354 results about "Reference beam" patented technology

The invention discloses an automatic calibration method and system for a mining laser gas detector, and relates to the technical field of instrument calibration. The method comprises the following steps: dividing detection beam parameters into measurement beam parameters and reference beam parameters; enabling the measurement light beam parameter to penetrate through the to-be-measured gas area to obtain a measurement signal, and enabling the reference light beam parameter to penetrate through the reference gas chamber to obtain a reference signal; performing photoelectric conversion calculation on the reference signal to obtain a gas concentration detection value; the gas concentration detection value is compared and analyzed with a reference data value according to the central wavelength position of the mining laser gas detector, and a calibration unit is activated according to a comparison result; and automatically correcting the mining laser gas detector, generating a correction parameter set, calculating a measurement signal, and generating a concentration value of the gas to be detected. The technical problems of low calibration efficiency and unstable calibration precision of the mining laser gas detector in the prior art are solved, and the technical effects of realizing automatic calibration of the mining laser gas detector and improving the calibration efficiency and precision are achieved.

The invention provides an optical measurement method and device, and belongs to the technical field of optical measurement, and the method comprises the steps: starting a light source with the wavelength changing dynamically to generate a sweep frequency optical signal; dividing the light into a measuring beam and a reference beam by using a light splitting component, guiding the measuring beam to irradiate a target to be measured and then return along the same path, and guiding the reference beam to enter an optical component of which the optical path changes along with the wavelength and then return; based on the low-coherence characteristic of the light source, when the optical paths of the two light beams meet the interference condition, detecting an interference signal by using a sensing component; the optical path difference is determined according to time information in the interference signal, and the thickness of each reflection interface is calculated by combining refractive index data of a target to be measured. Different from the traditional low-coherence interference measurement which depends on a motor and the like to control the movement of a reflector, the method avoids the limitation of mechanical driving on the measurement frequency, and achieves the high-speed optical thickness measurement.

The invention provides a cavity adjusting method and device for a laser gyroscope resonant cavity, and the method comprises the following steps: building a light beam loop: horizontally placing a resonant cavity substrate on a supporting seat, and forming the light beam loop with two plane reflectors and two spherical reflectors; light beam introduction: starting a sweep frequency laser assembly, and enabling the reference light beam to enter a resonant cavity light path after passing through a light beam collimation system; light spot form monitoring and coarse adjustment: after a light beam emitted by the resonant cavity is collected by an image collector, the main control computer analyzes the light spot form and judges the imbalance state, evaluation information is fed back to the control system, the control system adjusts the inclination amount of the horizontal dimension and the pitching dimension of the light beam in the light beam collimation system according to the feedback information, and the light spot form is obtained. And the light spot is located at the center of the cavity mirror to finish coarse adjustment of the cavity. According to the method, coarse cavity adjustment can be completed without depending on a complex optical cavity technology, the cavity adjustment time is greatly shortened, the overall operation is simple, and the cavity adjustment efficiency is improved.

A method for calibrating an optical sensor and / or a camera for a motor vehicle, wherein the optical sensor and / or the camera detects ambient light through a first pane (10) for the motor vehicle, the method comprising the following steps: receiving a first attenuation value of a first reference light beam reflected in a second pane (50) for a motor vehicle; receiving a second attenuation value of a second reference light beam passed through the second pane (50); transmitting a measuring light beam from a first side (12) of the first pane (10) into the first pane (10); receiving the measuring light beam reflected in the first pane (10) on the first side (12) of the first pane (10); determining a third attenuation value of the measuring light beam in the first pane (10) based on the transmitted measuring light beam and the received measuring light beam;and calibrating the optical sensor and / or the camera based on the first attenuation value of the second disc (50), the second attenuation value of the second disc (50) and the third attenuation value of the first disc (10);

The invention relates to the technical field of optical element surface shape dynamic measurement scheme design, in particular to an element surface shape dynamic measurement system based on a metasurface. According to the scheme, polarized light emitted by a laser is split into reference light and test light, the test light passes through a quarter-wave plate twice to realize polarization orthogonalization, and the test light is combined with the reference light to form elliptically polarized light; synchronously capturing component intensities of left-handed / right-handed circular polarized light and orthogonal line polarized light by using a detector, and resolving a phase difference delta in real time by combining a Stokes parameter; environmental interference is eliminated based on a common-path design, a polarization beam-splitting element is omitted, and the architecture is simplified; accurate dynamic measurement of the surface shape of the measured piece is realized by deducting the inherent surface shape error of the system. The system provided by the invention has the advantages of strong anti-interference performance, high measurement efficiency, remarkable cost reduction and the like, and is suitable for precise optical manufacturing and on-line detection scenes.

