This paper describes a method for hands-free speech recognition, and particularly for the simultaneous recognition of multiple sound sources. The method is based on the 3-D Viterbi search, i.e., extended to the 3-D N-best search method enabling the recognition of multiple sound sources. The baseline system integrates two existing technologies--3-D Viterbi search and conventional N-best search--into a complete system. Previously, the first evaluation of the 3-D N-best search-based system showed that new ideas are necessary to develop a system for the simultaneous recognition of multiple sound sources. It found two factors that play important roles in the performance of the system, namely the different likelihood ranges of the sound sources and the direction-based separation of the hypotheses. In order to solve these problems, we implemented a likelihood normalization and a path distance-based clustering technique into the baseline 3-D N-best search-based system. The performance of our system was evaluated through experiments on simulated data for the case of two talkers. The experiments showed significant improvements by implementing the above two techniques. The best results were obtained by implementing the two techniques and using a microphone array composed of 32 channels. More specifically, the Word Accuracy for the two talkers was higher than 80% and the Simultaneous Word Accuracy (where both sources are correctly recognized simultaneously) was higher than 70%, which are very promising results.

Technique of Measuring 3-D velocity vector components is important for the correct diagnosis of the blood flow pattern and quantitative assessment of intratumor perfusion. However, present equipment based on ultrasonic Doppler can not provide us true 3-D velocity. To overcome the problem, we previously proposed a new method of 3-D velocity vector measurement. The method uses 2-D array probe and enable us to obtain three components of velocity vector with real time by integrating the Doppler phase shift on the each element with the relative small single aperture compared with conventional method. Basic performance of the method has been evaluated by computer simulation. In this paper, to evaluate the feasibility of the proposed method, experimental investigation using a simple ring array probe and a phantom were carried out. Three components of velocity vector for different velocity magnitude and flow direction were measured. Experimental results validated its ability of measuring 3-D velocity and its feasibility.

Techniques for human-motion recovery are applicable to a variety of areas, such as sports, dancing, virtual reality, and video-game production. The people who work in this area focus their attention on recovering information on the motion of individuals rather than groups of people. It is important to demonstrate the possibility of recovering descriptions of the 3-D motion in team sports, since such information is able to provide us with a variety of information on the relations among players. This paper presents a new experimental result on 3-D motion recovery from a team sport. The result was obtained by a non-rigid shape recovery technique based on images from uncalibrated cameras. The technique was applied to recovering the 3-D motion of the players in a mini-basketball game which was played in a gymnasium. Some attention is focused on the analysis of the players' motion. Satisfactory results were obtained.

In the present GHz-clock high-density LSI, a design of signal lines is getting so critical that the transmission line analysis should be introduced to signal line design. This leads to the complex design of line structure and i/o drivers including impedance matching. Our target is to implement a system-in-package (SiP) for software-defined-radio (SDR). The SiP operates up to 10 GHz, and requires a compact and high-density packaging technology with a simple signal wiring design. In this paper, we propose a new concept of 3-D multilayer-stacked SiP. The new 3-D packaging concept includes (1) design guideline for interconnection lengths, (2) bridging register circuits in LSI chips, (3) flip-chip microbump bonding technology of chips onto system-buildup printed wiring boards (PWB), (4) multilayer-stacked 3-D package of several sets of chips and PWB, and (5) 100-µm-diameter bumps at peripheral region of PWB as vertical via-bump bus lines. A critical interconnect length, in which interconnect wiring is treated as a conventional RC line, is discussed for wiring design. Both wiring lengths in LSI chips and that among chips corresponding to total thickness of vertical bus lines are designed to be shorter than the critical length. The key points of the 3-D package for GHz signal transfer are a delay guarantee due to limitation of line length and separation between local lines in a chip and a bus line among chips.

This paper proposes a precise method of realizing simultaneous measurement of microscopic defects and the macroscopic three-dimensional shapes of planar objects having specular reflection surfaces. The direction vector field of surface tilt is evaluated directly by the introduction of a moving slit-light technique based on computer graphic animation. A reflected image created by the moving slit-light is captured by a video camera, and the image sequence of the slit-light deformation is analyzed. The obtained direction vector field of the surface tilt recovers the surface shape by means of integration. Two sample objects, a concave mirror and a plane plastic injection molding, are tested to measure the performance of the proposed method. Surface anomalies such as surface dent and warpage are detected quantitatively at a high resolution (about 0.2 [µm]) and a high accuracy (about 95%) in a wide area (about 15 [cm]) of the test object.

The present paper describes the finite difference time domain (FDTD) analysis of the light-beam diffraction from two- and three-dimensional (2-D and 3-D) magneto-optical (MO) disk structures. First, we show that the proposed new FDTD formulation is valid for MO disk medium and can avoid the divergence of fields encountered during the conventional FDTD calculations. Second, as the application of the present method to more complicated models, the main- and cross-polarized diffracted fields are numerically calculated for 2-D and 3-D four-layered MO disk models. The phase differences between two kinds of polarized components are shown. The results obtained here indicate that the proposed FDTD formulation can be applied to more complicated MO disk structures.

