Toshiyuki Kimura

• Ph. D.
• Professor (Associate) at Tohoku Gakuin University

We previously proposed a three-dimensional (3D) audio system using the multiple vertical panning (MVP) method to develop a 3D audio system that matches a multi-view 3D video display system (REI display). In this paper, in order to apply our proposed method to the teleconference system, we performed two audio-visual psychological experiments and eva...

We previously proposed a three-dimensional (3D) audio system using the multiple vertical panning (MVP) method to develop a 3D audio system that matches a multi-view 3D video display system (REI display). In this paper, in order to apply our proposed method to the teleconference system, we performed two audio-visual psychological experiments and eva...

NICT has developed a multi-view 3D video display system with a 200-inch screen (REI display). In this system, several viewers can simultaneously view natural 3D objects from their respective viewing positions without special glasses. We proposed a 3D audio system using multiple vertical panning (MVP), which is compatible with REI display systems. H...

We previously proposed a 3D audio system using the multiple vertical panning (MVP) method to develop a 3D audio system that matches a multi-view 3D video display system (REI display). In this paper, in order to apply our proposed method to the teleconference system, we performed an audiovisual psychological experiment and evaluated the effect of th...

NICT has developed a multiview 3D video display system with a 200-inch screen. In this system, several viewers can simultaneously view natural 3D objects from their respective viewing positions without special glasses. We have proposed a 3D audio system using multiple vertical panning, which is compatible with a large-screen multiview 3D video disp...

In this paper, a 3D audio system using multiple vertical panning (MVP), which matches audio to a large-screen multiview 3D video display system, is proposed. The vertical position of sound images is synthesized by the panning between two loudspeakers placed at the upper and lower sides of the screen. The horizontal position of the sound images is c...

In sound field simulation with conventional WE-FDTD, the simulated field and wave equation are discretized with symbol time domain and spatial domain with Cartesian coordinate, and sound pressure distribution is calculated. Spatial-discretization with Cartesian coordinate easily achieves calculation and sound synthesis. However, the discretized Car...

In this paper, in order to evaluate the audio-visual performance of the proposed three-dimensional (3D) audio system, which is based on Multiple Vertical Panning (MVP) method and matches to the glasses-free 3D video display system in which the size of screen is very large, the audio-visual experiment was designed by using the loudspeaker array in w...

In this paper, a personal 3D sound field reproduction technique using wave front synthesis and eight directional microphones is proposed for the remote control system. The localized performance of the proposed technique was evaluated by the localization test. As a result, it was indicated that the localized performance of the proposed technique was...

In this paper, the novel three-dimensional (3D) audio system is proposed. The proposed system is based on Multiple Vertical Panning (MVP) method and matches to the glasses-free 3D display system in which the size of screen is very large. The vertical position of sound images is synthesized by the panning between two loudspeakers placed at the top a...

Three-dimensional (3D) radiated sound field display systems are important toward realizing ultra-realistic communications systems such as 3D television. In this paper, a 3D radiated sound field display system using directional loudspeakers and wave field synthesis is proposed. The proposed system is based on the Fresnel-Kirchhoff diffraction formul...

In this paper, 3D sound field reproduction technique using directional microphones is proposed. This technique is based on wave field synthesis (WFS) technique, in which the 3D sound field of a listening area is reproduced by using directional microphones and loudspeakers placed at the boundary surface of the area. The position of loudspeakers is t...

We have developed a spherical loudspeaker consisting of multiple transducers embedded in a compact spherical enclosure, which aims to recreate sound quality equal to the original in the near-field by presenting 3D audio information with the loudspeaker. The radiation characteristics of violin and guitar sound reproduced by the loudspeaker were comp...

Near 3D sound field display systems are important toward realizing ultra-realistic communications systems such as 3D television. We have proposed the near 3D sound field reproduction systems using directional loudspeakers and wave field synthesis and developed the real system by constructing the surrounding microphone array and the radiated loudspe...

Three-dimensional sound field reproduction using directional microphones and wave field synthesis can be used to synthesize wave fronts in a listening area using directional microphones and loudspeakers placed at the boundary of the area; the position of the loudspeakers is the same as that of microphones in this technique. Thus, it is very difficu...

In order to realize a 3D radiated sound field with which multiple listeners can listen to a sound anywhere around the object without having to wear equipment such as headphones, we proposed a near 3D sound field reproduction system using directional loudspeakers and wave field synthesis. The size of the loudspeaker array, however, is the same as th...

We have developed a three-dimensional (3D) audio system depicting the presence of an object, i.e., a spherical loudspeaker with variable radiation characteristics. In this study, we perform computer simulations for numerical analysis of the 3D sound field generated by the spherical loudspeaker. We also evaluate the size and shape of a musician's so...

We have been prototyping loudspeakers with radial directionality that differs in all directions (including longitudinally, vertically and laterally), and building systems that reproduce sound expressions of musical instruments in a 3D manner, as technology for faithfully reproducing a sound source according to physical laws as much as possible. In...

In a conventional 3D sound field reproduction system using wave field synthesis, numerous loudspeakers are placed around the listener. However, since such a system is very expensive and loudspeakers are in the listener's field of vision, it is very difficult to construct an audio-visual virtual reality system. We have proposed a 3D sound field repr...

It is very important to develop near 3D sound field reproduction techniques in order to realize the ultra-realistic communications such as 3D television and 3D tele-conference. In this paper, the near 3D sound field reproduction system using directional loudspeakers and wave field synthesis is developed by constructing the surrounding microphone ar...