The invention relates to the technical field of optics, in particular to blade front and tail edge polishing and correcting equipment which comprises a clamp for loading a to-be-detected guide vane, a polishing system is arranged beside the clamp, and the to-be-detected guide vane is vertically placed on the clamp; the system also comprises a laser interferometer system. The laser interferometer system comprises a laser and a beam splitter, and the beam splitter splits a measuring light beam and a reference light beam; linear collimating lenses are respectively arranged on light paths of the measuring light beam and the reference light beam, and the measuring light beam and the reference light beam respectively penetrate through the collimating lenses to form horizontal linear light beams. On-line real-time detection is achieved through the laser interferometer system, the defect portions of the front edge and the tail edge of the guide vane are accurately positioned, the polishing head can conveniently move to the defect portions to conduct fine polishing, the production period is shortened, and the production cost is reduced.

The invention discloses a pattern wafer multi-parameter synchronous detection system and method based on double optical combs, and belongs to the field of wafer quality detection. The system comprises a signal light path, a reference light path, a detection light path and a synchronous detection module. After interference, the detection light beam and the reference light beam are decomposed into an H path and a V path through the polarization beam splitter, and are synchronously detected by the first camera and the second camera. The invention also provides a method which comprises the following steps: synchronously acquiring two paths of time domain interference data; fourier transform is carried out on each pixel point to obtain a plurality of spectrum pairs; the processing unit decodes in parallel based on the spectrum pair, and synchronously inverts multi-dimensional physical parameters such as three-dimensional morphology, stress and film parameters of the pattern wafer; and finally, comparing and identifying defects. According to the method, the problems of low detection efficiency and single information dimension in the prior art are solved, and wide-field, high-speed, high-precision and multi-parameter synchronous comprehensive characterization is realized.

The invention relates to the technical field of interferometers, in particular to an interferometer light path calibration method and method.The interferometer light path calibration method comprises the steps that an interferometer is started, a measurement light beam and a reference light beam generated by the interferometer are combined through a polarization splitting prism and then are emitted towards an observation screen, and a measurement light spot and a reference light spot are formed on the observation screen; adjusting a reflector group of the interferometer to enable the measurement light spot to coincide with the reference light spot; the observation screen is removed, an optical fiber is connected, and the combined light beams are coupled into the optical fiber; the output end of the optical fiber is connected to detection equipment, a light current signal is obtained through detection of the detection equipment, and the ratio of an alternating-current voltage component to a direct-current voltage component is shown; and a lambda / 4 wave plate in the interferometer is adjusted until the ratio reaches a preset condition, and calibration is completed. The method is accurate and reliable, is simple and convenient to operate, has repeatability, can give consideration to space alignment and polarization matching, and facilitates the improvement of the stability and measurement precision of an interference system.

The invention relates to a reflectivity spectrum obtaining method, an end point detection method and device and a polishing device.The reflectivity spectrum obtaining method comprises the steps that an influence factor distribution curve representing light intensity measured value volatility under different light intensity light source conditions is obtained, a critical light intensity value corresponding to the dominant light source factor is determined based on the influence factor distribution curve, and the critical light intensity value is calculated according to the critical light intensity value. The source light beam is split according to a preset proportion beta to obtain a required measurement light beam and a reference light beam, and the measurement light beam enters a sample to form a reflection light beam; the reflected light intensity is calibrated based on the reference light intensity to generate a target reflected light intensity. And calculating the reflectivity spectrum of the sample based on the target reflection light intensity. Wherein the measuring light beam and the reference light beam have the same light intensity volatility, so that when the reflected light intensity is calibrated based on the reference light intensity, the accuracy and the stability of reflectivity spectrum measurement are effectively improved.

