Systems and methods for sub-aperture based aberration measurement and correction in interferometric imaging

Patent metadata

Field	Value
Publication number	US-9775511-B2
Application number	US-201414758792-A
Country	US
Kind code	B2
Filing date	Jan 31, 2014
Priority date	Feb 1, 2013
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

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.

First claim

The invention claimed is:

1. A method for characterizing a wavefront in interferometric imaging data on a sample, wherein the interferometric data is generated using a broad bandwidth light source wherein the interferometric data contains information about lateral structure within the sample, said method comprising:
generating a beam from the broad bandwidth light source;
dividing the beam into reference and sample arms wherein the sample arm contains the sample to be imaged;
directing the beam to the sample;
combining light scattered from the sample and light returning from the reference arm;
detecting the combined light and generating signals in response thereto;
processing the signals to isolate an axial subset of the interferometric data corresponding to a depth in sample where the lateral structure is located;
dividing the axial subset into lateral subsections at a plane where the wavefront should be characterized;
determining a correspondence between at least two of the lateral subsections;
characterizing the wavefront using the correspondence; and
storing or displaying the wavefront characterization, or using the wavefront characterization as input to a subsequent process.

2. A method as recited in claim 1 , wherein the correspondence between subsections is determined by correlating versions of the structure contained in the at least two subsections.

3. A method as recited in claim 1 , wherein the correspondence between subsections is determined by correlating the subsections at a plane substantially optically conjugate to the object depth containing the structure.

4. A method as recited in claim 1 , further comprising propagating the axial subset to the plane where the characterization of the wavefront should be determined prior to the dividing step.

5. A method as recited in claim 1 , wherein the interferometric data is holoscopic imaging data.

6. A method as recited in claim 1 , wherein the sample is a human eye.

7. A method as recited in claim 1 , wherein the interferometric imaging data is one of full-field optical coherence tomography imaging data, line-field optical coherence tomography imaging data, and flying spot optical coherence tomography imaging data.

8. A method as recited in claim 1 , wherein the isolating is achieved using the coherence length of the source.

9. A method as recited in claim 1 , wherein the subsections overlap.

10. A method as recited in claim 1 , wherein the characterizing of the wavefront includes a derivation of the local wavefront orientation from the correspondence between the subsections.

11. A method as recited in claim 1 , wherein the characterizing of the wavefront includes using one of: Taylor monomials or Zernike polynomials.

12. A method as recited in claim 1 , further comprising using the characterization of the wavefront as input to a wavefront compensation device to create a compensated wavefront.

13. A method as recited in claim 12 , wherein the compensated wavefront is used to compensate for aberrations in a beam of radiation used in a diagnostic or treatment modality where high power or resolution is required.

14. A method as recited in claim 1 , further comprising using the wavefront characterization to correct the interferometric imaging data and generating an image from the interferometric data with reduced aberrations.

15. A method as recited in claim 1 , further comprising repeating the dividing, determining and characterizing steps until a desired level of correction is achieved.

16. A method as recited in claim 1 , wherein the axial subset is divided into two subsections and the wavefront characterization is used to determine defocus.

17. A method as recited in claim 1 , further comprising using the characterizing of the wavefront as an input to a manufacturing process.

18. A method as recited in claim 1 , further comprising using the characterizing of the wavefront as an input to a surgical process.

19. A method as recited in claim 1 , wherein the measurement area on the sample is non-isoplanatic and different wavefront characterizations are calculated for different regions of the sample.

20. A method as recited in claim 19 , wherein the different regions are separated in the transverse direction.

21. A method as recited in claim 19 , wherein the different regions are separated in the axial direction.

22. A method as recited in claim 1 , further comprising applying a phase adjustment to the interferometric imaging data.

23. A system for characterizing a wavefront in interferometric imaging data of a light scattering object containing lateral structure comprising:
a broadband light source arranged to generate a beam of radiation;
a beam divider for separating the beam into reference and sample arms, wherein the sample arm contains the light scattering object to be imaged;
optics to direct said beam of radiation on the light scattering object to be imaged and for combining light scattered from the object and light returning from the reference arm;
a detector for recording the combined light and generating signals in response thereto; and
a processor for isolating an axial subset of the generated signals corresponding to a depth in the sample where the lateral structure is located, dividing the axial subset into lateral subsections at plane where the wavefront should be characterized, said processor further for determining a correspondence between at least two of the subsections, and for using the correspondence to characterize the wavefront.

24. A system as recited in claim 23 , wherein the broadband light source is a swept-source.

25. A system as recited in claim 23 , in which the processor generates an aberration corrected image of the light scattering object using the wavefront characterization.

Assignees

• Zeiss Carl Meditec Inc

Inventors

• Kumar Abhishek
• Tumlinson Alexandre R
• Leitgeb Rainer

Classifications

• A61B3/14

  Arrangements specially adapted for eye photography · CPC title

• A61B3/0025

  characterised by electronic signal processing, e.g. eye models · CPC title

• A61B3/1015

  for wavefront analysis · CPC title

• G01N2021/1787

  Tomographic, i.e. computerised reconstruction from projective measurements · CPC title

• G03H2222/14

  Broadband source, e.g. sun light · CPC title