University of Kent

Oti Ophthalmic Technologies Inc.

Other

Optos Plc

National University of Ireland

University of Kent at Canterbury

Adrian Podoleanu

Adrian Bradu

Manuel Marques

John Rogers

Michael Leitner

Sylvain Rivet

Chris Dainty

Radu-Florin Stancu

David Merino

Adrian Fernandez Uceda

Michael Hughes

Michael Maria

Simon Tuohy

Methods and devices are disclosed to perform depth resolved imaging using parallel lateral detection employing a photodetector block in a detection path that is substantially perpendicular to the direction of light excitation, with applications in microscopy of samples. The photodetector block either comprises a single 1D array of photodetectors or a 2D array of photodetectors. Methods and devices are disclosed to perform coherence gating in configurations of light sheet tomography, to enable simultaneous depth resolved measurements of structure and of index of refraction variation.

Apparatus and method for light sheet imaging with optical coherence gating

The present disclosure relates to an apparatus and method that can be used to remotely acquire high resolution depth resolved images from a sample. The apparatus employs an adapter to an imaging device, where the adapter uses a minimum of components to produce interferometry patterns on the input facet of the imaging device. The imaging device can be a bundle endoscope terminated on a camera sensor or on several camera sensors or simply a camera sensor. In conjunction with a swept source or a broadband source, at least one camera sensor may be employed to provide optical coherence tomography (OCT) images of the sample. When the imaging device uses a bundle of optical fibers, the apparatus and method can provide OCT images tolerant to bending of the bundle.

Imaging apparatus and method

The present specification relates to Master-Slave (MS) interferometry for sensing the axial position of an object subject to optical coherence tomography (OCT) imaging, and to MS-OCT applied to curved and axially moving objects. The methods and apparatuses allow producing OCT signals from selected depths within the object irrespective of its axial position in respect to the imaging system. Images are obtained for curved objects that are flattened along a layer of interest in the object, images that are used to provide OCT angiography images less disturbed by axial movement or lateral scanning.

Optical coherence tomography (OCT) apparatus and OCT method for axial tracking and flattening

The present invention related to an apparatus and method for master slave interferometry, referred to as Complex Master Slave (CMS). The method and apparatus can be used to provide complex-valued measurements of a signal reflected from an axial position inside an object or of signals reflected from points at several axial positions inside an object.

Apparatus and method for processing the signal in master slave interferometry and apparatus and method for master slave optical coherence tomography with any number of sampled depths

A detuned resonant mechanism is employed in a laser cavity to modulate in frequency the mode-locking mechanism to achieve high frequency tuning rates, exceeding MHz. The configuration of the laser is compatible with working at sweeping rates close to multiples of the cavity resonance frequency as well as with buffering for increased tuning speeds.

Akinetic swept laser apparatus and method for fast sweeping of the same

Real-time depth measurements in sensing in spectral domain interferometry and for en-face and cross section image production in optical coherence tomography can operate without any need to linearize the data to maximize the output signal and achieve the theoretical depth resolution. Novel interferometry is disclosed, where parameters of a master interferometer dictate the results in a slave interferometer. The master interferometer can be the same measuring interferometer used in two stages. The master interferometer parameters are at least optical path difference (OPD) or the speed of variation of the OPD in the master interferometer. Coherence gated data are produced from selected axial positions which can be from positive or negative optical path differences, in parallel, enabling generation of en-face (C-scan) OCT images simultaneously from several depths, free from mirror terms, and production of A-scans and B-scan OCT images using plural reflectivity values measured in parallel from different depths within A-scans.

Method and apparatus for processing the signal in spectral domain interferometry and method and apparatus for spectral domain optical coherence tomography

The invention describes several embodiments of an adapter which can make use of the devices in any commercially available digital cameras to transform the digital camera into a fundus camera for inspecting the back of the eye, or into a microscope. The camera adapter is adapted to be placed between the camera device and the object. The devices in the camera being used are at least its optical source, photodetector sensor, memory, shutter and autofocus. Means in the adapter are provided to employ these devices and allow camera to operate its autofocus capability and its different color sensors. Methods of investigation of an object are also presented of using the adapter to transform the camera into an imaging instrument, where the effect of adjustments of elements inside the adapter are guided by the displaying screen of the camera.

Camera adapter based optical imaging apparatus

A spectral interferometry apparatus and method are disclosed, that can be used to monitor or measure an unknown length by following a characteristic of an indicating signal. The measurement is performed by adjusting an optical path difference (OPD) in an interferometer part of an interferometer configuration until sound or light or both are obtained with the desired strength and pitch. Embodiments are presented where the unknown length is the eye length. Spectral interrogation of the interferometer optical output is achieved by reading the signal of an analogue photodetector array in a spectrometer or by tuning a swept source and processing the signal of a photodetector. Sound of different pitches are produced either directly in this process, or by using a nonlinear amplifier, or a mixer. For enhanced signal, the array may be driven by a nonlinear clock or the swept source may be driven by a distorted driving signal.