The invention discloses a two-degree-of-freedom displacement simultaneous measurement system and method based on an orbital angular momentum beam interferometer. The system comprises a laser; the light field regulation and control module is used for converting the linearly polarized light into a light beam with orbital angular momentum; an optical isolator; a first beam splitter; a second beam splitter; the third beam splitter is used for combining the first reference light beam and the first measurement light beam to generate conjugate interference; a fourth beam splitter; a fifth beam splitter; the sixth beam splitter is used for combining the second reference light beam and the second measurement light beam to generate conjugate interference; a seventh beam splitter; a first reflector; a second reflector; a third reflector; a first Weive prism; a second Weive prism; a reflection grating; and the image acquisition and processing module is used for acquiring a petal-shaped interference pattern formed by conjugate interference. The system is compact in structure and high in demodulation sensitivity, and can realize non-contact and high-resolution synchronous two-degree-of-freedom measurement.

The invention discloses a light off-axis structured light digital holographic microscopy super-resolution imaging method based on a Kramers-Kronig relation. In a light off-axis structured light digital holographic microscopy system, structural illumination patterns with different angle directions and phase shift amounts are loaded on an object light beam to acquire a structural illumination hologram, and an unloaded reference light beam is acquired to acquire a reference light intensity graph; the structure illumination hologram is combined with the reference light intensity graph to calculate complex amplitude by utilizing a KK relation, phase distortion of the complex amplitude is compensated to obtain distortion-removed complex amplitude, a frequency spectrum separation matrix is constructed by combining information during acquisition to perform frequency spectrum separation on high and low frequency components in the complex amplitude, and finally frequency spectrum synthesis is performed to realize super-resolution object light reconstruction. According to the invention, high resolution improvement can be realized, the interference problem of zero-order item frequency spectrum of the hologram under the light off-axis condition is effectively solved, the noise is obviously reduced, the imaging quality is improved, and the method has important application value in the fields of biological tissue observation, microstructure measurement and the like.

The invention relates to a reflective double-beam interference exposure system reticle density and aberration considered adjustment method, which comprises the following steps: constructing a reticle density standard module, and generating a standard reference beam for adjusting the reticle density of an exposure system; a reflection type double-beam interference exposure system is built, points formed after + / -1-level standard reference beams are focused through an off-axis parabolic mirror serve as nominal focuses of all off-axis mirrors in a double-beam light path, the spatial position of the off-axis parabolic mirror is continuously adjusted, wavefront measurement is combined with a spherical interferometer, and the reflection type double-beam interference exposure system is obtained. And enabling the nominal focus of the off-axis mirror to coincide with the spatial position of the real focus, thereby completing the construction of the double-beam interference exposure system. According to the invention, the problem that the aberration and the scribed line density are difficult to accurately control at the same time in the adjustment process of the reflective double-beam interference exposure system is solved, and a new idea is provided for the high-precision adjustment of the meter-scale large-aperture reflective interference exposure system.

The invention provides an ultrafast scanning interferometer. The interferometer comprises an ultrafast laser system, an interference module, a coupling module and a spectral measurement module which are sequentially arranged along a light path. The ultrafast laser system emits a laser beam, the interference module splits the laser beam into a reference beam and a detection beam, and the detection beam carries information of a detected optical element. The coupling module is connected with the spectral measurement module through an optical fiber, the coupling module couples the detection light beam into the optical fiber, and the spectral measurement module demodulates the detection light beam which is output by the optical fiber and carries the information of the detected optical element in real time and calculates the peak-valley value of the detected optical element. The interference module adopts a Michelson interferometer structure, and the spectral measurement module comprises a dispersion module, a high-speed photoelectric detector and a high-speed photoelectric signal acquisition and analysis module. According to the invention, continuous single-frame detection is carried out on the measured optical element in the form of the optical pulse string, and high-precision and high-efficiency measurement of the surface topography of the optical element is realized.

