摘要:

AbstractGiven a triangulation of a simplen‐gonPand two pointsaandbinsideP, a parallel algorithm is presented for determining the path betweenaandbwith the shortest Euclidean distance insideP.The algorithm has time complexityO(logn) on CREW PRAM withn/lognprocessors and thus is optimal in the sense that the time‐processor product agrees with Ω(n)—the lower bound of time complexity of the sequential algo

ISSN:0882-1666    

DOI:10.1002/scj.4690240101

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

年代:1993

数据来源: WILEY

摘要:

AbstractRange finding based on the projected light method is superior as a highly reliable means of obtaining dense three‐dimensional (3‐D) information about scenes. The use of this method, however, demands the development of an accurate calibration method.This paper proposes a method in which the optical system of the range finder is divided into the region surrounding the video camera and the region surrounding the light sources and rotational mirror, and calibration is by the method of least squares.The optical system is modeled in three dimensions and includes geometrical parameters not taken into account in earlier methods such as the torsion of the rotational axis of the mirror. Therefore, this method can be used with the camera and the light source located in any positions. In addition, only a calibration board with a reference pattern is used as a jig. Therefore, highly reliable results are obtained easily because no components other than those of the range finder intervene. This calibration method was applied to the multilight‐sources range finder developed by the authors to evaluate its accuracy and to verify its val

ISSN:0882-1666    

DOI:10.1002/scj.4690240102

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

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper presents a systematic discussion of the relationship between classical multivariate analysis and various data compression methods arising from the nonlinear mapping capability of multilayer neural networks. The important points of a geometrical interpretation for the case of four or more layers are set down using the well known autoassociation model and the pulse‐input/pattern‐output network (PPN) model proposed by the authors. Next, the previously unused four‐layer autoassociative model is investigated and its effectiveness is demonstrated. Then, the four‐layer autoassociative mapping model and the four‐layer PPN are compared using a method based on multivariate analysis. That is, it is shown that each method can be related in an approximate fashion to piecewise‐linear data compression models as well as to factor analysis models. Finally, to back up these studies, several example experiments are described; a five‐layer autoassociative mapping model is then examined, and the data compression capabilities of all three models

ISSN:0882-1666    

DOI:10.1002/scj.4690240103

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe visibility and spatial‐frequency components of a design are discussed as visual features of yarn‐dyed fabric design. The aim is to introduce objective visual features that can be used for classification in a database of yarn‐dyed fabric designs. First, the visually effective distances are measured for yarn‐dyed fabric design elements that have also been subjectively evaluated. The visually effective distance expresses the perceived differences between designs in terms of visibility at different viewing distances. Next, low‐pass filtered images of the yarn‐dyed fabric designs are correlated with the original images in terms of the measurement of the yarn‐dyed fabric's identification distance. The spatial frequency components are a visual feature of yarn‐dyed fabric design related to visibility and expressed by the visually effective distance. In addition, the cross‐correlations between the original image and low‐pass filtered images at successively greater low‐pass spatial frequency ranges are investigated. Then the characteristics of the reconstructed images are compared for different designs. The results confirm the effectiveness of using spatial‐frequency components as visual features. This method uses the visually effective distance to capture the subjective visual features of a yarn‐dyed fabric design. By virtue of its correspondence with objective spatial frequency components, this method provides feature evaluation capabilities and objectivity not

ISSN:0882-1666    

DOI:10.1002/scj.4690240104

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe studies on automatic extraction of contour lines have attracted interest in building a map information system as an automatic composition of input data. However, many attempts reported so far considered only the local connection relationship of contour lines and did not use global information contained in the whole topographic map. Therefore, they could not cope with extraction of contour lines having various cut forms.The method proposed in this paper can deal with the interconnection of contour lines which are disconnected within a region enclosed by a curved contour line and also the interconnection of contour lines disconnected in the same region, which were difficult in the existing methods. This was because its processing is based on global information of contour lines contained in a topographic map.As an example of the global information, the neighbor relationship built by a Voronoi diagram is used. The proposed method is divided into the following five steps: construction of a Voronoi diagram; identification of neighbor relationships of line segments; determination of height relation of line segments; extraction of contour lines; and extraction of pairs of endpoints to be interconnected. Then, while comparing and verifying them with the features of contour lines, disconnected contour lines are identified and extracted. This paper reports the procedures for processing and then considers the effect of the proposed method by experimental results.

ISSN:0882-1666    

DOI:10.1002/scj.4690240105

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

年代:1993

数据来源: WILEY

摘要:

AbstractIn order to weave fabric based on a yarn‐dyed fabric sample, the information on the thread arrangement of the fabric must be obtained. In this paper, we will discuss a method for automatically extracting the design elements of yarn‐dyed fabric that correspond to thread placement information with the objective of automating a part of the fabric design process of yarn‐dyed fabrics. In yarn‐dyed fabrics, the pattern on the fabric's surface is formed by the placement of different colored warp and weft threads. Consequently, the features of the warp and weft threads are always continuous in the warp and weft directions. As a result, we show that the bandpass image obtained by filtering the fabric's surface in the spatial frequency domain with a rectangular filter restricted to the warp direction or weft direction extracts information related to the thread placement in that direction. In addition, a simple clustering preprocessing method that detects the brightness is proposed. Then it is verified that the design elements of yarn‐dyed fabric can be extracted based on clustering where the color difference in the bandpass image is the distance. When extracting yarn‐dyed fabric elements, these methods are not concerned with individual regions of the pattern on the fabric's surface or features of each thread but are only concerned with the placement of the colored threads that define the design elements of the yarn‐dyed fabric. They are also provided with an efficiency not available in ea

ISSN:0882-1666    

DOI:10.1002/scj.4690240106

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

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper proposes a new dialogue model that controls utterance initiatives dynamically according to the dialogue context. It classifies utterance intentions into two categories: active and passive. Based on this model, the authors have developed a telephone operator system that can understand utterance intentions by word‐spotting, respond suitably, induce utterances, and anticipate subsequent utterances. The system was developed through simulations using text data of real dialogues between a human telephone operator and callers. The system could understand the intentions of callers' utterances (97 percent) and generate the same reply as a human operator (96 percent

ISSN:0882-1666    

DOI:10.1002/scj.4690240107

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

年代:1993

数据来源: WILEY

摘要:

AbstractProgressive coding of color‐quantized images, a technique that allows a progressive increase in the number of image colors transmitted, is described. In most color‐quantized image coding techniques, the representative colors are assigned indices that bear no logical relationship to them. In this paper, algorithms that assign indices logically related to the representative colors are presented and it is shown that bitplane transmission with the indices assigned in this manner allows progressive transmission of color‐quantized images. Two coding algorithms are proposed: runlength coding of independent bitplanes and predictive coding based on the correlation between neighboring pixels and on interbitplane correlation. The coding efficiencies of the two methods for various kinds of color‐quantized images are evaluated. Predictive coding can reduce entropy by 10 percent for photographic images and by 30 percent for computer graphic

ISSN:0882-1666    

DOI:10.1002/scj.4690240108

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

年代:1993

数据来源: WILEY