3D Tomography of Elongated Samples With Uniform Electron Dosage
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Solution Overview
Problem
Conventional tomographic methods, such as tilt-series and helical tomography, face challenges in ensuring uniform electron dosage, image stitching efficiency, and positional stabilization, leading to potential artifacts and poor reconstruction quality, especially for radiation-sensitive samples.
Innovation Solution
The method involves acquiring a series of two-dimensional composite images at different angles while translating the sample relative to the electron beam, using stroboscopic or coded exposure imaging to minimize motion blur and ensure uniform electron distribution, and optionally tracking the sample's tilt and curvature for real-time corrections, allowing for more efficient and accurate three-dimensional reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If conventional tilt-series or helical tomography is used to acquire 3D volume information, then the sample volume can be enlarged, but the electron dosage distribution becomes non-uniform and image stitching complexity increases
Solution Approach 1:
The patent implements continuous translation of the sample along the beam direction during tilt series acquisition, transforming the static sampling approach into a dynamic helical trajectory. This continuous motion ensures uniform electron dosage distribution across the entire sample volume while eliminating the need for complex post-acquisition stitching operations
Solution Approach 2:
The patent maintains continuous electron beam exposure to the sample throughout the acquisition process by translating the sample continuously along the beam direction. This continuous action eliminates gaps between successive tilt series and ensures uniform dosage distribution, improving both efficiency and reconstruction quality
2Loss of information
If multiple tilt series are acquired to enlarge sample volume, then more 3D information is obtained, but acquisition time and processing complexity increase
Solution Approach 1:
The patent performs continuous translation of the sample along the beam direction during a single tilt series acquisition, eliminating the need to acquire multiple separate tilt series. This continuous approach obtains complete 3D volume information in one uninterrupted process, significantly reducing acquisition time while maintaining full volumetric coverage
Solution Approach 2:
The patent combines the functions of multiple tilt series acquisitions into a single continuous acquisition process by implementing helical translation of the sample. This merging of operations reduces both acquisition time and processing complexity while obtaining equivalent or superior 3D volume information
3Measurement precision
If the sample is tilted to multiple angles for 3D reconstruction, then tomographic resolution improves, but motion blur and positional stabilization difficulties increase
Solution Approach 1:
The patent replaces the conventional mechanical tilting approach with a combination of fixed tilting and continuous translational motion along the beam direction. This substitution eliminates the need for repeated mechanical tilting and stabilization cycles, reducing motion blur while maintaining high tomographic resolution through the helical sampling trajectory
Solution Approach 2:
The patent performs continuous translation of the sample along the beam direction during the entire tilt series acquisition process, preparing the complete 3D volume data set in advance. This preliminary continuous action eliminates the need for repeated positional stabilization at each tilt angle, reducing both motion blur and acquisition time
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 ensures uniform electron dosage, simplifies image stitching, and improves the quality and efficiency of three-dimensional reconstructions by minimizing artifacts and blurring, while enabling near-real-time corrections for sample position and curvature.
Implementation Method 1
The sample is generally sufficiently thin to be transparent to electrons. Although some electrons are absorbed, many electrons pass into and through the sample, either scattered or unscattered.
Implementation Method 2
Although some electrons are absorbed, many electrons pass into and through the sample, either scattered or unscattered.
Implementation Method 3
Another set of optical elements form an enlarged image of the sample on a detector, such as a CMOS camera, a CCD camera, a fluorescent screen, or a combination of fluorescent screen and camera connected via fiber optics. The image formed on the detector is a two-dimensional (2D) projection of the sample.
Implementation Method 4
using stroboscopic or coded exposure imaging to minimize motion blur
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A method of three-dimensional (3D) tomography comprising: providing a sample comprising an elongate section, the elongation of which defines an elongation axis having an axis length; acquiring a plurality of two-dimensional (2D) composite images of the elongate section along its axis length, each 2D composite image being generated from a respective series of image frames and comprising a projection of the elongate section that is parallel to the elongation axis, wherein each 2D composite image is acquired at a different respective angle of rotation of the sample, relative to an initial orientation of the sample, about a rotation axis that is substantially coincident with the elongation axis; and combining the plurality of projection images to obtain a 3D tomographic representation of the elongate section of the sample.