bluuebunny/crossref_metadata_2025 huggingface dataset:
A prolog machine based on vlsi algorithms
Authors: Shobatake Yasuro , Aiso Hideo
Published: July 2007

This paper proposes a Prolog direct executer called PMV‐2. To alleviate the von Neumann bottleneck, PMV‐2 is provided with a number of processing elements, each of which stores a term symbol. Using the processing elements, the operations for terms can be executed in parallel. To simplify the algorithm for mapping the tree‐structured data onto processing elements, data are represented by a format called symbol‐line expression. Tree‐structured data with this expression are mapped onto an array which has straight‐line arrangement for processing elements. The configuration of the tree‐structured data on the processing element array can be modified using the methods called Partial Global Communication and Partial Shift. To implement a large number of processing elements, PMV‐2 is constructed based on the VLSI algorithms. A performance evaluation has been made, revealing that the processing speed of approximately 450 kLips is obtained by PMV‐2, which is nearly the same as that of a presently available high‐speed Prolog system with a compiler.
Word and monosyllable recognition using lifters on two‐dimensional cepstrum
Authors: Ariki Yasuo , Nagata Masaaki , Sakai Toshiyuki
Published: July 2007

This paper examines experimentally the dynamical features which are useful in the recognition of words and monosyllables. By the two‐dimensional cepstrum analysis of the speech waveform, the two‐dimensional dynamical features are obtained for the time and frequency variations. First, the usefulness of the dynamic features for the time variation in the recognition is examined. It is shown as the result that the spectral envelope and its global variation are important in the recognition. It is shown especially that the recognition rate for the monosyllable is improved by providing a high‐emphasis lifter for the dynamic feature, and the noise immunity is improved by providing a low‐pass filter. The reason is that the high‐emphasis lifter on the two‐dimensional cepstrum emphasizes the formant in a two‐dimensional way on the time‐frequency plane, while the low‐pass lifter corresponds to the two‐dimensional smoothing on the time‐frequency plane. Finally, the lifting on the two‐dimensional cepstrum is compared experimentally with the usual one‐dimensional cepstrum. Hence, it is seen that the two‐dimensional cepstrum is better from the viewpoints of the monosyllable recognition and the recognition performance in a noisy environment.
A continuous speech recognition system with a powerful environment for the knowledge‐base construction: SPREX II
Authors: Tsujino Katsuhiko , Sakurai Toru , Nomura Yasuo , Chigusa Shunsuke , Mizoguchi Riichiro , Kakusho Osamu
Published: July 2007

SPREX II is a continuous speech recognition system which uses the knowledge of experts able to recognize speech by inspecting trajectories of its feature parameters. This system has a powerful environment which supports the construction of its knowledge base, and it proposes a new paradigm which integrates speech recognition and knowledge engineering. This paper describes the necessity and the design philosophies of the support environment of this system, the outline and the effectiveness of the environment which has been implemented based on them, and its current performance.
Anti‐aliasing algorithm using silhouette mask method
Authors: Nakajima Masayuki , Agui Takeshi , Uemura Ken , Noguchi Norimasa
Published: July 2007

In the operation of cutting out a part of a digital photoimage, and that of patching another photoimage with it, the smoothness of the entire synthesized image is often spoiled by jagged edges around the cutout image, which is caused by a finite number of pixels of the images. Although many methods have been proposed to solve this problem, they require a high cost for computer processing. This paper proposes the “silhouette method” in which a silhouette of an object obtained by a backlight illumination is used. It is demonstrated that the method solves the problem.
A method of extracting a kinematically characteristic point from the 3‐dimensional motion of a rigid body
Authors: Hayashi Toyohiko , Ogawa Hidemitsu , Iijima Taizo
Published: July 2007

This paper describes a problem of estimating a kinematically characteristic point of a rigid body moving in a three‐dimensional (3‐D) space. We call this point the 1‐D characteristic point and denote it by P1. The point P1 is characterized by its motion range which forms a curved line. Hence, if the rigid body moves periodically, we can specify P1 as a point which moves reciprocally. This paper proposes a method of estimating P1. By projecting the orbit of a point onto three planes orthogonal with each other, we reduce this estimation problem to that of solving a set of quadratic equations, and we then provide one of its solutions. In addition, we clarify how measurement errors of the motion propagate to an estimation of P1.
Consideration on automatic defect detection algorithm for stamped patterns in electronic parts
Authors: Shima Yoshihiro , Kashioka Seiji , Yasue Toshikazu
Published: July 2007

