Flow imaging in an optical coherence tomography (OCT) system

• US 10,426,337 B2
• Filed: 06/01/2017
• Issued: 10/01/2019
• Est. Priority Date: 06/01/2017
• Status: Active Grant

• Current Assignee: Santec Holdings Corp.
• Original Assignee: Santec Incorporated
• Inventors: Chong, Changho
• Primary Examiner(s): Thomas, Brandi N
• Application Number:
  US15/611,515
• Publication Number:
  US 20180344149A1
• Time in Patent Office: 852 Days
• Field of Search: 351221, 351222, 351243-246, 351200, 351205, 351206
• CPC Class Codes: A61B 3/0025 characterised by electronic signal processing, e.g. eye models
• CPC Class Codes: A61B 3/102 for optical coherence tomography [OCT]
• CPC Class Codes: A61B 3/1233 for measuring blood flow, e.g. at the retina

Abstract

A method for imaging includes scanning a B scan of a sample N times at a first slice of a sample. N is greater than or equal to 2. The B scan includes a plurality of A scans. A pixel of the first slice has an M number of A scans within the pixel. Each of the A scans have a spectrum range less than a full spectrum range of the light source. A number of pixels per B scan is an approximate B scan length divided by a lateral resolution size of the pixel. The method further includes determine a flow image of the sample using an optical coherence tomography (OCT) signal reflected back from the sample.

Claims

1. An optical coherence tomography (OCT) system comprising:

a light source configured to generate a probe beam having an adjustable swept rate and swept range;

an interferometer and beam scanning optics configured to scan the probe beam onto a sample;

a detector configured to measure an OCT interference signal returning from the sample;

a processor configured to generate an OCT image of a flow of the sample, wherein the processor is configured to;

scan a B scan of a sample N times at a first slice of the sample, wherein;

N is greater than or equal to 2,

the B scan comprises a plurality of A scans,

a pixel of the first slice has an M number of A scans within the pixel,

each of the A scans has a spectrum range less than a full spectrum range of the light source, and

a number of pixels per B scan is an approximate B scan length divided by a lateral resolution size of the pixel; and

determine a flow image of the sample using an optical coherence tomography (OCT) signal reflected back from the sample.

2. The OCT system of claim 1, wherein M is greater than 1.

3. The OCT system of claim 2, wherein the spectrum range of each of the A scans is approximately 1/M of the full spectrum of the light source.

4. The OCT system of claim 2, wherein each of the A scans within the pixel scans at a different spectrum range of the full spectrum.

5. The OCT system of claim 4, wherein determining the flow image further comprises performing speckle variance detection or amplitude-decorrelation of the OCT signal between corresponding A scans of the same spectrum range within the pixel.

6. The OCT system of claim 1, wherein the processor is configured to perform additional B scans of the sample at additional slices adjacent to the first slice.

7. The OCT system of claim 1, wherein determining the flow image further comprises detecting motion between consecutive B scans by comparing the N B scans to one another.

8. The OCT system of claim 1, wherein determining the flow image further comprises performing speckle variance detection or amplitude-decorrelation of the OCT signal of the M number of A scans.

9. The OCT system of claim 1, wherein determining the flow image further comprises performing speckle variance detection or amplitude-decorrelation of the OCT signal between the consecutive N B scans at the pixel.

10. The OCT system of claim 1, wherein determining the flow image further comprises averaging speckle variance detection or amplitude-decorrelation of the OCT signal over the M A scans of the pixel and/or over consecutive N B scans at the pixel.

11. The OCT system of claim 1, wherein M=1, wherein each of the N B scans at the pixel comprises a single A scan at the pixel.

12. The OCT system of claim 1, wherein each of the single A scans at the pixel performed N times have the same spectrum range of the light source.

13. A method for imaging comprising:

scanning a B scan of a sample N times at a first slice of the sample, wherein;

N is greater than or equal to 2,

the B scan comprises a plurality of A scans,

a pixel of the first slice has an M number of A scans within the pixel,

each of the A scans has a spectrum range less than a full spectrum range of a light source, and

a number of pixels per B scan is an approximate B scan length divided by a lateral resolution size of the pixel; and

determining a flow image of the sample using M segments of an optical coherence tomography (OCT) signal reflected back from the sample.

14. The method of claim 13, wherein M is greater than 1, the spectrum range of each of the A scans is approximately 1/M of the full spectrum of the light source, and each of the A scans within the pixel scans at a different spectrum range of the full spectrum.

15. The method of claim 13, wherein determining the flow image further comprises performing speckle variance detection or amplitude-decorrelation of the OCT signal:

between corresponding A scans of the same spectrum range within the pixel,

of the M number of A scans, and/or

between the consecutive N B scans at the pixel.

16. The method of claim 13, wherein determining the flow image further comprises averaging speckle variance detection or amplitude-decorrelation of the OCT signal over the M A scans of the pixel and/or over consecutive N B scans at the pixel.

17. A non-transitory computer readable medium having instructions thereon that, upon execution by a computing device, cause the computing device to perform operations comprising:

scanning a B scan of a sample N times at a first slice of the sample, wherein;

N is greater than or equal to 2,

the B scan comprises a plurality of A scans,

a pixel of the first slice has an M number of A scans within the pixel,

each of the A scans has a spectrum range less than a full spectrum range of a light source, and

a number of pixels per B scan is an approximate B scan length divided by a lateral resolution size of the pixel; and

determining a flow image of the sample using M segments of an optical coherence tomography (OCT) signal reflected back from the sample.

18. The non-transitory computer readable medium of claim 17, wherein M is greater than 1, the spectrum range of each of the A scans is approximately 1/M of the full spectrum of the light source, and each of the A scans within the pixel scans at a different spectrum range of the full spectrum.

19. The non-transitory computer readable medium of claim 17, wherein determining the flow image further comprises performing speckle variance detection or amplitude-decorrelation of the OCT signal:

between corresponding A scans of the same spectrum range within the pixel,

of the M number of A scans, and/or

between the consecutive N B scans at the pixel.

20. The non-transitory computer readable medium of claim 17, wherein determining the flow image further comprises averaging speckle variance detection or amplitude-decorrelation of the OCT signal over the M A scans of the pixel and/or over consecutive N B scans at the pixel.