Radiographic Image Device Using Distorted Grating for Phase Contrast
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Solution Overview
Problem
Conventional X-ray imaging techniques face challenges in achieving high sensitivity, especially for soft biological tissues and organic materials due to limited contrast, and require accurate grating translation and perfect grating geometry, which is difficult to manufacture and maintain.
Innovation Solution
A radiographic image generating device and method that uses a distorted grating with a grating group arranged between a radiation source and detection section, allowing for pixel value computation and image creation without mechanical grating translation, enabling the generation of absorption, refraction, and scattering images using intensity distribution images from moving samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Talbot interferometer with accurate grating translation is used to achieve high sensitivity X-ray phase contrast imaging, then measurement precision is improved, but device complexity and manufacturing cost increase due to requirements for perfect grating geometry and precise mechanical translation
Solution Approach 1:
The patent replaces the mechanical grating translation system with a computational approach. Instead of physically moving the grating to capture multiple intensity distributions, the system captures a single intensity distribution image and uses image processing algorithms to extract phase contrast information. This substitution eliminates complex mechanical translation mechanisms while maintaining measurement precision through computational methods.
Solution Approach 2:
The patent creates virtual copies of the intensity distribution at different grating positions through image processing. By processing a single captured image to simulate multiple positional measurements, the system achieves the same information as would be obtained through physical grating translation, thereby reducing mechanical complexity while preserving measurement capability.
2Measurement precision
If perfect grating geometry is manufactured to ensure accurate phase contrast measurements, then measurement precision is improved, but manufacturing cost and difficulty increase
Solution Approach 1:
The patent converts the previously harmful effect of grating geometric imperfections into a beneficial feature. By using a distorted grating where the distortion pattern is known or can be calibrated, the system achieves phase contrast measurements without requiring expensive perfect gratings. The distortion is compensated through computational methods, turning a manufacturing limitation into an acceptable design parameter.
Solution Approach 2:
The patent changes the parameter of grating geometric precision from a critical requirement to a flexible parameter. Instead of manufacturing gratings with extremely tight tolerances, the system accepts gratings with larger tolerances and compensates through image processing algorithms, thereby significantly reducing manufacturing difficulty and cost while maintaining measurement accuracy.
3Ease of manufacture
If conventional X-ray perspective imaging is used to reduce device complexity, then ease of manufacture is improved, but measurement precision deteriorates due to insufficient contrast for soft tissues
Solution Approach 1:
The patent applies local quality by extracting specific local information from the intensity distribution image. Instead of relying on overall absorption contrast, the system analyzes local variations in intensity that correspond to phase shifts caused by soft tissues. This localized analysis enables detection of subtle phase changes that are invisible in conventional absorption imaging, thereby improving soft tissue contrast without complicating the overall system.
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 reduces the cost of grating manufacture and device maintenance by allowing the use of distorted gratings and enables high-speed image generation with good accuracy, even with moving subjects, while maintaining low device costs.
Implementation Method 1
a phenomenon whereby an intensity pattern formed by a transmission grating that is being irradiated by X-rays on an X-ray detector varies due to slight refraction and dispersion of X-rays
Implementation Method 2
taking into consideration fractional Talbot effect due to interference effect (so-called diffraction effect) caused by the grating
Implementation Method 3
Radiation of high penetrating power, for example X-rays, are in widespread use as probes for visualizing the inside of a material
Implementation Method 4
an intensity distribution image for radiation that has passed through the sample and a grating group that have been arranged on a path from a radiation source section to a detection section
Data Source
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AI summary
The present invention provides technology that makes it possible, in a device that uses a grating to carry out high sensitivity radiographic image shooting using the wave nature of x-rays or the like, to shoot a sample that moves relative to a device. A pixel value computation section 51 determines, using a plurality of intensity distribution images of a sample 10 that moves in a direction that traverses the path of radiation, whether or on not a point (p, q) on the sample belongs in a region (Ak) on each intensity distribution image. Further, the pixel value computation section 51 obtains a sum pixel value (Jk) for each region (Ak) by summing pixel values on the each intensity distribution image for point (p, q) that belongs to each region (Ak). An image computation section 52 creates a required radiographic image using the sum pixel values (Jk) of the region (Ak) .