Fourier ptychographic tomography

• US 10,665,001 B2
• Filed: 01/21/2016
• Issued: 05/26/2020
• Est. Priority Date: 01/21/2015
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Horstmeyer, Roarke W., Yang, Changhuei
• Primary Examiner(s): Kir, Albert
• Application Number:
  US15/003,559
• Publication Number:
  US 20160210763A1
• Time in Patent Office: 1,587 Days
• Field of Search: 348 79, 348 77, 348 80, 356491, 356479, 382128
• CPC Class Codes: G02B 21/365 Control or image processing arrangements for digital or video microscopes G02B21/361, G02B21/362 take precedence
• CPC Class Codes: G02B 21/367 providing an output produced by processing a plurality of individual source images, e.g. image tiling, montage, composite images, depth sectioning, image comparison
• CPC Class Codes: G02B 27/58 Optics for apodization or superresolution; Optical synthetic aperture systems
• CPC Class Codes: G06T 11/006 Inverse problem, transformation from projection-space into object-space, e.g. transform methods, back-projection, algebraic methods

Abstract

Certain aspects pertain to Fourier ptychographic tomographic systems and methods for acquiring a plurality of uniquely illuminated intensity measurements based on light passing through a thick sample from plane wave illumination at different angles and for constructing three-dimensional tomographic data of the thick sample by iteratively determining three-dimensional tomographic data in the Fourier domain that is self-consistent with the uniquely illuminated intensity measurements.

Claims

1. A Fourier ptychographic tomographic system, comprising:

an array of light elements, each light element having at least one light source, wherein the array of light elements is configured to provide illumination that is approximately plane wave illumination at each one of a plurality of illumination angles, provided sequentially over time, to a stationary, thick sample being imaged;

an optical system configured to collect light passing through the thick sample from the array of light elements and focus the collected light;

an image sensor configured to receive the focused light from the optical system and acquire a sequence of uniquely-illuminated intensity measurements, each associated with one of the plurality of illumination angles, wherein the image sensor is configured to acquire each of the uniquely-illuminated intensity measurements while the array of light elements provides plane wave illumination at one of the plurality of illumination angles during operation,

wherein the array of light elements is configured to activate only one light element during each exposure time to provide the illumination that is approximately plane wave illumination at one illumination angle during acquisition of each uniquely-illuminated intensity measurement; and

a processor configured to execute instructions to construct three-dimensional tomographic data of index of refraction of the stationary, thick sample, by;

(i) using a current three-dimensional sample solution to generate data in each of a plurality of spherical cap regions in three-dimensional Fourier space;

(ii) inverse Fourier transforming data in the three-dimensional spherical cap region to generate image data, while leaving phase unchanged replacing magnitudes of the image data with measured magnitudes from a uniquely-illuminated intensity measurement associated with an illumination angle corresponding to a location of the three-dimensional spherical cap region in three-dimensional Fourier space to produce updated image data, Fourier transforming the updated image data, and inserting the Fourier-transformed updated image data into the three-dimensional spherical cap region;

(iii) repeating operations in (ii) for each of the plurality of spherical cap regions in three-dimension Fourier space to determine an updated three-dimensional sample solution; and

(iv) repeating operations in (iii) until a comparison of the updated three-dimensional sample solution and the current three-dimensional sample solution is less than a predefined percentage; and

(v) inverse Fourier transforming the updated three-dimensional sample spectrum to determine the three-dimensional tomographic data of index of refraction of the stationary, thick sample.

2. The Fourier ptychographic tomographic system of claim 1, wherein two or more adjacent spherical cap regions of the plurality of three-dimensional spherical cap regions have at least partially overlapping surface areas in three-dimensional Fourier space.

3. The Fourier ptychographic tomographic system of claim 2, wherein the at least partially overlapping surface areas overlap by at least 70%.

4. The Fourier ptychographic tomographic system of claim 2, wherein the at least partially overlapping surface areas overlap by at least 80%.

