Position Determination via Cross-Correlation of Object and Probe Functions

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for determining the position of an object with respect to incident radiation, such as ptychographical iterative engines and coherent diffraction imaging, face limitations in accuracy due to movement errors and drift, particularly when recording multiple diffraction patterns with varying illumination positions.

Innovation Solution

A method that cross-correlates estimates of the object and probe functions to determine the peak location, allowing for real-time adjustment of the object's position relative to the incident radiation, and iteratively updates these functions to improve image data resolution and reduce noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple diffraction patterns are recorded with varying illumination positions to improve image resolution, then manufacturing precision is improved, but measurement precision deteriorates due to movement errors and drift

Engineering Contradiction:
Improveimage resolutionVSAvoidposition accuracy
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent implements feedback by using cross-correlation between first and second estimates of object functions to determine peak locations, which provide feedback information about the actual positions. This feedback mechanism allows real-time correction of position deviations caused by movement errors and drift, thereby maintaining measurement precision while achieving high image resolution through multiple diffraction patterns

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces mechanical position measurement systems with a computational approach using cross-correlation of object function estimates. Instead of relying on mechanical encoders or physical position sensors that are subject to drift and errors, the system uses mathematical correlation of diffraction pattern data to determine positions, eliminating the mechanical measurement chain and its associated errors

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If the object or probe is moved to multiple positions to record diffraction patterns, then image data quality is improved, but device complexity increases due to translation stages and positioning systems

Engineering Contradiction:
Improveimage data qualityVSAvoidpositioning system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling the system to automatically determine its own position information through cross-correlation of object function estimates. The system does not require external complex positioning systems or manual intervention; instead, it extracts position data inherently from the diffraction pattern measurements themselves, making the positioning function self-contained and reducing overall device complexity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces cross-correlation computation as an intermediary process between diffraction pattern acquisition and image reconstruction. This computational intermediary extracts position information from the diffraction data without requiring direct mechanical measurement systems, thereby simplifying the physical device while maintaining the ability to handle multiple positions

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If only a single diffraction pattern is recorded to simplify the measurement process, then device complexity is reduced, but measurement precision deteriorates due to inability to eliminate drift

Engineering Contradiction:
Improvemeasurement process simplicityVSAvoiddrift elimination capability
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent uses feedback through cross-correlation of first and second estimates of object functions to continuously monitor and correct for drift. Even with a single diffraction pattern or limited patterns, the cross-correlation process provides feedback about position stability and enables real-time compensation for drift, maintaining measurement precision without requiring complex multi-position acquisition systems

Inventive Principle:
Principle #23Feedback

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 accurate, on-the-fly determination of the object's position with respect to incident radiation, enhancing image data resolution and convergence rate while reducing noise, thereby overcoming the limitations of previous methods.

Implementation Method 1

cross correlating first and second estimates of an object function indicating one or more characteristics of the object or a probe function indicative of one or characteristics of the incident radiation, and determining a peak of the cross correlation, wherein the location of the object with respect to the incident radiation is based at least in part on a location of the peak

Methodology Applied
Scientific EffectCross-correlation:

Implementation Method 2

detecting an intensity of radiation scattered by the target object with the incident radiation or the post target aperture at a first position with respect to the target object

Methodology Applied
Scientific EffectScattering: Scattering

Data Source

PatentEP2732274B1Method and apparatus for position determination
Publication Date: 2020.12.23 PHASE FOCUS
  • EP2732274B1 patent drawingFigure 1~3
  • EP2732274B1 patent drawingFigure 2
  • EP2732274B1 patent drawingFigure 4

AI summary

Embodiments of the invention provide a method of determining a position of an object with respect to incident radiation, comprising iteratively determining at least one of an object function indicating one or more characteristics of an object and a probe function indicative of one or more characteristics of incident radiation, iteratively determining the position of the object, wherein the iteratively determining the position of the object comprises cross correlating first and second estimates of the object function or the probe function, determining a location of a peak of the cross correlation, and determining a translation deviation indicative of a difference in position of the object between the first and second estimates based on the location of the peak.