Making up a microwave simulator is tried, which has an analysis method based on the finite-element method as a solver and commercial tools as a pre- and post-processor of a graphical user interface. The platform of this simulator is Windows, but, since the codes and configuration files to be created are common on Windows, Unix, and Linux, the simulator running on any platform may be made up at the same time, except a document on which all the commands of the simulator are embedded and executable. Using the simulator, the transmission properties of a 2- and 3-D waveguide discontinuity in a microwave circuit and eigenmodes of a 2- and 3-D waveguide are analyzed, and the computed results are presented in graphs of S parameters and plots of the electric field distribution.

Carrier mobilities in poly(3-alkylthiphene) cast films have been studied by means of fabricating a field effect transistor (FET) at the field range of (0.4-1.6)104 V/cm. It is found that the regioregurality is markedly effective to the mobilities than the side chain length. The FET mobilility of the regioregular poly(3-hexylthiophene), PHT is approximately 310-3 cm2/Vs which is larger than that of regiorandom PHT by 3 orders of magnitude. The mobility of regioregular poly(3-dodecylthiophene), PDDT is 810-4 cm2/Vs and is also 3 orders of magnitude larger than that of regiorandom PDDT. The mobilities of regioregular ones decrease, however, those of regiorandom ones increase at higher fields. The FET mobilities are nearly same to the mobilities estimated by the time of flight method. These results have been discussed taking the regularity of the main chain and the length of side chain into consideration.

The conventional shape from focus (SFF) methods have inaccuracies because of piecewise constant approximation of the focused image surface (FIS). We propose a more accurate scheme for SFF based on representation of three-dimensional FIS in terms of neural network weights. The neural networks are trained to learn the shape of the FIS that maximizes the focus measure.

The pseudo-lattice method has been developed for dynamic 3-D liquid-crystal director simulation in thin-film-transistor liquid-crystal displays. Its feature is that the equation of motion of the director is not formularized from the real-lattices, but from the pseudo-lattices organized between the real-lattices. The director on the pseudo-lattice is calculated from the real-lattices by insertion. The objective is to simulate the continuous nematic symmetry correctly and to reduce time and memory needed for the calculation. Especially in this paper, the pseudo-lattice method is explained in detail. Moreover, experiments have been done, and the simulated behavior and location of the bright line, which is caused by the distortion of the director profile, were confirmed to be the same as the actual ones. In particular, the movement and elimination process of the bright line were simulated for the first time.

Visualization of 3-D ultrasound images is a challenging task due to the noisy and fuzzy nature of ultrasound imaging. This paper presents an efficient volume rendering technique for 3-D ultrasound image. A preprocessing technique of 2-D truncated-median filtering is proposed to reduce speckle noise of the ultrasound image. This paper also introduces an adaptive boundary detection method to reduce the computation time for volume rendering of ultrasound image. The proposed technique is compared to the conventional volume rendering methods with respect to the computation time and the subjective image quality. According to the comparison study, the proposed volume rendering method shows good performance for visualization of 3-D ultrasound image.

Human visual system can perceive 3-D structure of an object by binocular disparity, gradient of illumination (shading), occlusion, textures, perspective and so forth. Among them, binocular disparity seems to be the essentially important cues for the 3-D space perception and it is used widely for displaying 3-D visual circumstances such as in VR (virtual reality) system or 3-D TV. Visual illusions seem to be one of the phenomena which are purely reflecting the mechanism of human visual system. In the recent several years, the authors found several new types of 3-D visual illusions with binocular viewing. Entire 3-D illusory object including volume perception, transparency, dynamic illusions can be perceived only from the visual stimuli of disparity given by some inducing objects arranged with suitable relations. In this report, the authors introduced these newly found visual illusions and made some considerations on the human visual mechanism of 3-D perception and on their exploitation for new effective techniques in 3-D display. They introduced especially on the visual effect in two kinds of arrangement with occlusion and sustaining relationship between the illusory object and inducing objects. In the former case, the inducing objects which provide the stimuli were named as occlusion cues and classified into two types: contour occlusion cues and bulky occlusion cues. In the later case, those inducing objects were named as sustaining cues and a 3-D fully transparent illusory object was perceived. The perception was just like imagined from the scenes of the actions and positions of the pantomimists; then this phenomena was named as "Mime (Pantomime) Effect. " According to the positions of sustaining cues, they played different actions in this perception, and they are classified into three types: front sustaining cues, side sustaining cues and back sustaining cues. In addition, dynamic fusion and separation of volumetrical illusory objects were perceived when the visual stimuli were moving continuously between two structurally different conditions. Then the hysteresis was recognized in geometrical position between the fusion and separation. The authors believe that the occlusion cues and sustaining cues introduced in this paper could be effective clues for exploiting the new techniques for 3-D display.

