A signal processing method executed by a signal processing device, includes performing a phase connection process on a position in a space and a phase value at each of a plurality of times, performing outlier correction of a phase value for each position in the space in a predetermined direction of the space at a predetermined time among the plurality of times based on a result of the phase connection process, and correcting a phase value at a time other than the predetermined time for each of correction target positions among positions in the space.

An apparatus and method are provided. In particular, at least one first electro-magnetic radiation may be provided to a sample and at least one second electro-magnetic radiation can be provided to a non-reflective reference. A frequency of the first and/or second radiations varies over time. An interference is detected between at least one third radiation associated with the first radiation and at least one fourth radiation associated with the second radiation. Alternatively, the first electro-magnetic radiation and/or second electro-magnetic radiation have a spectrum which changes over time. The spectrum may contain multiple frequencies at a particular time. In addition, it is possible to detect the interference signal between the third radiation and the fourth radiation in a first polarization state. Further, it may be preferable to detect a further interference signal between the third and fourth radiations in a second polarization state which is different from the first polarization state. The first and/or second electro-magnetic radiations may have a spectrum whose mean frequency changes substantially continuously over time at a tuning speed that is greater than 100 Tera Hertz per millisecond.

An objective of the present invention is to provide a technique for reducing measurement errors when measuring specimen using light. An aspect of an optical measurement method according to the present invention: acquires relationship data that describes a relationship between an intensity of reflection light when irradiating light onto a specimen and a size of the specimen; and acquires the size of the specimen using the relationship data and the intensity of the reflection light. Another aspect of an optical measurement method according to the present invention subtracts a component due to an inclination of a vessel of a specimen from a detection signal representing an intensity of reflection light when irradiating light onto the specimen, thereby correcting the inclination of the vessel.

By utilizing the fact that the observation object has a three-dimensional shape and the boundary surface can be regarded as a plane surface, phase or intensity distribution is applied into a luminous flux of reference light, thereby selectively attenuating the influence of the reflected light from the boundary surface so as to obtain a high-quality OCT image.

A three-dimensional measurement device includes an optical system that: splits an incident light into two lights; radiates one light to a measurement object and the other light to a reference surface; and emits the combined light; a first irradiator that emits a first light that comprises a polarized light of a first wavelength and enters a first element of the optical system; a second irradiator that emits a second light that comprises a polarized light of a second wavelength and enters a second element of the optical system; a first camera that takes an image of the first light emitted from the second element when the first light enters the first element; a second camera that takes an image of the second light emitted from the first element when the second light enters the second element; and an image processor that performs measurement based on the images.

The invention discloses a four-quadrant interferometry system based on an integrated array wave plate. PBS splits an output laser light into two paths, the reflected light and the transmitted light are respectively transformed into reference light and measuring light, the reference light and the measuring light are converged in PBS, the converging light enters a signal receiving unit and is split into four beams, and the four beams irradiate on a four-quadrant interference signal detector with an integrated array wave plate. The invention solves the problems that the existing signal detection system occupies a large space, is not conducive to array integration, and cannot be used in scenes with high space and size requirements.

Provided are a thickness measuring apparatus and a thickness measuring method. The thickness measuring method includes irradiating a first laser beam of a first wavelength .sub.1 to a transparent substrate and measuring intensity of the first laser beam transmitting through the transparent substrate; irradiating a second laser beam of a second wavelength .sub.2 to the transparent substrate and measuring intensity of the second laser beam transmitting through the transparent substrate; and extracting a rotation angle on a Lissajous graph using the first and second laser beams transmitting through the transparent substrate. A phase difference between adjacent rays by multiple internal reflection of the first laser beam and a phase difference between adjacent rays by multiple internal reflection of the second laser beam is maintained at /2.

A measurement device is provided for inspecting a bonding zone between samples, including a low-coherence interferometer illuminated by a polychromatic light source having a measurement arm crossing the connection zone and a reference arm, at least one optical detector and optical and/or mechanical conditioning apparatus arranged to enable the acquisition of at least two interference measurements having different phase conditions between a measurement optical beam coming from the measurement arm and a reference optical beam coming from the reference arm; and calculation apparatus provided to calculate contrast information relating to the interference and to search, on the basis of the contrast information, for defects in the bonding zone.

A truncated non-linear interferometer-based sensor system includes an input port that receives an optical beam and a non-linear amplifier that amplifies the optical beam with a pump beam and renders a probe beam and a conjugate beam. The system's local oscillators have a relationship with the respective beams. The system includes a sensor that transduces an input with the probe beam and the conjugate beam or their respective local oscillators. It includes one or more phase-sensitive detectors that detect a phase modulation between the respective local oscillators and the probe beam and the conjugate beam. Output from the phase-sensitive-detectors is based on the detected phase modulation. The phase-sensor-detectors include measurement circuitry that measure the phase signals. The measurement is the sum or difference of the phase signals in which the measured combination exhibit a quantum noise reduction in an intensity difference or a phase sum or an amplitude difference quadrature.

A velocity-compensated frequency sweeping interferometer has a single measurement light producing device that produces a coherent light source consisting of a single light beam. The light producing device produces a scanning wavelength light beam. A primary beam splitter produces a first reference beam and a first measurement beam from said single light beam. The first reference beam travels a fixed path length to a primary reference reflector and the first measurement beam travels to and from a moveable reflective target over an unknown path length. A distance measurement interferometer is created by interfering the first reference beam with the first measurement beam. A return frequency measurement interferometer provides a measure of frequency of the return beam from the target which, when compared with the frequency of the outgoing beam, allows for velocity compensation of the target.