Multi-class classifier for fast landmark point location in medical volumes

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Solution Overview

Problem

Conventional landmark point location systems in medical imaging are computationally intensive and time-consuming due to exhaustive searches, necessitating more efficient methods for locating landmark points of interest in volumetric data.

Innovation Solution

A learning-based system that trains multi-class classifiers using extracted features from volumes near sample points offset from landmark points, employing discrete displacement vectors to efficiently locate landmark points by refining the search process through a hierarchical approach.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an exhaustive search is performed by sliding a scanning window over the input image to locate landmark points, then the location accuracy is improved, but the computational time and intensity increase significantly

Engineering Contradiction:
Improvelandmark point location accuracyVSAvoidsearch time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by training multi-class classifiers in advance using labeled training images. The classifiers are pre-trained to recognize landmark points and predict their locations, so that during actual operation, the system can quickly locate landmarks without performing exhaustive searches. This pre-computation of classification models resolves the contradiction by shifting computational burden from runtime to training time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical exhaustive sliding window search with a learning-based classification system. Instead of systematically scanning every possible location, the trained multi-class classifiers directly predict landmark positions based on image features. This substitution of mechanical search with intelligent prediction resolves the time-accuracy contradiction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a scanning window is slid exhaustively over the input image to locate landmark points, then complete coverage and accuracy are improved, but the computational intensity increases

Engineering Contradiction:
Improvelandmark point detection accuracyVSAvoidcomputational intensity
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent extracts only the essential features needed for landmark detection using trained multi-class classifiers, rather than processing the entire image exhaustively. The classifiers are designed to focus computational resources on relevant image regions and features, extracting only the necessary information for accurate landmark localization. This selective extraction reduces computational intensity while maintaining detection accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameter of computational approach from exhaustive enumeration to learned classification. By transforming the problem from a search-based parameter space exploration to a classification-based direct prediction, the system achieves the same detection accuracy with significantly reduced computational intensity. The multi-class classifiers learn optimal parameter configurations during training, enabling efficient inference.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional exhaustive search methods are used to locate landmark points, then thorough search coverage is achieved, but the system efficiency decreases

Engineering Contradiction:
Improvesearch completenessVSAvoiddiagnosis efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements self-service by enabling the system to automatically locate landmark points using trained multi-class classifiers without requiring manual intervention or exhaustive systematic searching. The classifiers autonomously identify landmark positions based on learned patterns, providing both thorough detection and high efficiency. This automation resolves the contradiction between reliability and productivity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS8160323B2Learning a coarse-to-fine matching pursuit for fast point search in images or volumetric data using multi-class classification
Publication Date: 2012.04.17 SIEMENS HEALTHCARE GMBH
  • US8160323B2 patent drawing
  • US8160323B2 patent drawing
  • US8160323B2 patent drawing

AI summary

A landmark location system for locating landmarks in volumes includes a medical image database including volumes of medical images, a learning unit that trains a multi-class classifier to locate a landmark point in each volume from extracted features of the volumes near a sample point offset from the landmark point and discrete displacements of the sample point to the landmark point, and a landmark locator that locates the landmark point in an input volume using the trained multi-class classifiers.