A phase gradient calculation unit calculates a phase gradient on a plane intersecting an irradiation direction of light corresponding to an optical coherence tomography signal indicating a state of a sample for each of sample points arranged on the plane. A bulk phase error calculation unit integrates, for each of plurality of paths from an origin that is a sample point where a bulk phase error is determined to a destination that is a sample point where the bulk phase error is not determined, the phase gradient for each of the sample points along each of the plurality of corresponding paths to calculate a path specific phase error at the destination, and combines the path specific phase errors among the plurality of corresponding paths to determine the bulk phase error at the destination.

Sensor data is captured with a sensor. The sensor data includes a lens-position of a prescription lens relative to a reference point of an optical coherence tomography (OCT) system. A mirror of a reference arm of the OCT system is positioned at an optical pathlength between an eye region of the prescription lens based at least in part on the sensor data. An OCT signal is generated while the mirror is positioned at the optical pathlength. At least one depth profile is generated that includes the prescription lens and the eye region.

Retinal imaging systems and related methods employ a user specific approach for controlling the reference arm length in an optical coherence tomography (OCT) imaging device. A method includes restraining a user's head relative to an OCT imaging device. A reference arm length adjustment module is controlled to vary a reference arm length to search a user specific range of reference arm lengths to identify a reference arm length for which the OCT image detector produces an OCT signal corresponding to the retina of the user. The user specific range of reference arm lengths covers a smaller range of reference arm lengths than a reference arm length adjustment range of the reference arm length adjustment module.

Systems and methods for measuring displacements at the picometer level are provided. A system can include a Michelson interferometer having a fixed arm and a measurement arm. As the length of the measurement arm changes, the output supplied to the interferometer from a variable wavelength light source is changed until the intensity of the resulting inference pattern is maximized. The wavelength of the light at the point the interference pattern is maximized is then measured by mixing light from the light source with the output from a frequency comb generator. The resulting frequency measurement is then converted to a length measurement.

The present disclosure relates to a method of correcting a three-dimensional image. To correct an image distorted by coherence gate curvature (CGC) occurring by an optical system, the method generates a three-dimensional image of a sample holder on which an object to be measured is placed from an interference signal, generates a CGC profile on the basis of an image of a cover glass of the sample holder appearing in the three-dimensional image, generates a CGC fitting curve from the CGC profile, and corrects the interference signal by using the CGC fitting curve. The present disclosure also relates to an OCT system capable of performing a method of correcting a three-dimensional image.

Retinal imaging systems and related methods employ a user specific approach for controlling the reference arm length in an optical coherence tomography (OCT) imaging device. A method includes restraining a user's head relative to an OCT imaging device. A reference arm length adjustment module is controlled to vary a reference arm length to search a user specific range of reference arm lengths to identify a reference arm length for which the OCT image detector produces an OCT signal corresponding to the retina of the user. The user specific range of reference arm lengths covers a smaller range of reference arm lengths than a reference arm length adjustment range of the reference arm length adjustment module.

An OCT device that selectively captures OCT data of a fundus of a subject eye and OCT data of an anterior segment of the subject eye. The OCT device includes a spectroscopic optical system that spectroscopically detects interference light between reference light and reflection light of measurement light irradiated on the subject eye. The spectroscopic optical system includes a collimating system that collimates the interference light, a spectrally dispersive element that spectrally disperses the collimated interference light for each spectral wavelength, an image formation system that forms an image of the interference light for each spectral wavelength on an imaging surface, and a light receiving element disposed on the imaging surface. An object-side focal length of the collimating system is shorter than an image-side focal length of the image formation system.

Distance to a target is sensed using a common path interferometer, wherein a first fraction of light from a light source is collected after reflection by a partially reflective element together with reflection from a target of a second fraction of light from the light source that has been transmitted by the partially reflective element. The collected light is split in two parts, both containing a part of the first fraction and part of the reflection from the target. The parts are fed through a first and second optical branch path to an input side of a three-way optical coupler respectively. Light from at three terminals on a second side of the N way coupler is fed to respective light intensity detectors. Information representing an excess distance traveled by the first fraction from detection signals determined by the least three light intensity detectors.

The present invention relates to the field of instruments for imaging internal structures of the human body, and in particular of the eye. More specifically it relates to an optimized process and an optical coherence tomography system thereof to measure the distances between the eye interfaces that is, the corneal surfaces, the surfaces of the crystalline lens, the retina and so on. A tiltable selection means, e.g. a titable mirror, is used to switch between different optical sample paths having different lengths, such that information relative to portions of the sample at different depths can be collected.

It is provided a method for quick switching to realize anterior and posterior eye segments imaging, which can realize quick switch and real-time image for locations at different depths. On one hand, with an ability of quick switch, objects at different depths can be measured, and the detection scope of the OCT system can be enhanced; the switch system is able to work stably and change positions accurately without influencing the signal-to-noise ratio of the system. On the other hand, the light beam can be respectively focalized at different locations. Thus, high quality of anterior and posterior eye segments imaging can be achieved with a relatively high lateral resolution for human eyes having different ametropia. Furthermore, based on the anterior and posterior eye segments imaging, an ability of real-time eye axial length measurement can be added.