Document Layer Separation for OCR and Non-Text Content Extraction

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Solution Overview

Problem

Existing document processing technologies face challenges in accurately extracting and handling non-textual content, such as logos, charts, and signatures, which can interfere with OCR accuracy and often fail to capture important information due to overlapping or mixed background colors.

Innovation Solution

A machine learning-based system separates document content into logical layers by content type, using a modified U-Net convolutional neural network, and applies specific handlers for each layer to process and extract relevant information, including text, logos, and barcodes, with context-sensitive cross-referencing for enhanced accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional OCR is used to process documents with non-textual content, then text recognition can be performed, but OCR accuracy deteriorates due to overlapping elements and non-textual content interference

Engineering Contradiction:
ImproveOCR accuracyVSAvoidnon-textual content interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent segments the document image into multiple semantic layers (e.g., text layer, table layer, chart layer, watermark layer) based on content type and spatial relationships. This segmentation allows traditional OCR to process only the text layer while other layers are handled by specialized modules, thereby improving OCR accuracy by eliminating interference from non-textual content.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a multi-layer processing framework where an intermediary layer separation module divides the complex document into manageable semantic layers. This intermediary structure enables specialized handlers to process each layer appropriately, with the text layer being processed by OCR and other layers by dedicated content extraction modules, thus resolving the interference problem.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If traditional single-layer document processing is used, then processing simplicity is maintained, but important non-textual information is lost

Engineering Contradiction:
Improvenon-textual information captureVSAvoidprocessing system complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent segments the document into multiple semantic layers (text, table, chart, watermark) and assigns specialized handlers to each layer. This segmentation enables comprehensive extraction of both textual and non-textual information while maintaining modular processing architecture, thus capturing important non-textual information without excessive system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal multi-layer processing framework where a single system can handle multiple content types through layer-specific handlers. The framework is designed to be extensible, allowing new content types to be added as separate layers without redesigning the entire system, thus achieving comprehensive information capture with manageable complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If color-based document segmentation is used, then content separation can be achieved, but the method fails on black and white documents or documents without sufficient color information

Engineering Contradiction:
Improvedocument type compatibilityVSAvoidsegmentation reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the segmentation parameters from color-based to a combination of spatial position, content type classification, and visual characteristics. This parameter transformation enables the system to effectively segment documents regardless of color information, making it reliable for both colored and black-and-white documents, as well as documents with insufficient color data.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a universal segmentation approach that works across diverse document types (colored, black-and-white, scanned, printed) by using multiple feature dimensions beyond color. This multi-functional segmentation mechanism ensures reliable content separation across all document types, significantly improving adaptability and reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Measurement precision

If simple background extraction is used, then processing speed is maintained, but accuracy deteriorates for documents with different or mixed background colors

Engineering Contradiction:
Improvebackground extraction accuracyVSAvoidprocessing speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the background extraction task into multiple semantic layers, where each layer is processed independently based on its content type. This allows the system to maintain high processing speed by parallel processing while achieving high accuracy through specialized extraction methods for each layer, including intelligent handling of mixed and varying background colors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the background extraction approach from simple color-based thresholding to a multi-parameter system considering spatial relationships, content type classification, and visual characteristics. This parameter enhancement enables accurate extraction of backgrounds with different or mixed colors while maintaining processing efficiency through optimized algorithms for each semantic layer.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12567276B2Method and apparatus for document analysis through layer separation by machine learning with cross-layer reasoning
Publication Date: 2026.03.03 HONG KONG APPLIED SCI & TECH RES INST
  • US12567276B2 patent drawing
  • US12567276B2 patent drawing
  • US12567276B2 patent drawing

AI summary

A method for processing electronic documents, comprising: receiving an electronic document; recognizing one or more content components in the electronic document; identifying a content type for each of the recognized content components; creating, by a layer separator, one or more logical layers from the recognized content components such that each of the logical layer contains only the content components of the same content type; and invoking a content-type specific content handler for each of the logical layers created. The layer separator comprises a machine learning (ML) model based on a modified U-Net convolutional neural network and trained to classify the content types of the content components. The modified U-Net CNN is improved over traditional U-Net CNN with transformers at each layer to achieve high recovery rate.