Vision-based Tactile Sensor for Endoscopy

Endoscopy would become more useful if the visual information obtained with it could be combined with tactile information. We therefore developed a new tactile sensor system with this feature using image processing of an infrared cut pattern. It is possible to install this sensor on the tip of an endoscope easily because wires for power delivery and transmission of signals are unnecessary. Doctors can use this sensor for visual diagnosis because it does not degrade diagnostic images. In this study, changes were made in the sensor to improve the accuracy of measurement and detect stiffness of living tissue. First, we corrected sensor output by considering sensor deformation characteristics, and were thus able to evaluate state of contact in inserting the endoscope into a vessel model. Second, we modified the sensor to detect not only three-axis force but also compressive modulus. The difference in compressive moduli between several industrial materials is discernible by measurement with the prototype of this sensor.