摘要:

AbstractDue to upscaling of digital systems, the development of efficient representations and manipulating algorithms of Boolean functions is becoming increasingly important. This paper considers the representation by the disjoint disjunctive form from representations of Boolean functions, and describes the properties, characteristics and manipulating algorithms. Conventionally used sharp operation and disjoint sharp operation are made more efficient for the algorithm which generates disjoint disjunctive forms. Moreover, a binary tree method is proposed as a method which generates disjoint disjunctive forms of positive and negative functions simultaneously. This binary tree method is also very powerful as a method to obtain negation of logical formulas, and is five to ten times faster than the conventional one using disjoint sharp operation in a case of 10‐variable function. Also, for the problem of number of product terms, which is generally regarded as a shortcoming of the disjoint disjunctive form, we conduct further studies by considering the simplest disjoint disjunctive form. Moreover, we show a unique negation algorithm as an example of using the properties of the disjoint disjunctive form more aggressivel

ISSN:0882-1666    

DOI:10.1002/scj.4690181101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractStereovision is the simplest method for acquiring three‐dimensional information. A problem then is that sometimes it is difficult to establish a correspondence between the left and right images in such cases as: (1) multiple correspondence; (2) occlusion; (3) positional reversals; and (4) horizontal edge. This paper proposes a method to determine the three‐dimensional structure of the scene from the sequences of images obtained by moving camera. First, a two‐dimensional image is constructed from the sequence of images in which the apparent locus of motion is represented as a segment. The corresponding problem here is simplified as the detection of segments on the synthetic image. By examining the relations among the detected segments, the occlusions can be detected, and the correspondence can be established where positional reversals occur. By moving the camera not only in one direction, but also in orthogonal directions, the unique correspondence can be established, independently of the direction of the edge. An input system was constructed which can accept a large number of stereo image sequences with a high speed, and a complex three‐dimensional structure of the scene was actually r

ISSN:0882-1666    

DOI:10.1002/scj.4690181102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThis paper assumes the situation where the existing drawing is to be re‐utilized after a partial modification, and discusses a system, which can easily improve or modify with a high speed the characters and figures at the image level. First, the input drawing is segmented automatically and described in terms of the composing elements of the drawing, such as the character, the segment, the connecting point and the frame surrounding characters. Since the description is the structure description of the drawing, and no particular drawing is assumed, the method can be applied to various kinds of drawings. Then based on the description, the desired transformation is planned. Finally, based on the transformed description, the image is transformed. The proposed system features the following: (1) A versatile structure description is available; (2) two‐stage transformation, i.e., the transformation at the description level and the transformation at the image level, is employed. This two‐stage transformation makes possible the global transformation of the drawings, such that the frame surrounding the characters can be transformed according to the change of the character string length; and (3) the real‐time image processing, such as extraction of the composing elements and image generation is realized by the data‐flow

ISSN:0882-1666    

DOI:10.1002/scj.4690181103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractIn general, the shapes of mountains, shore lines, clouds and other natural features are irregular and difficult to define. Furthermore, the conventional (noncompressed) method of storing 3‐dimensional (3D) data of such natural features requires a very large storage space. There is a need to automatically extract key features of natural figures for data compression and accurate reconstruction of the figures.This paper proposes a reconstruction method for 3D mountainous shapes from feature points of contour lines. First, a method for extracting a model of mountainous shape will be described. Then a reconstruction method based on the model will be discussed. The proposed method is applicable for the generation of a database of background scene for computer animatio

ISSN:0882-1666    

DOI:10.1002/scj.4690181104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractRay‐tracing is a very powerful method of generating realistic synthetic images. However, the conventional ray‐tracing technique requires complicated computation for each pixel in the image and a long processing time. Advantage is taken of the similarity among neighboring pixels, and ray‐tracing is executed only to certain selected pixels while using interpolation to determine the value of other pixels. A pixel‐selected ray‐tracing algorithm is proposed. This paper presents first a description of the pixel‐selected ray‐tracing concept/algorithm. Then methods of determining whether a pixel value should be calculated by ray‐tracing or by interpolation are discussed. Experiments were conducted to compare the proposed method with the standard ray‐tracing method. Experimental results indicated that the proposed method required only 20 to 63 percent of the computation time of the standard method, while rendering a comparable level

