X-ray phase imaging grating displacement correction
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Solution Overview
Problem
Conventional X-ray phase imaging apparatuses experience phase folding due to positional displacements of gratings caused by heat fluctuations, leading to erroneous measurements as phase-contrast signals near object edges become indistinguishable.
Innovation Solution
An X-ray phase imaging apparatus that corrects for grating positional displacements by calculating and adjusting the relative positions of gratings based on intensity-modulated signals, using a representative value from a region not affected by the object's presence to minimize errors and prevent phase folding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a plurality of gratings is used for phase imaging, then phase-contrast imaging capability is improved, but positional displacement of gratings due to heat causes phase folding and measurement errors
Solution Approach 1:
The patent applies preliminary action by measuring the grating position using the intensity-modulated signal before generating the phase differential image. This allows the system to detect positional displacements of the gratings due to heat fluctuations and correct them in advance, preventing phase folding from occurring in the final image. The grating position measurement is performed as a preliminary step to ensure accurate phase-contrast imaging.
2Device complexity
If grating position is not corrected, then device complexity is reduced, but phase folding occurs causing erroneous measurements
Solution Approach 1:
The patent implements feedback by using the intensity-modulated signal to continuously monitor and measure the actual position of the gratings. This measured position information is then fed back into the phase differential image generation process to correct for any positional displacements. The feedback mechanism ensures that even though the device structure remains relatively simple, the system can dynamically compensate for thermal effects and maintain high measurement precision.
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
This approach effectively suppresses phase folding, ensuring accurate phase-contrast imaging by correcting grating displacements before they cause significant phase-contrast signal offset, thereby maintaining image quality and distinguishing between different phase-contrast values.
Implementation Method 1
an X-ray source; an X-ray image detector (detection unit) arranged in the irradiation direction of the X-ray source
Implementation Method 2
by interfering the X-ray irradiated from the X-ray source using a plural of gratings
Implementation Method 3
the intensity-modulated signal representing the intensity change of the X-ray detected by the X-ray image detector
Data Source
AI summary
The X-ray phase imaging apparatus is configured to include an image generation unit that generates an X-ray phase-contrast image based on a phase-contrast between a step curve representing an intensity change of an X-ray when an object is placed between an X-ray source and a phase grating or between a phase grating and an absorption grating and a step curve when no object is placed therebetween, and is configured to obtain a displacement amount of relative positions of a plurality of gratings based on a plurality of step curves.