Fluorescence-enhanced Whisker Array with Vision-based Deformation Analysis for Underwater Source Localization

2026-10-05

AI Summary

This study addresses the behavioral disturbance to aquatic organisms caused by conventional optical and acoustic sensing methods by proposing a non-invasive hydrodynamic source localization approach based on fluorescence-enhanced whisker-like arrays. The proposed sensor features a nickel-titanium alloy core with a fluorescent shell, which converts local flow field deformations into optical signals under ultraviolet excitation. These signals are captured by a monocular camera and processed through image segmentation and a lightweight convolutional neural network to achieve dynamic source localization. By employing local optical readout rather than direct imaging, the method is well-suited for low-light environments. Water tank experiments demonstrate that the system achieves a mean localization error of only 88 mm while tracking a moving thruster in real time, offering a novel paradigm for eco-friendly underwater perception.

Abstract

Deep-water biological observation is essential for understanding marine organisms and their interactions with the environment. However, conventional optical and acoustic approaches can introduce stimuli that alter animal behavior and bias biological observations. This paper proposes a fluorescence-enhanced whisker array sensing system that pinpoints underwater hydrodynamic sources through local optical readout rather than direct source imaging. Five spatially oriented whiskers, fabricated with nitinol cores and fluorescent urethane shells, are integrated with ultraviolet excitation and a monocular camera. Image enhancement and segmentation are applied to track the whisker deformation. A lightweight convolutional neural network captures temporal and cross-whisker features from 2 s sequences to estimate source localization. Pool experiments achieve a mean spatial localization error of 88 mm, with 73.5 mm in radius and $2.5^\circ$ in angle, across a test region of 600 mm with $\pm30^\circ$. Real-time localization of a moving thruster demonstrates the capability of the proposed method in dynamic scenarios, highlighting its potential for integration into underwater robots for hydrodynamic source detection, localization, and tracking in low-light environments.

Problem

• underwater source localization
• biological observation
• hydrodynamic sensing
• whisker array
• low-light environment

Innovation

• Fluorescence-enhanced whisker array
• Vision-based deformation analysis
• Lightweight convolutional neural network
• Underwater source localization
• Hydrodynamic sensing