Mammography Image Alignment Using Virtual Projection Position

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Solution Overview

Problem

Interpreting radiation images obtained by mammography imaging is challenging due to differences in radiation source position, lesion positional relationships, and mammary gland overlap, making it difficult to compare composite two-dimensional images from tomosynthesis with previous two-dimensional images.

Innovation Solution

An image processing apparatus and method that calculates a virtual projection position based on the radiation source position during two-dimensional imaging, generating a composite two-dimensional image from projection or tomographic images using this position to align and correct magnification ratios, facilitating comparison with previous images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If tomosynthesis imaging is performed with a different radiation source position, then three-dimensional information and lesion separability are improved, but positional relationship alignment with previous two-dimensional images deteriorates

Engineering Contradiction:
Improvelesion separabilityVSAvoidpositional relationship alignment
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent creates a virtual copy of the two-dimensional image at the tomosynthesis radiation source position, allowing comparison while maintaining positional relationship information. The virtual image serves as a reference that preserves the original spatial context even when the radiation source position changes.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent introduces a virtual image as an intermediary between the tomosynthesis three-dimensional data and the original two-dimensional image. This virtual image acts as a bridge that maintains positional relationship alignment while enabling the benefits of tomosynthesis imaging.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If composite two-dimensional images are generated from tomosynthesis projection images, then mammary gland overlap is reduced, but image magnification ratio alignment with previous images deteriorates

Engineering Contradiction:
Improvemammary gland separationVSAvoidmagnification ratio alignment
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent changes the parameter of image magnification ratio by generating a virtual image that accounts for the different radiation source position. This allows the virtual image to have a magnification ratio that matches the original two-dimensional image, enabling proper alignment despite the tomosynthesis imaging geometry.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If radiation source position is changed during tomosynthesis imaging, then imaging angle coverage is improved, but positional relationship consistency with previous images deteriorates

Engineering Contradiction:
Improveimaging angle coverageVSAvoidpositional relationship consistency
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent transitions from two-dimensional image space to three-dimensional virtual image space, then projects back to two dimensions. This dimensional transformation allows the system to incorporate multiple imaging angles from tomosynthesis while maintaining consistency with the original two-dimensional image positional relationships.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4678108A1Image processing apparatus, image processing method, and image processing program
Publication Date: 2026.01.14 FUJIFILM CORP
  • EP4678108A1 patent drawingFigure 1
  • EP4678108A1 patent drawingFigure 2~3
  • EP4678108A1 patent drawingFigure 4~5A

AI summary

An image processing apparatus (16) includes a CPU. The CPU acquires a two-dimensional image captured by irradiating a breast (U) with radiation; acquires a position of a radiation source that emits the radiation in a case in which the two-dimensional image is captured; acquires a series of a plurality of projection images or a plurality of tomographic images obtained by performing tomosynthesis imaging of the breast (U); calculates a virtual projection position, which is a position at which the breast (U) is virtually projected during the tomosynthesis imaging, from the position of the radiation source in a case in which the two-dimensional image is captured; and generates a composite two-dimensional image from the plurality of projection images or the plurality of tomographic images based on the virtual projection position.