Provided are a method for operating a device in a wireless communication system, and a device using the method. The method comprises: measuring a plurality of reference beams; selecting at least one beam from among the plurality of reference beams; and communicating with a base station using the at least one selected beam, wherein the plurality of reference beams are beams transmitted according to a first scheme or a second scheme. In the first scheme, N (N is a natural number greater than or equal to two) reference beams are transmitted at a first transmission time, and an offset is applied to the N reference beams at a second transmission time. In the second scheme, 2N reference beams are transmitted, wherein a second frequency interval between adjacent beams of the 2N reference beams is half a first frequency interval between adjacent beams of the N reference beams.

Example embodiments relate to phase difference detection systems and method for detecting phase difference. One embodiment includes a phase difference detection system for a single target location. The system includes a laser source to generate a laser beam. The system also includes a phase difference detector coupled to the laser source and having a multi-layer structure. The phase difference detector includes a planar waveguide for guiding the laser beam. The phase difference detector also includes a grating coupler to split the laser beam into a reference beam and a measurement beam. Additionally, the phase detector includes a planar imager array forming a second layer of the multi-layer structure. Further, the phase difference detector includes an optical system configured to focus the measurement beam output from the phase difference detector on the single target location and to focus signals reflected at the target location to the phase difference detector.

The invention discloses a focus tracking control system and method applied to laser processing. The system comprises a laser, a focus detection module, a tracking control module and a light path adjusting module. The method comprises the steps that S1, a laser beam is emitted into a light path adjusting module to be split into reference light and sample light, and a focus detection module detects the reference light to obtain focus information before machining and outputs the focus information to a tracking control module; s2, the tracking control module sends a first control signal to an optical path adjusting module; s3, the light path adjusting module adjusts the sample light to enable the sample light to be emitted into the processing object to process the processing object; s4, the tracking control module detects the processing object and sends a second control signal to the light path adjusting module; s5, the light path adjusting module adjusts the reference light and the sample light, and the adjusted sample light continues to be emitted into the processing object to process the processing object; returning to the step S4, and entering the step S6 until the processing of the processing object is completed; and S6, the focus detection module records the obtained focus information in processing. The machining process of the laser beam can be accurately corrected.

The invention discloses a displacement measurement method and system based on orbital angular momentum light beam conjugate interference, and the method comprises the steps: enabling linearly polarized light emitted by a laser to pass through an optical attenuator, a light beam expander, a quarter-wave plate and a vortex wave plate to form a light beam with orbital angular momentum, and enabling the light beam to pass through a beam splitter to be divided into a reference light beam and a measurement light beam. A measurement light beam is vertically incident on a reflection grating, and the mth-order diffraction light is incident on a first cube-corner prism and is reflected back to a diffraction grating to be subjected to secondary diffraction. And after the reference beam passes through the second cube-corner prism, the topological charge symbol of the reference beam is changed by the Dove prism. The reference light beam and the measurement light beam generate conjugate interference at the beam splitter prism, a petal-shaped interference pattern collected by the CCD is demodulated, and in-plane and out-of-plane two-dimensional displacement of the grating is calculated. The system has the characteristics of simple and compact structure, strong anti-interference capability, high precision and the like, and can be widely applied to the fields of high-end equipment manufacturing, semiconductor industry, precision metering and the like.

A method includes illuminating a first optical element with an illumination beam to generate a beam of interest and noise from the first optical element. The first optical element is a master copy to be replicated. The method also includes recording in a first recording medium an interference pattern between the beam of interest and a reference beam. The first recording medium is positioned in an optical path of the beam of interest and outside an optical path of the noise. The method further includes illuminating the recorded interference pattern in the first recording medium with a conjugate of the reference beam to generate a conjugate of the beam of interest. The method additionally includes replicating the first optical element in a second recording medium by recording in the second recording medium an interference pattern between the conjugate of the beam of interest and a conjugate of the illumination beam.

