Multi-Frame Text Aggregation for OCR Accuracy

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Solution Overview

Problem

Conventional OCR systems fail to accurately recognize text due to poor lighting, contrast, and focus conditions, and are limited by the need for a minimum character size, which restricts their ability to capture and process large volumes of text in a single image frame, especially in real-world documents.

Innovation Solution

The system aggregates OCR results from multiple image frames over time, using techniques like RANSAC and affine transforms to stitch together text from overlapping regions, improving accuracy and enabling the recognition of larger documents by generating a more comprehensive digital representation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single image frame is used for OCR, then the system is simple and fast, but text recognition accuracy deteriorates due to poor lighting, contrast, and focus conditions

Engineering Contradiction:
Improvetext recognition accuracyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the text capture process into multiple image frames captured at different positions, lighting conditions, or focal depths. Each frame captures a portion of the text under different conditions, and the OCR system processes each frame separately before aggregating results. This segmentation allows the system to overcome limitations of single-frame OCR by combining multiple partial observations into a complete and accurate text recognition.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If a single image frame is used, then processing is fast, but the volume of text that can be captured is limited by character size requirements

Engineering Contradiction:
Improvevolume of text capturedVSAvoidprocessing time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent transitions from capturing text in a single two-dimensional image frame to capturing text across multiple dimensions by taking several images at different positions, angles, or focal planes. This dimensional expansion allows the system to capture larger volumes of text that would not fit in a single frame while maintaining character size requirements for OCR recognition.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If multiple image frames are aggregated, then text recognition accuracy and volume improve, but system complexity and processing time increase

Engineering Contradiction:
Improvetext recognition accuracyVSAvoidprocessing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent performs preliminary actions by capturing multiple image frames in advance under different conditions before the OCR processing begins. The images are pre-positioned, pre-focused, and pre-lit to optimize text visibility. This preliminary capture phase allows the subsequent OCR aggregation to work with already-optimized data, improving overall processing efficiency despite handling multiple frames.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS9292739B1Automated recognition of text utilizing multiple images
Publication Date: 2016.03.22 AMAZON TECH INC
  • US9292739B1 patent drawing
  • US9292739B1 patent drawing
  • US9292739B1 patent drawing

AI summary

Various embodiments enable text aggregation from multiple image frames of text. Accordingly, in order to stitch newly scanned areas of a document together, text in a respective image is recognized and analyzed using an algorithm to identify pairs of corresponding words in other images. Upon identifying a minimum number of matching pairs between two respective images, a mapping between the same can be determined based at least in part on a geometric correspondence between respective identified pairs. Based on this mapping, the recognized text of the two images can be merged by adding words of one image to the other using the matching word pairs as alignment data points.