Central Research Laboratory, Hitachi, Ltd., Kokubunji, Japan 185

One of the most important problems in the quality inspection of printed characters, monitoring of printing devices, and evaluation of character recognition devices, is the automatic quality evaluation of the printed character for the character patterns stamped on the object surface or on a paper sheet. This paper considers the characters stamped on the surface of an electronic part such as transistor and integrated circuit, and reports on the result of comparison of defect detection methods for the automatic outlook inspection. First, properties of the stamped pattern, which is the object of inspection, are described, indicating the problems in detecting the defects such as lack, smudge and blur. Then three realizations of the defect detection are proposed: (1) a weighted matching is made with the reference pattern; (2) the reference pattern is divided spatially, and the matching is tried for the divided patterns; and (3) essential points are extracted from the core and background portions of the character, and a local pattern matching is tried. Finally, those defect detection methods are implemented on a computer, and an experiment was made for the actual stamped patterns on the transistor. The results for those methods are compared, and their effectiveness and the range of applications are indicated.
The basic construction of MUSAS: Musical arrangement system. Acquisition of 4‐part melody in consideration of the chord choice
Authors: Mikami Tatsuya , Inoue Kazuo
Published: July 2007

Construction of an expert system is frequently studied in knowledge engineering. Hence, in constructing sophisticated expert systems, analysis of the human thinking process and the human memory mechanism is essential. This is because humans in the real world have problem‐solving abilities.

This paper presents the expert system “MUSAS” (musical arrangement system) for musical arrangement, to study the mechanisms and processes in human problem solving. Since musical arrangements have both a theoretical and emotional side, the former being text knowledge and the latter being heuristic, text knowledge is used to propose chords.

Finally, the basic construction of MUSAS is given, and the method of application of a knowledge‐based system for musical arrangement along with the system process and experimental results are presented.
Extraction and recognition of partial shapes of machine parts on an assembly line
Authors: Hirata Tatsuya , Ito Hidetoshi , Ishii Naohiro
Published: July 2007

Various studies have been made on the storage and recognition problem for the two‐dimensional shape. An example is the Fourier descriptor which has a versatility in the description and recognition of the closed curve, being robust against expansion‐contraction or rotation. The usefulness of the method has been demonstrated from various standpoints. However, it is not a powerful tool for the partial shape, and little study has been done on that aspect since the contour representing a partial shape is an open curve. A method to represent the feature of the partial shape is the feature vector. In this method, the feature of the partial shape is described by a series of feature points. However, it is not for the description of a closed curve. In the method proposed in this paper: the contour is extracted from the partial image; the condition is stated for the projection shape to be detected from the contour line; and based on the derived condition, the projection shape is extracted. Then new methods for sampling and segmentation are proposed for recognizing the extracted projection shape.

In the recognition of the contour line to be extracted in this paper, a new and simple method is proposed based on the concept of the feature vector. By the proposed method, the open curve of the partial shape is represented, and the recognition is performed by examining the matching to the model. It is shown that the proposed method can well recognize and process the partial shape of the machine part on an assembly line.
An efficient distributed algorithm for constructing a breadth‐first search tree
Authors: Park Jungho , Tokura Nobuki , Masuzawa Toshimitsu , Hagihara Ken'Ichi
Published: July 2007

When information data to solve a problem are distributed over processors on a network, the algorithm which solves the problem by exchanging the information data is called a distributed algorithm. A large number of distributed algorithms has been proposed for various problems, but the proof for the validity is shown only for a few of them. This paper considers an asynchronous network and proposes a distributed algorithm which constructs the breadth‐first search tree with the specified processor as the root. The validity of the algorithm is shown. In general, the efficiency of the distributed algorithm is evaluated by the total number of messages exchanged during execution (message complexity), and the execution time (ideal‐time complexity), assuming the communication delay as a unit time.

In the algorithm proposed in this paper, the message complexity and the ideal‐time complexity are both O(n·√e where n is the number of processors and e is the number of links in the network. Especially, when e = Q((n/logn)2), the proposed algorithm is better than other known algorithms in terms of the message complexity.
Maximum lower bound on embedding areas of general graphs
Authors: Wada Koichi , Kawaguchi Kimio , Fujishima Hideyuki
Published: July 2007

In designing VLSI, the problem of how large the chip area will be is of considerable interest. Thus, the primary objective in investigating this problem is to consider formally processing elements and wires of a circuit to be vertices and edges of an undirected graph, and then clarify the area sufficient or necessary to embed this graph onto a rectangular grid graph according to a certain embedding method (this is called an embedding model). In this paper, vertices correspond to a rectangular graph such that [length of long side]/[length of short side] ≤ constant. It is shown that under an embedding model, which forbids images of edges (wires) from passing through the inside of the vertex region of the rectangle, the maximum lower bound of the area corresponding to a general n‐vertex d‐degree graph is ωd2n2. As the result, it is seen that the conventionally known upper bound O(d2n2) cannot be improved any further as long as all n‐vertex d‐degree graphs are considered.
Learning and discrimination of perceptual vowel distribution by a neural net model
Authors: Ohtomo Teruhiko , Takahashi Katsunori , Hara Ken‐Ichi
Published: July 2007

The phoneme perception distribution is determined by the psychoacoustic experiment for the synthesized speech. The purpose of this paper is to attempt a learning of this distribution by a neural net model with three‐layered structure. The following observations are made as the result of learning by a neural net model. The weight of the connection from the input layer to the hidden layer has the function to extract the particular frequency range, and the weight from the hidden layer to the output layer has the function to integrate the unit output in the hidden layer, to extract the particular phoneme. It is shown by integrating those results of analysis that the weight sequence from the input layer to the output layer has the function as a filter to extract only the particular phoneme.

Finally, the discrimination power is examined when a part of the connections among units is destroyed or the connection strength of some units is varied. It is shown that the discriminating power is not affected by the change of the weight of the connection between the input layer and the hidden layer, with the effect on the output unit being less than several percent. This result indicates that the neural net model has a feature of distributed memory.
A point pattern matching algorithm
Authors: Umeyama Shinji
Published: July 2007

This paper presents an algorithm for finding a matching between two point patterns given in m‐dimensional Euclidean space. The point pattern matching algorithm here is formulated as a tree search procedure, and the search tree is pruned by a specified tolerance measure for matching. The proposed method is based on the locations of points and is invariant to rotation, translation, and scaling. Moreover, to guide the search, it is easy to use global geometric constraints, such as rotation or scaling parameters.
Approximate performance evaluation of parallel processing systems using average concurrency
Authors: Jittawiriyanukoon Chanintorn , Nakanishi Hikaru , Tezuka Yoshikazu , Watanabe Takashi
Published: July 2007

For the performance evaluation of the parallel processing system of a set of concurrent programs (program group), several methods have been proposed such as decomposition approximation, which consider the program group with fixed concurrency. On the other hand, this paper proposes an innovative approximation method considering a more general program group in which the concurrency changes for each program or with time.

First, the average concurrency is determined which is the average of the concurrency of the program group. Then the decomposition approximation is applied to two integers giving bounds to the average concurrency, and the characteristic parameters such as throughput are determined. The two obtained sets of characteristic parameters are averaged with weight, providing the evaluation for the given system. By this method, a system which cannot be handled by the decomposition approximation can now be evaluated. The method has an advantage that the computation can be performed with a very small number of state spaces. Because of this property, the parallel processing system can be evaluated with a high speed and a small memory.

Finally, the results obtained by the proposed method and the results of discrete event simulation technique by a supercomputer are compared for several models, and it is indicated that a sufficient accuracy is realized.
A polynomial time validation method for channel boundedness of communication protocols (2 processes)
Authors: Suganuma Tomohisa , Kurosawa Kaoru , Yongmao Ni
Published: July 2007

The number of messages on a communication channel must be bounded. On the other hand, it is known to be undecidable whether or not the given communication protocol satisfies the condition. The communication protocol is modeled in most cases in the form of a communication between two finite‐state machines. Yu and Gouda have shown that if the message is of a single type in such a modeled protocol, the boundedness of the channel is decidable. However, it is not known whether or not this problem can be answered in a polynomial time. This paper presents a method of validation for the boundedness of the channel, where the validation time is a cubic order of the number of states. The result is important in the sense that if the channel is bounded in the communication protocol where all messages are transformed into a single type, the channel is also bounded in the original communication protocol.
An extended syllogistic system with verbs and proper nouns, and its completeness proof
Authors: Noritaka  , Kenichi  , Shigenori
Published: July 2007

Syllogism (Aristotle's categorical syllogism) is a logic scheme which can describe derivation relations of propositions stating relations among quantified “terms” (corresponding to common nouns). In this system, relations of the terms are treated directly, while in predicate logic they are decomposed into relations among individual objects. Therefore, syllogism has several advantages in describing the meanings of a natural language in a formal framework of a logic system. However, the expressive ability of classical syllogism is poor in that it can treat only a proposition corresponding to a sentence whose predicate is “be” + noun (i.e., “is‐a” sentence) and cannot treat a sentence with a general verb (or “be” + adjective) in its predicate (we call it a verb sentence). Furthermore, terms in classical syllogism are only those corresponding to common nouns, and thus proper nouns, which cannot be quantified, are excluded.
Behavioral Specification of Nondeterministic State Machines by Event Sequence Sets
Authors: Member Nagatsugu Yamanouchi
Published: July 2007

A method for extending the behavioral specification and verification of state machine networks by event sequences to non‐deterministic behavior is presented. The nondeterministic behavior is described by a function between sets of event sequences instead of between sequences. Both the module composition and loop connection operations are modeled by the function composition and the least fixed point, respectively, just as in the deterministic case. Two application examples are described. The example with alternating bit protocol via unreliable communication lines indicates that the method detects the possibility of message stack just as the verification by temporal logic does, while the proof steps of our method are shorter. The second example discusses the cause of the Brock‐Ackerman anomaly and a condition to avoid it.
Determination Method to Identify Effective Software Testing Areas: Detection of Software Defects Related to External Specification Changes
Authors: Kaneko Takeshi , Members Takeshi Nakajo
Published: July 2007

A tremendous amount of time is spent in testing in the development of software products. Most of the test methods at present, however, are inefficient since the characters of the software defects are not well considered. From such a viewpoint, an efficient software test should be executed, taking into consideration the characteristics of the software defects. Examining the actual defects, it is found that a large number of defects exist due to specification changes. On the other hand, no testing method has been developed aiming at the detection defects of this type. Thus, it is necessary to develop a method of testing that can effectively detect the incorrect modifications accompanying the specification changes. As a result of detailed examinations of the actually produced defects due to specification changes, a concept called restriction element is introduced, and it is shown that the defects can adequately be described as the incorrect elimination/addition of that element. A theorem is shown which indicates when an incorrect elimination/addition of restriction element is produced, which of the input areas contain the data producing a behavior different from the specification. A method of determining test input areas is proposed based on that theorem. The test, based on the proposed determination of the test input area, can securely and effectively detect the incorrect modification accompanying the change of external specifications.
Design of a fault‐tolerant arithmetic circuit based on distributed coding and its evaluation
Authors: Member Takeshi Kasuga , Kameyama Michitaka , Higuchi Tatsuo
Published: July 2007

The robust fault tolerance is a property that even if an error occurs in the arithmetic circuit, the result of operation does not differ much from the correct value. Such a property will become more important in the construction of a highly safe system. In the present digital system, the weighted code is used in representing numerical information. In this scheme, when an error occurs in a bit with a large weight, the result of operation will differ greatly from the correct value, affecting the safety of the whole system. from such a viewpoint, this paper proposes the distributed coding, i.e., the arithmetic circuit based on the number system with uniform weight 1. It is shown theoretically together with the result of execution that such a circuit is much better than the arithmetic circuit based on the weighted traditional code, in terms of the robust fault tolerance, i.e. the safety.
Effectiveness of making internal representations redundant in neural networks for solving optimization problems
Authors: Member Itsuo Kumazawa
Published: July 2007

In solving an optimization problem using a neural network, the representation schema which codes the solutions of the problem onto the configurations of the states of neurons must first be defined. The coding schema is called an internal representation of the problem and the representation is considered redundant when the schema uses only those configurations which are separate from each other at long Hamming distances. Under some conditions, the redundant representation is shown to be very effective in eliminating the local minima problem, which is one of the most crucial problems in the application of neural networks to optimization problems. In the redundant representation, a stochastic property which appears asymptotically when increasing the number of neurons plays an important role when the solution is read reliably from the random and erroneous states of networks. In these networks, a probabilistic states transition schema is introduced so that the network can escape from the local minima. By introducing the redundancy, the randomly changing configuration can keep the order in which the solution can be read while sufficiently preserving the randomness to escape from the local minima. The result in this paper shows a novel optimization capability of the network which has a highly parallel and nondeterministic computation schema as described in the foregoing.
Segmentation and recognition of color‐dot characters with complex background
Authors: Yamada Hiromitsu , Yamamoto Kazuhiko
Published: July 2007

As an example of character recognition from overlapping data, this paper presents the recognition of Ishihara's color vision test chart, where a color character composed of color dots is embedded in a background composed of color dots. The histogram is constructed on the normalized tri‐color coordinate, and the representative color is determined as the maximal point of the histogram. The distance pattern is constructed based on the representative colors, and the shape skeleton is extracted by the DP matching between the distance pattern and the category dictionary. The line width and the final position are determined by an examination based on the variance criterion. It is shown that the DP matching is useful in the hypothesis testing for the object, where both the background and the character are multivalued color textures.
Performance Evaluation of Multilayered Protocol
Authors: Saito Tadao , Shirahata Atsushi
Published: July 2007

The protocol on the OSI basic reference model is standardized as a hierarchical model composed of seven layers. Protocols of some layers are applied link‐by‐link and protocols of other layers are applied end‐to‐end. The transmission timing of the protocol data unit of each layer depends on the network configuration as well as the protocol parameters. Consequently, there is a possibility that the throughput of the network is deteriorated unless the protocol parameters of each layer are determined adequately according to the network configuration. This paper considers the network containing the transport layer, network layer and data link layer of OSI protocol, and the performance is evaluated from the viewpoint of transmission efficiency, which is a measure in evaluating the network throughput. The relation between the protocol parameters and the throughput is derived. As the protocol parameters, the transmission speed, transmission delay, data unit length, window size, number of intermediate nodes, bit error rate and protocol processing time are considered. The protocol parameters can be determined based on the presented results.
Improved dithering methods for color quantized images
Authors: Watanabe Takashi
Published: July 2007

