A calibration method of optical coherence tomography device using a non-transmissive planar target includes obtaining three-dimensional image of a surface and an inside of a calibration target (T) by scanning the calibration target (T) using the optical coherence tomography device, and extracting a surface shape image of the calibration target (T) from the obtained the three-dimensional image; and calibrating the surface shape image of the calibration target (T) obtained by the optical coherence tomography device, according to an actual surface shape of the calibration target (T).

A optical measurement apparatus includes: an optical system which generates a pupil image of a measurement target, using light; a polarization generator which generates a polarized light from the light; a self-interference generator which generates a plurality of beams divided from the pupil image, using the polarized light, and causes the plurality of beams to interfere with each other to generate a self-interference image; and an image analysis unit configured to extract phase data from the self-interference image, and to move the measurement target to a focus position on the basis of the phase data.

The invention provides a method for calibration of an optical measurement system, which may be a heterodyne interferometer system, wherein a first optical axis and a second optical axis have a different optical path length, the method comprises: .sup.∘measuring a first measurement value along the first optical axis using a first measurement beam, .sup.∘measuring a second measurement value along the second optical axis using a second measurement beam, .sup.∘changing a wavelength of the first measurement beam and the second measurement beam, .sup.∘measuring a further first measurement value along the first optical axis using the first measurement beam with changed wavelength, measuring a further second measurement value along the second optical axis using the second measurement beam with changed wavelength, .sup.∘determining a cyclic error of the optical measurement system on the basis of the measured values, and .sup.∘storing a corrective value based on the cyclic error.

A system (1) for generating a signal from a surface (22) having a speed V in a direction U, comprising: a light source (2) emitting a Gaussian light beam along a first optical path (11); a sensor (3) able to evaluate the effects of the electromagnetic interference of the first beam; a means (2′, 4) for generating a second Gaussian light beam along a second optical path (12); a second sensor (3′) able to evaluate the effects of electromagnetic interference of the second beam; a focusing lens (5, 6) located on the first and/or the second optical path (11, 12), focusing the light beam at a distance f and defining an upstream optical path (11′, 12′); and a means (4′, 7) for routing the second beam able to redirect the second path (12′) in the direction of the first path (11′).

A method comprises: splitting laser light into sample light, reference light, and monitor light; routing the reference light into a reference arm of an OCT interferometer; routing the monitor light into a monitor device, which generates at least one optical monitor signal representing at least one time-dependent property of the monitor light; generating at least one electric monitor signal from the at least one optical monitor signal; illuminating in a point-shaped manner a sample with sample light, wherein the illumination point is guided on the surface of the sample along a predetermined trajectory; superimposing the light scattered by the sample with the reference light emerging from the reference arm to generate an electric OCT signal; wherein the at least one electric monitor signal and the electric OCT signal are AD-converted in alternating sequence, in each case equidistantly in time, to form a single digital data stream.

Our high phase sensitivity wide-field phase cancellation interferometry system allows single-shot, label-free optical sensing of neural action potentials via imaging of optical path length changes. Single-shot sensing and monitoring of single neurons within a neural network should lead to a more comprehensive understanding neural network processing, which is beneficial for the advancement in the field of neuroscience as well as its biomedical applications and impact. Our system cancels the phase profile of the resting neuron from the phase profile of the spiking neuron, improving the sensitivity by two orders of magnitude. Using a detector with an extremely large well depth and an appropriately biased interferometer increases the sensitivity by another order of magnitude, yielding a measurement that is three orders of magnitude more sensitive than those possible with other microscopes.

An adaptive optics scanning system and method using a beam projection module with four or more axes of motion that can project and control the position and angle of a beam of light to or from an adaptive optics element. The adaptive optics scanning system is compact in size, overcoming the challenges of a traditional lens and mirror based pupil relay design. The adaptive optics scanning system has little to no dispersion, chromatic aberration, and off-axis aberration for improved optical performance. The system and methods for calibrating and optimizing the system are described. A modular adaptive optics unit that scans and interfaces an adaptive optics element is described.

The invention relates to a method for compensating a magnetic locator in the presence of a magnetic-field-disturbing material, comprising: an emitter (10) comprising at least one coil emitting an emission magnetic field; a receiver (20) comprising at least one receiving coil and a device providing a plurality of measurements Ip.sub.i of a receiving magnetic field induced by the emission field in each receiving coil; and a processing unit (25) comprising a field model allowing the calculation of a position (P) and/or an orientation (Q) of the receiver by means of calculation of a prediction H.sub.i of the measurements according to a criterion (C) calculated according to an error E.sub.i which is itself calculated in relation to the measurements Ip.sub.i. The invention is characterised in that the error E.sub.i is calculated by successive iterations from initial values prescribed by the prediction H.sub.i as being the difference between the measurements Ip.sub.i and a disturbed model Hp.sub.i, according to the equation E.sub.i=Ip.sub.i−Hp.sub.i, the disturbed model Hp.sub.i satisfying Hp.sub.i=H.sub.i+P.sub.i (α.sub.i=−arctan(βω.sub.i), (I) the parameter β being identical for all of the measurements Ip.sub.i, the calculation being carried out in such a way as to minimise the criterion C.

A method and an apparatus for determining a plurality of spatial coordinates on a measurement object using a working head having an image sensor for recording images of the measurement object. A first image of a first feature of the object with the working head in a first working position is recorded. First spatial coordinates representing a spatial position of the first feature are determined using first position information of the working head supplied by an encoder arrangement. The working head is then moved relative to the object to a second working position, where a second image of the object is recorded. Using the first and the second images, second position information which represents a spatial offset of the working head relative to the object is determined. Spatial coordinates for a second feature of the measurement object are determined on the basis of the second position information.

Embodiments of systems for classifying interference signals are disclosed. In an example, a system for classifying interference signals includes an interferometer including a light source and a detector, and at least one processor. The interferometer is configured to provide a plurality of interference signals each corresponding to a respective one of a plurality of positions on a surface of a semiconductor chip. A spectrum of the light source is greater than a spectrum of white light. The at least one processor is configured to classify the interference signals into a plurality of categories using a model. Each of the categories corresponds to a region having a same material on the surface of the semiconductor chip.