Collimation Edge Detection in Digital Radiography

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Solution Overview

Problem

Conventional X-ray systems face challenges in precisely locating collimation edges in X-ray images, especially when feedback from mechanical positioners is incomplete or non-existent, leading to less than precise data and inconvenient manual input for image processing.

Innovation Solution

A computer-based system that detects collimation edges directly from the X-ray image data, using image processing techniques such as edge detection, Radon transform, and statistical analysis to generate collimation edge data for precise localization and image cropping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If positioner feedback is used for collimation edge localization, then the process is automated, but the measurement precision deteriorates due to incomplete or non-existent feedback data

Engineering Contradiction:
Improveautomation of collimation edge localizationVSAvoidprecision of collimation edge location
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary computational model that maps positioner data to collimation edge locations. This mediator layer processes and interprets the positioner feedback data, allowing the system to use available automated data while compensating for its imperfections through algorithmic correction and validation against image-based features.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements a feedback mechanism where the detected collimation edges from the image are compared with expected positions from positioner data. This closed-loop feedback allows the system to validate and refine edge localization, improving precision by cross-referencing multiple data sources and correcting discrepancies.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If manual input is used for collimation edge data, then measurement precision can be maintained, but ease of operation deteriorates due to operator burden

Engineering Contradiction:
Improveprecision of collimation edge locationVSAvoidconvenience for operators
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system performs self-service by automatically detecting collimation edges directly from the X-ray image data without requiring manual operator input. The algorithm autonomously identifies edge features, determines their locations, and integrates this information into the imaging workflow, eliminating the need for operators to manually enter or adjust collimation edge data.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the manual mechanical input process with an automated image processing system. Instead of operators using keyboards or mice to input data, the system uses computational algorithms to automatically extract and process collimation edge information from the digital image, substituting human interaction with automated computational methods.

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

3Device complexity

If positioner feedback is integrated into fixed X-ray systems, then device complexity is reduced, but measurement precision worsens due to lack of rotation-angle feedback

Engineering Contradiction:
Improveintegration of positioner feedbackVSAvoidprecision of collimation edge location
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system compensates for the lack of rotation-angle feedback by changing the parameters used for edge detection. Instead of relying on precise angular position data, the algorithm uses image intensity gradients, edge detection filters, and spatial relationship analysis to determine collimation edge locations, adapting to the available data parameters.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transitions from relying solely on one-dimensional positioner feedback data to utilizing two-dimensional image space information. By analyzing the spatial distribution of X-ray intensities and edge features across the image plane, the system extracts collimation edge location information from a different dimensional domain, compensating for the limitations of positioner feedback.

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

Data Source

PatentUS7508970B2Systems, methods and apparatus for detecting a collimation edge in digital image radiography
Publication Date: 2009.03.24 GE PRECISION HEALTHCARE LLC
  • US7508970B2 patent drawing
  • US7508970B2 patent drawing
  • US7508970B2 patent drawing

AI summary

Systems, methods and apparatus are provided through which collimation edges in an X-ray image are located from information in the X-ray image.