Interferometric Imaging Wavefront Correction via Sub-Aperture Correlation

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Solution Overview

Problem

Existing methods for wavefront aberration correction in interferometric imaging are limited in precision and require long execution times, particularly when dealing with samples that exhibit non-homogeneous structures and unknown aberrations, and they rely on assumptions about sample isotropy and well-defined aberrations.

Innovation Solution

A method for characterizing wavefronts in interferometric imaging data using sub-aperture correlation, which isolates axial subsets of data corresponding to specific depths, divides them into lateral subsections, determines correspondence between these subsections, and applies phase corrections without requiring adaptive optics or additional cameras, allowing for near diffraction-limited resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If iterative methods are used to solve for unknown aberrations, then aberration correction can be achieved, but execution time becomes very long and precision is limited

Engineering Contradiction:
Improveaberration correction precisionVSAvoidexecution time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the wavefront aberration measurement into multiple sub-aperture regions. By dividing the aperture into sub-apertures and measuring each independently, the system obtains multiple local wavefront measurements that can be combined to achieve high-precision full-aperture aberration correction without requiring long iterative calculations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary wavefront measurements using sub-aperture techniques before combining the results. This preliminary action of measuring each sub-aperture separately provides sufficient information to reconstruct the full wavefront aberration directly, eliminating the need for time-consuming iterative optimization.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If adaptive optics with Shack-Hartmann sensor are used for wavefront correction, then diffraction limited imaging can be achieved, but the system complexity increases and additional hardware is required

Engineering Contradiction:
Improveimaging resolutionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces physical adaptive optics hardware (Shack-Hartmann sensors, deformable mirrors) with computational methods. By using sub-aperture correlation algorithms and digital signal processing, the system achieves wavefront measurement and correction purely through software, eliminating complex optical components.

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

Solution Approach 2:

The patent creates virtual copies of the wavefront measurement process by dividing the aperture into multiple sub-apertures and independently analyzing each. These computational copies provide sufficient information to reconstruct the full wavefront without requiring physical wavefront sensing hardware.

Inventive Principle:
Principle #26Copying

3Reliability

If iterative optimization methods are used for phase correction, then aberration can be corrected, but the calculation time increases significantly

Engineering Contradiction:
Improveaberration correction accuracyVSAvoidcalculation speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the optimization problem into multiple independent sub-aperture measurements. Each sub-aperture provides local wavefront information that can be determined directly through correlation methods, avoiding the need for iterative optimization across the entire aperture while maintaining high accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables each sub-aperture to independently provide its own wavefront information through self-correlation methods. This self-service approach allows direct calculation of local wavefront slopes without requiring iterative optimization, significantly reducing computation time while maintaining reliability.

Inventive Principle:
Principle #25Self-service

4Measurement precision

If broad bandwidth light is used in coherence microscopy, then depth resolution improves, but aberration effects become more complex and harder to correct

Engineering Contradiction:
Improvedepth resolutionVSAvoidaberration correction complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the wavefront measurement process to work independently at each depth location. By measuring sub-aperture wavefronts at specific axial positions using the broad bandwidth light, the system obtains depth-resolved aberration information that can be corrected without the complexity increasing, because each depth plane is treated separately.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local wavefront correction at each depth plane rather than attempting global correction. This local quality approach allows the system to handle complex aberrations at different depths independently, maintaining simplicity while utilizing the full capability of broad bandwidth light for depth resolution.

Inventive Principle:
Principle #3Local quality

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 provides fast and precise aberration correction in a single step, improving image quality by correcting wavefront aberrations at arbitrary planes without needing system knowledge, and is applicable to various interferometric imaging techniques, including optical coherence tomography (OCT), without relying on sample homogeneity assumptions.

Implementation Method 1

collected interferometric imaging data of a sample

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

the phase information in the original detected data set can be mathematically manipulated to correct for known aberrations

Methodology Applied
Scientific EffectPhase information:

Data Source

PatentEP2951648B1Systems and methods for sub-aperture based aberration measurement and correction in interferometric imaging
Publication Date: 2025.08.06 CARL ZEISS MEDITEC AG
  • EP2951648B1 patent drawingFigure 1~2
  • EP2951648B1 patent drawingFigure 3~4
  • EP2951648B1 patent drawingFigure 5(a)~6

AI summary

Systems and methods for sub-aperture correlation based wavefront measurement in a thick sample and correction as a post processing technique for interferometric imaging to achieve near diffraction limited resolution are described. Theory, simulation and experimental results are presented for the case of full field interference microscopy. The inventive technique can be applied to any coherent interferometric imaging technique and does not require knowledge of any system parameters. In one embodiment of the present application, a fast and simple way to correct for defocus aberration is described. A variety of applications for the method are presented.