Talbot Imaging Apparatus Grating Shift Exposure Control
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Solution Overview
Problem
Existing X-ray Talbot imaging apparatuses face challenges in maintaining consistent X-ray irradiation during Moire image capture due to grating position shifts, leading to image quality issues and impaired reconstruction of differential phase, absorption, and small-angle scattering images.
Innovation Solution
A Talbot imaging apparatus with a radiation source, multiple gratings, a capturing control unit for shifting gratings, a radiation detector for acquiring Moire images, a setting unit for adjusting capturing conditions based on reference images, and an irradiation control unit to manage radiation exposure, ensuring consistent image capture and reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the first grating and the second grating are relatively shifted to capture multiple Moire images, then the reconstruction of differential phase images, absorption images and small-angle scattering images can be achieved, but the incident amount of X ray to the detector becomes dispersed depending on grating position, affecting image quality
Solution Approach 1:
The patent applies preliminary action by setting the capturing condition for subsequent Moire images based on the capturing result of a reference Moire image captured before the grating shift. The setting unit establishes the reference capturing condition from the first Moire image, then uses this reference to determine the capturing conditions for all subsequent images, ensuring consistent exposure across all grating positions
Solution Approach 2:
The patent implements feedback by using the capturing result of each reference Moire image to adjust and set the capturing conditions for subsequent Moire images. The irradiation control unit continuously adjusts the X-ray irradiation amount based on feedback from previously captured images, ensuring that the incident X-ray amount remains consistent despite grating position changes
2Extent of automation
If automatic exposure control is applied to maintain constant irradiation time, then the radiation exposure can be controlled, but the incident amount of X ray to the detector still disperses depending on grating position due to subject thickness variations
Solution Approach 1:
The system uses feedback from the reference Moire image capturing result to continuously adjust the irradiation conditions. The setting unit compares the reference image data with subsequent images and adjusts the capturing conditions accordingly, creating a closed-loop control system that compensates for variations in incident X-ray amount
Solution Approach 2:
The patent changes the irradiation parameters dynamically based on the reference capturing condition. Instead of maintaining a fixed irradiation time, the system adjusts the X-ray irradiation amount as a variable parameter based on the reference image data, allowing the irradiation conditions to adapt to different grating positions and subject variations
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
Enables proper capture and reconstruction of Moire images even with grating shifts, maintaining image quality and facilitating the generation of accurate differential phase, absorption, and small-angle scattering images by controlling radiation exposure.
Implementation Method 1
a first grating (G1 grating) and a second grating (G2 grating) which are provided with slits at regular intervals. The second grating is disposed at one of the positions where self images of the first grating are formed at regular intervals on downstream side of the first grating by irradiating X ray to the first grating from an X ray radiation source
Implementation Method 2
A Moire fringe is formed on the second grating by disposing the second grating such that the extending direction of the slits of the second grating is slightly inclined relative to the extending direction of the slits of the first grating
Implementation Method 3
The X-ray Talbot imaging apparatus is configured to detect and capture the image overlapped with this Moire fringe (hereinafter referred to as a Moire image) by an X-ray detector disposed on downstream side of the second grating
Data Source
AI summary
A Talbot imaging apparatus includes a radiation source, a plurality of gratings, a capturing control unit, a radiation detector, a setting unit and an irradiation control unit. The radiation source irradiates radiation. The capturing control unit relatively shifts the plurality of gratings and performs control of capturing a plurality of Moire images of a subject to generate a reconstructed image. The radiation detector acquires a captured Moire image. The setting unit sets a capturing condition for capturing a second and further Moire images by making a capturing result of a first Moire image be a reference, or sets a capturing condition for the plurality of Moire images by making another Moire image captured before capturing the plurality of Moire images be a reference. The irradiation control unit controls irradiation of radiation from the radiation source based on the capturing condition set by the setting unit.