ISSN:0882-1666    

DOI:10.1002/scj.4690181105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractImproving the reliability of information transmission in communications networks and computer networks economically and efficiently is an important subject. A communications network (computer network) is represented by a graph whose nodes and edges correspond to switching offices (computers) and links, respectively, and communication between two nodes is made through a path in a graph. Routing is defined as the determination of a communication path between two nodes in a network. The diameter of the surviving route graph, where two nonfaulty nodes are connected by an edge if there are no faults on the route between them, could be one of the fault‐tolerant measures for a routing. In this paper, for the routing of any (k+ 1)‐node connected graphGdefined by Dolev et al., we discuss the upper and lower bounds of the diameter of the surviving route graph for any fault. We can also construct a routing for (k+ 1)‐edge connected graphGsuch that the diameter of the surviving route graph is constant for any edge f

ISSN:0882-1666    

DOI:10.1002/scj.4690181106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractIn a previous paper the authors proposed a pass transistor network composed of PMOS and NMOS transistors with different threshold voltages, which were realized by a multilevel ion‐implant technique. As a result, any quaternary logic system could be implemented. In the quaternary CMOS make‐break operator circuit, which is the basic cell of the network, the steady‐state current is essentially zero and therefore micro‐power quaternary combinational circuits can be implemented.In this paper, a micropower quaternary D‐latch circuit is designed using quaternary CMOS make‐break operator circuits. Then using the D‐latch circuit as a unit, a quaternary master‐slave flip‐flop and an up‐down T‐flip‐flop circuit are designed. Computer simulation for these circuits with SPICE‐2 confirmed their correct operation with low power dissipation. The power dissipation during the transient increases in proportion to the operating frequency. Also, a quaternary maximal‐length sequence generator is

ISSN:0882-1666    

DOI:10.1002/scj.4690181107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractResearches on the coding and filing of such binary image data as versatile links of drawings or topographical maps have been conducted widely [5 ‐ 19]. The reasons for this activity are tied to the advances made in techniques for processing topographical information [1, 2], automatic drawing reading [3], and image datebases [4].These techniques are aimed at high‐density compressions in image coding, but especially at greater flexibility in figure reconstruction. Additionally, some of these techniques have found practical application in such commercial areas as image databases of topographical maps or drawings or visual communications by facsimile.However, these techniques are difficult when using coding image data to obtain such flexible image processings as skeletonization or border following of figures, the detection of width or branch points of line figures, or structural analysis of line or surface drawings. As a result, this paper proposes an MSM figure‐file system which codes a binary image via the MSM method and files it as a figure, and retrieves figure data from the

ISSN:0882-1666    

DOI:10.1002/scj.4690181108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe use of a pyramid structure has been known to reduce the time required for image registration. Discussions on a required search range without backtracking, however, have been mostly experimental. In Tanimoto's example the range of 2 × 2 was insufficient, and he suggested the use of a 4 × 4 range, namely, the choice of the best of 16. However, his discussion was not complete. This paper presents a theory based on geometric rather than analog correspondence between levels. First, the upper left corner candidate and best estimate positions in template images of each level, respectively, are defined. Then a required search range is considered. It is shown that even a range of 4 × 4 is insufficient. The discussion is extended to cover the case of analog correspondence. Results obtained are applied to the registration of dynamic images using SSDA (Sequential Similarity Detection Algorithm). A substantial reduction of time is achieved by the use of a pyramid structure in comparison with a conventional method, which uses only the lowest lev

ISSN:0882-1666    

DOI:10.1002/scj.4690181109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractConventional gray‐scaled image thresholding consists in finding the threshold according to the bimodality of a gray‐level histogram of an input image. However, few discussions have been made on the thresholding problem from the viewpoint of the optimality of the results. As far as image perception (human perception) is concerned, we naturally see the image as simply as possible. Taking such situation into account, the threshold for image thresholding operation should be determined on the same basis. This paper presents a principle in which the optimality of the thresholding process is evaluated according to the complexity change of the binarized picture against the change of the threshold value. Specifically, we show that the complexity curves are categorized into either unimodal or multimodal. For the multimodal case, we show that a good thresholding can be obtained by choosing a minimal point on the curve as the threshold. For a unimodal case we introduce another strategy which depends on the local multimodality of the complexity cu

ISSN:0882-1666    

DOI:10.1002/scj.4690181110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY