bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved dithering methods for color quantized images
Authors: Watanabe Takashi 
Published: July 2007

AbstractA 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

AbstractIn 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

AbstractIt 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

AbstractThis 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

AbstractA 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

AbstractAt 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

AbstractThis 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

AbstractOften, 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

AbstractWith 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

AbstractThis 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

AbstractAs 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

AbstractA 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

AbstractA 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

AbstractThis 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

AbstractA 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

AbstractWhen 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

AbstractNumerous 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

AbstractIt 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

AbstractA 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.