A system includes: a swept laser light source generating laser light having a frequency swept across a frequency bandwidth as a function of time; a sample path directing a first portion of the laser light to an eye as a probe beam and receiving a returned portion of the probe beam from the eye; a reference path passing therethrough a second portion of the laser light, the reference path having a defined optical path length; and a detector receiving the returned portion of the probe beam from the eye and the second portion of the laser light from the reference path, and in response thereto outputting an optical coherence tomography (OCT) output signal having OCT peaks whose relative timing represents the depths of surfaces of structures of the eye, wherein the sample path includes a fiducial generator which produces a fiducial peak in the OCT output signal.

An optical coherence tomographic device may include a light source, a measurement light generator, a reference light generator, an interference light generator, an interference light detector, and a processor. The interference light detector may include a first and second detector that convert interference light to interference signals, a first signal processing unit that samples the interference signal from the first detector, and a second signal processing unit that samples the interference signal from the second detector. Each of the first and second signal processing units may sample the interference signal at a timing from outside. Light generated by the measurement light generator may at least include first and second correction light. The processor may correct a time lag between sampling timings of the first and second signal processing units by using a first and second correction signal converted from the first and second correction light.

A calibration system for calibrating a tilt angle of the fast steering mirror includes a position sensing device configured to generate a beam of electromagnetic radiation, and a diffractive optical element, positioned between the position sensing device and the fast steering mirror, the diffractive optical element being configured to divide the input beam into a plurality of output beams directed to the fast steering mirror. The position sensing device is configured to determine a tilt angle of the fast steering mirror. A method to calibrate a tilt angle of the fast steering mirror is further disclosed.

Optical coherence tomography light sources can be non-linear and attempts to linearize them can lead to asynchrony between the light source and A-line scans and missampling in the scans causing signal noise. Accordingly, a system and methods are provided herein to detect missampling by obtaining a plurality of interferograms; providing at least two wavenumber reference signals at different wavenumbers, wherein the wavenumber reference signals comprise attenuated or enhanced portions of each of the plurality of interferograms; aligning each of the plurality of interferograms according to one of the at least two wavenumber reference signals; and for each of the plurality of interferograms, identifying an interferogram as missampled if another of the at least two reference signals does not align with a corresponding reference signal in a statistically significant number of the plurality of interferograms. An optical element, for example, an optical notch, may be used to generate the reference signals.

An imaging apparatus images an imaging object which is stored in a container having an optical transparent wall part tomographically via the wall part. An FD-OCT imaging apparatus sets an optical path length of a reference light in conjunction with a setting of a focal depth such that a position corresponding to the focal depth is between a position conjugate with a first surface and a position conjugate with a second surface in a reflected light intensity distribution representing a relationship between a position in an incident direction of an illumination light and a reflected light intensity. Here, the first surface is a surface on the imaging object side out of surfaces of the wall part. The second surface is another surface on a side opposite to the imaging object out of the surfaces of the wall part.

A calibration method for improving distortion of a waveform of a point-spread-function without constantly executing feedback control to a wavelength-swept light source is provided. An interference signal is generated by varying voltage to be applied to a light source within one period, the interference signal is sampled at equal time intervals on a time axis, the point-spread-function is obtained through Fourier transform by multiplying by a first window function, and a complex analysis signal including frequency information of light is obtained through inverse Fourier transform by multiplying the point-spread-function by a second window function. After a variation in a frequency of the light relative to a time within one period is obtained at equal time intervals by unwrapping phase information of the complex analysis signal, a correspondence relationship between the variation in the frequency of the light within one period and a variation in voltage within one period is obtained.

An agile optical imaging system for optical coherence tomography imaging using a tunable source comprising a wavelength tunable VCL laser is disclosed. The tunable source has long coherence length and is capable of high sweep repetition rate, as well as changing the sweep trajectory, sweep speed, sweep repetition rate, sweep linearity, and emission wavelength range on the fly to support multiple modes of OCT imaging. The imaging system also offers new enhanced dynamic range imaging capability for accommodating bright reflections. Multiscale imaging capability allows measurement over orders of magnitude dimensional scales. The imaging system and methods for generating the waveforms to drive the tunable laser in flexible and agile modes of operation are also described.

Disclosed are systems and methods to extract information about the size and shape of an object by observing variations of the radiation pattern caused by illuminating the object with coherent radiation sources and changing the wavelengths of the source. Sensing and image-reconstruction systems and methods are described for recovering the image of an object utilizing projected and transparent reference points and radiation sources such as tunable lasers. Sensing and image-reconstruction systems and methods are also described for rapid sensing of such radiation patterns. A computational system and method is also described for sensing and reconstructing the image from its autocorrelation. This computational approach uses the fact that the autocorrelation is the weighted sum of shifted copies of an image, where the shifts are obtained by sequentially placing each individual scattering cell of the object at the origin of the autocorrelation space.

The invention relates to a method for signal processing in optical coherence tomography by means of a tunable light source (swept source), comprising the following steps: tuning the light source and sensing a signal intensity of the light source in linear dependence on the respective wave number (k) of the tunable light source and producing a signal intensity distribution in dependence on k; applying a window function to the sensed signal intensity distribution and producing a weighted signal intensity distribution; and applying a fast Fourier transform (FFT) to the weighted signal intensity distribution; and characterized in that, in the tuning of the light source, the tuned frequency spectrum is limited to a passband of the window function.

An agile optical imaging system for optical coherence tomography imaging using a tunable source comprising a wavelength tunable VCL laser is disclosed. The tunable source has long coherence length and is capable of high sweep repetition rate, as well as changing the sweep trajectory, sweep speed, sweep repetition rate, sweep linearity, and emission wavelength range on the fly to support multiple modes of OCT imaging. The imaging system also offers new enhanced dynamic range imaging capability for accommodating bright reflections. Multiscale imaging capability allows measurement over orders of magnitude dimensional scales. The imaging system and methods for generating the waveforms to drive the tunable laser in flexible and agile modes of operation are also described.