Hierarchical Motion Captioning Utilizing External Text Data Source

Clayton Leite; Yu Xiao

Home/Archive/arXiv

arXiv · 2509.01471

Hierarchical Motion Captioning Utilizing External Text Data Source

Clayton Leite·Yu Xiao

View original source ↗Read source document ↗Export metadata ↓

Abstract

This paper introduces a novel approach to enhance existing motion captioning methods, which directly map representations of movement to high-level descriptive captions (e.g., ``a person doing jumping jacks"). The existing methods require motion data annotated with high-level descriptions (e.g., ``jumping jacks"). However, such data is rarely available in existing motion-text datasets, which additionally do not include low-level motion descriptions. To address this, we propose a two-step hierarchical approach. First, we employ large language models to create detailed descriptions corresponding to each high-level caption that appears in the motion-text datasets (e.g., ``jumping while synchronizing arm extensions with the opening and closing of legs" for ``jumping jacks"). These refined annotations are used to retrain motion-to-text models to produce captions with low-level details. Second, we introduce a pioneering retrieval-based mechanism. It aligns the detailed low-level captions with candidate high-level captions from additional text data sources, and combine them with motion features to fabricate precise high-level captions. Our methodology is distinctive in its ability to harness knowledge from external text sources to greatly increase motion captioning accuracy, especially for movements not covered in existing motion-text datasets. Experiments on three distinct motion-text datasets (HumanML3D, KIT, and BOTH57M) demonstrate that our method achieves an improvement in average performance (across BLEU-1, BLEU-4, CIDEr, and ROUGE-L) ranging from 6% to 50% compared to the state-of-the-art M2T-Interpretable.

Explore related subjects

cs.LG

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Clayton Leite, Yu Xiao. 2025-09-01. Hierarchical Motion Captioning Utilizing External Text Data Source. https://arxiv.org/abs/2509.01471

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Analysis of Regularized Learning in Banach Spaces for Linear-functional Data

This article delves into the study of the theory of regularized learning in Banach spaces for linear-functional data. It encompasses discussions on representer theorems, pseudo-approximation theorems, and convergence theorems. Regularized learning is designed to minimize regularized empirical risks over a Banach space. The empirical risks are calculated by utilizing training data and multi-loss functions. The input training data are composed of linear functionals in a predual space of the Banach space to capture discrete local information from multimodal data and multiscale models. Through the regularized learning, approximations of the exact solution to an unidentified or uncertain original problem are globally achieved. In the convergence theorems, the convergence of the approximate solutions to the exact solution is established through the utilization of the weak* topology of the Banach space. The theorems of regularized learning are utilized in the interpretation of classical machine learning, such as support vector machines and artificial neural networks.

cs.LG↗

arXiv2026

On Minimal Depth in Neural Networks

Understanding the relationship between the depth of a neural network and its representational capacity is a central problem in deep learning theory. In this work, we develop a geometric framework to analyze the expressivity of ReLU networks with the notion of depth complexity for convex polytopes. The depth of a polytope recursively quantifies the number of alternating convex hull and Minkowski sum operations required to construct it. This geometric perspective serves as a rigorous tool for deriving depth lower bounds and understanding the structural limits of deep neural architectures. We establish lower and upper bounds on the depth of polytopes, as well as tight bounds for classical families. These results yield two main consequences. First, we provide a purely geometric proof of the expressivity bound by Arora et al. (2018), confirming that $\lceil \log_2(n+1)\rceil$ hidden layers suffice to represent any continuous piecewise linear (CPWL) function. Second, we prove that, unlike general ReLU networks, convex polytopes do not admit a universal depth bound. Specifically, the depth of cyclic polytopes in dimensions $n \geq 4$ grows unboundedly with the number of vertices. This result implies that Input Convex Neural Networks (ICNNs) cannot represent all convex CPWL functions with a fixed depth, revealing a sharp separation in expressivity between ICNNs and standard ReLU networks.

cs.LG↗

arXiv2026

ELEMENT: Episodic and Lifelong Exploration via Maximum Entropy

Reinforcement learning agents depend on reward signals whose density is rarely under the designer's control, and when such signals are absent, an agent must generate its own drive to explore. State entropy maximization offers a principled objective for this, but existing methods break down at scale in two ways: the intrinsic reward vanishes once a state has been visited, discouraging revisits to the very gateways that lead onward, and estimating entropy over millions of accumulated observations becomes computationally prohibitive. We address both with Episodic and Lifelong Exploration via Maximum Entropy (ELEMENT), a multiscale intrinsically motivated framework for reward-free exploration that transfers to downstream tasks. ELEMENT couples lifelong entropy maximization with a complementary episodic term acting on a faster timescale. For the episodic term, we derive average episodic state entropy, an intrinsic reward that is the exact minimizer of a tractable upper bound on the reward-decomposition objective; for the lifelong term, we propose a $k$NN graph-based estimator that keeps entropy tractable without forgetting. ELEMENT consistently outperforms state-of-the-art intrinsic reward baselines on state coverage and unsupervised pre-training. Videos, code, and supplementary material: https://sites.google.com/view/element-rl.

cs.LG↗