The invention relates to a quasi-differential wavefront segmentation double-beam interference device with a planar light path structural design, which has the structural characteristic of a non-closed optical path for transmitting a measurement light beam in a one-way manner. Space coherent light of a transverse mode vector filtering mechanism based on the Huygens principle / phased array principle instead of homologous transmission time coherent light is used as each light source, and a non-closed optical path is realized under the cooperation of a one-way transmission mode on a divided measuring light beam. The problem that the sum of the loop wavelength increment or the frequency increment of a closed path interference device is zero is solved, so that the purpose of measuring the first-level effect of anisotropic physical parameters of a measured object in a linear system is achieved, and the device is particularly suitable for immersion type online measurement. The optical elements have stable performance and sound self-adaptive mechanism and self-diagnosis capability through careful layout of the optical elements; and the method also has wide application prospects in basic physical research and novel navigation / positioning systems. The invention also provides a differential wavefront segmentation and semi-transparent and semi-reflective mirror beam combination interferometer device based on the planar light path structure design, and a wavefront segmentation interferometer device based on the planar light path structure design and provided with a pre-crossing area and a bending type one-way-two-way-common mode combination light path structure. The invention relates to a wavefront segmentation interferometer device of a one-way-two-way combined light path structure which is designed based on a planar light path structure and adopts polarization light splitting-beam combination, optical rotation processing of a reference light beam and original path returning, and a use method of an interference device.

A system for a full-field OCT eye measurement, comprising:—a source (1) of a light beam (2),—a detector (3), preferably in form of a camera,—an interferometer, comprising a reference arm (4) and a sample arm (5),—a beam splitter (6), configured to receive the light beam (2) and to split the light beam (2) into a sample beam (7) and a reference beam (8) and further configured to direct the sample beam (2) to the sample arm (5) and the reference beam (8) to the reference arm (4) respectively, wherein the sample arm (5) is configured for guiding the sample beam (7) through a point on the cornea of a subject's eye (9) into the subject's eye (9) and back to the detector through the beam splitter (6), wherein the reference arm (4) is configured for guiding the reference beam (8) to a mirror (10) and back to the detector (3) through the beam splitter (6), wherein said detector (3) is configured and programmed for comparing the sample beam (7) and the reference beam (8) for detecting diseases of the subject's eye (9). The system is characterized in that it comprises an arrangement for decreasing the intensity of the sample beam (7) passing through the point of the cornea of the subject's eye (9).

This invention relates to an interferometric measurement method and apparatus for large warp wafers, belonging to the field of optical detection and semiconductor measurement technology. The detection light is polarized and birefringently split to form P-beams and S-beams, which are then further divided into P-reference beams, S-silicon beams, S-reference beams, and P-silicon beams, respectively. By adjusting the spatial orientation of the reference mirror and the wafer under test, and using an aperture for spatial filtering, the P-reference beam and S-silicon beam are allowed to enter the subsequent optical path, while the S-reference beam and P-silicon beam are blocked. The S-silicon beam forms a measurement wavefront carrying information about the surface shape of the wafer under test. The P-reference beam is modulated by a deformable mirror to form a modulated reference wavefront similar to the measurement wavefront. The two form a resolvable interference fringe pattern at the camera. A wavefront sensor measures the surface shape information of the deformable mirror, and a calculation system obtains the surface shape information of the wafer under test based on the deformable mirror surface shape information and the relative surface shape change. This invention can reduce the interference fringe density in the detection of large warp wafers, reduce splicing measurement errors, and improve detection efficiency and accuracy.

A laser ranging method and device using the autocorrelation characteristics of light intensity random noise, the method comprising: step S1, a wide spectrum light source emits laser light, which is divided into a first light beam and a second light beam by a ranging probe, and the first light beam is defined as a reference light beam; step S2, the second light beam is emitted to a target object to be measured, and a light beam reflected by the target object to be measured is obtained and defined as a signal light beam; step S3, the reference light beam and the signal light beam are coupled to form a coupled light beam; and step S4, the coupled light beam is processed to obtain absolute distance information of the target object to be measured to the light emitting end surface of the probe. The device obtains absolute distance information of the target object to be measured based on light source intensity noise. The present application has the advantages of high time resolution and high precision measurement.

