Yuki Tamai

Three ring microphone array for 3D sound localization and separation for mobile robot audition

This paper describes a three ring microphone array estimates the horizontal/vertical direction and distance of sound sources and separates multiple sound sources for mobile robot audition. Arrangement of microphones is simulated and an optimized pattern which has three rings is implemented with 32 microphones. Sound localization and separation are achieved by delay and sum beam forming (DSBF) and frequency band selection (FBS). From on-line experiments results of sound horizontal and vertical localization, we confirmed that one or two sounds sources could be localized with an error of about 5 degrees and 200 to 300 mm in the case of the distance of about lm. The off-line experiments of sound separation were evaluated by power spectrums in each frequency of separated sounds, and we confirmed that an appropriate frequency band could be selected by DSBF and FBS. The system can separate 3 different pressure speech sources without drowning out.

2D sound source localization on a mobile robot with a concentric microphone array

The purpose of this paper is to report the devised arrangement of a microphone array suitable for a mobile robot and to develop a robotic audition system to recognize the environment. The paper first describes the sum and delay beam forming (SDBF) algorithm and its common problem: side lobes. The array we developed shows smaller side lobes when beam forming. It provides high quality localization and separation for multiple sound sources. Then we achieved a sound sources mapping system by using a wheeled robot equipped with the microphone array. The robot localizes sound direction on the run and estimates sound positions using triangulation. Accumulation of data results in high accuracy. The system can estimate 3 different pressure sounds with a 200 mm position error. Moreover, the high quality sound source separation has proved useful in improving speech recognition.

Invisible messenger: visually steerable sound beam forming system based on face tracking and speaker array

This paper presents a novel human-machine interface, named invisible messenger. It integrates real time visual tracking of face and sound beam forming by speaker array, and realizes remote whispering effect as if an invisible messenger were standing by you. Construction of a working prototype system and actual measurement using the system prove the feasibility and effectiveness of the proposed idea.

Detecting and segmenting sound sources by using microphone array

This paper describes microphone array that can be used for sound localization and sound capture. The system has omni-directional sensitivity, and can be as a tele-microphone for apropriate direction. Sound capture by microphone array is achieved by Sum and Delay Beam Former (SDBF). SimuIation of sound pressure distribution of 32 & 64ch circular microphone array are shown. According to simulation results, dedicated Firewire (IEEE1394) 32-channel board are developed with maximum sampling rate of llkHz sample. The 32ch circular microphone array system is evaluated by using frequency components of the sound.

Software‐centered implementation of 128 channel huge speaker array with stock PC

A huge speaker array system of 128 loudspeakers was constructed and experimented. It was implemented as ‘‘software‐centered’’ style utilizing stock loudspeakers and a PC. No dedicated hardware nor DSP was utilized. Spot forming, instead of beam forming, could be realized by 32 by 4 square layout of the array. Spot means small area of higher sound pressure level. Number of the spot was not limited to one. In the experiment, within 3 m by 3 m area, four spots of different sounds could be simultaneously formed. This spot forming was confirmed by actually measured spatial distribution of sound pressure level. The effect of the spot was also confirmed auditorily. Since the system was software‐centered, it was dynamic. By simply changing software parameters, location of the spot can be easily moved even while the system was running. This movability of the spot was intended to be basis for visual steering. To realize the system, a simultaneous 128 channel 14‐bit DA converter PCI board was developed. 44.1 kHz sam...