Kaoru Miyata

Development of a tactile sensor system for reading Braille: fundamental characteristics of the prototype sensor system

This paper is a study on the development of a tactile sensor system for reading Braille. The tactile sensor uses a PVDF (polyvinylidene fluoride) film as the sensory material. The sensor is attached to a slider driven by a DC servomotor and it is slid over a string of Braille with a constant speed to obtain the sensor output. A recognition system of Braille is proposed. In a recognition experiment, the sensor system is verified as to whether it has enough performance to recognize a string of letters appropriately. The obtained result shows that the proposed sensor and sensor system are effective to recognize Braille.

A Wearable Braille Sensor System With a Post Processing

This paper is a study on the development of a wearable sensor system for reading Braille. The study is intended to develop a compact tactile sensor system, which uses a polyvinylidene fluoride (PVDF) film for the sensory receptor. The sensor is mounted onto a fingertip and moved over Braille manually to obtain the output. Since the unsteady movements yield variations in the waveforms, a robust recognition system has been developed. In this study, the post processing is introduced into the recognition system for the improvement of the performance. Two different methods of post processing are developed and examined. In the first method, an appropriate letter string is generated by evaluating the connectivity of letters with information on signals. In the second method, the dictionary in which letter strings are recorded is incorporated as the prior knowledge. Finally, both the methods of post processing are combined to enhance the performance. The combined post processing is incorporated to the wearable sensor system, and the performance of the sensor system is evaluated experimentally. The results show that the sensor system is effective to recognize Braille.

Development of a Wearable Braille Sensor with a Robust Recognition System

This paper is a study on the development of a wearable sensor system for reading Braille. The study is intended to develop a compact tactile sensor system which uses a PVDF (polyvinylidene fluoride) film for the sensory receptor. The sensor is mounted onto a fingertip and moved over Braille manually to obtain the output. Since the unsteady movements yield variations in the waveforms, a robust recognition system is required. The performance of the recognition system is highly affected by the transformation method and the classification method. As the investigation of the transformation method, feature vectors of some different forms are extracted and effective forms are explored. In the classification, two methods based on MLPs (multi-layered perceptrons) are examined. The first method uses plural classifiers, each of which uses the different form of vectors. The next method uses MLPs in the form of dichotomizers to enhance the training quality. The performance of each method is evaluated using test signals. The obtained results show that the robust recognition is achieved appropriately