into cartographic images. The system makes use of both a bottom-up (data driven) and a top-down (object driven) analysis scheme. The bottom-up analysis makes use of a classical pattern recognition approach. This is done by implementing separate object recognition algorithms to obtain regions that will serve as the foci of attention (FOA). The modular composition of the system makes the extensibility of the software a major feature of the system. A scene description obtained from the bottom-up analysis is then analyzed by the top-down analysis engine. This scheme consists of a rule base, which describes the relationship between the objects in the scene. The top-down analysis is very important in that it reduces the false alarm rate (FAR) of the system. The IUS was implemented using a combination of serial computers and transputer networks. The transputer network implemented all the low-level imageprocessing functions, while the serial computers were left free to selectively apply the rules to the various reported objects. The IUS developed is demonstrated on a number of synthetic images to show the FAR in the case of an exactly determinable image. A true aerial photograph is also analyzed and the quality of the analysis is discussed in relation to existing systems.< >
This work examines the network performance of mesh-connected multicomputers applied to parallel volume rendering algorithms. This issue has not been addressed in papers describing particular parallel implementations, ...
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This work examines the network performance of mesh-connected multicomputers applied to parallel volume rendering algorithms. This issue has not been addressed in papers describing particular parallel implementations, but is pertinent to anyone designing or implementing parallel rendering algorithms. Parallel volume rendering algorithms fall into two main classes-image and object partitions. Communication requirements for algorithms in these classes are analyzed. Network performance for these algorithms is estimated by using an existing model of mesh network behavior. The performance estimates are verified by tests on the Touchstone Delta. The results indicate that, for a fixed screen size, the performance of 2D mesh networks scales very well then used with object partition algorithms-the time required for communication actually decreases as the data and system sizes increase. A Touchstone Delta implementation of an object partition algorithm is briefly described to illustrate the algorithm's low communication requirements.
In this paper we apply computer visualization techniques such as computer (3D) graphics, animation, and photorealistic color rendering to the simulation of dynamical processes and control systems in limited-resource e...
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The Conference materials contain 86 papers. Architecture, communications, computational linguistics, computer assisted instruction, data structures, databases, expert systems, fuzzy systems, graphics, GUI, and image p...
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ISBN:
(纸本)089791502X
The Conference materials contain 86 papers. Architecture, communications, computational linguistics, computer assisted instruction, data structures, databases, expert systems, fuzzy systems, graphics, GUI, and imageprocessing, information theory, intelligent systems, logic programming, machine learning and decision trees, and networking are the main topics covered.
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