Zernike Phase Contrast Artifact Removal via Fourier Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Zernike phase contrast imaging in 3D CT imaging is hindered by artifacts from mixed absorption and phase contrast signals, leading to distortions and challenges in specimen segmentation.
Innovation Solution
A full-field x-ray imaging system that applies Fourier filtering to separate and remove absorption contrast artifacts, reconstructing the quantitative phase shift using a phase-shifting device and image processor, allowing for accurate 3D image generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Zernike phase contrast imaging is used to observe features, then phase contrast information is improved, but absorption contrast artifacts are introduced
Solution Approach 1:
The patent extracts and removes the harmful absorption contrast artifacts from the phase contrast image through computational methods. By separating the phase contrast signal from the absorption contrast artifact, the system preserves the useful phase information while eliminating the harmful artifacts that cause halos and distortions.
Solution Approach 2:
The patent converts the harmful mixed absorption and phase contrast signals into beneficial separate components. By using the known relationship between absorption and phase contrast and applying computational algorithms, the system transforms the problematic mixed signal into purified phase contrast information.
2Measurement precision
If Zernike phase contrast imaging is used for 3D CT imaging, then phase contrast capability is improved, but artifact distortions are amplified
Solution Approach 1:
The patent extracts and removes absorption contrast artifacts from each 2D projection image before performing 3D CT reconstruction. This prevents artifact distortions from being amplified during the tomographic reconstruction process, ensuring accurate 3D images.
Solution Approach 2:
The patent applies artifact removal algorithms to each 2D projection image before feeding them into the 3D CT reconstruction algorithm. This preliminary processing step ensures that only purified phase contrast information is used for 3D reconstruction, preventing artifact amplification.
3Productivity
If automated segmentation is performed on images with artifacts, then processing speed is improved, but segmentation accuracy deteriorates
Solution Approach 1:
The patent removes absorption contrast artifacts from the images before automated segmentation. This ensures that segmentation algorithms work with clean phase contrast images, achieving both high processing speed and high segmentation accuracy.
Solution Approach 2:
The patent performs artifact removal as a preliminary step before automated segmentation. By preparing clean images in advance, the system enables fast and accurate automated segmentation without compromising either speed or accuracy.
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 method effectively reduces artifacts in Zernike phase contrast images, enabling clearer 3D imaging by isolating phase shift information, thus improving image interpretation and specimen segmentation.
Implementation Method 1
a phase-shifting device to shift the phase of portions of x-ray radiation by a determined amount
Implementation Method 2
an objective x-ray lens for imaging the x-ray radiation transmitted through the specimen
Implementation Method 3
a condenser x-ray lens for projecting the x-ray radiation onto the specimen
Implementation Method 4
an x-ray detector that detects the x-ray radiation transmitted through the specimen to generate a detected image
Data Source
AI summary
The principle of reciprocity states that full-field and scanning microscopes can produce equivalent images by interchanging the roles of condenser and detector. Thus, the contrast transfer function inversion previously used for images from scanning systems can be applied to Zernike phase contrast images. In more detail, a full-field x-ray imaging system for quantitatively reconstructing the phase shift through a specimen comprises a source that generates x-ray radiation, a condenser x-ray lens for projecting the x-ray radiation onto the specimen, an objective x-ray lens for imaging the x-ray radiation transmitted through the specimen, a phase-shifting device to shift the phase of portions of x-ray radiation by a determined amount, and an x-ray detector that detects the x-ray radiation transmitted through the specimen to generate a detected image. An image processor then determines a Fourier filtering function and reconstructs the quantitative phase shift through the specimen by application of the Fourier filtering function to the detected image. As a result, artifacts due to absorption contrast can be removed from the detecting image. This corrected image can then be used in generating three dimensional (3D) images using computed tomography.