OCR Training Image Generation for Partial Handwritten Character Entry

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Solution Overview

Problem

Existing methods struggle to efficiently generate training data for optical character recognition (OCR) of handwritten characters that protrude from document frames, particularly due to the difficulty in collecting and augmenting images of characters entering from various directions, which affects recognition accuracy.

Innovation Solution

An image processing apparatus that adds noise to character images near their ends to simulate partial entry from other rows, generating training data by associating these modified images with correct answer classes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If data augmentation is performed by adding noises to random positions within a character image, then the quantity of training data is increased, but the effectiveness for generating part-entered images is insufficient

Engineering Contradiction:
Improvequantity of training dataVSAvoideffectiveness for generating part-entered images
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by changing the noise addition strategy from random positions to specific end portions of character images. By concentrating noise addition at the ends where characters most likely to protrude, the augmentation process generates more effective part-entered images that accurately represent real-world scenarios where characters extend beyond their designated entry fields.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by proactively adding noise to simulate character protrusion before the actual OCR recognition process. This pre-simulation of part-entered images allows the training model to learn from artificially generated but realistic protrusion cases, improving its ability to handle such situations during actual document processing.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If character row separation processing is performed to separate character blocks, then the structure of scanned images is organized, but character blocks may be entered by part of characters from other rows

Engineering Contradiction:
Improveorganization of scanned imagesVSAvoidaccuracy of character block extraction
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-training the OCR model with part-entered images that simulate characters protruding from other rows. This preparation allows the model to anticipate and correctly handle character blocks that contain partial intrusions, maintaining high recognition accuracy even when character row separation processing results in blocks entered by characters from adjacent rows.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If training is performed with comprehensive images including various entering aspects, then the recognition accuracy for part-entered images is improved, but the difficulty of collecting and creating such images increases

Engineering Contradiction:
Improverecognition accuracy for part-entered imagesVSAvoiddifficulty of collecting and creating images
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies copying by creating artificial copies of character images with added noise to simulate part-entered scenarios. Instead of manually collecting diverse real-world examples of character protrusion, the system generates synthetic training images by copying existing character images and adding noise at end portions, efficiently creating comprehensive training data covering various entering aspects.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent implements parameter changes by modifying the noise addition parameters to specifically target end portions of character images. By adjusting the noise addition strategy to focus on terminal regions where protrusion occurs, the system efficiently generates training images that capture various entering aspects without requiring complex manual image collection processes.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12586400B2Image processing apparatus, control method thereof, and storage medium
Publication Date: 2026.03.24 CANON KK
  • US12586400B2 patent drawing
  • US12586400B2 patent drawing
  • US12586400B2 patent drawing

AI summary

A training image that simulates a character block entered by part of a character in another row is generated efficiently. A noise is added in the vicinity of an end portion of a character image so that a noise that seems to be caused by entering of part of a character in another row is reproduced for the character image representing a handwritten character.