Multi-threshold Peripheral Equalization for Digital Mammography

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Solution Overview

Problem

In mammography and breast tomosynthesis images, the peripheral areas often have lower intensity than the central areas due to varying breast thickness, requiring radiologists to adjust window levels, leading to increased reading time and undesirable artifacts like segmentation lines when using prior PE methods.

Innovation Solution

A peripheral equalization method using multiple thresholds to process pixel data, with a fixed intensity for the central part and variable thresholds for the peripheral part, eliminating segmentation lines and enhancing image visibility across the entire breast at a single window level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If peripheral equalization methods are used to enhance peripheral area intensity, then image visibility is improved, but segmentation lines and overshoot banding artifacts are introduced

Engineering Contradiction:
Improveperipheral area intensityVSAvoidsegmentation lines and overshoot banding
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent applies different processing thresholds to different regions of the image. The peripheral area uses multiple thresholds to enhance intensity, while the central area uses a fixed threshold. This local differentiation allows peripheral equalization without introducing artifacts across the entire image, as each region is processed according to its specific characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the breast image into central and peripheral areas based on spatial location. By dividing the image into these distinct regions, the system can apply different processing methods to each segment - multiple thresholds for the periphery and fixed threshold for the center - thereby achieving peripheral equalization without propagating artifacts to other regions.

Inventive Principle:
Principle #1Segmentation

2Illumination intensity

If window level adjustment is performed for different breast regions, then image quality is improved, but reading time increases

Engineering Contradiction:
Improveimage qualityVSAvoidreading time
Core Design Contradiction:
Illumination intensityVSLoss of time

Solution Approach 1:

The patent performs preliminary processing by automatically equalizing the peripheral area intensity before the radiologist views the image. This pre-processing step prepares the image in advance, eliminating the need for the reader to manually adjust window levels for different regions, thereby reducing reading time while maintaining image quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system performs self-service by automatically detecting and correcting the intensity imbalance between central and peripheral areas. The peripheral equalization algorithm autonomously processes the image without requiring user intervention, thereby saving the radiologist's time that would otherwise be spent manually adjusting window levels.

Inventive Principle:
Principle #25Self-service

3Object-generated harmful factors

If multiple thresholds are used to process peripheral pixel data, then peripheral equalization is achieved without segmentation lines, but processing complexity increases

Engineering Contradiction:
Improvesegmentation linesVSAvoidprocessing complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies multiple thresholds only to the peripheral area processing, while using a single fixed threshold for the central area. This localized application of complex processing only where needed reduces the overall processing complexity burden, as the computationally intensive multi-threshold operation is confined to a specific region rather than the entire image.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

By segmenting the image into central and peripheral regions, the patent confines the complex multi-threshold processing to only the peripheral segment. This segmentation strategy isolates the computational complexity to a specific area, making the overall system more manageable and efficient compared to applying complex processing uniformly across the entire image.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS7764820B2Multi-threshold peripheral equalization method and apparatus for digital mammography and breast tomosynthesis
Publication Date: 2010.07.27 THE GENERAL HOSPITAL CORP
  • US7764820B2 patent drawing
  • US7764820B2 patent drawing
  • US7764820B2 patent drawing

AI summary

A peripheral equalization (PE) method and apparatus for compensating for thickness reduction in outer edges of the breast in a mammogram (i.e. a two-dimensional image) while keeping the central area substantially unchanged. The PE method and apparatus can also be applied to three dimensional (tomosynthesis) images of a breast. The peripheral equalization is achieved by segmenting the image of the breast into at least two regions and using a multi-threshold technique to process the data in at least one of the two regions.