ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1987.tb00339.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractAn algorithm for the rotation of a raster image by an arbitrary angle is described. The image data structure is closely related to runlength code. The algorithm has been designed to exploit SIMD parallel architectures. It has been implemented on an ICL DAP on which non trivial images can be rotated in times very close to real time.

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1987.tb00340.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractFor economic raster graphics equipment capable of the display of high resolution dynamic pictures of 3‐D solids, 3‐D wire frames, and 2‐D wire frames ‐ in decreasing order of stringency, the design of the pixel memory system is a key issue, due to the high pixel writing speeds required. This paper discusses some new architectural possibilities for such a memory system.To give some idea of problem scale, present investigations indicate that pixel generation rates from an economic tiling circuit of up to 25 Mhz may be possible ‐ 40 ns per pixel. However, using contemporary dynamic RAM'S memory read‐modify‐write cycle, including computation on the data read from the memory (for example masking in the new pixel data or z‐depth‐buffer arithmetic) may take 400 ns i.e. a speed difference of about 10:l exists.The matching of these differing data rates demands a departure from traditional pixel memory architecture. Here a possible philosophy of approach is discussed together with the results of a simulation study. The proposed architecture is able to keep costs, bulk and power consumption down by using cheap, industry standard, high density memory components. Its use is additionally shown to be compatible with the generation of dynamic views of bolids using dep

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1987.tb00341.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractChaos theory involves the study of how complicated behaviour can arise in systems which are based on simple rules, and how minute changes in the input of a system can lead to large differences in the output. In this paper, bifurcation maps of the education Xt+1=αλXt[1+Xt]‐β, whereα=1 or α=e‐Xi, are presented, and they reveal a visually striking and intricate class of patterns ranging from stable points, to a bifurcating hierarchy of stable cycles, to apparently random fluctuations. The computer‐based system presented is special in its primary focus on the fast characterization of simple “chacs equation” data using an interactive graphics system with a variety of controll

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1987.tb00342.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractFor applications such as daylight visual pilot training simulators, the correct representation of aerial haze, mist and fog is of major importance in providing accurate depth cues and training in poor visibility conditions.We present a straightforward derivation of a formula to express this and then show various pictorial examples to illustrate its effectiveness.

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1987.tb00343.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractWhen regions are represented by their boundary, the number of points ((x, y) coordinate pairs) used to define the boundary can vary. Many more points are required to satisfactorily display a region at a detailed scale than at a broad scale. The area of a region is an important property in geographic and other applications, and it can easily be computed from the sequence of points. However, reducing or increasing the number of points in the sequence will usually alter the area. This paper considers how the region's area could be preserved by approximation algorithms, which reduce the number of points, and by enhancement algorithms, which increase the number of points.

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1987.tb00344.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA method is described for filling polygons according to the GKS Fill Area definition on terminals that provide only region‐filling capabilities. The advantages and disadvantages of using this algorithm in GKS device drivers are considere

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1987.tb00345.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1987.tb00346.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1987.tb00347.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1987.tb00348.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY