Look-to-Touch: A Vision-Enhanced Proximity and Tactile Sensor for Distance and Geometry Perception in Robotic Manipulation

Camera-based tactile sensors provide robots with a high-performance tactile sensing approach for environment perception and dexterous manipulation. However, achieving comprehensive environmental perception still requires cooperation with additional sensors, which makes the system bulky and limits its adaptability to unstructured environments. In this work, we present a vision-enhanced, camera-based dual-modality sensor that integrates proximity and tactile sensing, enabling accurate long-distance proximity sensing while simultaneously maintaining ultra-high-resolution texture sensing and reconstruction capabilities. Unlike conventional designs with fixed opaque gel layers, our sensor features a partially transparent sliding window, enabling mechanical switching between tactile and visual modes. For each sensing mode, a dynamic distance sensing model and a contact geometry reconstruction model are proposed. Through integration with soft robotic fingers, we systematically evaluate the performance of each mode, as well as in their synergistic operation. Experimental results show robust distance tracking across various speeds, nanometer-scale roughness detection, and submillimeter 3D texture reconstruction. The combination of both modalities improves the robot’s efficiency in executing grasping tasks. Furthermore, the embedded mechanical transmission in sensor allows for fine-grained intrahand adjustments and precise manipulation, unlocking new capabilities for soft robotic hands.