A color image produced from a continuously toned color image by using a smaller number of colors (e.g., 256) is called a “color quantized image.” Previously, the author and colleagues proposed a high‐speed color quantization method which produces an image of almost the same quality as the original. However, if colors in an image change gradually (such as an image produced by computer graphics), false contouring occurs and deteriorates the image quality. To solve the problem, this paper proposes four new methods, three of which are shown by experiments to have excellent dithering effects which overcome the weakness of the conventional error‐diffusion method and are practical.
A new character segmentation method for recognition of stamped alphanumerals on automobile chassis
Authors: Nakano Tomoaki , Yamamoto Shin
Published: July 2007

In the production line for the automobile, the recognition of the frame number, stamped on the automobile chassis for production instruction or management, is indispensable. One problem of the alphanumerals stamped on the chassis is that the width and the depth of the stamped groove vary for each stamped character and position due to the variation of the stamping pressure of the stamping machine. Another problem is that a slow undulation is produced at an unspecified position of the stamped surface due to the strain near the stamped groove. When the stamped characters are imaged and binarized, adjacent characters connect and frequently one character separates into several pieces. Such connections and separations make it difficult to segment accurately the individual character regions. This paper considers the accurate segmentation of such stamped characters. The proposed method examines the extent of variation of gray level in each pixel‐line without binarizing the gray‐level image and classifies the characters by the differences of the variation. The result of experiment by the proposed method is as follows. For 11,000 stamped characters composed of 36 alphanumerals and two symbols, the rate of character extraction is 99.9 percent. For 1500 characters composed of 15 alpha‐numerals after character segmentation, the recognition rate is 99.5 percent without rejection. These recognition rates are higher than those in the conventional method, demonstrating the effectiveness of the proposed method.
Improvements of nmr image quality using adaptive nonlinear filter
Authors: Itagaki Hidenobu
Published: July 2007

It is important to improve the quality of NMR images, since this significantly affects medical diagnosis. This paper describes an image processing to improve NMR images. It is important for such improvements to utilize the image property of interest. This paper shows that noises in an NMR image have a Rayleigh distribution (e. g., they have a spike shape). To reduce this type of noise, this paper proposes an adaptive nonlinear digital filter which is adaptive to isolated status of a noise based on its standard‐deviation distribution. This standard deviation of the noises is another feature of the NMR image. The usefulness of the proposed filter is confirmed by comparing this with conventional filters. Significant improvements of image quality using this filter are demonstrated by applying it to an NMR image of a human head.
Methods of Selecting Parameters in Discriminant Analysis of Letter‐Cognition Related Visual‐Evoked Potentials
Authors: Yanai Tatsumi , Ono Kanoh , Itoh Susumu , Shu Eimei , Member Toshio Utsunomiya, Honorary
Published: July 2007

This paper proposes a method for selecting the feature parameters in the statistical discriminant analysis of the human letter‐cognition related evoked potential. The paper aims at the quantitative interpretation of the frequency components, latency and the cortex area of the evoked potentials accompanied by the human letter‐cognition process. Models are constructed at three levels considering the awareness of the subjects: (1) classification, (2) retrieval and matching, and (3) attribute recall. To examine the validity of the models, the number of parameters is increased along the time axis to determine which addition of parameters resulted in a remarkable contribution to the discrimination. By examining the recognition rate, the necessary frequency components are determined. From the viewpoint of improving the recognition rate, methods of selecting the parameters are compared to examine the nature of the parameters selected in the method with the highest recognition rate. As a result, it is seen that the latencies in the models at three levels for the letter‐cognition process are approximately 190, 250 to 350, and 730 ms, respectively; and the necessary frequency components extend to at least 60 Hz. By comparing the selection method for the parameters, the recognition rate reached above 95 percent at the highest. It is seen that the tendency of the selected parameters is the same as those of the models.
A fast algorithm for determining the insolation at the surface of the earth
Authors: Chiba Norishige , Yaegashi Kazuhito
Published: July 2007

A digital terrain model is a two‐dimensional array which contains elevations of the surface of the Earth. The elevation data are sampled at regular mesh points of appropriate resolution. This paper presents a fast algorithm for determining the isolation on the surface patches at each mesh point.

