Enhancing Table Recognition with Vision LLMs: A Benchmark and Neighbor-Guided Toolchain Reasoner
Organizations: State Key Laboratory of Cognitive Intelligence, University of Science and Technology of China · Artificial Intelligence Research Institute, iFLYTEK Co., Ltd
Abstract
Pre-trained foundation models have recently made significant progress in table-related tasks such as table understanding and reasoning. However, recognizing the structure and content of unstructured tables using Vision Large Language Models (VLLMs) remains under-explored. To bridge this gap, we propose a benchmark based on a hierarchical design philosophy to evaluate the recognition capabilities of VLLMs in training-free scenarios. Through in-depth evaluations, we find that low-quality image input is a significant bottleneck in the recognition process. Drawing inspiration from this, we propose the Neighbor-Guided Toolchain Reasoner (NGTR) framework, which is characterized by integrating diverse lightweight tools for visual operations aimed at mitigating issues with low-quality images. Specifically, we transfer a tool selection experience from a similar neighbor to the input and design a reflection module to supervise the tool invocation process. Extensive experiments on public datasets demonstrate that our approach significantly enhances the recognition capabilities of the vanilla VLLMs. We believe that the benchmark and framework could provide an alternative solution to table recognition.
Figures & tables
| Granularity | Recognition Task | Description |
|---|---|---|
| Table-level | Visual Table Size Detection | Get the number of rows and columns. |
| Row-level | Row Index-based Data Recognition | Get the content list of a specific row. |
| Column-level | Column Index-based Data Recognition | Get the content list of a specific column. |
| Cell-level | Merged Cell Detection | Get contents of all merged cells. |
| Content-based Cell recognition | Get the location of specific cell content. | |
| Index-based Cell Recognition | Get the cell content of specific location. |
| Challenge | Scenario | Description |
|---|---|---|
| Visual Conditions | Blur | The image is out of focus, with details appearing smeared or indistinct. |
| Underexposure | The image is too dark, which may cause the content to be unclear. | |
| Overexposure | The image is overly bright, losing detail in some regions. | |
| Table Border Quality | Unclear Borders | The image’s table borders are faint, blending into the background. |
| Missing Borders | The table is without expected borders or separators. | |
| Thickened Borders | The table borders are thickened. |
| Tool | Descriptions |
|---|---|
| Border Enhancement | The border enhancement tool improves the legibility of tables and their structures by thickening the border lines in the image. This process enhances the structural information features of tabular data. |
| Image Upscaling | Image upscaling optimize image resolution to improve visual quality. This technique is commonly employed to repair and enhance blurry images. |
| Noise Reduction | The noise reduction tool enhances image quality by adjusting brightness and contrast to mitigate noise interference and underexposure issues. |
| Binarization | This tool converts images to black and white, highlighting key features for easier extraction. |
| Detection and Cropping | This tool identifies table regions within an image and crops them into independent segments. It is particularly suitable for processing images of tables embedded in complex backgrounds. |
| Dataset | Metrics | Lightweight OCR Model | Prompt Tuning in VLLMs | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| EDD | LGPMA | LORE | Phi | GPT-mini | Qwen | Llama | Gemini | GPT-4o | ||||||
| direct | NGTR | direct | NGTR | |||||||||||
| SciTSR | TEDS | - | 95.08 | - | 66.18 | 87.18 | 89.40 | 87.24 | 90.15 | 91.07 | +0.92 | 90.70 | 92.58 | +1.88 |
| TEDS-Struct | - | 96.24 | 97.22 | 71.56 | 92.03 | 93.06 | 92.31 | 93.73 | 95.09 | +1.36 | 94.20 | 95.78 | +1.58 | |
| PubTabNet | TEDS | 89.67 | 94.63 | - | 49.92 | 58.68 | 52.53 | 79.04 | 81.00 | 84.80 | +3.80 | 74.46 | 85.03 | +10.57 |
| TEDS-Struct | - | 96.70 | 96.94 | 57.65 | 73.00 | 63.90 | 87.64 | 85.28 | 89.30 | +4.02 | 84.91 | 92.31 | +7.40 | |
| Method | SciTSR | PubTabNet | ||
|---|---|---|---|---|
| TEDS | TEDS-Struct | TEDS | TEDS-Struct | |
| NGTR | 92.56 | 95.43 | 85.03 | 92.31 |
| w/o EXP | 90.33 | 93.68 | 80.57 | 88.40 |
| w/o REF | 91.53 | 94.77 | 82.08 | 91.85 |
| Dataset | Image Upscaling | Border Enhancement | Binarization | Noise Reduction | Detection and Cropping |
|---|---|---|---|---|---|
| PubTabNet | 93.71 | 76.42 | 4.40 | 15.64 | 64.39 |
| SciTSR | 77.97 | 90.79 | 3.70 | 20.64 | 54.23 |
| WTW | 79.81 | 86.86 | 6.65 | 15.46 | 82.93 |
Appendix figures & tables14 assets
Supplementary material from the paper’s appendix.
Appendix
| Dataset | Tables | Source | Markup Sequence Annotations | Textual Annotations | Year |
|---|---|---|---|---|---|
| SciTSR | 15K | ArXiv | 2019 | ||
| PubTabNet | 568K | PubMed | 2020 | ||
| WTW | 14.6K | Wild Scenarios | 2021 |
Table Structure Recognition
Table structure recognition recovers rows, columns, cells, spans, and hierarchy from table images and documents.
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