Myoung-Jong Yoon

Psychophysical Experiment of Vibrotactile Pattern Perception by Human Fingertip

In this paper, a preliminary experimentation is carried out to investigate the necessary stimulation conditions for a pattern display that may be used for the blind to display obstacle distribution. To design an efficient vibrotactile display device of array-type and compact size, the effect of some main parameters, such as the amplitude and frequency of vibration and the spacing and quantity of vibrated pins on vibrotactile perception, should be considered. Through experiment and analysis, the minimal amplitude of vibrating stimuli and the spacing effect on the perception of vibrotactile pattern are investigated and discussed. Also an appropriate type of actuator satisfying the requirements of a compact tactile display device for the effective transfer of pattern information is discussed.

Generation of space grid map by 3D detection of obstacle distribution

In walking guide robot, a guide vehicle detects an obstacle distribution in walking space using range sensors, and generates a space grid map to mapping the obstacle information and the tactile display. And the obstacle information is transferred to a blind pedestrian using tactile feedback. Based on the obstacle information a user plans walking route and controls the guide vehicle. The algorithm of 3-D obstacle detection and the method of mapping the generated obstacle map and the tactile display device are proposed in this paper. The experiment for the 3-D detection of the obstacle distribution using ultrasonic sensors is performed and estimated. The experimental system consisted of ultrasonic sensors (SRF05, Devantech Co. Ltd.) and control system (PCI-6221 DAQ board & LabVIEW, National Instruments Co.). In the experiment, the detection of fixed obstacles on the ground and the detection of down step are performed. The performance for the 3D detection of obstacle distribution and mapping space is verified through the experiment.

Development of portable ECG measurement device and PC software for automatic ST analysis

ECG is used on purpose to keep good health or monitor cardiac function of aged person as well as on purpose to diagnose the disease of heart patients. The ambulatory ECG monitoring system under guarantee of safety and accuracy is very efficient to prevent the progress of heart disease and sudden death. These systems can detect the temporary change of ECG that is very significant to diagnose heart disease such as myocardial ischemia, arrhythmia and cardiac infarction. In this paper, we describe the ECG signal analysis algorithm and measurement system for ECG monitoring. The designed small-size portable ECG device consisted of instrumentation amplifier, micro-controller, filter and RF module. The developed device measures ECG with four electrodes in the body and detects QRS complex and ST level change in real-time. Also it transmits the measured signal to the personal computer. The developed software for ECG analysis in personal computer has the function to detect the feature points and ST level change.

3D detection of obstacle distribution and mapping for tactile stimulation

In walking guide system for a blind pedestrian, it is needed to detect an obstacle distribution in walking space not only 2D but space including pendent and/or protruded obstacles, and feedback to the blind for safe walking. The obstacle information is transferred to a blind pedestrian by a tactile stimulation. Based on the obstacle information a user plans walking route, and controls the walking guide system. In this paper, the methods for a 3D obstacle detection using ultrasonic sensors and mapping to an array type tactile stimulator are proposed. The experiment for the 3D detection of an obstacle distribution using ultrasonic sensors is performed and estimated. The experimental system consisted of ultrasonic sensors and control system. In the experiment, the detection of obstacles on the ground and the detection of down step are performed. The performance for the 3D detection of obstacle distribution and mapping for tactile stimulation are verified through the experiment.

Recognition of obstacle distribution via vibrotactile stimulation for the visually disabled

A tactile display is able to help the walking support system of a visually disabled person. A walking guide system must detect an obstacles distribution in walking space including hanging and/or protruding obstacles, and provide useful feedback for safe walking. In this study, we investigate the applicability of a tactile display to the walking guide. The obstacle information is transmitted to the palm by tactile stimulation. The three dimensional (3D) detection of an obstacles distribution using ultrasonic sensors, the fabrication of a tactile stimulator using vibration motors, and the mapping of the detected results to an array-type tactile stimulator are proposed. An experiment on the recognition of an obstacles distribution via tactile stimulation is performed to evaluate the possibility of a walking guide. In the experimental result, the average recognition rate was 95.14 % (5.73, standard error).

