Ptychography Probe Weighting for Sub-Pixel Position Correction
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Solution Overview
Problem
Current ptychography methods suffer from contrast degradation due to position errors, slow convergence speeds, and a tendency to converge to local optimal solutions or fail to converge entirely, especially when dealing with large amounts of experimental data.
Innovation Solution
A method for ptychography position correction based on probe weighting, involving the formation of a probe matrix, cross-correlation gradient-based updates, and weight function optimization to enhance convergence stability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the simulated annealing position correction method is used, then the position correction can be performed, but the calculation cost is large and the convergence speed is slow
Solution Approach 1:
The patent changes the optimization parameters by introducing a weight function that assigns different weights to different probe positions based on their overlap ratios. This transforms the uniform optimization problem into a weighted optimization problem, enabling faster convergence by focusing computational resources on more informative probe positions.
Solution Approach 2:
The patent implements an iterative feedback mechanism where the position correction is performed multiple times with increasing weight functions. In each iteration, the weight function is updated based on the overlap ratio of probe positions, providing feedback that guides the optimization process toward the correct position more efficiently.
2Measurement precision
If the cross-correlation position correction method is used, then the calculation accuracy is high, but the position correction speed is relatively slow
Solution Approach 1:
The patent modifies the cross-correlation approach by introducing a weight function that dynamically adjusts the importance of different probe positions. This parameter change enables the method to achieve high accuracy while improving speed by reducing the search space and focusing computation on critical regions.
Solution Approach 2:
Instead of uniformly processing all probe positions, the patent applies partial action by selectively weighting only the most informative probe positions (those with higher overlap ratios) more heavily. This partial focus on critical regions achieves the desired accuracy faster than processing all positions equally.
3Reliability
If the conventional ptychography method is used, then the imaging can be performed, but the contrast degradation occurs due to position errors
Solution Approach 1:
The patent implements a feedback mechanism where the weight function is continuously updated based on the overlap ratio of probe positions. This feedback loop allows the system to automatically adjust and correct position errors, maintaining high imaging quality and contrast accuracy throughout the ptychography process.
Solution Approach 2:
The patent changes the parameter of probe position weighting by introducing a weight function that dynamically adjusts the significance of each probe position based on its overlap ratio. This parameter change enables the system to compensate for position errors and maintain high contrast accuracy in the final image reconstruction.
Data Source
AI summary
The disclosure provides a method for ptychography position correction based on probe weighting. The method includes: collecting diffraction light field intensity information and simultaneously initializing information functions of illumination probes and a sample to be tested and probe positions; obtaining and importing an exit wave into a propagation model to obtain a simulated diffraction light field and replacing the diffraction light field intensity information to obtain an updated diffraction light field; importing the updated diffraction light field into a backpropagation model and obtaining a diffraction exit wave and updating the information functions of the sample to be tested and the illumination probes at each scan position; and forming a probe matrix around the probe positions, updating the probe positions after calculating a correlation, and repeating the above steps to iterate until the predetermined number of iterations is completed or a predetermined condition is reached.