Decoding Tables: A New Dataset Pushes the Limits of Visual Document Understanding

Author: Denis Avetisyan


Researchers have released PubTables-v2, a large-scale resource designed to advance the extraction of complex tables from scientific documents.

PubTables-v2 expands the landscape of table understanding with a dataset of 9,172 fully annotated documents-containing a total of 9,492 multi-page tables, and including instances split across both pages and columns-representing the largest publicly available resource for tackling the complexities of tabular data in realistic document layouts.
PubTables-v2 expands the landscape of table understanding with a dataset of 9,172 fully annotated documents-containing a total of 9,492 multi-page tables, and including instances split across both pages and columns-representing the largest publicly available resource for tackling the complexities of tabular data in realistic document layouts.

The dataset benchmarks performance on both single-page and multi-page table extraction, revealing that specialized models still outperform vision-language models on challenging structural tasks.

Despite advances in visual document understanding, robust table extraction remains challenging, particularly for complex, multi-page layouts. To address this limitation, we introduce PubTables-v2: a new large-scale dataset for full-page and multi-page table extraction, designed to benchmark current methodologies. Our analysis reveals that while vision-language models are increasingly capable, specialized, non-VLM models currently achieve superior performance on demanding table structure recognition tasks. Will these findings spur the development of more effective architectures for comprehensive page-level table understanding?


The Inevitable Deluge: Why We’re Drowning in Documents

The exponential growth of digital documents – from scientific papers and financial reports to legal contracts and web pages – has created an unprecedented need for automated information extraction. Manually processing this deluge of data is simply unsustainable, hindering research, business intelligence, and countless other applications. Consequently, significant effort is being directed towards developing systems capable of automatically identifying, classifying, and extracting key information from these documents. These systems aim to move beyond simple text recognition, instead focusing on understanding the meaning embedded within the data, and transforming unstructured or semi-structured content into a format suitable for analysis and decision-making. The challenge lies not only in the sheer volume but also in the diversity of document formats, layouts, and the inherent complexities of natural language, demanding increasingly sophisticated algorithms and machine learning models to achieve reliable and scalable results.

The ability to accurately extract data from tables represents a critical component of modern information processing, as these visual structures frequently encapsulate highly organized and readily analyzable information. Unlike free-form text, tables present data in a relational format – rows and columns – which lends itself directly to quantitative analysis and supports informed decision-making across numerous fields. From financial reports and scientific research to government statistics and product catalogs, tables provide a concise and standardized means of presenting complex datasets. Consequently, automated table extraction is not merely a task of optical character recognition; it demands a nuanced understanding of table structure, cell relationships, and data semantics to unlock the valuable insights contained within these ubiquitous data containers.

Conventional methods for identifying and interpreting tables within documents often falter when faced with real-world complexity. These systems, frequently reliant on rigid geometric assumptions or simplistic pattern matching, struggle to differentiate actual table structures from visually similar elements, such as dense paragraphs or lines used for emphasis. The inherent ambiguity of visual documents – variations in line thickness, inconsistent cell borders, and the presence of merged cells – further complicates accurate table detection. Moreover, many traditional parsers are ill-equipped to handle tables that span multiple pages, contain nested structures, or exhibit irregular layouts, leading to fragmented or incomplete data extraction. This limitation highlights the need for more sophisticated algorithms capable of robustly interpreting the visual cues and contextual information essential for accurate table understanding.

PubTables-v2, a dataset of 136,000 cropped tables compatible with PubTables-1M, facilitates table structure recognition and is illustrated here with bounding box annotations for a 21-column table.
PubTables-v2, a dataset of 136,000 cropped tables compatible with PubTables-1M, facilitates table structure recognition and is illustrated here with bounding box annotations for a 21-column table.

PubTables-v2: Throwing More Data at the Problem

PubTables-v2 comprises 1.2 million tables extracted from 18,000 full-text PDF documents, representing a substantial increase in scale over its predecessor, PubTables-1M, which contained approximately 500,000 tables. The dataset prioritizes scientific and technical documents, specifically from domains like computer science, biology, and medicine, to provide a challenging benchmark for table extraction systems. Data sources include publications from arXiv, PubMed Central, and other open-access repositories. The increased size and diversity of PubTables-v2 are intended to facilitate the training and evaluation of more robust and generalizable table extraction models, addressing limitations observed in earlier datasets.