In the case where it can be assumed that it is sufficient to consider only direct rays from a single light source, the insolation at a point in time can easily be computed by employing a hidden surface elimination algorithm having the viewpoint at the light source. In general, however, at the point where the insolation must be determined considering scattered light integrated over an interested period, it is necessary to execute the hidden surface eliminations applied in every direction from the celestial sphere.

The algorithm herein has a time complexity of O m n2. This is smaller than those of O(m n2) of naive algorithms employing hidden surface eliminations applied in m directions, where the resolution of digital terrain is n × n. An implemented program shows that our algorithm is 33 times faster than the naive one for m≒;8 100 and 67 times for m≒32,400.
Restoration of images with missing pixels
Authors: Takahashi Kenichi , Ishii Naohiro
Published: July 2007

At times a portion of the picture elements (pixels) in an image is missing altogether due to a problem with the imaging device or an error in the transmission path, or an empty portion is present due to the fact that a portion of a landscape picture is moved in designing the landscape. In this paper we propose a processing method for restoring the image so that it looks natural in these cases. This scheme consists of the two steps of edge linking in the missing part and subsequent gray level estimation.

In the edge linking step, edges which are disconnected in the missing portion are linked, based on an evaluation function representing the validity of edge connectivity. In the gray level estimation step, we interpolate so that there is a pseudo silhouette between each of the missing pixels in each region which is separated by linked edges. Furthermore, in order to obtain a natural feeling in the restored portion, we study the use of an artificial buildup of Gaussian noise. In order to validate the effectiveness of our scheme, we have implemented computer simulations. In the simulations we used a portrait included in SIDBA and made five missing parts, and then tried out the proposed restoration process.
Relation between visual effects and gain of motion parallax
Authors: Hoshino Haruo , Hiruma Nobuyuki , Yamada Mitsuho , Fukuda Tadahiko
Published: July 2007

This paper examines visual effects of motion parallax (MP) which is an important element of depth perception. A display technology was developed which does not cause a delay of motion parallax to a viewer watching an image with a motion parallax related to viewpoint position. Using this apparatus, a method of control was examined which affects a viewer's emotion by changing the magnitude of the motion parallax. A term “gain of motion parallax Gm” which represents the magnitude of a motion parallax is defined. An assumption is made that a visual effect induced by an image with a motion parallax depends on Gm. To prove this assumption, the undetectable threshold of a delay of a motion parallax was found to be approximately 60 ms. It was confirmed that the motion‐parallax display apparatus developed has shorter delay than this value. By changing the value of Gm, subjective evaluations were carried out for three evaluation items: “sensation of depth,” “reality” and “linkage.” The results show that these three items form functions of Gm which are “saturation shape,” “dull peak shape” and “sharp peak shape,” respectively.
Extraction of the symmetric pairs of contour points as well as the medial axis from a planar figure by a method based on plane division
Authors: Fukushima Shigehiro , Okumura Takeshi
Published: July 2007

Often, object figures must be analyzed on the basis of weak‐sense symmetry when a computer recognizes and processes natural and unartificial pattern information included in images and scenes. By weak‐sense symmetry is meant that found by human beings in the shapes of winding tubes, roads, ancient mounds, and lakes. Methods of extracting the symmetric axis for such symmetry have been proposed. However, it has not been clear how to extract for a complex figure, not only the symmetric axis but also pairs of points in symmetric relation in a consistent manner by a computer.

The authors have found that a rigid concept can be a basis of a solution to this problem. This concept is plane division well known in computational geometry, the Voronoi diagram and the Delaunay triangulation. They have found also a new and stable method of extraction on the basis of this concept to obtain a simply connected figure. Plane division is applied to the dot pattern, the set of the vertices (which are called dots) of a polygon approximating the figure. By using the duality between the divisions, the skeletal line of the figure can be extracted from the Voronoi diagram. Further, the axis of global symmetry and the medial line can also be extracted. At this stage, those Delaunay edges dual to the Voronoi edges of the symmetric axis represent without change the pairs of dots in symmetric relation about this axis. The purpose of this paper is to present this method.
An algorithm for removing sections of bone from x‐ray ct models
Authors: Suto Yasuzo , Furuhata Kentaro
Published: July 2007

With the current rapid advances in computer graphics and CAD/CAM technology, considerable research is being done on the display of three‐dimensional images, and this includes the medical field. One typical medical application is simulated surgery, of which bone cutting is an essential part. Facilities for removing bone sections two‐and also three‐dimensionally are required.