In this paper, we describe an experimental evaluation of visual fatigue in a binocular disparity type 3-D display system. To evaluate this fatigue, we use a subjective assessment method and focus on mismatching between convergence and accommodation, which is a major weakness of binocular disparity 3-D displays. For this subjective assessment, we use a newly-developed binocular disparity 3-D display system with a compensation function for accommodation. Because this equipment only allowed us to compare the terms of the mismatching itself, the evaluation is more accurate than similar previous works.

Texture has been investigated as a cue for reconstructing 3-D structure. There are various textures in a natural scene. In this paper, the regularity of alignment of texture elements was manipulated to investigate its effect on human perception. The results show that the regularity affects human perception when only the texel density gradient is given as cue or the density cue is inconsistent with the compression cue. We introduce a model based on a MAP estimation to account for the result from a viewpoint of an integration of 3-D cues. The model simultaneously estimates texture properties and 3-D surface orientation by using prior knowledge about texture and 3-D surface. The performance of the model accounts for the experimental result well.

If a four-port network is terminated by arbitrary impedances, the conventional methods for even- and/or odd-mode excitation analyses are not available because no symmetry planes exist. Under these conditions, two types of new design equations for asymmetric 3-dB branch-line hybrids are reported. To make sure that the derived design equations are correct and adaptable, simulations were performed under assumed ideal conditions for one type of asymmetric 3-dB branch-line hybrid and a uniplanar branch-line hybrid terminated by 50 Ω, 41.6 Ω, 55.6 Ω and 62.5 Ω was fabricated and measured for another type of asymmetric 3-dB branch-line hybrid.

This paper surveys the results of various studies on 3-D image coding. Themes are focused on efficient compression and display-independent representation of 3-D images. Most of the works on 3-D image coding have been concentrated on the compression methods tuned for each of the 3-D image formats (stereo pairs, multi-view images, volumetric images, holograms and so on). For the compression of stereo images, several techniques concerned with the concept of disparity compensation have been developed. For the compression of multi-view images, the concepts of disparity compensation and epipolar plane image (EPI) are the efficient ways of exploiting redundancies between multiple views. These techniques, however, heavily depend on the limited camera configurations. In order to consider many other multi-view configurations and other types of 3-D images comprehensively, more general platform for the 3-D image representation is introduced, aiming to outgrow the framework of 3-D "image" communication and to open up a novel field of technology, which should be called the "spatial" communication. Especially, the light ray based method has a wide range of application, including efficient transmission of the physical world, as well as integration of the virtual and physical worlds.

We discuss optimal rotation estimation from two sets of 3-D points in the presence of anisotropic and inhomogeneous noise. We first present a theoretical accuracy bound and then give a method that attains that bound, which can be viewed as describing the reliability of the solution. We also show that an efficient computational scheme can be obtained by using quaternions and applying renormalization. Using real stereo images for 3-D reconstruction, we demonstrate that our method is superior to the least-squares method and confirm the theoretical predictions of our theory by applying bootstrap procedure.

This paper describes a neuro-based optimization algorithm for three dimensional (3-D) rectangular puzzles which are the problems to arrange the irregular-shaped blocks so that they perfectly fit into a fixed three dimensional rectangular shape. First, the fitting function of the 3-D block, which means the fitting degree of each irregular block to the neighboring block and the rectangular configuration, is described. Next, the energy function for the 3-D rectangular puzzles is proposed, where the horizontal rotation of the block is also considered. Finally, our optimization method is applied to several examples using the 3-D analog neural array and it is shown that our algorithm is useful for solving 3-D rectangular puzzles.

Three-dimensional (3-D) instrumentation using an image sequence is a promising instrumentation method for intelligent systems in which accurate 3-D information is required. However, real-time instrumentation is difficult since much computation time and a large memory bandwidth are required. In this paper, a 3-D instrumentation VLSI processor with a concurrent memory-access scheme is proposed. To reduce the access time, frequently used data are stored in a cache register array and are concurrently transferred to processing elements using simple interconnections to the 8-nearest neighbor registers. Based on a row and column memory access pattern, we propose a diagonally interleaved frame memory by which pixel values of a row and column are stored across memory modules. Based on the concurrent memory-access scheme, a 40 GOPS vprocessor is designed and the delay time for the instrumentation is estimated to be 42 ms for a 256256 images.

Advanced scientific and engineering problems require massively parallel computing. Critical to the designand ultimately the performanceof such computing systems is the interconnection network binding the computing elements, just as is the cardiovascular network to the human body. This paper develops a new interconnection network, "Tori connected mESHes (TESH)," consisting of k-ary n-cube connection of supernodes that comprise meshes of lower level nodes. Its key features are the following: it is hierarchical, thus allowing exploitation of computation locality as well as easy expansion (up to a million processors), and it appears to be well suited for 3-D VLSI implementation, for it requires far fewer number of vertical wires than almost all known multi-computer networks. Presented in the paper are the architecture of the new network, node addressing and message routing, 3-D VLSI/ULSI considerations, and application of the network to massively parallel computing. Specifically, we discuss the mapping on to the network of stack filtering, a hardware oriented technique for order statistic image filtering.