Fourier Ptychography Illumination Correction

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Solution Overview

Problem

Existing microscopy techniques using Fourier ptychography face limitations due to imperfections in illumination devices, such as limited coherence, inhomogeneous illumination, and restricted illumination directions, which degrade image quality and are not easily integratable with conventional microscopes.

Innovation Solution

A method that accounts for beam shape properties of illumination fields by adding and removing their effects during image evaluation using Fourier ptychography techniques, allowing for the determination of high-quality images even with imperfect illumination, and enabling simpler and more cost-effective microscopy device designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a matrix-shaped LED array is used to provide coherent illumination from different directions, then illumination coherence and resolution are improved, but device complexity and installation space increase

Engineering Contradiction:
Improveimage resolutionVSAvoidillumination device structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of providing coherent illumination from different directions without requiring a complex matrix-shaped LED array. By using a simpler illumination device that can still achieve the necessary coherence and angular diversity, the invention removes unnecessary structural complexity while maintaining the core functionality needed for Fourier ptychography.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the approach from modifying the physical structure of the illumination device to modifying the parameter handling in image evaluation. By incorporating beam shape properties into the reconstruction algorithm, the system achieves high-resolution imaging without requiring complex illumination hardware, thus resolving the contradiction between measurement precision and device complexity.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If LEDs at the edge of the array are used to provide strongly deflected illumination directions, then illumination angle diversity is improved, but light output and illumination homogeneity deteriorate

Engineering Contradiction:
Improveillumination direction rangeVSAvoidlight output and homogeneity
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent introduces beam shape properties as an intermediary parameter that mediates between illumination direction diversity and light output quality. By characterizing and compensating for the beam shape effects of edge LEDs in the image evaluation process, the system can utilize a broader range of illumination directions without sacrificing illumination homogeneity or light output, thus resolving the contradiction between adaptability and illumination intensity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If conventional Fourier ptychography techniques are used without considering beam shape properties, then image evaluation simplicity is maintained, but image quality deteriorates due to illumination imperfections

Engineering Contradiction:
Improveimage evaluation simplicityVSAvoidimage quality
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by pre-characterizing the beam shape properties of the illumination device and incorporating this information into the image evaluation process. This preparation step allows the system to maintain relative simplicity in operation while significantly improving image quality, as the beam shape compensation is automatically applied during reconstruction without requiring complex real-time adjustments.

Inventive Principle:
Principle #10Preliminary action

4Device complexity

If a simple illumination device is used, then device complexity and cost are reduced, but illumination quality and coherence deteriorate

Engineering Contradiction:
Improveillumination device structureVSAvoidillumination quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces the mechanical/optical approach of improving illumination quality through complex hardware with a computational approach. By using algorithms that account for beam shape properties in image evaluation, the system achieves reliable, high-quality illumination effects using a simple illumination device, thus resolving the contradiction between device complexity and illumination quality.

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

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 image quality by diversifying illumination fields and correcting aberrations, making it suitable for a wide range of microscopy devices without requiring complex or high-quality illumination systems, thus improving resolution and robustness while reducing implementation complexity.

Implementation Method 1

an illumination field is assigned to each of the at least two images and illuminates the object when the respective image is captured

Methodology Applied
Scientific EffectLight: Light

Implementation Method 2

a phase and amplitude distribution of the object is then calculated using an iterative algorithm, for example an error reduction algorithm, a hybrid input-output algorithm, and/or a Gerchberg-Saxton algorithm (image evaluation). This can be saved and displayed as a result image, which has a comparatively high resolution. Instead of the object itself, a spectrum of the object is reconstructed by the algorithm so that the phase and amplitude distribution of the object can be obtained using a further Fourier transformation.

Methodology Applied
Scientific EffectFourier transformation:

Data Source

PatentEP3172611B1Method and device for imaging an object
Publication Date: 2020.01.29 CARL ZEISS MICROSCOPY GMBH
  • EP3172611B1 patent drawingFigure 1
  • EP3172611B1 patent drawingFigure 2~3
  • EP3172611B1 patent drawingFigure 4

AI summary

According to the invention, at least two images of an object (100) are obtained, each of which is assigned an illumination field (110-1 - 110-3) which is associated with predetermined beam shaping properties (111-1 - 111-3). An effect of the beam-shaping properties (111-1 - 111-3) is added for each of the at least two images to a predetermined approximation of the object (100), the approximation is then adapted by means of techniques of the Fourier ptychography in the k-space on the basis of the respective image and, subsequently, the effect of the beam-shaping properties (111-1 - 111-3) is removed from the adapted approximation of the object (100).