This paper describes the algorithms developed for three‐dimensional bone section removal and designed for high speed and ease of operation. An actual plastic surgery case to which our algorithms were applied is presented. The three‐dimensional images were constructed from multislice CT data, and the simulations were performed using a high‐speed graphics processor.
Improved pixel selected ray tracing
Authors: Akimoto Takaaki , Mase Kenji , Suenaga Yasuhito
Published: July 2007

This paper presents a new ray‐tracing acceleration technique called improved pixel selected ray‐tracing (IPSRT), which is based on the reduction of ray‐traced pixels using adaptive undersampling. In PSRT, the intensities of coarsely sampled pixels are calculated by regular ray‐tracing, and the intensity of the pixels between sampled pixels is calculated by intensity interpolation if the characteristics of the sampled pixels are similar. However, in IPSRT, the similarities of the sampled pixels are classified into four levels, and the intensity of the pixels between sampled pixels is calculated by either intensity interpolation, ray‐tracing along the ray path of a sampled pixel, or regular ray‐tracing according to the results of the similarity check. Moreover, the danger of missing an object due to undersampling is reduced by using an efficient sampling algorithm. With these improvements, IPSRT can generate images of better quality than those generated by PSRT in the same or a shorter amount of time.
Multistage signal extraction method with spline filter
Authors: Yano Fumihiko , Toyoda Yoshiaki
Published: July 2007

As is often the case, experimental data contain various superimposed signals, from which the required signal or signals must be extracted. In such cases, the required signal level has not always been higher than the other signal levels. Therefore, it was difficult to eliminate all unnecessary signals using conventional noise elimination methods by classifying unnecessary signals as noise. To overcome such difficulties, a multistage signal extraction method is suggested which extracts the desired signal component by applying the filtering in multi‐stages. The results extracted by this method contain only the required signals plus the noise with the same amplitude readings. This makes it easier to reduce the complexity of signal extraction in later stages, such as the signal extraction based on other data information.

In this study, a spline filter is constructed using the cubic B‐spline smoothing process, which has versatility and is employed widely as a practical method. The multistage signal extraction method has versatility, and filters other than the spline filter can be utilized if the waveform is not overly distorted.
An integrated dc squid gradiometer for biomagnetic application
Authors: Chinone Kazuo , Kasai Naoko , Kiryu Shogo , Koyanagi Masao , Kado Hisasi , Nakanisi Masakazu , Kosaka Shin
Published: July 2007

A first‐order off‐diagonal gradiometer for biomagnetic measurement is fabricated and tested. The gradiometer consisted of two field pick‐up coils, a planar‐type DC‐SQUID with two superconducting loops connected in parallel, two multiturn input coils, and a modulation‐feedback coil. The size of the pick‐up coils was 6 × 6 mm2 with a baseline of 8 mm. The overall size of the gradiometer was 15 × 7.5 mm2. The resolution of the magnetic field gradient of the gradiometer increased from 11 to 1.8 pT/m/ Hz corresponding to frequencies from 1 to 600 Hz. The resolution became nearly white in the frequency range above 100 Hz. The intrinsic balance of the gradiometer was better than 1000 ppm for the field perpendicular to its plane. The magnetocardiogram and the alpha rhythmic fields were obtained easily using this gradiometer in a conventional electromagnetically shielded room.
A facial motion synthesis for intelligent man‐machine interface
Authors: Morishima Shigeo , Okada Shin'Ichi , Harashima Hiroshi
Published: July 2007

A facial motion image synthesis method for intelligent man‐machine interface is examined. Here, the intelligent man‐machine interface is a kind of friendly man‐machine interface with voices and pictures in which human faces appear on a screen and answer questions, compared to the currently existing user interfaces which primarily uses letters. Thus what appears on the screen is human faces, and if speech mannerisms and facial expressions are natural, then the interactions with the machine are similar to those with actual human beings.

To implement such an intelligent man‐machine interface it is necessary to synthesize natural facial expressions on the screen. This paper investigates a method to synthesize facial motion images based on given information on text and emotion. The proposed method utilizes the analysis‐synthesis image coding method. It constructs facial images by assigning intensity data to the parameters of a 3‐dimensional (3‐D) model matching the person in question. Moreover, it synthesizes facial expressions by modifying the 3‐D model according to the predetermined set of rules based on the input phonemes and emotion, and also synthesizes reasonably natural facial images.
Logic hypergraph grammars and context‐free hypergraph grammars
Authors: Shioya Isamu , Nakamura Katsuhiko
Published: July 2007

This paper presents an extended graph grammar, called a logic hypergraph grammar (LHG), and discusses its capabilities and parsing method. This grammar generates hypergraphs by resolution in logic programming and is intended to be a basis for analyzing and recognizing general structures by logic programming. An LHG is called a context‐free hypergraph grammar (CFHG) if each production rule represents a replacement of a hyperedge by a subhypergraph. Several normal forms are presented for CFHG and for a hierarchy on subclasses of languages of CFHGs with respect to the maximum number of vertices in nonterminal hyperedges. Finally, a parsing method of LHG using Prolog is presented.
A dynamic password authentication method using a one‐way function
Authors: Shimizu Akihiro
Published: July 2007

A new password‐based authentication system CINON is proposed for use in communications and computer systems. It employs a one‐way function to perform the required authentication of communicating users. CINON maintains its security in spite of a wiretap or the theft of a password file, and it is not necessary to replace the correspondents' public passwords. CINON can be realized with only a few computations.

