Axsun Technologies, Inc.

Brian Goldberg

Bartley C Johnson

Dale C Flanders

Mark E Kuznetsov

Walid A Atia

Noble G Larson

Real-time swept source OCT data is most often sampled using a specially cut hardware k-clock. The present invention involves mathematically resampling signals within an FPGA-based data acquisition board based on data sampled from a wide free spectral range reference interferometer. The FPGA can then multiply up the reference clock rate to achieve greater imaging depth. The Nyquist fold-over depth can thus be programmed from a standard reference to an arbitrary depth, much as PLL frequency synthesizer can produce many frequencies from a standard stable reference. The system is also capable of real-time performance.

Real time FPGA resampling for swept source optical coherence tomography

A system and method for resampling interference datasets of samples in segments, in a swept-source based Optical Coherence Tomography (OCT) system. The resampling is preferably performed within a Field Programmable Gate Array (FPGA) of the OCT system, the FPGA preferably having Fourier-transform based signal processing capabilities such as Fast Fourier Transform (FFT) cores. Resampling the interference datasets in segments provides a flexible approach to resampling that makes efficient use of system resources such as FFT cores. By resampling the interference datasets in segments, the system adjusts to an increased number of resampling points as the imaging depth upon the sample increases. The OCT system then combines the segments using overlapping values of the resampling points between adjacent resampling regions of the resampled segments, and performs Fourier Transform based post-processing on the combined segments to obtain axial profiles of the sample at desired imaging depths.

System and method for resampling optical coherence tomography signals in segments

An optical coherence analysis system comprising: a first swept source that generates a first optical signal that is tuned over a first spectral scan band, a second swept source that generates a second optical signal that is tuned over a second spectral scan band, a combiner for combining the first optical signal and the second optical signal for form a combined optical signal, an interferometer for dividing the combined optical signal between a reference arm leading to a reference reflector and a sample arm leading to a sample, and a detector system for detecting an interference signal generated from the combined optical signal from the reference arm and from the sample arm. In embodiments, the swept sources are tunable lasers that have shared laser cavities.

Integrated dual swept source for OCT medical imaging

A system and method for spectral filtering of a k-clock signal in a swept-source Optical Coherence Tomography ('OCT') system to remove artifacts in the k-clock signal. The system synchronizes sampling of the k-clock and interference signals generated from scanning a sample. Using a filtered k-clock signal, the system resamples an interference dataset of the interference signals. The system then performs Fourier transform based processing upon the resampled interference dataset to yield axial depth images of the sample. The system preferably performs the reconstruction, resampling, and associated Fourier-Domain signal processing in software via a Field Programmable Gate Array ('FPGA') of a rendering system.

Spectral filtering of k-clock signal in OCT system and method

An optical coherence tomography system utilizes an optical swept source that frequency scans at least two different sweep rates. In this way, the system can perform large depth scans of the sample and then the same system can perform shorter depth high precision scans, in one specific example. In order to optimally use the analog to digital converter that samples the interference signal, the system further samples the interference signals at different optical frequency sampling intervals depending upon the selected sweep rates of the optical swept source. This allows the system to adapt to different sweep rates in an optimal fashion.

Growing community of inventors

Cambridge, MA, United States of America

Brian Goldberg