Line Enhancing Filter for Medical Image Fissure Detection

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Solution Overview

Problem

Current image processing methods fail to accurately detect thin, faint, and non-continuous line structures in medical images, such as lobar fissures in CT scans, due to noise, anatomical anomalies, and the need for large ground truth annotations.

Innovation Solution

A line enhancing filter that calculates correlation values between a line model and image data, testing multiple hypotheses for line orientations, which is robust against noise and effective for detecting thin line structures, even when they are faint or non-continuous, using a rectangular or cuboidal line model and iterative refinement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If Hessian matrix eigenvector analysis is used to detect bright plate-like fissures, then detection capability is improved, but the filter gives low responses for fissure voxels due to noise and thin structure challenges

Engineering Contradiction:
Improvefissure detection accuracyVSAvoidfilter response reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the detection parameters from Hessian matrix eigenvector analysis to a line structure filter that tests multiple hypotheses for line orientations. This parameter change allows the filter to adapt to different line orientations and maintain reliable responses even in noisy conditions and for thin fissure structures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a dynamic filtering approach where the filter adapts its response based on local image characteristics. The filter dynamically adjusts its behavior by testing multiple orientation hypotheses and selecting the best match, making it reliable for detecting thin, faint lines with varying orientations.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If supervised learning filter is used for fissure detection, then detection accuracy is improved, but large set of ground truth annotations is required

Engineering Contradiction:
Improvefissure detection accuracyVSAvoidannotation requirement
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a self-service approach where the filter does not require external ground truth annotations for training. Instead, it uses the image data itself and tests multiple orientation hypotheses to automatically determine the best fit, making the system independent of manual annotation processes.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts the essential characteristics of line structures directly from the image data without requiring separate training datasets. By taking out only the necessary image features and testing multiple orientation hypotheses, the system achieves accurate detection without the complexity of supervised learning pipelines.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If standard line detection algorithms are used, then processing speed is maintained, but they fail to detect non-continuous, curved, or faint line structures

Engineering Contradiction:
Improveprocessing speedVSAvoidline structure detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces a dynamic filtering approach where the filter adapts its response based on local image characteristics. The filter dynamically adjusts its behavior by testing multiple orientation hypotheses and selecting the best match, making it reliable for detecting thin, faint lines with varying orientations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent extends the detection approach by adding the orientation dimension. Instead of checking for lines in a single fixed orientation, the filter tests multiple orientation hypotheses, effectively adding an angular dimension to the detection process. This allows detection of lines with various orientations while maintaining processing efficiency.

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

Data Source

PatentEP2926318B1Image processing device and method
Publication Date: 2020.10.28 PHILIPS GMBH
  • EP2926318B1 patent drawingFigure 1
  • EP2926318B1 patent drawingFigure 2A~3
  • EP2926318B1 patent drawingFigure 4A~5D

AI summary

The present invention relates to an image processing device for detecting line structures in an image data set. The device comprises a model definition unit (12) for defining a line model of a line structure to be detected, said line model comprising a number of voxels, a calculation unit (14) for calculating, per voxel of interest of said image data set, several correlation values of a correlation between said line model and an image area around said voxel of interest, said image area comprising a corresponding number of voxels as said line model, wherein for each of a number of different relative orientations of said line model with respect to said image area a respective correlation value is calculated, and a determining unit (16) for determining, per voxel of interest, the maximum correlation value from said calculated correlation values and the corresponding optimal orientation at which said maximum correlation value is obtained.