3D Image Construction via Sample Rotation to Resolve EDS Shadowing
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Solution Overview
Problem
In electron tomography, the accuracy of three-dimensional images is compromised due to the EDS detector being shadowed by the sample holder, leading to reduced X-ray intensity and brightness levels in elemental mapping images, which increases the dependence on tilt angle for constructing accurate three-dimensional images.
Innovation Solution
A method and image processor that obtain two series of tilted images by rotating the sample about an axis perpendicular to its surface and tilting it in increments, allowing for the replacement of deteriorated images in the first series with brighter images from the second series, reducing the dependence on tilt angle and enhancing image accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sample is tilted at various angles to obtain a series of tilted images for three-dimensional reconstruction, then the three-dimensional elemental distribution can be obtained, but the EDS detector is hidden in the shadow of the sample holder at certain tilt angles, causing reduced X-ray intensity and decreased brightness levels of elemental mapping images
Solution Approach 1:
The patent applies inversion by rotating the sample 180 degrees about an axis perpendicular to its surface, thereby inverting the shadowing relationship. The sample holder that previously blocked the detector at certain tilt angles now allows unobstructed X-ray detection after rotation, enabling acquisition of high-quality images at the same tilt angles from the rotated position.
Solution Approach 2:
The patent introduces a rotational dimension to the traditional tilt-series acquisition. Instead of only tilting the sample, the method adds a 180-degree rotation about a perpendicular axis, creating a second series of tilted images from a different spatial orientation. This dimensional change allows selection of optimal images free from shadowing artifacts.
2Ease of manufacture
If images with reduced brightness levels are used due to shadowing, then the acquisition process is simplified, but the accuracy of three-dimensional images deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-rotating the sample 180 degrees before acquiring the second series of tilted images. This preliminary rotation ensures that the shadowing problem is avoided from the beginning of the second acquisition series, allowing direct selection of high-quality images without requiring complex post-acquisition correction or processing.
3Ease of operation
If the sample is held on a mesh with a diameter of 3 mm for observation, then the sample can be properly positioned in the electron microscope, but the frame of the sample holder, mesh, or sample blocks the EDS detector at certain tilt angles, cutting off characteristic X-rays and decreasing X-ray intensity
Solution Approach 1:
The patent applies inversion by rotating the entire sample assembly 180 degrees about an axis perpendicular to the sample surface. This rotation inverts the spatial relationship between the sample holder frame and the EDS detector, transforming positions where the frame blocked the detector into positions where the frame no longer interferes with X-ray detection.
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 enables the construction of accurate three-dimensional images by replacing images with reduced brightness levels, thereby improving the accuracy and reliability of elemental distribution maps.
Implementation Method 1
characteristic X-rays produced from the sample
Implementation Method 2
energy dispersive X-ray spectroscopy (EDS)
Implementation Method 3
signals arising from the sample such as secondary electrons
Data Source
AI summary
A method capable of constructing an accurate three-dimensional image is offered. The method comprises the step (S10) of obtaining a first series of tilted images which are constituted by electron microscope images or elemental mapping images of a sample (S) at different tilt angles and which have been obtained by tilting the sample in angular increments, the step (S14) of obtaining a second series of tilted images which are constituted by electron microscope images or elemental mapping images of the sample at different tilt angles and which have been obtained by rotating the sample about an axis (P) perpendicular to a surface (Sf) of the sample and then tilting the sample in angular increments, and the step (S16) of constructing the three-dimensional image on the basis of the first and second series of tilted images.