Enhancing IMU-Based Online Handwriting Recognition via Contrastive Learning with Zero Inference Overhead

Fuente: arXiv
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Autores principales: Li, Jindong, Zanca, Dario, Christlein, Vincent, Hamann, Tim, Barth, Jens, Kämpf, Peter, Eskofier, Björn
Formato: Preprint
Publicado: 2026
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author Li, Jindong
Zanca, Dario
Christlein, Vincent
Hamann, Tim
Barth, Jens
Kämpf, Peter
Eskofier, Björn
author_facet Li, Jindong
Zanca, Dario
Christlein, Vincent
Hamann, Tim
Barth, Jens
Kämpf, Peter
Eskofier, Björn
contents Online handwriting recognition using inertial measurement units opens up handwriting on paper as input for digital devices. Doing it on edge hardware improves privacy and lowers latency, but entails memory constraints. To address this, we propose Error-enhanced Contrastive Handwriting Recognition (ECHWR), a training framework designed to improve feature representation and recognition accuracy without increasing inference costs. ECHWR utilizes a temporary auxiliary branch that aligns sensor signals with semantic text embeddings during the training phase. This alignment is maintained through a dual contrastive objective: an in-batch contrastive loss for general modality alignment and a novel error-based contrastive loss that distinguishes between correct signals and synthetic hard negatives. The auxiliary branch is discarded after training, which allows the deployed model to keep its original, efficient architecture. Evaluations on the OnHW-Words500 dataset show that ECHWR significantly outperforms state-of-the-art baselines, reducing character error rates by up to 7.4% on the writer-independent split and 10.4% on the writer-dependent split. Finally, although our ablation studies indicate that solving specific challenges require specific architectural and objective configurations, error-based contrastive loss shows its effectiveness for handling unseen writing styles.
format Preprint
id arxiv_https___arxiv_org_abs_2602_07049
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Enhancing IMU-Based Online Handwriting Recognition via Contrastive Learning with Zero Inference Overhead
Li, Jindong
Zanca, Dario
Christlein, Vincent
Hamann, Tim
Barth, Jens
Kämpf, Peter
Eskofier, Björn
Computer Vision and Pattern Recognition
Machine Learning
Online handwriting recognition using inertial measurement units opens up handwriting on paper as input for digital devices. Doing it on edge hardware improves privacy and lowers latency, but entails memory constraints. To address this, we propose Error-enhanced Contrastive Handwriting Recognition (ECHWR), a training framework designed to improve feature representation and recognition accuracy without increasing inference costs. ECHWR utilizes a temporary auxiliary branch that aligns sensor signals with semantic text embeddings during the training phase. This alignment is maintained through a dual contrastive objective: an in-batch contrastive loss for general modality alignment and a novel error-based contrastive loss that distinguishes between correct signals and synthetic hard negatives. The auxiliary branch is discarded after training, which allows the deployed model to keep its original, efficient architecture. Evaluations on the OnHW-Words500 dataset show that ECHWR significantly outperforms state-of-the-art baselines, reducing character error rates by up to 7.4% on the writer-independent split and 10.4% on the writer-dependent split. Finally, although our ablation studies indicate that solving specific challenges require specific architectural and objective configurations, error-based contrastive loss shows its effectiveness for handling unseen writing styles.
title Enhancing IMU-Based Online Handwriting Recognition via Contrastive Learning with Zero Inference Overhead
topic Computer Vision and Pattern Recognition
Machine Learning
url https://arxiv.org/abs/2602.07049