Continuous body 3-D reconstruction of limbless animals

TL;DR

This paper introduces a novel interpolation method for accurately reconstructing the 3-D shape and motion of limbless animals, improving upon existing techniques and applicable to various biological and robotic systems.

Contribution

It presents a backbone optimization-based interpolation approach that enhances 3-D shape and orientation accuracy for limbless animals, surpassing traditional cubic B-spline methods.

Findings

Achieves ~50% error reduction in 3-D shape and orientation interpolation.

Applicable to various limbless animals and continuum robots.

Provides accessible code and demo files for implementation.

Abstract

Limbless animals such as snakes, limbless lizards, worms, eels, and lampreys move their slender, long bodies in three dimensions to traverse diverse environments. Accurately quantifying their continuous body's 3-D shape and motion is important for understanding body-environment interactions in complex terrain, but this is difficult to achieve (especially for local orientation and rotation). Here, we describe an interpolation method to quantify continuous body 3-D position and orientation. We simplify the body as an elastic rod and apply a backbone optimization method to interpolate continuous body shape between end constraints imposed by tracked markers. Despite over-simplifying the biomechanics, our method achieves a higher interpolation accuracy (~50% error) in both 3-D position and orientation compared with the widely-used cubic B-spline interpolation method. Beyond snakes traversing large obstacles as demonstrated, our method applies to other long, slender, limbless animals and continuum robots. We provide codes and demo files for easy application of our method.