ThinTact:Thin Vision-Based Tactile Sensor by Lensless Imaging

TL;DR

ThinTact introduces a compact, lensless vision-based tactile sensor with real-time reconstruction capabilities, enabling effective tactile sensing in space-constrained robotics applications.

Contribution

The paper presents a novel lensless tactile sensor design, a fast DCT-based reconstruction algorithm, and a mask optimization method, advancing tactile sensing technology in size and speed.

Findings

Achieves over 200 mm2 sensing area with less than 10 mm thickness.

Provides real-time tactile reconstruction significantly faster than existing methods.

Demonstrates effective texture recognition and object manipulation applications.

Abstract

Vision-based tactile sensors have drawn increasing interest in the robotics community. However, traditional lens-based designs impose minimum thickness constraints on these sensors, limiting their applicability in space-restricted settings. In this paper, we propose ThinTact, a novel lensless vision-based tactile sensor with a sensing field of over 200 mm2 and a thickness of less than 10 mm.ThinTact utilizes the mask-based lensless imaging technique to map the contact information to CMOS signals. To ensure real-time tactile sensing, we propose a real-time lensless reconstruction algorithm that leverages a frequency-spatial-domain joint filter based on discrete cosine transform (DCT). This algorithm achieves computation significantly faster than existing optimization-based methods. Additionally, to improve the sensing quality, we develop a mask optimization method based on the generic algorithm and the corresponding system matrix calibration algorithm.We evaluate the performance of our proposed lensless reconstruction and tactile sensing through qualitative and quantitative experiments. Furthermore, we demonstrate ThinTact's practical applicability in diverse applications, including texture recognition and contact-rich object manipulation. The paper will appear in the IEEE Transactions on Robotics: https://ieeexplore.ieee.org/document/10842357. Video: https://youtu.be/YrOO9BDMAHo