Apparatus and method of monitoring and measurement using spectral low coherence interferometry

An adapter which can make use of the devices in any commercially available digital cameras to accomplish different functions, the invention admits addition of confocal detection and provides simultaneous measurements or imaging in at least two channels, confocal and OCT, where the confocal channel provides an en-face image simultaneous with the acquisition of OCT cross sections, to guide the acquisition as well as to be used subsequently in the visualization of OCT images. Different technical solutions are provided for the assembly of one or two digital cameras which together with such adapters lead to modular and portable high resolution imaging systems which can accomplish various functions with a minimum of extra components while adapting the elements in the digital camera.

The invention discloses an optical interferometer which can be used to provide simultaneous measurements over multiple path lengths and methods to employ such an interferometer as to achieve a variety of functions covering simultaneous measurements at different depths separated by an increment of a multiple differential delay matched in the interferometer as well as imaging. Optical sensors, optical coherence tomography (OCT) set-ups, optical sensing methods and OCT methods are disclosed which can provide: (i) multiple en-face images at several depths with dynamic dispersion compensation, (ii) fast acquisition of cross sections, (iii) fast acquisition of 3D volumes of a scattering object while maintaining dynamic focus; (iv) fast acquisition of long axial measurement profiles, non mechanical, with dynamic focus, range scalable, with applications in tracking and OTDR. Methods are disclosed on the combination of scanning regimes and modes of operation to achieve versatile functionality in measurements, in the 3D imaging of moving tissue such as the eye, heart, or moving embryos or functional/low noise imaging by making use of angular compounding or polarisation. A method for elimination of axial movement effects in measuring the flow profile is also disclosed.

Multiple path interferometer and method

A spectral interferometry apparatus and method is provided to supply unambiguous profiles (A-scans free of mirror terms) of the reflectivity versus optical path difference and make difference between the positive and negative optical path difference or provide output in a selected interval of optical path differences. The apparatus comprises object optics that transfer a beam from an optical source to a target object () to produce an object beam and reference optics that produce a reference beam. Displacing means () are provided to produce a gap (g) between the object beam (') and the reference beam (&#x2032;). Optical spectrum dispersing means () such as a grating or a prism receive the two relatively displaced beams, and disperse their spectral content onto a reading element such as a CCD. The combination of the displacing means and the optical spectrum dispersing means creates an intrinsic optical delay between the wavetrains of the object beam and the reference beam which can be used with the optical path difference in the interferometer to generate a channelled spectrum for the optical path difference in the interferometer on the reading element.

Spectral interferometry method and apparatus

Methods and devices are disclosed for acquiring depth resolved aberration information using principles of low coherence interferometry and perform coherence gated wavefront sensing (CG-WFS). The wavefront aberrations is collected using spectral domain low coherence interferometry (SD-LCI) or time domain low coherence interferometry (TD-LCI) principles. When using SD-LCI, chromatic aberrations can also be evaluated. Methods and devices are disclosed in using a wavefront corrector to compensate for the aberration information provided by CG-WFS, in a combined imaging system, that can use one or more channels from the class of (i) optical coherence tomography (OCT), (ii) scanning laser ophthalmoscopy, (iii) microscopy, such as confocal or phase microscopy, (iv) multiphoton microscopy, such as harmonic generation and multiphoton absorption. For some implementations, simultaneous and dynamic aberration measurements/correction with the imaging process is achieved. The methods and devices disclosed can provide wavefront sensing in the presence of stray reflections from optical interfaces.

Method for depth resolved wavefront sensing, depth resolved wavefront sensors and method and apparatus for optical imaging

An optical coherence tomography (OCT) apparatus includes an optical source, an interferometer generating an object beam and a reference beam, a transverse scanner for scanning an object with said object beam, and a processor for generating an OCT image from an OCT signal returned by said interferometer. At least the optical source, the interferometer, and the scanner are mounted on a common translation stage displaceable towards and away from said object. A dynamic focus solution is provided when the scanner and a folded object path are placed on the translation stage.

Compact high resolution imaging apparatus

A spectral interferometry apparatus and method is provided to supply unambiguous profiles (A&#x2014;scans free of mirror terms) of the reflectivity versus optical path difference and make difference between the positive and negative optical path difference or provide output in a selected interval of optical path differences. The apparatus comprises object optics that transfer a beam from an optical source to a target object () to produce an object beam and reference optics that produce a reference beam. Displacing means () are provided to produce a gap (g) between the object beam (') and the reference beam (&#x2032;). Optical spectrum dispersing means () such as a grating or a prism receive the two relatively displaced beams, and disperse their spectral content onto a reading element such as a CCD. The combination of the displacing means and the optical spectrum dispersing means creates an intrinsic optical delay between the wavetrains of the object beam and the reference beam which can be used with the optical path difference in the interferometer to generate a channeled spectrum for the optical path difference in the interferometer on the reading element.

OCT cross section images of a part of a curved object are displayed by creating a series of image points and placing each image point into a corrected image in such a way that the positions of scattering points within the image coincide with or are at least closer to their real spatial distribution within the curved object.

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Canterbury, United Kingdom

Adrian Podoleanu