Histological Image Color Normalization Through Iterative Segmentation

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Solution Overview

Problem

Variability in histological tissue staining due to operator experience, dye aging, and scanner type affects diagnostic accuracy and efficiency, particularly impacting less experienced pathologists and automatic recognition systems.

Innovation Solution

An iterative image processing method normalizes histological tissue images by calculating comparison colors, segmenting regions, and applying corrective factors to align with a predetermined reference image, ensuring convergence and reliability regardless of initial conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual initialization technique is used for color normalization, then processing can be performed, but variability in results and time consumption increase

Engineering Contradiction:
Improvecolor normalization reliabilityVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs self-service by automatically determining color normalization parameters through iterative calculation of average colors and comparison with reference images, eliminating the need for manual initialization while achieving reliable and consistent results across different histological preparations

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system dynamically adjusts color parameters through iterative optimization, calculating average colors from segmented regions and computing correction factors to transform image colors toward reference values, thereby achieving consistent normalization without manual intervention

Inventive Principle:
Principle #35Parameter changes

2Productivity

If staining variability is present, then histological preparation is completed, but diagnostic accuracy and inspection time are adversely affected

Engineering Contradiction:
Improvediagnostic inspection efficiencyVSAvoiddiagnostic accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system corrects staining variability by calculating correction factors that transform the actual color parameters of the histological image toward the reference color parameters, thereby normalizing the appearance regardless of staining variations and improving both diagnostic accuracy and consistency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The color normalization system serves multiple functions: it corrects staining variability, compensates for scanner differences, and provides consistent color representation across different preparations, making the diagnostic process more reliable and efficient for both human pathologists and automated systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4128148B1System for processing an image relating to a histological tissue
Publication Date: 2025.09.24 POLITECNICO DI TORINO
  • EP4128148B1 patent drawing

AI summary

Method of processing a digital image relating to a histological tissue, to vary a color by forcing it towards a "target average color" of a digital reference image. The method includes a segmentation of the image regions that express a hue in a neighborhood of the hue of a "comparison color" and the calculation of an "average coloration" of the segmented area and if this "average coloration" differs under a predetermined threshold from the "comparison color", then calculation and application of a corrective factor for each point of the image that expresses a hue around the hue of the "average color", if instead the "average color" deviates beyond the predetermined one threshold from the "comparison staining", then (Step 5) the "average staining" is set as the "comparison staining" and the segmentation is resumed from (Step 2).