RadarEye: Robust Liquid Level Tracking Using mmWave Radar in Robotic Pouring

TL;DR

RadarEye introduces a mmWave radar-based system for precise, real-time liquid level tracking in robotic pouring, overcoming visual perception challenges caused by transparency, reflections, and lighting variability.

Contribution

It presents a novel radar signal processing pipeline combining high-resolution sensing and physics-informed tracking for robust liquid level estimation.

Findings

Achieves 0.35 cm median height error in real-robot experiments.

Operates with sub-millisecond latency for real-time performance.

Outperforms vision and ultrasound baselines in accuracy.

Abstract

Transparent liquid manipulation in robotic pouring remains challenging for perception systems: specular/refraction effects and lighting variability degrade visual cues, undermining reliable level estimation. To address this challenge, we introduce RadarEye, a real-time mmWave radar signal processing pipeline for robust liquid level estimation and tracking during the whole pouring process. RadarEye integrates (i) a high-resolution range-angle beamforming module for liquid level sensing and (ii) a physics-informed mid-pour tracker that suppresses multipath to maintain lock on the liquid surface despite stream-induced clutter and source container reflections. The pipeline delivers sub-millisecond latency. In real-robot water-pouring experiments, RadarEye achieves a 0.35 cm median absolute height error at 0.62 ms per update, substantially outperforming vision and ultrasound baselines.