TextDART Γ— SCANNER

Blame errant words,
not the canvas.

Defect-Aware Spatial Credit Assignment
for Visual Text Generation

Paper

Sujie Hu1,6, Huaisong Zhang2,6, Pujing Yang3,6, Qian Wang4,6, Xiaomin Li5,6,
Xinhang Leng6,†, Chen Li6, Jing Lyu6, Xiu Li2, Ling Pan1,βˆ—

1 The Hong Kong University of Science and Technology2 Tsinghua University3 Zhejiang University4 Peking University5 Dalian University of Technology6 Weixin, Tencent

† Project lead   βˆ— Corresponding author

Abstract

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Recent reinforcement learning approaches have improved visual text generation, yet generated images still suffer from incorrect wording and malformed glyphs. We identify two coupled limitations: recognition-based rewards often overlook visible glyph defects, while whole-image scalar feedback obscures the uneven quality of individual text regions. These limitations motivate our central principle: Blame errant words, not the canvas, to effectively preserve local quality distinctions from evaluation to policy optimization.

First, we introduce TextDART, a defect-aware region-targeted reward model that localizes individual text regions and independently evaluates their semantic correctness and glyph quality, providing fine-grained, region-precise feedback. Building on TextDART, we propose SCANNER, which turns these regional judgments into spatially differentiated policy feedback. It normalizes rewards for each text target across sampled images and casts the resulting regional advantages onto the corresponding latent tokens. Extensive experiments on existing benchmarks and our newly established PolyText-Bench demonstrate that our approach achieves state-of-the-art performance in text accuracy and glyph fidelity.

Method

TextDART

Defect-Aware Region-Targeted Rewards

  1. Localized Defect Perception

    Localize each text region and recognize its content while identifying malformed glyphs.

  2. Regional rewards

    Evaluate semantic correctness and glyph quality independently to produce region-targeted rewards.

SCANNER

Spatial Credit Assignment with noise-awareness

  1. Target-group advantages

    Normalize rewards for each text target across sampled images and project the regional advantages onto their latent tokens.

  2. Noise-aware schedule

    Fuse global and regional advantages as noise decreases, shifting from global guidance to local feedback.

  3. Target-level policy ratios

    Pool policy ratios over each target’s token support to retain regional distinctions during optimization.

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Interactive demo

<#>RESH DAILY

Recognition results

PP-OCRv5, TextPecker and TextDART on five challenging text scenes. Images and transcriptions are displayed directly from the supplied files.

Generation

Qualitative results

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Quantitative results

Visual text generation across five benchmarks: English results for FLUX.1-dev, and English and Chinese results for Qwen-Image-2512.

↑ Higher is better. ↓ Lower is better. Bold indicates the best result within each backbone and language setting. β€œβ€”β€ denotes no reward model, no RL algorithm, or an unsupported metric.

Citation

BibTeX
@article{hu2026textdartscanner,
  title={Blame Errant Words, Not the Canvas: Defect-Aware Spatial Credit Assignment for Visual Text Generation},
  author={Hu, Sujie and Zhang, Huaisong and Yang, Pujing and Wang, Qian and Li, Xiaomin and Leng, Xinhang and Li, Chen and Lyu, Jing and Li, Xiu and Pan, Ling},
  journal={arXiv preprint arXiv:2610.20794},
  year={2026}
}

Image