TextAlign: Preference Alignment for Text Rendering with Hierarchical Rewards

Fuente: arXiv
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Autori principali: Cui, Mingxuan, Yang, Jingpu, Ji, Fengxian, Jiang, Qian, Shi, Zhecheng, Wang, Jiaming, Song, Zirui, Koto, Fajri, Chen, Xiuying
Natura: Preprint
Pubblicazione: 2026
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author Cui, Mingxuan
Yang, Jingpu
Ji, Fengxian
Jiang, Qian
Shi, Zhecheng
Wang, Jiaming
Song, Zirui
Koto, Fajri
Chen, Xiuying
author_facet Cui, Mingxuan
Yang, Jingpu
Ji, Fengxian
Jiang, Qian
Shi, Zhecheng
Wang, Jiaming
Song, Zirui
Koto, Fajri
Chen, Xiuying
contents Faithful text rendering remains a persistent weakness of large text-to-image generative models, as it requires both semantic instruction following and fine-grained glyph-level structure. Prior methods often improve this ability through architecture-specific modules or encoder modifications, which complicate deployment across foundation models. We study text rendering as a post-training preference-alignment problem and propose TextAlign, a non-invasive framework that keeps the generator architecture unchanged. The key component is a hierarchical vision-language model (VLM)-based reward that decomposes rendering errors into global, word, and glyph levels, then converts binary defect judgments into a scalar preference signal. The resulting signal supports both Group Relative Policy Optimization (GRPO) and Direct Preference Optimization (DPO). Experiments on FLUX.1-dev and Z-Image-Turbo show consistent gains in OCR-based text accuracy without degrading general generation quality. Compared with strong foundation and text-rendering baselines, including SD3.5, Qwen-Image, AnyText, and TextDiffuser, these results indicate that reward design offers a scalable alternative to model redesign for improving text rendering.
format Preprint
id arxiv_https___arxiv_org_abs_2605_19320
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle TextAlign: Preference Alignment for Text Rendering with Hierarchical Rewards
Cui, Mingxuan
Yang, Jingpu
Ji, Fengxian
Jiang, Qian
Shi, Zhecheng
Wang, Jiaming
Song, Zirui
Koto, Fajri
Chen, Xiuying
Computer Vision and Pattern Recognition
Databases
Faithful text rendering remains a persistent weakness of large text-to-image generative models, as it requires both semantic instruction following and fine-grained glyph-level structure. Prior methods often improve this ability through architecture-specific modules or encoder modifications, which complicate deployment across foundation models. We study text rendering as a post-training preference-alignment problem and propose TextAlign, a non-invasive framework that keeps the generator architecture unchanged. The key component is a hierarchical vision-language model (VLM)-based reward that decomposes rendering errors into global, word, and glyph levels, then converts binary defect judgments into a scalar preference signal. The resulting signal supports both Group Relative Policy Optimization (GRPO) and Direct Preference Optimization (DPO). Experiments on FLUX.1-dev and Z-Image-Turbo show consistent gains in OCR-based text accuracy without degrading general generation quality. Compared with strong foundation and text-rendering baselines, including SD3.5, Qwen-Image, AnyText, and TextDiffuser, these results indicate that reward design offers a scalable alternative to model redesign for improving text rendering.
title TextAlign: Preference Alignment for Text Rendering with Hierarchical Rewards
topic Computer Vision and Pattern Recognition
Databases
url https://arxiv.org/abs/2605.19320