NLiPsCalib: An Efficient Calibration Framework for High-Fidelity 3D Reconstruction of Curved Visuotactile Sensors

TL;DR

NLiPsCalib introduces an efficient, physics-consistent calibration method for curved visuotactile sensors that simplifies the process and improves 3D reconstruction accuracy, making tactile sensing more accessible.

Contribution

The paper presents NLiPsCalib, a novel calibration framework using controllable light sources and Near-Light Photometric Stereo for high-fidelity 3D reconstruction of curved sensors, requiring minimal calibration data.

Findings

Enables accurate 3D reconstruction across various curved sensors.

Simplifies calibration to a few contacts with everyday objects.

Reduces cost and complexity compared to existing methods.

Abstract

Recent advances in visuotactile sensors increasingly employ biomimetic curved surfaces to enhance sensorimotor capabilities. Although such curved visuotactile sensors enable more conformal object contact, their perceptual quality is often degraded by non-uniform illumination, which reduces reconstruction accuracy and typically necessitates calibration. Existing calibration methods commonly rely on customized indenters and specialized devices to collect large-scale photometric data, but these processes are expensive and labor-intensive. To overcome these calibration challenges, we present NLiPsCalib, a physics-consistent and efficient calibration framework for curved visuotactile sensors. NLiPsCalib integrates controllable near-field light sources and leverages Near-Light Photometric Stereo (NLiPs) to estimate contact geometry, simplifying calibration to just a few simple contacts with everyday objects. We further introduce NLiPsTac, a controllable-light-source tactile sensor developed to validate our framework. Experimental results demonstrate that our approach enables high-fidelity 3D reconstruction across diverse curved form factors with a simple calibration procedure. We emphasize that our approach lowers the barrier to developing customized visuotactile sensors of diverse geometries, thereby making visuotactile sensing more accessible to the broader community.