In this paper, we propose a new system for controlling radiated sound directivity. The proposed system artificially induces a bending vibration on a planar diaphragm by vibrating it artificially using multiple vibrators. Because the bending vibration in this case is determined by not one but all of the accelerated vibrations, the vibration of the d...

It is very important to develop 3D audio display systems compatible with future 3D visual displays in order to realize future 3D multimodal communications systems such as 3D television. In this paper, two 3D audio display systems using the radiated loudspeaker, that were developed by the authors, are described. In one system, the spherical radiated...

We have realized a sound directivity control of a large planar diaphragm by controlling the bending vibrations using multiple vibrators. This paper proposes a method to determine the parameters such as the shape and thickness of the diaphragm and the position of the vibrators. In this method, the finite element method (FEM) is used to simulate the...

A conventional 3D sound field reproduction system using wave field synthesis places a lot of loudspeakers around the listener. However, since such a system is very expensive and loudspeakers come into the listener's field of vision, it is very difficult to construct an audio-visual system with it. We developed and evaluated a 3D sound field reprodu...

In this paper, we have developed a fast and accurate 3-dimensional registration algorithm using surface gradients for motion tracking of Time-Varying Meshes (TVM). Hierarchical skeleton-based mesh decomposition is used to segment each TVM frame into ...

The development of near 3D sound field reproduction techniques is an important part of achieving ultra-realistic communication for applications such as 3D television and 3D teleconferencing. In this paper, the principle of a near 3D sound field reproduction technique using wave field synthesis is defined from the Kirchhoff-Helmholtz integral equati...

Although it is very important to conduct listening tests when constructing a practical sound field reproduction system based on wave field synthesis, listening tests are very expensive. A localization model of synthesized sound images that predicts the results of listening tests is proposed. This model reduces the costs of constructing a reproducti...

A conventional 3D sound field reproduction system using wave field synthesis places a lot of loudspeakers around the listener. However, since such a system is very expensive and loudspeakers come into the listener's field of vision, it is very difficult to construct an audio-visual system with it. We developed and evaluated a 3D sound field reprodu...

It is very important to develop near 3D sound field reproduction techniques in order to realize the ultra-realistic communication such as 3D TV and 3D tele-conference. In this report, the principle of the near 3D sound field reproduction technique using wave field synthesis is defined from Kirchhoff-Helmholtz integral equation and two methods (dipo...

Many musical instruments, including violins and guitars, vibrate their resonant bodies differently over their surface when they make a sound. This paper aims to reveal the influences of such vibration variation of a soundboard surface on the width and depth perception of the sound image when listeners were in a near-field 50 cm or 1 m away from the...

This paper aims to construct a system that produces directional sound radiation. Directional sound is intrinsically radiated from a vibrating resonant body of such instrument as a violin. The directivity is said to give the sound a realistic and spatial effect. To reproduce a sound with such directivity, we propose a method that uses multiple vibra...

Sound field reproduction based on wave field synthesis is a technique that synthesizes wave fronts in a listening area using multiple microphones and loudspeakers placed at the boundary of the area. This study evaluates the effects of the directivity of microphones and loudspeakers on the accuracy of synthesized wave fronts. Three directional patte...

Sound field reproduction based on wave field synthesis proposed by Camras [M. Camras, J. Acoust. Soc. Am. 43, 1425–1431 (1968)] is a technique that synthesizes wave fronts of a control area at a listening area using directional microphones and loudspeakers placed at the boundary of those areas. This study evaluates the effects of the directivity of...

The use of physical features in the estimation of head-related transfer function (HRTF) was evaluated. The relationship between HRTFs and physical features was investigated with multiple regression analysis. After multiple regression models were calculated, then only the physical features were measured to estimate the HRTFs. The results indicate th...

The free viewpoint television (FTV) system, which consists of a lot of cameras, is developed in order to visualize the three-dimensional object in free viewpoints. In this study, the free listening-point auralization system is proposed in order to append the sound information to FTV system and appreciate a musical player in free positions. The prop...

It is important to evaluate the effect of the number of channel signals in the sound field auralization system based on wave field synthesis. Although the effect of the number of channel signals on the physical accuracy of wave fronts was investigated, the effect of the number of channel signals on sound field perception was not evaluated. In this...

The sound field reproduction technique is important to realize the more realistic communication system. However, a transmission data should be reduced for the remote system based on wave field synthesis since the technique usually needs a great number of channel signals. The spatial coding method for moving sound sources is proposed in this paper....

Since a sound field reproduction system based on wavefield synthesis usually needs a great number of channel signals, the amount of data transmitted should be reduced. This paper therefore proposes a spatial coding method that is based on the extraction of moving sound sources and reduces the amount of data transmitted from an amount proportional t...

To study the number of required channel signals is very important to reproduce a realistic sound field based on wavefield synthesis. In this paper, 2 subjective assess-ments were performed to evaluate the effect of the num-ber of channel signals on the directional perception of a sound source and on the spatial impression. From the results, it was...

The sound field reproduction technique based on the Huygens's principle is important to realize auditory virtual reality. However, it is necessary to transmit many multi-channel signals. In this paper, a new spatial coding technique for the multi-channel signals is proposed to reduce transmission bit rate. Source signals are extracted by convolving...

It is very important to study the affect of the number of channel signals in the sound field reproduction technique based on wavefield synthesis. Though there are many studies of objective affect such as wavefront accuracy, there are not as many studies of the subjective affect such as sound field perception. Therefore, the subjective assessment wa...

A large number of transmission audio channels are necessary for reproduction of a sound field based on Huygens principle. A method is proposed for spatial compression of the multi-channel audio signals. The signals are compressed by convolving them with the inverse filter of the room impulse response to reduce the number of transmission channels to...