5. The Fourier ptychographic tomographic system of claim 1, wherein the array of light elements is a light emitting diode (LED) matrix.

6. The Fourier ptychographic tomographic system of claim 5, wherein the LED matrix is a two-dimensional matrix.

7. The Fourier ptychographic tomographic system of claim 5, wherein the LED matrix comprise a plurality of concentric rings, each concentric ring having two or more LEDs.

8. The Fourier ptychographic tomographic system of claim 1, wherein the optical system is comprises at least one objective lens.

9. The Fourier ptychographic tomographic system of claim 1, further comprising a display for displaying an image of the sample determined using the three-dimensional tomographic data.

16. The Fourier ptychographic tomographic system of claim 1, wherein constructing the three-dimensional tomographic data comprises recovering phase data from the uniquely-illuminated intensity measurements.

18. The Fourier ptychographic tomographic system of claim 1, wherein each uniquely-illuminated intensity measurement corresponds to a different spherical cap region in three-dimensional Fourier space.

19. The Fourier ptychographic tomographic system of claim 1, wherein each uniquely-illuminated intensity measurement corresponds to a different spherical cap region in three-dimensional Fourier space.

10. A Fourier ptychographic tomographic imaging method, comprising:

receiving a plurality of uniquely-illuminated intensity measurements from an image sensor, the plurality of uniquely-illuminated intensity measurements based on light passing through a stationary, thick sample from an array of light elements, each light element having at least one light source,

wherein each of the uniquely-illuminated intensity measurements is acquired by the image sensor while the array of light elements provides illumination that is approximately plane wave illumination to the stationary, thick sample at one of a plurality of illumination angles, wherein only one light element of the array is configured to be activated at each image acquisition time in order to provide the illumination that is approximately plane wave illumination at one of the illumination angles; and

constructing three-dimensional tomographic data of index of refraction of the thick sample by;

(i) using a current three-dimensional sample solution to generate data in each of a plurality of spherical cap regions in three-dimensional Fourier space;

(ii) inverse Fourier transforming data in the three-dimensional spherical cap region to generate image data, while leaving phase unchanged replacing magnitudes of the image data with measured magnitudes from a uniquely-illuminated intensity measurement associated with an illumination angle corresponding to a location of the three-dimensional spherical cap region in three-dimensional Fourier space to produce updated image data, Fourier transforming the updated image data, and inserting the Fourier-transformed updated image data into the three-dimensional spherical cap region;

(iii) repeating operations in (ii) for each of the plurality of spherical cap regions in three-dimension Fourier space to determine an updated three-dimensional sample solution; and

(iv) repeating operations in (iii) until a comparison of the updated three-dimensional sample solution and the current three-dimensional sample solution is less than a predefined percentage; and

(v) inverse Fourier transforming the updated three-dimensional sample spectrum to determine the three-dimensional tomographic data of index of refraction data of the thick sample.

11. The Fourier ptychographic tomographic imaging method of claim 10, wherein two or more adjacent spherical cap regions of the plurality of three-dimensional cap regions have at least partially overlapping surface areas in three-dimensional Fourier space.

12. The Fourier ptychographic tomographic imaging method of claim 11, further comprising determining the current three-dimensional sample solution as an initialized three-dimensional sample solution or a previous three-dimensional sample solution of another iteration.

13. The Fourier ptychographic tomographic imaging method of claim 11, wherein the updated image data is updated in (ii) along a circular path in the three-dimensional sample solution.

14. The Fourier ptychographic tomographic method of claim 11, wherein the overlapping surface areas overlap by at least 70%.

15. The Fourier ptychographic tomographic method of claim 11, wherein the overlapping surface areas overlap by at least 80%.

17. The Fourier ptychographic tomographic imaging method of claim 11, wherein constructing the three-dimensional tomographic data of the thick sample comprises recovering phase data from the uniquely-illuminated intensity measurements.