***, a mature, UNIX (FOOTNOTE: UNIX is a trademark of Bell Laboratories)-based computer-aided design tool is described. Its structure, performance, and limitations are discussed together with its applications to the d...
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ISBN:
(纸本)9780818600265
***, a mature, UNIX (FOOTNOTE: UNIX is a trademark of Bell Laboratories)-based computer-aided design tool is described. Its structure, performance, and limitations are discussed together with its applications to the design of multiple processor hardware/software systems and VLSI.
Algorithms for adaptive, tapered quantization of color images are described. The research is motivated by the desire to display high-quality reproductions of color images with small frame buffers. It is demonstrated t...
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ISBN:
(纸本)9780897910767
Algorithms for adaptive, tapered quantization of color images are described. The research is motivated by the desire to display high-quality reproductions of color images with small frame buffers. It is demonstrated that many color images which would normally require a frame buffer having 15 bits per pixel can be quantized to 8 or fewer bits per pixel with little subjective degradation. In most cases, the resulting images look significantly better than those made with uniform *** color image quantization task is broken into four phases:1) Sampling the original image for color statistics2) Choosing a colormap based on the color statistics3) Mapping original colors to their nearest neighbors in the colormap4) Quantizing and redrawing the original image (with optional dither).Several algorithms for each of phases 2-4 are described, and images created by each given.
The appearance of raster-scan renderings of polyhedral approximations to curved surfaces can be enhanced greatly by shading them in a manner that varies smoothly aoross each polygon and which matches the correct shade...
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The system described uses frame buffers to provide digital analogues to the traditional processes of copying pencil drawings onto cels, painting them, and photographing them. The copying process is replaced by scannin...
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The generation of computer-shaded pictures requires that a program calculate intensities for each pixel. These intensities are then viewed on a monitor or transferred to film. It is desirable that the intensity values...
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To fill a connected area of a digital image is to change the color of all and only those pixels in the area. Fill algorithms for areas defined by sharp boundaries (e.g., a white area surrounded by a black curve) have ...
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This paper describes a method for recursively generating surfaces that approximate points lying-on a mesh of arbitrary topology. The method is presented as a generalization of a recursive bicubic B-spline patch subdiv...
This paper describes a method for recursively generating surfaces that approximate points lying-on a mesh of arbitrary topology. The method is presented as a generalization of a recursive bicubic B-spline patch subdivision algorithm. For rectangular control-point meshes, the method generates a standard B-spline surface. For non-rectangular meshes, it generates surfaces that are shown to reduce to a standard B-spline surface except at a small number of points, called extraordinary points. Therefore, everywhere except at these points the surface is continuous in tangent and curvature. At the extraordinary points, the pictures of the surface indicate that the surface is at least continuous in tangent, but no proof of continuity is given. A similar algorithm for biquadratic B-splines is also presented.
Digital control of color television monitors-in particular, via frame buffers-has added precise control of a large subset of human colorspace to the capabilities of computergraphics. This subset is the gamut of color...
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Shadowing has historically been used to increase the intelligibility of scenes in electron microscopy and aerial survey. Various methods have been published for the determination of shadows in computer synthesized sce...
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