Iterative Probe Function Estimation for Lensless X-ray Imaging
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Solution Overview
Problem
Conventional imaging techniques face challenges such as resolution limits, aberrations, and the need for complex equipment, particularly when using short wavelength radiation like X-rays or electrons, and require accurate knowledge of the probe function, which can be time-consuming and prone to inaccuracies.
Innovation Solution
An iterative method where the probe function is iteratively calculated step-by-step, allowing for efficient image data collection without prior knowledge of the probe function, using an optical setup to measure illumination both before and after analyzing the target object, and updating both the object and probe functions concurrently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional transmission imaging with plane wave illumination and lens is used, then image formation is achieved, but resolution is limited by lens aberrations and instabilities
Solution Approach 1:
The patent removes the lens from the imaging system entirely, extracting the problematic optical element that causes aberrations and instabilities. The imaging function is achieved through computational methods (iterative algorithms) rather than traditional optical focusing, eliminating the source of resolution degradation while maintaining image formation capability.
Solution Approach 2:
The patent replaces the mechanical/optical lens-based imaging system with a computational approach. Instead of using physical lenses to focus and form images, the system uses iterative mathematical algorithms to reconstruct images from diffraction pattern measurements, substituting mechanical optical components with computational processing.
2Measurement precision
If accurate probe function measurement is performed before imaging, then image accuracy is improved, but time consumption increases
Solution Approach 1:
The patent performs preliminary measurement of the probe function (illumination profile) before the main imaging process. By characterizing the illumination conditions in advance, the system can use this information in iterative algorithms to improve image reconstruction accuracy without requiring time-consuming adjustments during the actual imaging process.
Solution Approach 2:
The patent employs iterative algorithms that use feedback from measured diffraction patterns to progressively refine the image reconstruction. The system continuously compares calculated diffraction patterns with actual measurements and adjusts the reconstructed image accordingly, improving accuracy through iterative feedback rather than requiring perfect initial probe function knowledge.
3Measurement precision
If iterative process with probe function calculation is used, then image data accuracy is improved, but processing time increases
Solution Approach 1:
The patent uses partial information about the probe function (such as its intensity profile or support region) rather than requiring complete and precise knowledge. The iterative algorithms can converge to accurate solutions even with incomplete or approximate initial probe function information, performing partial measurements that are sufficient for high-quality reconstruction without excessive processing requirements.
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 high-resolution image data collection efficiently, reducing the need for precise probe function measurement and overcoming resolution limitations, while providing accurate image data characteristics of the target object.
Implementation Method 1
detecting the intensity of radiation scattered by the target object
Implementation Method 2
Each diffraction pattern is formed by illuminating an object with a known wave front of coherent radiation
Implementation Method 3
The exit wave function is propagated across distance D where a diffraction pattern is formed on an array of detectors
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A method and apparatus are disclosed for providing image data. The method includes the steps of providing image data for constructing an image of a region of a target object, comprising the steps of: providing incident radiation from a radiation source at a target object and, via at least one detector, detecting an intensity of radiation scattered by the target object; estimating an object function indicating at least one characteristic of a region of the target object; estimating a probe function indicating at least one characteristic of the incident radiation; providing image data via an iterative process responsive to the detected intensity of radiation scattered by the target object, wherein in said iterative process each of the object function and probe function are iteratively re-estimated step by step with a running estimate of the probe function being utilised to determine a running estimate of the object function associated with the target object.