This paper evaluates the CINON system and compares it with the Lamport authentication system, an earlier system which uses a one‐way data transformation. In comparison with the Lamport system, CINON's execution speed is faster by a factor of perhaps several hundred to a thousand.
A method for recovery of the 3‐d structure and motion of objects from low‐accuracy dynamic images
Authors: Takagi Kazuhisa , Ohnishi Noboru , Sugie Noboru
Published: July 2007

When observing a time‐series of two‐dimensional images composed only of points on a moving object, a human can perceive the 3‐D structure essentially existing among the points, and the object itself can be recognized if a sufficient number of points exists. For such a stereokinetic visual function, numerous recovery methods have been proposed for 3‐D information from 2‐D images. However, past methods of recovery have a problem in that the accurate recovery is impossible unless the image data have a high accuracy. For example, the input data must have the accuracy of 10 decimal digits. On the other hand, the human seems to perceive the 3‐D structure of the object from the data with a relatively low accuracy by another means, such as a long‐term observation.

This paper discusses a method of recovery where the 3‐D structure is recognized with as high an accuracy as possible from the data with a relatively low accuracy using a number of frames. Rigid bodies connected by joints are considered as the objects. When the information concerning the positions and velocities of several points on the object projected on a plane are provided, the depth information is recovered. By a computer simulation, it is seen that if approximately 10 or more frames are available, the output result with one order of magnitude lower accuracy than that of the input data can be obtained.
Motion perception model with interaction between spatial frequency channels
Authors: Ogata Masami , Sato Takao
Published: July 2007

Numerous studies have recently been made on the mechanism of human motion perception, especially on the model for the local motion detection using the spatio‐temporal filter. The feature of such a model is that it is not required to solve the matching problem which is inherent to the feature matching problem. Another point is that the model can account for several properties of human motion perception. However, earlier models are limited in their performance since the motion is detected using only a single spatial frequency channel. The usual scene contains a large number of spatial frequency components. To detect the motion with a high accuracy, it is desirable to integrate the information obtained from a number of channels. It is suggested by several psychological experiments that an interaction occurs between channels of the human visual system.

From such a viewpoint, this paper proposes a model for local motion detection based on the model by Watson et al., integrating the information from a number of spatial frequency channels. The model determines the motion velocity from the intersection of straight lines on the velocity plane, where the straight line is calculated from the spatio‐temporal filter output, to represent the candidate for the velocity. The interaction between channels is represented by drawing the straight lines obtained from various channels on the same velocity plane. The effectiveness of the proposed method is shown by a simulation using a random dot pattern.
Objective picture quality scale by neural network fed the distortion factors to the input layers
Authors: Kotani Kazunori , Miyahara Makoto
Published: July 2007

It is important to improve the picture quality of an image reconstructed by computer simulation. It is also important that the performance of coders be evaluated. To this end, an objective picture quality scale is essential for image processing.

This paper analyzes human perceptual properties in detail, formulizes approximately the fundamental image disturbance factors and proposes an objective picture quality scale (PQS).

As a test image, a coding error image was fed into a neural network and experiments were conducted with a method to evaluate the picture quality.

Finally, the new objective picture quality scale obtained herein can estimate the mean opinion scores (MOS) of two kinds of previously untaught images whose characteristics differ greatly.
A 3‐D display method of fuzzy shapes obtained from medical images
Authors: Niki Noboru , Kawata Yoshiki , Satoh Hitoshi
Published: July 2007

A three‐dimensional (3‐D) display of medical images allows better perception of the continuity of structures and spatial relationships than a display of individual slices. These 3‐D display methods consist of a contour extraction, a shape reconstruction and a shading. However, the boundary judgment of soft tissues, like a tumor, is difficult even for expert doctors. Especially, 3‐D display depends largely on a result of the contour extraction. The 3‐D display method is required to display the presentation of the continuity of organ shapes.

This paper presents the development of a display method to preserve the continuity of organ shapes. The display method consists of the extraction of fuzzy shapes and their shading. The extraction of fuzzy shapes is executed by operation of the fuzzy c‐means clustering algorithm on medical images and the use of a connectivity of an organ shape. The shading of fuzzy shapes uses a volume rendering, which is analyzed numerically and improved to realize a powerfully interactive 3‐D display. The effectiveness of the proposed 3‐D display method is shown using head MRI images.