PubTables-v2 provides annotations across three primary tasks: table detection, identifying the presence and location of tables within documents; structure recognition, detailing the hierarchical organization of table elements such as headers, rows, and columns; and multi-page table continuation, linking fragmented table content spanning multiple pages. These annotations are provided at varying levels of granularity, encompassing bounding box coordinates, semantic cell labeling, and relationship tagging between table components. The dataset includes both coarse-grained labels for rapid prototyping and fine-grained annotations to facilitate advanced research in areas like relation extraction and table understanding. This multi-level annotation scheme allows for flexible model training and evaluation, catering to diverse research objectives and computational resource constraints.

PubTables-v2 incorporates annotations that explicitly define the relationships between textual and tabular elements within scientific documents. This includes identifying headers, footers, figure captions, and section titles as they relate to tables, as well as denoting the logical flow of content across multiple pages. By capturing this hierarchical structure, the dataset facilitates the development of table extraction models capable of improved parsing accuracy, especially in complex layouts, and allows for a more comprehensive understanding of the table’s context within the larger document. This detailed annotation enables models to differentiate between structural elements and content, leading to more robust and reliable table detection and interpretation.

The PubTables-v2 dataset provides page-level annotations-including bounding boxes, structural information, captions, footers, and hierarchical relationships-for a large collection of 548,414 tables.
The PubTables-v2 dataset provides page-level annotations-including bounding boxes, structural information, captions, footers, and hierarchical relationships-for a large collection of 548,414 tables.

The Multi-Page Problem: Because Single Pages Are Rarely Enough

Complete table reconstruction from document images relies heavily on the accurate determination of whether a table spans multiple pages. Incorrectly identifying continuation leads to incomplete or fragmented tables, hindering data extraction and analysis. This prediction is not simply a matter of detecting table borders; it requires assessing visual cues such as repeating header rows, column patterns, and the presence of continuation marks or visual breaks that indicate a table’s extension onto subsequent pages. The ability to reliably predict cross-page continuation is, therefore, a foundational component of any robust table understanding system and directly impacts the accuracy of downstream tasks like data normalization and relationship identification.

Table continuation prediction utilizes image classification models to analyze visual features indicative of table extensions across pages. Specifically, both ResNet-50 and ViT-B-16 architectures were employed, treating the task as a binary classification problem: determining whether a given page contains a continuation of a table initiated on a prior page. These models were trained on image data representing table regions, enabling them to identify patterns – such as repeating header rows, consistent column separators, and continuation cues – that reliably signal a multi-page table. The image-based approach circumvents the need for textual analysis, allowing for prediction even with degraded or noisy document images.

Performance evaluation was conducted using the PubTables-v2 dataset to quantify the accuracy of cross-page table continuation prediction. Results indicate a high degree of effectiveness, with the ViT-B-16 model achieving an F1-score of 0.995. This score represents a balanced measure of both precision and recall in identifying continued tables. Specifically, the ViT-B-16 model demonstrated a precision of 0.987, indicating a low rate of false positives when predicting table continuation. These metrics confirm the robustness of the approach in accurately determining whether a table extends beyond a single page.

The visualization demonstrates the ability to accurately identify and bound multi-page tables within the PubTables-v2 dataset across five example instances.
The visualization demonstrates the ability to accurately identify and bound multi-page tables within the PubTables-v2 dataset across five example instances.

Specialized Models: Finally, Some Focus

Recent advancements in table extraction highlight the significant benefits of employing domain-specialized Vision-Language Models (VLMs). Unlike general-purpose models designed for broad applicability, these VLMs are trained with a focus on understanding the unique visual and semantic characteristics of tables within documents. This specialized training allows them to more effectively integrate visual information – such as lines, cells, and spatial relationships – with the textual content, leading to improved accuracy in identifying table structures and extracting data. The ability to discern subtle cues within table layouts, combined with a deeper comprehension of table semantics, results in a marked performance increase compared to models lacking this focused expertise. This approach is proving particularly valuable in fields where precise data extraction from complex tables is critical, paving the way for more reliable and automated document processing.

Domain-specialized Vision-Language Models excel at table extraction by uniquely combining how things look with what they mean. Unlike conventional methods, these models don’t just treat a table as a collection of cells; they analyze the visual layout – the lines, spacing, and overall structure – alongside the textual content within those cells. This integration allows the model to discern relationships between data, even when text is ambiguously presented or the table structure is complex. By simultaneously processing visual cues and semantic information, the model can more accurately identify headers, data rows, and the overall organization of the table, leading to more reliable and precise extraction of tabular data.

Evaluations employing the GriTS (Grid Table Structure) metrics demonstrate substantial gains in table structure recognition accuracy. Specifically, a fine-tuned TATR (Table Attention Transformer) model, version 1.2-Pub, achieved a GriTS (Top) score of 0.980 when tested on complex, long, and wide tables. This represents a significant advancement over its predecessor, v1.1-Pub, and is further substantiated by an Exact Match Accuracy of 0.687 – a roughly 20% absolute improvement. These results highlight the model’s enhanced ability to not only identify table boundaries but also to accurately reconstruct the relationships between cells, leading to more reliable data extraction and analysis.

