Kiyohide Ito

Coupling of Head and Body Movement With Motion of the Audible Environment

The authors asked whether standing posture could be controlled relative to audible oscillation of the environment. Blindfolded sighted adults were exposed to acoustic flow in a moving room, and were asked to move so as to maintain a constant distance between their head and the room. Acoustic flow had direct (source) and indirect (reflected) components. Participants exhibited strong coupling of postural motion with room motion, even when direct information about room motion was masked and was available only in reflected sound. Patterns of hip-ankle coordination closely resembled patterns observed in previous research involving coupling of sway with a visible moving room. The results demonstrate that blindfolded adults can control the dynamics of stance relative to motion of the audible environment.

The Development of Virtual 3D Acoustic Environment for Training ‘Perception of Crossability’

This study attempted to reveal the role of auditory information in the accurate “perception of crossability” for people with severe visual impairment (‘the blind’). We created a ‘virtual 3D acoustic environment’ in which listeners feel a car passing in front of them to help them cross the street safely. An idea of this acoustic system originated from a previous research that showed that the blind make good use of reflected sounds or reverberations in identifying sources and in specifying distances from objects. The system is useful not only for analyzing critical cues of perception of ‘crossability’ but also for training the blind how to cross a street. Such auditory information can provide the blind with a safe training system for acquiring such auditory information.

CyARM-interactive device for environment recognition using a non-visual modality

The purpose of this research is to develop an interactive device for environment recognition, which uses senses other than vision. At present there is no interactive device with which a person who is visually handicapped can gain an intuitive impression of the external world. Our device, which we have named CyARM, has a mechanism that controls the motion of a visually impaired person’s arm according to information about distance gathered by an ultrasonic sensor. We refined the features of CyARM through experimentation. The user can identify not only the existence of an object, but also its form.

Coloration perception depending on sound direction

Coloration is a phenomenon in which timbre changes when reflected and direct sounds are mixed. We studied the relationship between the perception of coloration and direction for two sounds. Our psychological experiments using 11 subjects suggested that a 50% threshold of coloration appears to have no difference depending on direction. When the level ratio of two sounds is closer to 0 dB, a difference appears: If direct sound comes from a lateral direction and reflected sound comes from the opposite direction, coloration perception does not increase monotonically even if the ratio approaches 0 dB. We assumed that the difference depending on direction resulted from the directional dependence of the spectrum including the head-related transfer function (HRTF) and proposed a numerical model for predicting psychological results using the comb structure on the spectrum observed at the eardrum. We measured spectra using a head and torso simulator (HATS) and calculated the area, eventually finding a quantitative relationship between the area and psychological results and proposing a prediction model based on this relationship.

Dynamic Lighting Sign System for Way-Finding by People with Low Vision

We developed and proposed a dynamic lighting sign (DLS for short) system for people with poor vision to use to find their way. The DLS system uses a chain of lighting units with LED to indicate the way and is controlled by means of a PC. We implemented the DLS system for helping people to find their way and evaluated it in terms of light-flashing time, spatial interval and colour. We also carried out an experiment to evaluate its effectiveness in helping people find their way.

Coupling of head and body movements to acoustic flow in sighted adults

Blindfolded sighted persons were found to detect acoustic flow patterns and use this information to control action. A moving room (a large box on wheels, with no floor, that moved in the subject’s fore–aft axis) was used. Blindfolded sighted persons (1) stood comfortably or (2) moved their head backward and forward to track audible room motion. Pink noise was presented through four speakers attached to the room, or mounted on stationary stands. Room motion was a sinusoid at 0.2 Hz, 22 cm, along subject’s fore–aft axis. When standing comfortably, participants exhibited weak but consistent coupling of body sway with room motion. Tracking of room motion with head movements was robust, matching both the frequency and amplitude of room motion. This was true even when the only information about room motion came from reflected sound (i.e., when the speakers were stationary). The results suggest a strong ability of sighted persons to use acoustic flow in the perception and control of their own action. [Work suppo...

A Unimodal Interface Device Coupling Distance with Intensities in Luminance and Temperature

In this paper, we report the unimodal interface device coupling with intensities in luminance and temperature. It enables the user to recognize two or three types of information through the finger’s angle motion and vibration independently and simultaneously. We describe the developed device, as well as its experimental results.

Analysis of awareness while touching the tactile figures using near-infrared spectroscopy

In this paper, we propose a method to measuring how the blind to touch the tactile images using Near-Infrared Spectroscopy (NIRS). The tactile image is one of powerful tool to give any visual information for the blind. On the other hand, it is difficult to estimate the process that the blind has understood the tactile images because the only trajectories of the hand are too vague to identify when the blind know the target image. Some experimental results insist that the brain is strongly activated at beginning of a task rather than the process of the task. Then, NIRS is confirmed to be useful to analyze process of understanding tactile figures by touching.

Postural Responses of Blind Adults to a Moving Room

We evaluated the possibility that there may be functional relations between body sway and audition, as predicted by Stoffregen & Pittenger (1995). The experiments were conducted using blind participants, who could be expected to have an increased sensitivity to any functional relation between postural control and audition. Participants stood in a moving room. Ambient acoustic fields were generated in the room from the font wall and participants postural responses to four conditions (room movement 14 cm, room stationary, stand on floor, stand on low balance beam) were recorded. Results show that the standard deviation of body position in the movement condition was different than the stationary condition (t(2) = 5.12, p < .05). Cross-correlation coefficients calculated to assess the coupling of body sway to room movement did not differ in the balance beam (.984) and floor (.957) conditions. In blind adults, body sway was influenced by motion of the room. The results are consistent with the hypothesis that ambient sound fields can provide information that can be used for the perception and control of bodily orientation (Stoffregen & Pittenger, 1995).