Spatial Index Text Extraction for Unstructured PDF Documents
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods fail to accurately and efficiently extract text from unstructured PDF documents, particularly those with multi-column layouts, tables, and figures, which hinders text mining and analysis, as they struggle to reconstruct the original text flow and sectionate content effectively.
Innovation Solution
A spatial indexing method is employed to store words with their coordinates, allowing for efficient detection of column boundaries and section identification, enabling the reconstruction of text flows and replacement of inline citations with bibliographic information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional text extraction methods are used on unstructured PDF documents, then the process is simple, but the accuracy of text flow reconstruction is poor
Solution Approach 1:
The patent segments the text extraction process into distinct modules: spatial index creation, column detection, line aggregation, and text flow reconstruction. Each module handles a specific aspect of the extraction task, allowing the system to achieve high accuracy through coordinated processing of multiple segments rather than attempting to solve the entire complex problem at once.
Solution Approach 2:
The patent introduces a spatial index as an intermediary data structure that stores word positions and relationships. This intermediary enables efficient querying of spatial relationships between words, lines, and columns, facilitating accurate text flow reconstruction without requiring complex direct analysis of the entire document structure.
2Quantity of substance
If multi-column layouts are processed, then more information can be extracted, but the difficulty of correctly ordering text increases
Solution Approach 1:
The patent transitions from linear text processing to two-dimensional spatial analysis by creating a spatial index that captures the positional relationships of words, lines, and columns on the page. This dimensional approach enables the system to correctly order text across multiple columns by considering both horizontal and vertical positions, thereby accurately reconstructing text flow in complex multi-column layouts.
3Quantity of substance
If tables and figures are present in the document, then more content is available, but the disruption of text flow increases
Solution Approach 1:
The patent extracts and separates tables and figures from the main text flow by detecting their spatial boundaries and isolating them as distinct elements. This allows the system to process the remaining text content independently, maintaining text flow continuity while still capturing the complete document information including tables and figures as separate extractable entities.
4Speed
If simple word search is performed, then the search process is fast, but the utility of common word searches is limited
Solution Approach 1:
The patent uses the spatial index as an intermediary structure that enables efficient querying of word positions, contexts, and relationships. This allows the system to perform both fast searches for common words and sophisticated searches for contextual information, leveraging the spatial index to quickly retrieve positional data that enables understanding of word usage context without sacrificing search speed.
Data Source
AI summary
According to one aspect, the subject matter described herein includes a method for extracting text from unstructured documents. The method includes creating a spatial index for storing information about words on a page of a document to be analyzed; using the spatial index to detect white space that indicates boundaries of columns within the page, aggregate words into lines, identify lines that are part of a header or footer of the page, and identify lines that are part of a table or a figures within the page; and joining lines together to generate continuous text flows. In one embodiment, the continuous text is divided into sections. In one embodiment, references within the document are identified. In one embodiment, inline citations within the document body are replaced with the corresponding reference information, or portions thereof.