Methods, systems and computer program products for processing images generated using Fourier domain optical coherence tomography (FDOCT)

• US 8,977,023 B2
• Filed: 01/23/2014
• Issued: 03/10/2015
• Est. Priority Date: 01/19/2007
• Status: Active Grant

• Current Assignee: Leica Microsystems NC, Inc. (Danaher Corporation)
• Original Assignee: Bioptigen, Inc. (Danaher Corporation)
• Inventors: Buckland, Eric L.
• Primary Examiner(s): IPPOLITO, NICOLE MARIE
• Application Number:
  US14/162,001
• Publication Number:
  US 20140132944A1
• Time in Patent Office: 411 Days
• Field of Search: 382/128, 382/131, 382/132, 382/191, 382/276, 382/280
• US Class Current: 382/128
• CPC Class Codes: A61B 3/102 for optical coherence tomography [OCT]
• CPC Class Codes: A61B 3/117 for examining the anterior chamber or the anterior chamber angle, e.g. gonioscopes
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence
• CPC Class Codes: G01N 21/4795 spatially resolved investigating of object in scattering medium in vivo A61B
• CPC Class Codes: G01P 3/36 Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light G01P3/68 takes precedence; gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams G01C19/64
• CPC Class Codes: G06T 11/003 Reconstruction from projections, e.g. tomography

Abstract

Methods, systems and computer program products for managing frequency domain optical coherence tomography (FDOCT) image resolution. A spectrum used to acquire an image of a subject is calibrated and default dispersion correction parameters are set. Default dispersion management parameters associated with a region of the image of the subject are also set. The image of the subject is acquires after setting the default dispersion correction parameters and the default dispersion management parameters. A quality of the acquired image is compared to a quality metric for the acquired image. The dispersion correction parameters are adjusted if the quality of the acquired image does not meet or exceed the quality metric for the acquired image. The acquired image is reprocesses based on the adjusted dispersion correction parameters. The steps of comparing, adjusting and reprocessing are repeated until the acquired image meets or exceeds the quality metric for the acquired image.

Claims

1. A system for measuring group velocity dispersion of a sample, the system comprising:

a Fourier domain optical coherence tomography imaging system configured to acquire spectral interference data corresponding to a region of a sample; and

a processor coupled to the Fourier domain optical coherence tomography imaging system, the processor configured to;

convert the spectral interference data into spatial image data;

apply a phase to the spectral interference data to modify a spatial domain image; and

compare a first phase expression corresponding to the region of the sample to a second phase expression to derive a measure of group velocity dispersion associated with the sample.

2. The system of claim 1, wherein the processor is further configured to apply the phase to the spectral interference data corresponding to the region of the sample to optimize an image quality metric associated with the spatial domain image of the region of the sample.

3. The system of claim 2, wherein the second phase expression is associated with a reference having a known group velocity dispersion.

4. The system of claim 3, wherein the processor is further configured to compute a difference between the first phase expression associated with the sample and the second phase expression associated with the reference to derive a dispersive phase expression associated with the sample.

5. The system of claim 4, wherein the processor is further configured to compute the group velocity of the sample from the derived dispersive phase expression.

6. A method for measuring dispersion of a sample, the method comprising

acquiring a spectral interferogram of a region of a sample using a Fourier domain optical coherence tomography system;

identifying a first frequency-dependent phase expression;

combining the first frequency-dependent phase expression with a first spectral interferogram;

transforming the combined first frequency-dependent phase expression and the first spectral interferogram to a spatial domain image;

optimizing an image quality metric associated with the spatial domain image associated with the first spectral interferogram;

identifying a second frequency-dependent phase expression;

combining the second frequency-dependent phase expression with a second spectral interferogram;

transforming the combined second frequency-dependent phase expression and the second interferogram to a spatial domain image;

optimizing an image quality metric associated with the spatial domain image associated with the second spectral interferogram; and

computing a difference between the first phase expression and the second phase expression.

7. The method of claim 6, wherein the first phase expression is a series expansion corresponding to group velocity dispersion of the imaging system and the sample.

8. The method of claim 6, wherein the second phase expression is a series expansion corresponding to group velocity dispersion of the imaging system and a reference.

9. The method of claim 6, wherein the difference between the first phase expression and the second phase expression corresponds to a difference in group velocity dispersions between the sample and a reference.

10. The method of claim 6, wherein a group velocity dispersion of the reference is a known quantity and a correspondence between the second phase expression and the group velocity dispersion of the reference is known.

11. The method of claim 10, further comprising computing the group velocity dispersion of the sample from the difference between the first phase expression and the second phase expression and the correspondence between the second phase expression and the known group velocity dispersion of the reference.

12. A system for imaging a sample having a means for computing a dispersion of the sample, the system comprising:

a Fourier domain optical coherence tomography imaging system for acquiring spectral interference data corresponding to a region of a sample;

a processor coupled to the Fourier domain optical coherence tomography imaging system, the processor configured to convert spectral interference data to spatial image data;

means for optimizing a computed spatial domain image by numerically modifying a phase associated with the spectral interference data; and

means for comparing the phase associated with the sample to the phase associated with a reference to derive an expression for a group velocity dispersion of the sample.

13. The system of claim 12, wherein the means for optimizing a computed spatial domain image comprises:

iteratively applying phase terms to a spectral interferogram to provide a modified interferogram;

Fourier transforming the modified spectral interferogram into a spatial domain image; and

applying an image quality metric to a test image until a target value for the image quality metric is obtained.

14. The system of claim 12, wherein the means for comparing the phase associated with a sample to the phase associated with a reference to derive an expression for the group velocity dispersion of the sample comprises subtracting a phase expression derived for the reference when an image quality metric of the reference is optimized from the phase expression derived for the sample when the image quality metric of the sample is optimized.

15. A computer program product for obtaining values of optimized parameters for a frequency domain optical coherence tomography (FDOCT) system, the computer program product comprising:

a non-transitory computer readable storage medium having computer readable program code embodied in said medium, the computer readable program code comprising;

computer readable program code configured to obtain the optimized parameters based on the following equations;

D1=dD+Ds

D2=dD+Dr

Ds=(D1-D2)+Dr.

wherein D1 equals dispersive terms obtained through image optimization of a sample, D2 equals dispersive terms obtained through image optimization of a reference, dD equals differential dispersion between subject-free reference and sample paths, Ds equals dispersive terms of the sample and Dr equals dispersive terms of the reference.