Masami Shinohara

Three-dimensional tactile display for the blind

A tactile display device that can present tangible relief graphics for visually impaired persons has been developed. The tactile surface consists of a 64 x 64 arrangement of tactorpins with 3 mm interspacing. The tactor-pins are aligned in a hexagonal, rather than a square formation, to assure smooth depiction. The matrix has a total area of 200 mm x 170 mm. Each pin can be raised in 0.1 mm steps to a maximum height of 10 mm. Users can get certain information by touching the pins raised at varying heights with fingers and/or palms. Laboratory assessment of the device with six blind subjects showed its ability to transmit various kinds of information.

Human shape recognition performance for 3D tactile display

The paper describes the relationship between the pin-matrix density of a tactile display and the recognition performance of displayed 3D shapes. Three types of pin-matrix tactile display, that generate 3D shapes, were used for the experiment. The pitch of pins was 2 mm, 3 mm, 5 mm each. We assumed that surfaces, edges, and vertices were primitive 3D shape information, so tested shapes were classified into these three categories. We assumed two types of finger touching mode: 1) fingertip-only, allowed full use of spatial shape information given to the fingertip; and 2) allowed tracing of the object. Recognition time and the classified error rate were measured. We obtained results on the relationship between pin pitch and recognition performance data. Regression curves for pin pitch and recognition time were plotted. A significance test of recognition time versus pin pitch was done. The error rate of identification versus pin pitch was described. Our results provide basic knowledge for developing tactile presentation devices.

Shape identification performance and pin-matrix density in a 3 dimensional tactile display

Tactile display devices use an array of pins mounted in the form of a matrix to present three-dimensional shapes to the user by raising and lowering the pins. With a denser matrix of mounted pins, it can be expected that shape identification will become easier and the time required for identification will also become shorter, but that problems of difficulty in fabrication will arise. It is necessary to consider such trade-offs in the development of such devices. The authors conducted experiments to study the effect of pin pitch on shape identification as part of the fundamental investigation of this subject. The experiment used three tactile display devices with pin pitches of 2 mm, 3 mm and 5 mm for geometrical shape identification, with response time and rate of misidentification taken as the performance data. Surfaces, edges and vertices of three-dimensional shapes were used as the shape primitives for displayed shapes and several of each type were selected for presentation. The results obtained revealed that performance has different relationships to pin pitch with different shape primitives.

An approach for direct manipulation by tactile modality for blind computer users: development of the second trial production

A basic device combining a tactile display function and a touch position sensing function is proposed. The trial device consists of two major components, a tactile graphic display and a six–axis force/torque sensor. The force sensor measures six dynamic values generated by touch action on the display surface and a PC estimates the touch position based on the data. Since the defects of the first trial production are the weakness of the touch surface, an assembly error, and the measurement error of six–axis force/torque sensor, they are solved in the second trial production. The effect of a contact force on the estimated position are examined respectively by a vertical component and a horizontal component. It is shown from the above experimental results that the second trial production is practically sufficient estimated position accuracy

An Approach for Direct Manipulation by Tactile Modality for Blind Computer Users: Principle and Practice of Detecting Information Generated by Touch Action

A basic device combining a tactile display function and a touch position/force direction sensing function is proposed. The trial device consists of two major components, a tactile graphic display and a 6-axis force/torque sensor. The force sensor measures six dynamic values generated by touch action on the display surface and a PC estimates the point based on the data and a simple dynamic principle. Preliminary investigation indicated the validity of this device and its promising capability for HC using tactile modality.

Improvement of User Interface for Blind PC Users

An application by which blind users can operate two tactile devices by themselves was developed. Laboratory assessment showed the possibility to transmit certain kinds of non-textual information.

New design for a dynamic tactile graphic system for blind computer users

An interactive tactile graphic display which acts by touch force has been developed as a trial. The trial model showed four usability problems through several usability experiments. Thus we re-designed three operation rules and developed a new image resampling algorithm to solve the problems. As the result, all problems shown in the previous system were solved. Furthermore a strategy of user interface design for interactive tactile graphic displays was shown through the development. In addition, an audio-tactile graphic system which can be used mainly to overcome tactile cognitive limitation was implemented as an application of the system.

Development for an interactive communication display for blind computer users

This study is the development of the interface for visually handicapped persons using the knowledge of the robotics field. A basic device combining a tactile graphic display function and a touch position/force direction sensing function is proposed. The trial device consists of two major components, a tactile graphic display and a 6-axis force/torque sensor. The force sensor measures six dynamic values generated by touch action on the display surface and a PC estimates the point based on the data. The fundamental function for achieving the interactive communication is to detect the location where user is touching a tangible surface. By applying this functions, the click and scroll function by an empty hand are realized. In addition, an audio-tactile graphic system which can be used mainly to overcome tactile cognitive limitation is implemented as an application of the system. The validity of the developed tactile graphic system has been confirmed through subjective experiments.

Human shape recognition performance and pin-matrix density in a 3 dimensional tactile display

The purpose of this paper is to provide the relationship between the pin-matrix density of a tactile display and the recognition performance of displayed 3-dimensional shapes. Three kinds of pin-matrix tactile displays, that generate 3D shapes, were used for the experiment. The pitch of pin was 5mm, 3mm, 2mm for each. As we assumed that surfaces, edges and vertices were the primitive information of the 3D shapes, tested shapes were classified into these three categories. The results obtained revealed that performance has different relationships to pin pitch with different shape primitives. The results of this study should be effective as fundamental knowledge to be used in developing tactile presentation devices, which have been receiving attention in recent years in the study of human interfaces, especially in the area of virtual reality technology.