@inproceedings{shu-zhou-2026-multi,
title = "Multi-Task Learning Trade-offs in Vision{--}Language Models for {A}ncient {C}hinese {OCR}: An Empirical Analysis of Parameter-Efficient Adaptation",
author = "Shu, Yuhan and
Zhou, Huizi",
editor = "Sprugnoli, Rachele and
Passarotti, Marco",
booktitle = "Proceedings of the Fourth Workshop on Language Technologies for Historical and Ancient Languages ({LT}4{HALA} 2026) @ {LREC} 2026",
month = may,
year = "2026",
address = "Palma, Mallorca (Spain)",
publisher = "ELRA Language Resources Association (ELRA)",
url = "https://aclanthology.org/2026.lt4hala-1.34/",
doi = "10.63317/5hvjskashyjv",
pages = "330--338",
abstract = "This study evaluates the efficacy of multi-task adaptation in large-scale vision{--}language models (VLMs), specifically Qwen2.5-VL, for the simultaneous recognition and structural parsing of historical Chinese documents within the EvaHan2026 benchmark. Utilizing a parameter-efficient fine-tuning (PEFT) strategy via LoRA (rank 64), our framework demonstrates superior performance in layout analysis (Task B), achieving an mAP of 0.2802{---}a 39.6{\%} improvement over the competitive baseline{---}and a Macro F1 of 0.3609. Conversely, a pronounced performance-utility trade-off is observed in printed OCR (Task A), where the character error rate (CER) escalates from 0.0618 to 0.1100 (+78{\%} relative). This divergence highlights a critical catastrophic forgetting effect induced by gradient interference during multi-task optimization. While handwritten OCR (Task C) remains relatively stable (CER of 0.0963), our findings suggest that although unified VLM architectures excel at high-level structural detection, they encounter significant parameter capacity bottlenecks when concurrently optimizing fine-grained character-level transcription. This analysis highlights the optimization challenges when balancing spatial detection and character recognition in a unified framework."
}<?xml version="1.0" encoding="UTF-8"?>
<modsCollection xmlns="http://www.loc.gov/mods/v3">
<mods ID="shu-zhou-2026-multi">
<titleInfo>
<title>Multi-Task Learning Trade-offs in Vision–Language Models for Ancient Chinese OCR: An Empirical Analysis of Parameter-Efficient Adaptation</title>
</titleInfo>
<name type="personal">
<namePart type="given">Yuhan</namePart>
<namePart type="family">Shu</namePart>
<role>
<roleTerm authority="marcrelator" type="text">author</roleTerm>
</role>
</name>
<name type="personal">
<namePart type="given">Huizi</namePart>
<namePart type="family">Zhou</namePart>
<role>
<roleTerm authority="marcrelator" type="text">author</roleTerm>
</role>
</name>
<originInfo>
<dateIssued>2026-05</dateIssued>
</originInfo>
<typeOfResource>text</typeOfResource>
<relatedItem type="host">
<titleInfo>
<title>Proceedings of the Fourth Workshop on Language Technologies for Historical and Ancient Languages (LT4HALA 2026) @ LREC 2026</title>
</titleInfo>
<name type="personal">
<namePart type="given">Rachele</namePart>
<namePart type="family">Sprugnoli</namePart>
<role>
<roleTerm authority="marcrelator" type="text">editor</roleTerm>
</role>
</name>
<name type="personal">
<namePart type="given">Marco</namePart>
<namePart type="family">Passarotti</namePart>
<role>
<roleTerm authority="marcrelator" type="text">editor</roleTerm>
</role>
</name>
<originInfo>
<publisher>ELRA Language Resources Association (ELRA)</publisher>
<place>
<placeTerm type="text">Palma, Mallorca (Spain)</placeTerm>
</place>
</originInfo>
<genre authority="marcgt">conference publication</genre>
</relatedItem>
<abstract>This study evaluates the efficacy of multi-task adaptation in large-scale vision–language models (VLMs), specifically Qwen2.5-VL, for the simultaneous recognition and structural parsing of historical Chinese documents within the EvaHan2026 benchmark. Utilizing a parameter-efficient fine-tuning (PEFT) strategy via LoRA (rank 64), our framework demonstrates superior performance in layout analysis (Task B), achieving an mAP of 0.2802—a 39.6% improvement over the competitive baseline—and a Macro F1 of 0.3609. Conversely, a pronounced performance-utility trade-off is observed in printed OCR (Task A), where the character error rate (CER) escalates from 0.0618 to 0.1100 (+78% relative). This divergence highlights a critical catastrophic forgetting effect induced by gradient interference during multi-task optimization. While handwritten OCR (Task C) remains relatively stable (CER of 0.0963), our findings suggest that although unified VLM architectures excel at high-level structural detection, they encounter significant parameter capacity bottlenecks when concurrently optimizing fine-grained character-level transcription. This analysis highlights the optimization challenges when balancing spatial detection and character recognition in a unified framework.</abstract>
<identifier type="citekey">shu-zhou-2026-multi</identifier>
<identifier type="doi">10.63317/5hvjskashyjv</identifier>
<location>
<url>https://aclanthology.org/2026.lt4hala-1.34/</url>
</location>
<part>
<date>2026-05</date>
<extent unit="page">
<start>330</start>
<end>338</end>
</extent>
</part>
</mods>
</modsCollection>
%0 Conference Proceedings
%T Multi-Task Learning Trade-offs in Vision–Language Models for Ancient Chinese OCR: An Empirical Analysis of Parameter-Efficient Adaptation
%A Shu, Yuhan
%A Zhou, Huizi
%Y Sprugnoli, Rachele
%Y Passarotti, Marco
%S Proceedings of the Fourth Workshop on Language Technologies for Historical and Ancient Languages (LT4HALA 2026) @ LREC 2026
%D 2026
%8 May
%I ELRA Language Resources Association (ELRA)
%C Palma, Mallorca (Spain)
%F shu-zhou-2026-multi
%X This study evaluates the efficacy of multi-task adaptation in large-scale vision–language models (VLMs), specifically Qwen2.5-VL, for the simultaneous recognition and structural parsing of historical Chinese documents within the EvaHan2026 benchmark. Utilizing a parameter-efficient fine-tuning (PEFT) strategy via LoRA (rank 64), our framework demonstrates superior performance in layout analysis (Task B), achieving an mAP of 0.2802—a 39.6% improvement over the competitive baseline—and a Macro F1 of 0.3609. Conversely, a pronounced performance-utility trade-off is observed in printed OCR (Task A), where the character error rate (CER) escalates from 0.0618 to 0.1100 (+78% relative). This divergence highlights a critical catastrophic forgetting effect induced by gradient interference during multi-task optimization. While handwritten OCR (Task C) remains relatively stable (CER of 0.0963), our findings suggest that although unified VLM architectures excel at high-level structural detection, they encounter significant parameter capacity bottlenecks when concurrently optimizing fine-grained character-level transcription. This analysis highlights the optimization challenges when balancing spatial detection and character recognition in a unified framework.
%R 10.63317/5hvjskashyjv
%U https://aclanthology.org/2026.lt4hala-1.34/
%U https://doi.org/10.63317/5hvjskashyjv
%P 330-338
Markdown (Informal)
[Multi-Task Learning Trade-offs in Vision–Language Models for Ancient Chinese OCR: An Empirical Analysis of Parameter-Efficient Adaptation](https://aclanthology.org/2026.lt4hala-1.34/) (Shu & Zhou, LT4HALA 2026)
ACL