A Study of Walking Guide for the Blind by Tactile Display

In this paper, firstly, we propose a generating method of the 3-D obstacle map using ultrasonic sensors. Secondly, we try to find the necessary stimulation conditions of compact tactile display device for effective transfer of obstacle information. The final goal of this research is the development of a walking guide system for the blind to walk safely. The walking guide system consists of a guide vehicle for the obstacle detection and a tactile display device for the transfer of the obstacle information. The guide vehicle, located in front of the walking blind, detects the obstacle using ultrasonic sensors. The processed information makes an obstacle map and transmits safe path and emergency situation to the blind by the tactile display. The tactile display device, located in the handle which is connected with the guide vehicle by cane, offers the processed obstacle information such as position, size, moving, shape of obstacle and safe path, etc. The concept of a walking guide system with tactile display is introduced, and experiments of 3-D obstacle detection and tactile perception are carried out and analyzed.

Psychophysical Experiment of Vibrotactile Pattern Recognition at Fingertip

For the psychophysical experiment of vibrotactile pattern recognition, experimental system consists of vibrator, vibrotactile pattern, measurement and control system is designed and prepared. The psychophysical experiment of vibrotactile pattern recognition at fingertip is carried out by the estimation of the subject group. Through the experiment, appropriate frequency bandwidth, displacement of vibrating stimuli and effect of spacing of vibrated pins for recognition of vibrotactile pattern in the human finger are discussed and derived to apply to an effective vibrotactile stimulator to be developed for tactile display.

Development of Realtime ECG Analysis and Monitoring System

ECG is used on purpose to keep good health or monitor cardiac function of aged person as well as on purpose to diagnose the disease of heart patients. The ambulatory ECG monitoring system under guarantee of safety and accuracy is very efficient to prevent the progress of heart disease and sudden death. These systems can detect the temporary change of ECG that is very significant to diagnose heart disease such as myocardial ischemia, arrhyamia and cardiac infarction. In this paper, we describe the ECG signal analysis algorithm and measurement device for ECG monitoring. The authors designed a small-size portable ECG device that consisted of instrumentation amplifier, micro-controller, filter and RF module. The device measures ECG with four electrodes on the body and detects QRS complex and ST level change in realtime. Also it transmits the measured signals to the personal computer. The developed software for ECG analysis in personal computer has the function to detect the feature points and ST level changes.

3D Detection of Obstacle Distribution and Mapping for Walking Guide of the Blind

In walking guide robot, a guide vehicle detects an obstacle distribution in the walking space using range sensors, and generates a 3D grid map to map the obstacle information and the tactile display. And the obstacle information is transferred to a blind pedestrian using tactile feedback. Based on the obstacle information a user plans a walking route and controls the guide vehicle. The algorithm for 3D detection of an obstacle distribution and the method of mapping the generated obstacle map and the tactile display device are proposed in this paper. The experiment for the 3D detection of an obstacle distribution using ultrasonic sensors is performed and estimated. The experimental system consisted of ultrasonic sensors and control system. In the experiment, the detection of fixed obstacles on the ground, the moving obstacle, and the detection of down-step are performed. The performance for the 3D detection of an obstacle distribution and space mapping is verified through the experiment.

STUDY ON TACTILE PERCEPTION OF SHAPE FOR EFFECTIVE TACTILE DISPLAY

Abstract The experiment of the shape recognition for a tactile display is carried out and analysed in this paper. The purpose of this research is the development of a tactile stimulator array to represent the obstacle information for the visually impaired to walk safely. As a first step of this research, we investigate the characteristics of tactile stimuli and design the experimental system for the physiological characteristic test based on the investigated results. In order to determine the appropriate and optimal range of the actuating frequency and displacement for the tactile stimulation array, the psychophysical experiment for the threshold of perception and recognition ability of multi-stimulation with some shapes are carried out by the estimation of the subject group. As a result the appropriate tactile stimulus intensity and frequency of the tactile stimulation array to recognize arbitrary line shapes effectively are discussed and derived.