Chrono CDI Phase Retrieval for Dynamic Process Imaging
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Solution Overview
Problem
Current phase retrieval algorithms in coherent diffraction imaging require excessive oversampling, limiting the temporal resolution and making it difficult to image dynamic processes such as crystal growth or strain in battery cathode nanoparticles due to prolonged radiation dose and measurement time.
Innovation Solution
The chrono CDI method reduces oversampling by acquiring a plurality of 3D data sets at different time states, using information from all time states to reconstruct 3D images with reduced diffraction patterns, allowing for image fidelity maintenance with fewer measurements than conventional methods, thereby improving temporal resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional phase retrieval algorithms are used to ensure image fidelity, then measurement precision is maintained, but measurement time increases and temporal resolution deteriorates
Solution Approach 1:
The patent applies preliminary action by using the initial and final time state data sets (which satisfy Nyquist sampling) to compute reference images before reconstructing intermediate time states. This pre-computed information from boundary time points guides the reconstruction of intermediate states, allowing fewer measurements while maintaining fidelity.
Solution Approach 2:
The patent uses copying by generating a reference image from the initial and final time state data sets and using this reference to guide the reconstruction of intermediate time states. The reference acts as a template that copies structural information, allowing intermediate states to be reconstructed with fewer measurements while maintaining image fidelity through correlation with the reference.
2Measurement precision
If Nyquist sampling requirements are satisfied to maintain image fidelity, then measurement precision is improved, but the number of measurements increases and productivity decreases
Solution Approach 1:
The patent applies partial action by requiring full Nyquist sampling only at the initial and final time states, while using reduced sampling for intermediate time states. This partial application of the sampling requirement at critical boundary points provides sufficient information to guide reconstructions at intermediate points with fewer measurements, improving productivity while maintaining fidelity.
Solution Approach 2:
The patent changes the sampling parameter dynamically across different time states. Full sampling is applied at initial and final states where complete information is needed, while reduced sampling is applied at intermediate states where temporal correlation with boundary states allows fidelity to be maintained with fewer measurements, thus improving temporal resolution.
3Loss of time
If the number of diffraction patterns is reduced to improve temporal resolution, then measurement time decreases, but image fidelity may be compromised
Solution Approach 1:
The patent implements feedback by using the reference image computed from initial and final time states to guide and evaluate the reconstruction of intermediate time states. The correlation between reconstructed intermediate images and the reference provides feedback that ensures fidelity is maintained even when fewer diffraction patterns are used, allowing reduced measurement time without compromising quality.
4Measurement precision
If full sampling is performed at all time states to ensure accurate reconstruction, then measurement precision is maintained, but radiation dose increases
Solution Approach 1:
The patent applies preliminary action by performing full sampling at the initial and final time states to establish accurate reference images, then using these references to guide reduced-sampling reconstructions at intermediate states. This ensures reconstruction accuracy is maintained through the reference guidance while reducing the total number of measurements and associated radiation dose.
Solution Approach 2:
The patent uses copying by creating a reference image from fully-sampled boundary time states and using this reference to guide intermediate state reconstructions. The reference copies essential structural information, allowing accurate reconstruction with fewer measurements and reduced radiation exposure.
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 enhances the temporal resolution of coherent diffraction imaging by reducing the number of measurements required, enabling the imaging of faster dynamics and reducing radiation dose, while maintaining image fidelity, with the ability to image processes up to 20 times faster than conventional methods.
Implementation Method 1
the beam scattered by the object produces a diffraction pattern that is measured by an area detector
Data Source
AI summary
A method for retrieving phase information in a coherent diffraction imaging process includes acquiring a plurality of 3D data sets, each 3D data set corresponding to one of a plurality of time states, and reconstructing a 3D image of the object at a given time state using the 3D data set from all of the time states. Each 3D data set is acquired by: illuminating an object positioned in a first position with a coherent beam; measuring a first 2D diffraction pattern using an area detector; rotating the object around a tilt axis thereof to a second position that is different from the first position; re-illuminating the object positioned in the second position with the coherent beam; re-measuring a second 2D diffraction pattern using the area detector; and repeating the rotating, re-illuminating and re-measuring steps such that each 3D data set includes a predetermined number of diffraction patterns.