Talbot Interferometer Image Unevenness Correction
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Solution Overview
Problem
Existing medical image systems using Talbot interferometers or Talbot-Lau interferometers face challenges in reducing image unevenness caused by gratings, which persist even after background correction, requiring complex procedures like BG radiographing with a member causing equivalent X-ray spectral changes.
Innovation Solution
A medical image system and processing device that generate subject and subjectless absorption images using moire fringe images, with an image unevenness correction unit that corrects only the high-frequency component of the subject absorption image using a corrected subjectless absorption image, setting different correction coefficients for bone and soft tissue areas, and adjusting coefficients based on pixel values and high-frequency components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If BG radiographing is conducted with a homogeneous member that causes the same X-ray spectral change as the subject, then image unevenness due to X-ray spectral change is reduced, but the procedure becomes more troublesome and complicated
Solution Approach 1:
The invention extracts only the high-frequency component from the subjectless absorption image, which contains the image unevenness information, and applies it for correction. This separates the correction function from the need for complex BG radiographing with homogeneous members, achieving image unevenness reduction without the troublesome procedure of placing equivalent spectral change members during BG radiographing
Solution Approach 2:
The invention uses a simple subjectless absorption image as a proxy for the complex BG radiographing with homogeneous members. By copying the high-frequency component from the subjectless absorption image and applying it to correct the subject absorption image, the system achieves the same correction effect without requiring the complicated BG radiographing procedure
2Ease of operation
If simple BG radiographing is conducted without a homogeneous member, then the procedure remains simple, but image unevenness caused by X-ray spectral change persists in the corrected image
Solution Approach 1:
The invention introduces a mediator - the high-frequency component extracted from the subjectless absorption image - that bridges the gap between simple BG radiographing and the need to correct X-ray spectral change effects. This intermediary allows simple radiographing procedures to achieve correction results previously requiring complex homogeneous member radiographing
Solution Approach 2:
The invention changes the parameter being corrected by focusing specifically on the high-frequency component rather than attempting to correct the entire absorption image. This parameter change allows effective correction of image unevenness while maintaining procedural simplicity, as the high-frequency component contains the essential unevenness information
3Measurement precision
If the entire subjectless absorption image is used for correction, then correction is comprehensive, but high-frequency noise is also amplified along with the high-frequency component
Solution Approach 1:
The invention segments the subjectless absorption image into different frequency components and applies correction only to the high-frequency component. This segmentation allows selective correction of image unevenness while avoiding the amplification of high-frequency noise that would occur if the entire image were used for correction
Solution Approach 2:
The invention applies different correction strategies to different frequency components of the image. By focusing correction efforts specifically on the high-frequency component where unevenness information resides, while leaving the low-frequency component unchanged, the system achieves localized correction that avoids noise amplification while maintaining correction effectiveness
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
Effectively reduces image unevenness without the need for a member causing X-ray spectral changes, improving image quality by correcting high-frequency components specifically, thus simplifying the BG radiographing process and maintaining image quality.
Implementation Method 1
an X-ray source configured to emit X-rays
Implementation Method 2
The Talbot effect refers to a phenomenon of coherent light, which has passed through a first grating having slits formed at regular intervals, forming a lattice image of the first grating in regular cycles in the light traveling direction
Implementation Method 3
an X-ray detector irradiated by the X-ray source, the X-ray detector having conversion elements for accumulating charge according to X rays having passed through the gratings and generating electrical signals
Data Source
AI summary
A medical image system includes: X-ray equipment having a Talbot interferometer or a Talbot-Lau interferometer and including: an X-ray source configured to emit X-rays; a plurality of gratings arranged in a emitting direction of the X-rays; and an X-ray detector irradiated by the X-ray source and having conversion elements for accumulating charge and generating electrical signal to read the electrical signals generated to acquire moire fringe image; a subject absorption image generation unit configured to generate a subject absorption image based on moire fringe images containing a subject; a subjectless absorption image generation unit configured to generate a subjectless absorption image based on subjectless more fringe images; and an image unevenness correction unit configured to correct image unevenness of the subject absorption image, the medical image system further including a subjectless absorption image correction unit, wherein the image unevenness correction unit corrects image unevenness of the subject absorption image.