Optimum method for real-time reconstruction of sensor surface in total-internal-reflection based tactile sensor

In recent years, many tactile sensors have been developed for the practical use in robotics and to meet the increasing demand for intuitive interfaces. However, the implementation of conventional tactile sensors is very complex. We develop a simple total-internal-reflection based tactile sensor that measures the shape of the sensor surface from a reflection image of the surface and evaluate its performance. We previously proposed a reconstruction method which solves geometric optical constraints of the sensor surface by optimization, however this method could not meet real-time and accurate reconstruction simultaneously. To solve this problem, in this paper, we propose a new reconstruction method based on the previously proposed one. By reconstruction experiments with simulated reflection images, we found that the proposed method could perform real-time and accurate reconstruction and was applicable to various sensor shapes and robust to feature tracking error and the presence of contact areas on the sensor surface without total-internal-reflection property. Then, we implemented the proposed method on the actual sensor and confirmed that the sensor could perform real-time reconstruction.