X-ray Phase Contrast Imaging Grating Positioning Correction

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Solution Overview

Problem

Existing X-ray phase contrast imaging systems face challenges in adjusting grating positional displacement without relying on knowledge or experience, leading to increased adjustment time and image artifacts due to unintended moire fringes.

Innovation Solution

An X-ray phase contrast imaging system that utilizes a grating positional displacement acquisition unit to automatically correct grating positioning based on Fourier transform images, eliminating the need for manual visual inspection and reducing adjustment time by analyzing peak distances and magnitudes in the Fourier transform images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual visual inspection is used to adjust grating positioning, then the measurer can judge positional displacements, but it requires knowledge and experience and takes time

Engineering Contradiction:
Improvegrating positioning accuracyVSAvoidadjustment time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the manual visual inspection method with an automated image processing system. The detector captures moire fringe images, and a computer automatically analyzes these images to determine grating positional displacements, substituting the mechanical/visual adjustment process with an automated computational system that eliminates the need for operator knowledge and experience while reducing adjustment time

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

Solution Approach 2:

The system enables self-adjustment by automatically capturing images, processing them to identify moire fringe patterns, calculating positional displacements, and guiding grating repositioning without requiring external expert intervention. The computer system performs the measurement and adjustment guidance functions that previously required a skilled measurer

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If the relative position between phase grating and absorption grating is displaced from design position, then unintended moire fringe is generated, but this causes artifacts in captured images

Engineering Contradiction:
Improvegrating position toleranceVSAvoidimage artifacts
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent performs preliminary measurement of grating positions using image capture and processing before actual imaging. By detecting positional displacements in advance through moire fringe analysis and calculating required corrections, the system prevents the generation of harmful artifacts during the main imaging process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system establishes a feedback loop where the detector continuously monitors grating positions via moire fringe patterns, the computer processes this information to determine positional accuracy, and the system guides adjustments to maintain optimal positioning. This closed-loop feedback prevents the accumulation of positional errors that would lead to image artifacts

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system enables precise and efficient adjustment of grating positions without requiring operator expertise, reducing artifacts and shortening the adjustment process by using image processing to analyze and correct positional displacements in the X-ray phase contrast imaging system.

Implementation Method 1

an X-ray that has passed through a source grating is irradiated to a phase grating. The irradiated X-ray diffracts as it passes through the phase grating and forms a self-image of the phase grating at a position separated by a predetermined distance (Talbot distance)

Methodology Applied
Scientific EffectTalbot effect: Diffraction

Implementation Method 2

an absorption grating is placed at the position where a self-image of a phase grating is formed to form a moire fringe which can be detected even by a general-purpose detector

Methodology Applied
Scientific EffectMoiré effect: Moiré Interferometry

Data Source

PatentEP3391821B1X-ray phase contrast imaging system
Publication Date: 2024.05.08 SHIMADZU CORP
  • EP3391821B1 patent drawingFigure 1
  • EP3391821B1 patent drawingFigure 2
  • EP3391821B1 patent drawingFigure 3

AI summary

An X-ray phase contrast imaging system (100) includes an X-ray source (1), a detector (5), a plurality of gratings including a first grating (3) and a second grating (4), and a grating positional displacement acquisition unit (6) configured to obtain a positional displacement of the grating based on a Fourier transform image (14) obtained by Fourier transforming an interference fringe image (13) detected by the detector.