Character-Wise OCR Training With Contrastive Learning and Location Tokens

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Solution Overview

Problem

Existing OCR systems face challenges with data augmentation techniques that can lead to character loss or alteration, and loss functions are not suitable for improving character recognition accuracy.

Innovation Solution

A character-wise supervised contrastive learning method using a deep learning model that generates synthetic images with varying character appearances and incorporates location information for training, enabling effective feature extraction and recognition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If data augmentation techniques are applied to increase training data diversity, then the amount of training data increases, but character loss or alteration occurs

Engineering Contradiction:
Improveamount of training dataVSAvoidcharacter integrity
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent segments the training data into character-level units with explicit location information (bounding boxes). By processing images at the character level rather than applying global augmentation transformations, the system can generate diverse training samples without losing or altering character integrity. Each character is independently identified and labeled with its position, allowing precise control over data augmentation while maintaining character reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces location information (bounding boxes) as an intermediary element that mediates between the original image and the augmented training data. This intermediary provides precise spatial information about each character, enabling the system to apply data augmentation techniques while tracking and preserving character positions and integrity throughout the transformation process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If conventional loss functions are used for training, then the training process is simple, but character recognition accuracy does not improve

Engineering Contradiction:
Improvetraining efficiencyVSAvoidcharacter recognition accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent changes the loss function parameters from conventional approaches to a character-wise supervised contrastive loss function. This new loss function incorporates location information and character-level supervision signals, fundamentally altering the training objective to simultaneously optimize for character recognition accuracy and spatial positioning. The modified loss function maintains training efficiency while significantly improving measurement precision in character recognition.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If real images without location information are used for training, then data collection is easier, but the model cannot learn spatial positioning of characters

Engineering Contradiction:
Improvedata collection easeVSAvoidlocation information
Core Design Contradiction:
Ease of manufactureVSLoss of information

Solution Approach 1:

The patent applies preliminary action by generating synthetic training images with embedded location information before actual training begins. Using a text rendering engine, the system pre-generates images with known character positions and bounding boxes, creating a foundation of labeled training data that enables the model to learn spatial positioning from the outset, even when real images lack such information.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates synthetic copies of text images with known location information using a text rendering engine. These synthetic copies serve as proxy training data that replicates the characteristics of real images while providing the necessary location annotations. The model learns from these copied synthetic images and generalizes to real images, effectively transferring the location information learning capability without requiring manually annotated real image data.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS20260017967A1OCR method and system based on character-wise supervised contrastive learning model
Publication Date: 2026.01.15 NAVER CORP
  • US20260017967A1 patent drawing
  • US20260017967A1 patent drawing
  • US20260017967A1 patent drawing

AI summary

An OCR method using a character-wise supervised contrastive learning model includes receiving an input image; extracting, from the input image, a token sequence representing character information and location information of the input image by means of a character-wise supervised contrastive learning model; and converting the token sequence into visualized information.