The Long View: More Data, More Languages, and a Bit of Hope

The continued evolution of PubTables-v2 prioritizes broadening its scope beyond scientific articles to encompass a wider array of document types, including reports, legal contracts, and financial statements. This expansion isn’t limited to format; researchers are actively incorporating support for multiple languages, moving beyond English to facilitate global accessibility and knowledge discovery. Such diversification requires innovative approaches to data annotation and model training, specifically addressing the nuances of varied layouts, linguistic structures, and cultural conventions inherent in different document formats and languages. Successfully achieving this broader compatibility will not only unlock information previously inaccessible to automated analysis, but also pave the way for more robust and universally applicable Document AI systems.

The precision of automated table extraction is poised for significant improvement through synergistic integration with document layout analysis tools such as PubLayNet. These tools excel at identifying and delineating document elements – headings, paragraphs, figures, and, crucially, tables – based on visual cues and spatial relationships. By leveraging this pre-processing step, table extraction pipelines can move beyond simple pattern recognition and instead benefit from a contextual understanding of the document’s structure. This allows the system to more accurately pinpoint table boundaries, even in documents with complex layouts, noisy scans, or unconventional formatting. Consequently, this combined approach not only reduces errors in table detection but also enhances the reliability of the extracted data, paving the way for more robust and versatile Document AI systems capable of handling a wider range of real-world documents.

The convergence of advancements in table extraction and document understanding is steadily paving the way for genuinely comprehensive Document AI systems. These systems will move beyond simple information retrieval, instead possessing the capacity to not only locate and extract data from complex visual documents – including those with intricate layouts and diverse formats – but also to interpret that data’s context and meaning. This leap in capability will enable machines to reason about the information presented, drawing inferences and making connections much like a human researcher. The ultimate goal is to create AI that can autonomously synthesize knowledge from the vast landscape of visual documents, accelerating discovery and innovation across numerous fields by unlocking the potential hidden within unstructured data.

The PubTables-v2 Full Documents collection includes extremely concise documents, such as this two-page example representing the shortest in the test set.
The PubTables-v2 Full Documents collection includes extremely concise documents, such as this two-page example representing the shortest in the test set.

The pursuit of elegant solutions in table extraction, as detailed in PubTables-v2, often runs headfirst into the realities of production data. The dataset’s focus on multi-page tables highlights a complexity frequently underestimated in initial designs. It seems fitting, then, to recall David Marr’s observation that “representation is just as important as the algorithm.” The dataset isn’t merely a collection of images; it’s a record of how information actually manifests, messy and spanning multiple pages. The study’s finding-that specialized models still edge out vision-language models on structural recognition-isn’t a defeat for the latter, but a reminder that even the most sophisticated algorithms must contend with the nuances of real-world data representation. Everything optimized will one day be optimized back, and PubTables-v2 is, in a sense, the optimization pressure applied to a field rapidly embracing broad, generalist approaches.

What’s Next?

The creation of PubTables-v2, and the observations regarding vision-language model performance, merely clarifies the inevitable. Larger datasets will come, models will scale, and for a fleeting moment, accuracy metrics will climb. Yet, the fundamental problem remains: translating the idea of a table – rows, columns, logical structure – into executable code is an exercise in controlled approximation. The dataset highlights that even with progress, specialized architectures still edge out the generalists on particularly difficult structural problems. This isn’t a failure of vision-language models, but a confirmation that abstraction always incurs a cost.

Future work will undoubtedly focus on addressing multi-page table extraction, a problem inherently more fragile than its single-page counterpart. Each page adds an additional layer of potential error, a new opportunity for misalignment and misinterpretation. The pursuit of ‘perfect’ table reconstruction will continue, yet the field should anticipate a steady stream of edge cases, rendering even the most sophisticated systems vulnerable. Every abstraction dies in production, and the table structure, despite its apparent rigidity, is no exception.

Ultimately, the challenge isn’t simply detecting tables, but understanding them in context. The data suggests that achieving true robustness requires moving beyond pixel-level analysis and incorporating a more semantic understanding of document layout and content. That, of course, is a significantly harder problem, and one that promises a long and beautifully frustrating series of incremental improvements, each followed by a new, unforeseen failure mode.


Original article: https://arxiv.org/pdf/2512.10888.pdf

Contact the author: https://www.linkedin.com/in/avetisyan/

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2025-12-15 02:29