X-ray detector pose estimation using occluded marker inference

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Solution Overview

Problem

Manual alignment of X-ray detectors and sources in robotic X-ray systems is inconsistent, time-consuming, and prone to inaccuracies due to occluded or out-of-view markers, limiting the quality of X-ray images.

Innovation Solution

A machine-learned model is used to estimate the pose of X-ray detectors by identifying visible and occluded markers from images, even when they are not directly visible, allowing for automatic alignment of the X-ray source with the detector, using a combination of deep neural networks to localize and refine marker positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual alignment is used to position the X-ray detector and source, then the system provides flexibility in imaging, but the alignment quality becomes inconsistent and time-consuming

Engineering Contradiction:
Improveflexibility in imagingVSAvoidalignment quality
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces manual mechanical alignment operations with an automated computer vision system. A camera captures images of the detector, and software automatically identifies markers and calculates detector pose and alignment parameters, eliminating the need for manual measurement and positioning while maintaining flexibility.

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

Solution Approach 2:

The system enables self-alignment by using the detector's own markers as reference points. The automated detection system processes images of the detector markers to determine detector position and orientation, allowing the system to self-correct and self-align without external intervention.

Inventive Principle:
Principle #25Self-service

2Productivity

If automatic alignment using marker detection is implemented, then alignment speed improves, but accuracy deteriorates when markers are occluded or out-of-view

Engineering Contradiction:
Improvealignment speedVSAvoidpose prediction accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary actions by capturing multiple images of the detector from different angles and positions before the actual alignment process. This creates a library of marker positions that can be referenced even when some markers are occluded during the alignment operation, ensuring continuous accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary computational model that predicts the positions of occluded or out-of-view markers based on visible markers and the detector's known geometry. This virtual marker generation acts as a mediator between visible markers and the complete set of markers needed for accurate pose estimation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If hand-crafted filters and Hough transform are used for marker detection, then the detection process is straightforward, but the system struggles with large distance variations and occlusions

Engineering Contradiction:
Improvedetection process simplicityVSAvoidhandling distance variation and occlusion
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent changes the detection parameters dynamically based on imaging conditions. The system adjusts marker detection thresholds, search regions, and filtering criteria according to the detected distance variations and occlusion levels, allowing the same system to handle diverse imaging scenarios effectively.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transforms the static marker detection approach into a dynamic system that adapts to varying conditions. The detection algorithm continuously adjusts its parameters based on real-time image quality, marker visibility, and distance measurements, making the system flexible rather than rigid.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS10779793B1X-ray detector pose estimation in medical imaging
Publication Date: 2020.09.22 SIEMENS HEALTHINEERS AG
  • US10779793B1 patent drawing
  • US10779793B1 patent drawing
  • US10779793B1 patent drawing

AI summary

For x-ray detector pose estimation, a machine-learned model is used to estimate locations of markers, including occluded or other non-visible markers, from an image. The locations of the markers, including the non-visible markers are used to determine the pose of the X-ray detector for aligning an X-ray tube with the X-ray detector.