Organizations: School of Communication and Information Engineering, Shanghai University, Shanghai 200444, China · Huawei Translation Services Center, China · School of Computer Science and Technology, East China Normal University, Shanghai 200062, China · State Key Laboratory of Submarine Geoscience, School of Automation and Intelligent Sensing, Shanghai Jiao Tong University, Shanghai 200240, China
Text Image Machine Translation (TIMT) aims to translate text embedded in images in the source-language into target-language, requiring synergistic integration of visual perception and linguistic understanding. Existing TIMT methods, whether cascaded pipelines or end-to-end multimodal large language models (MLLMs),struggle with high-resolution text-rich images due to cluttered layouts, diverse fonts, and non-textual distractions, resulting in text omission, semantic drift, and contextual inconsistency. To address these challenges, we propose GLoTran, a global-local dual visual perception framework for MLLM-based TIMT. GLoTran integrates a low-resolution global image with multi-scale region-level text image slices under an instruction-guided alignment strategy, conditioning MLLMs to maintain scene-level contextual consistency while faithfully capturing fine-grained textual details. Moreover, to realize this dual-perception paradigm, we construct GLoD, a large-scale text-rich TIMT dataset comprising 510K high-resolution global-local image-text pairs covering diverse real-world scenarios. Extensive experiments demonstrate that GLoTran substantially improves translation completeness and accuracy over state-of-the-art MLLMs, offering a new paradigm for fine-grained TIMT under high-resolution and text-rich conditions.
Figures & tables
Figure 1: Comparison of (a) cascade methods, (b) traditional end-to-end models, (c) MLLMs-based models, and (d) our proposed GLoTran for TIMT. Through a dual visual perception strategy integrating global contextual understanding and local textual focus, we enable more complete and accurate TIMT.
Figure 2: Overview of the proposed GLoTran framework. (a) The high-resolution input image is processed by a text region detector to identify candidate textual regions, which are subsequently sorted, merged, and cropped into localized slices. (b) The global image and the local slices are fed into GLoTran with a structured prompt, enabling global contextual understanding and local textual focus for TIMT.
Figure 3: An illustration of the structured prompt design in GLoTran.
Dataset
Text-Rich
Global-Local
Language
Images
Image-Text
ECOIT [ 65 ]
✗
✗
2
479,490
479,490
OCRMT30K [ 25 ]
✗
✗
2
30,000
30,000
DoTA [ 28 ]
✓
✗
2
126,345
126,000
IIMT [ 24 ]
✗
✗
1
89,033
89,033
MIT-10M [ 26 ]
✗
✗
14
840,855
10,931,115
GLoD
✓
✓
5
517,354
517,354
Table 1: The statistics of GLoD and other TIMT dataset.
Figure 4: Overview of GLoD curation pipeline. The construction pipeline systematically generates high-quality global and local translation pairs through five core stages: conceptualization, data collection and pre-filtering, text region detection and grouping, global-local translation, and quality control.
Document
Scene
Poster
Method
Size
Paper ↑
News ↑
Novel ↑
Title ↑
Sign ↑
Introduction ↑
Cover ↑
Leaflet ↑
Avg ↑
Close-Source MLLMs
GPT-4o [ 23 ]
∼ 200B
62.1 / 86.3
51.6 / 85.6
44.2 / 83.4
51.3 / 83.4
46.1 / 83.3
40.1 / 75.3
34.9 / 69.1
43.9 / 71.7
46.8 / 79.9
Qwen-VL-Max [ 1 ]
∼ 72B
60.5 / 85.7
58.3 / 85.7
44.8 / 83.5
50.1 / 81.6
43.2 / 80.5
37.8 / 74.6
34.2 / 67.3
43.7 / 69.9
46.5 / 78.6
Open-Source MLLMs
Qwen2.5-VL-Instruct [ 2 ]
7B
60.7 / 85.8
53.4 / 85.5
27.4 / 78.1
47.9 / 80.1
44.0 / 82.2
36.2 / 72.8
30.3 / 64.4
43.6 / 72.4
42.9 / 77.7
Table 2: Performance comparison of translating English into Chinese with open-source and close-source MLLMs on the MCiTon [ 66 ] test set. We report BLEU/COMET for translation quality of each real-world scenarios. ↑ indicates higher is better. The bold represents the best results, and the underline represents the second best results.
Figure 5: (a)-(b) performance comparison of multilingual translating task with open-source MLLMs on MTIT6 [ 40 ] . (c)-(d) performance analysis with respect to global image resolution and the pre-region translation replay window size η .
