Unsupervised Medical Image Segmentation via Superpixel Graph Minimization

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Solution Overview

Problem

Current image segmentation methods, particularly in medical imaging, face challenges due to unclear boundaries, limited information in single-channel medical images, and the need for extensive annotated data, making accurate segmentation difficult and time-consuming, especially in precision medicine applications.

Innovation Solution

An unsupervised image segmentation method using superpixel segmentation, undirected graphs, and a minimization objective function to automatically segment images without annotated data, reducing manual intervention and processing time by converting pixel-level segmentation to superpixel-level and applying the Chan-Vese model with a maximum flow algorithm.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional image segmentation methods are used on medical images, then segmentation can be performed, but the boundaries are unclear and accuracy is reduced due to limited information in single-channel medical images

Engineering Contradiction:
Improvesegmentation accuracyVSAvoidinformation loss in single-channel medical images
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent applies superpixel segmentation to divide the medical image into multiple superpixel regions before performing graph-based segmentation. This pre-segmentation step groups adjacent pixels with similar characteristics, reducing the complexity of the segmentation problem and preserving boundary information better than direct pixel-level segmentation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the image segmentation problem from pixel-level to superpixel-level, effectively changing the dimension of processing units. By working with superpixels instead of individual pixels, the method retains more structural information and reduces the impact of noise and limited information in single-channel medical images.

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

2Measurement precision

If supervised segmentation methods are used, then accurate segmentation can be achieved, but extensive annotated data is required which is time-consuming and expensive to obtain

Engineering Contradiction:
Improvesegmentation accuracyVSAvoidtime for obtaining annotated data
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs unsupervised segmentation that automatically segments medical images without requiring manually annotated training data. The method uses the inherent structural and intensity information in the images themselves to perform segmentation, making the system self-sufficient and eliminating the time-consuming data annotation process.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the approach from supervised learning with fixed training data to unsupervised learning that adapts to the specific characteristics of each input image. By modifying the segmentation parameters dynamically based on image content rather than relying on pre-trained models, the system achieves accuracy without extensive annotated data.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If pixel-level segmentation is performed, then detailed segmentation is achieved, but the processing time and computational complexity increase significantly

Engineering Contradiction:
Improvesegmentation detailVSAvoidprocessing speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent performs a two-level segmentation: first dividing the image into superpixel regions, then performing graph-based segmentation on the superpixel graph. This hierarchical approach maintains detailed segmentation boundaries while reducing the number of elements to process, thereby improving computational efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges adjacent pixels into superpixels based on similarity criteria, reducing the total number of segmentation units from thousands of pixels to hundreds of superpixels. This merging preserves the essential boundary information while significantly reducing computational complexity and processing time.

Inventive Principle:
Principle #5Merging (Combining)

4Measurement precision

If manual correction is applied to improve segmentation accuracy, then precision is improved, but the ease of operation decreases and more manual intervention is required

Engineering Contradiction:
Improvesegmentation precisionVSAvoidmanual intervention requirement
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent implements an iterative segmentation process where the algorithm automatically refines the segmentation results by comparing the segmented regions with the original image characteristics. This feedback mechanism allows the system to self-correct and improve precision without requiring manual intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The unsupervised segmentation algorithm automatically adjusts and optimizes segmentation parameters based on the specific characteristics of each medical image, eliminating the need for manual parameter tuning and correction that would reduce ease of operation.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS11928825B2Unsupervised image segmentation method and electronic device
Publication Date: 2024.03.12 TSINGHUA UNIVERSITY
  • US11928825B2 patent drawing
  • US11928825B2 patent drawing
  • US11928825B2 patent drawing

AI summary

An unsupervised image segmentation method includes: performing a superpixel segmentation on an image containing a target object to acquire a plurality of superpixel sets, each superpixel set corresponding to a respective superpixel node; generating an undirected graph according to superpixel nodes; determining foreground superpixel nodes and background superpixel nodes in the undirected graph according to a first label set corresponding to the plurality of superpixel nodes; generating a minimization objective function according to the foreground superpixel nodes and the background superpixel nodes; segmenting the undirected graph according to the minimization objective function to acquire a foreground part and a background part and to generate a second label set; and performing an image segmentation on the image according to a comparison result of the first label set and the second label set.