Optical Character Recognition Using Letter Property Analysis

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Solution Overview

Problem

Converting physical books into digital format is time-consuming and often inaccurate, especially when dealing with text that lacks clear grid-based demarcations, such as italicized or certain font styles, due to difficulties in separating and recognizing individual letters.

Innovation Solution

A method that analyzes images of text to determine letter properties and classify them into letterform classes, using iterative processes and OCR to generate representative shapes, allowing for accurate conversion of text into digital format without relying on grid-based separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If grid-based separation methods are used to recognize letters, then recognition accuracy is improved for standard text, but conversion accuracy deteriorates for italicized or stylistically varied text

Engineering Contradiction:
Improveletter recognition accuracyVSAvoidconversion accuracy for varied text styles
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the fundamental parameters of text analysis from grid-based spatial segmentation to feature-based characteristic extraction. Instead of relying on fixed grid positions, the system extracts multiple characteristics (shape, size, position, slope, curvature) from letter images and uses these parameters to identify letters, enabling accurate recognition of italicized and stylistically varied text.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the letter recognition task into multiple independent characteristic extraction steps. Each letter is analyzed for multiple features (shape, size, position, slope, curvature) separately, and these segmented characteristics are then combined to identify the letter. This allows the system to handle complex text styles by considering individual feature components rather than relying on overall grid-based structure.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If iterative classification processes are used to improve letter identification, then conversion accuracy is improved, but processing time increases

Engineering Contradiction:
Improveletter identification accuracyVSAvoidconversion time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary actions by extracting and storing multiple letter characteristics (shape, size, position, slope, curvature) during the initial image analysis phase. These pre-extracted characteristics are then used in subsequent classification steps without re-processing the entire image, reducing the time required for iterative classification while maintaining high accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the classification results from one iteration are used to refine subsequent iterations. The system continuously compares extracted characteristics against known letter patterns and adjusts classifications based on feedback from previous iterations, efficiently converging on accurate letter identification without requiring excessive processing time.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If detailed letter property analysis is performed, then conversion accuracy for various fonts and styles is improved, but computational complexity increases

Engineering Contradiction:
Improveconversion accuracy for different fontsVSAvoidprocessing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality analysis by examining specific localized features of each letter (shape, size, position, slope, curvature) rather than analyzing the entire text image as a whole. This allows the system to maintain high conversion accuracy for different fonts by focusing on local characteristic patterns while keeping the overall processing approach manageable and systematic.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS9330311B1Optical character recognition
Publication Date: 2016.05.03 AMAZON TECH INC
  • US9330311B1 patent drawing
  • US9330311B1 patent drawing
  • US9330311B1 patent drawing

AI summary

Systems and methods for analyzing letters in an image of text are described. For each letter, a number of properties are determined and the letters are classified into letterform classes. The properties may include independent letter properties based on only the letter itself, such as a slanted bounding box encompassing the letter. The properties may also include dependent letter properties that are based, in part, on other letters, such as adjacent letters or letters in the same word or line.