Figure 6: Qualitative comparison. The results in □ indicates omissions, those in □ indicate mistranslations, and those in □ indicate hallucinations caused by contextual misunderstanding.
Method
zh → en
zh → ko
ko → zh
jp → zh
Novel
Title
Introduction
Leaflet
InternVL2.5 4B
4.02 / 70.78
1.19 / 60.44
2.57 / 48.20
28.37 / 76.66
18.48 / 75.67
31.44 / 76.10
26.16 / 71.09
21.22 / 63.92
GLoTran (InternVL2.5 4B)
6.68 / 71.46
2.26 / 60.86
5.97 / 58.89
29.93 / 78.33
25.80 / 77.51
38.20 / 79.82
29.47 / 71.52
23.27 / 65.50
Gain △
+66.17 / +0.96
+89.92 / +0.69
+132.29 / +22.18
+5.50 / +2.18
+39.61 / +2.43
+21.56 / +4.88
+12.65 / +0.61
+9.66 / +2.47
Qwen2.5-VL 7B
9.54 / 74.45
4.13 / 66.76
20.23 / 70.27
35.83 / 79.09
27.43 / 78.09
47.91 / 80.09
36.18 / 72.78
43.66 / 72.40
GLoTran (Qwen2.5-VL 7B)
10.99 / 76.78
5.45 / 68.49
22.39 / 70.99
43.81 / 81.84
44.59 / 83.60
53.15 / 82.92
38.93 / 74.12
45.64 / 73.74
Gain △
+15.20 / +3.13
+31.96 / +2.59
+10.68 / +1.02
+22.27 / +3.48
+62.59 / +7.06
+10.93 / +3.53
+7.60 / +1.84
+4.54 / +1.85
Table 3: Ablation study on the effect of GLoTran across different backbone models. We report BLEU and COMET scores for each translation task. The Gain row denotes the relative improvement (%) of GLoTran over its baseline, calculated as (GLoTran−Baseline)/Baseline×100% .
Document
Scene
Poster
Method
Size
Paper ↑
News ↑
Novel ↑
Title ↑
Sign ↑
Introduction ↑
Cover ↑
Leaflet ↑
InternVL3
8B
59.8/86.0
48.9/83.9
31.2/79.8
50.5/82.1
41.8/81.6
32.8/72.6
29.5/66.1
35.8/70.9
InternVL3 ♢
8B
60.5/86.0
45.0/83.7
36.8/81.2
48.1/77.9
36.8/75.6
37.4/73.4
27.8/63.7
46.9/72.9
Qwen2.5-VL
7B
60.7/85.8
53.4/85.5
27.4/78.1
47.9/80.1
44.0/82.2
36.2/72.8
30.3/64.4
43.6/72.4
Qwen2.5-VL ♢
7B
63.5/86.5
46.3/84.0
37.6/81.9
42.6/78.8
37.5/75.2
40.3/73.4
32.9/65.8
44.6/72.9
Qwen3-VL
8B
60.9/86.1
54.3/86.2
43.6/83.1
52.3/81.8
44.2/83.0
33.6/75.8
36.2/70.4
48.2/75.1
Table 4: Components analysis results (BLEU/COMET) of GLoTran on the MCiTon dataset.
Method
Size
Token V ↓
Novel
zh → jp
FTL s ↓
FPS ↑
BLEU ↑
FTL s ↓
FPS ↑
BLEU ↑
Qwen2.5-VL ♡
7B
6.1K
0.098
0.061
27.36
0.098
3.755
11.85
InternVL3 ♡
8B
10K
0.033
0.065
31.74
0.149
2.016
15.02
Qwen3-VL ♡
8B
6.1K
0.099
0.028
9.98
0.093
2.572
18.79
Qwen3-VL ♠
8B
164K
1.081
0.041
43.56
3.297
0.275
22.06
GLoTran ♡
8B
8.4K
3.002
0.035
48.12
0.253
2.285
26.74
Table 5: Comparison of MLLMs in terms of efficiency and accuracy for TIMI. The superscripts ♣ , ♡ , and ♠ denote input resolutions of 224 × 224, 448 × 448, and the original size, respectively.
PRHLT Research Center - Universitat Polit`ecnica de Val`encia, Camino de Vera, s/n - Valencia · ValgrAI - Valencian Graduate School and Research Network for Artificial Intelligence, Camino de Vera s/n
Institute of Information Engineering, Chinese Academy of Science, China · MiLM Plus, Xiaomi Inc, China · School of Cyber Security, University of Chinese Academy of Science, China +2