Synthetic Text Encoding for Noisy Document Retrieval

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Solution Overview

Problem

Retrieving electronic documents from blurry or illegible images is challenging, especially with low-quality camera inputs, as existing methods fail to provide accurate matches due to noise and poor feature recognition.

Innovation Solution

A system that converts electronic documents to synthetic text, allowing for reliable feature recognition and discrimination, even from noisy images, using an indexing mechanism that leverages existing text search algorithms for efficient retrieval.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If Optical Character Recognition (OCR) is applied on the input image to search text strings, then text retrieval is enabled, but the poor image quality causes high error rates making the search ineffective

Engineering Contradiction:
Improvetext retrieval capabilityVSAvoidrecognition accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary representation called 'synthetic text' that bridges the gap between image features and natural language text. Instead of directly applying OCR to the noisy image, the system extracts image features, converts them to synthetic text using a trained model, and then performs search on this intermediate representation. This intermediary layer filters out noise while preserving meaningful information, enabling effective retrieval without suffering from high OCR error rates.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system creates a synthetic copy of the document's textual content in a transformed representation space. Rather than relying on direct OCR transcription of the noisy image, it generates a synthetic text version that captures the essential semantic information while being robust to image quality variations. This synthetic copy can then be searched using standard text retrieval methods with high accuracy.

Inventive Principle:
Principle #26Copying

2Productivity

If image features are extracted and used with an index to retrieve documents, then retrieval is possible, but the features do not provide enough context information for consistent and accurate matches

Engineering Contradiction:
Improveretrieval speedVSAvoidmatch accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent transforms the feature representation parameters from raw image features to synthetic text parameters through a learned mapping model. This parameter transformation changes the feature space from one that preserves spatial and visual characteristics to one that emphasizes semantic and contextual information. The synthetic text parameters provide both the efficiency needed for fast indexing and retrieval, and the contextual richness required for accurate matching.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If the corpus of documents is large, then comprehensive coverage is achieved, but retrieving a document from a blurry or illegible image becomes increasingly difficult

Engineering Contradiction:
Improvedocument corpus sizeVSAvoidretrieval difficulty
Core Design Contradiction:
Quantity of substanceVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces traditional image-matching mechanisms with a text-based search mechanism. Instead of comparing noisy image patches against document images (which becomes exponentially more difficult as corpus size grows), the system converts the query image to synthetic text and performs efficient text string matching. This substitution of the matching mechanism allows the system to scale to large corpora while maintaining retrieval effectiveness, as text search is computationally more efficient and less sensitive to image quality than image similarity search.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9092423B2Retrieving electronic documents by converting them to synthetic text
Publication Date: 2015.07.28 RICOH CO LTD
  • US9092423B2 patent drawing
  • US9092423B2 patent drawing
  • US9092423B2 patent drawing

AI summary

The present invention relies on the two-dimensional information in documents and encodes two-dimensional structures into a one-dimensional synthetic language such that two-dimensional documents can be searched at text search speed. The system comprises: an indexing module, a retrieval module, an encoder, a quantization module, a retrieval engine and a control module coupled by a bus. Electronic documents are first indexed by the indexing module and stored as a synthetic text library. The retrieval module then converts an input image to synthetic text and searches for matches to the synthetic text in the synthetic text library. The matches can be in turn used to retrieve the corresponding electronic documents. In one or more embodiments, the present invention includes a method for comparing the synthetic text to documents that have been converted to synthetic text for a match.