A light source projects a light beam. An interferometer includes a splitting unit that splits the light beam. The interferometer generates interference beams with the respective split light beams. Each of the interference beam is generated by interference between a measurement beam radiated toward the measurement target and reflected at the measurement beam and a reference beam passing through an optical path. A light-receiving unit receives the interference beams. A processor calculates a distance to the measurement target by associating at least one detected peak with at least one of the spots in accordance with a mirror surface mode or a rough surface mode. The optical path length difference is made different among the split light beams. In the mirror surface mode, the processor uses a distance calculated based on a peak corresponding to a spot for which the optical path length difference is shortest.

The present invention provides a long-range, high-precision frequency-modulated continuous wave (FMCW) ranging system that uses an optical switch to rapidly switch optical paths, and relates to the field of interferometric ranging technology. This system, based on existing FMCW interferometric ranging systems, adds a time-of-flight (TOF) infrared ranging module and a semiconductor optical switch switching module. The TOF infrared ranging module measures the approximate distances between different parts of a workpiece to be measured and the measurement module. When the interferometric ranging module measures a beat frequency signal, the semiconductor optical switch switching module switches the optical path of a reference beam to delay lines with different optical path differences based on the distance measured by the TOF infrared ranging module. This matches the optical path of the measurement path and the reference path, maintaining them at the coherent length, thereby ensuring that measurement accuracy does not degrade with increasing distance. Finally, the distance to the workpiece to be measured is demodulated using the ratio of the optical path difference to the actual optical path, thereby completing the distance measurement.

Optical coherence tomograph for examining an eye (3) which features: - a lighting device (4, 5) for providing source radiation, - an illumination and measurement beam path (7) comprising a splitting element (6) for splitting the source radiation into illumination radiation (B) and reference radiation (R), with the illumination radiation (B) illuminating an illumination field in the eye (3) and collecting backscattered illumination radiation in the eye (3) as measurement radiation (M), wherein the illumination and measurement beam path (7) comprises a scanner (13) for adjusting the lateral position of the illumination field in the eye (3) and a front optic (12), - a reference beam path (8) which provides for the reference radiation (R) an optical path length (21) corresponding to an optical path length from the splitting element (6) to the illumination field and back to a superposition point (71), - a detection beam path (14, 15, 17) which receives the measuring radiation (M) from the illumination and measuring beam path (7) and the reference radiation (R) from the reference beam path (8) and superimposes them at the superposition point (71) and directs them onto a detector (19), - the illumination and measuring beam path (7) further exhibits - a beam splitter (11) for separating the measuring radiation (M) collected by the eye (3) from the illumination radiation (B) directed to the eye (3), wherein the beam splitter (11) directs the separated measuring radiation (M) to the detection beam path (14, 15, 17), and - a light splitting element (32, 34) that splits the illumination radiation (B) into spots in order to illuminate the retina (2) with a multi-spot pattern, characterized in that - the lighting device (4, 5) is tunable with respect to the wavelength of the source radiation, - the detector is an area detector (19), - the detection beam path further - an optical element (14) acting only on the measuring radiation (M), which interacts with the front optics (12) and adjusts the numerical aperture with which measuring radiation (M) is collected in the eye (3), and - an aperture (15) which is arranged in front of the area detector (19), in or near an intermediate image plane and which defines the size of an object field from which the measuring radiation (M) reaches the area detector (19), and - wherein the aperture prior to the area detector is designed as a first multi-hole aperture (15) and a first multi-lens array (36) is arranged between this multi-hole aperture and the area detector (19), which focuses the radiation emanating from each hole of the first multi-hole aperture (15, 15a, 15b) onto a pixel area of ​​the area detector (19) which has a spatial resolution of 4 to 100 pixels in one direction, preferably as a 2D pixel area with 5 to 50 pixels or 5 to 40 pixels per direction.

A user equipment (UE) including a transceiver and a processor is disclosed. The processor is configured to: receive a beam measurement configuration for performing beam measurements on a first set of beams of a first network access point and a second set of beams of a second network access point; receiving ephemeris information, wherein the ephemeris information comprises first ephemeris information corresponding to the first network access point and second ephemeris information corresponding to the second network access point; identifying a receive (Rx) beam in the first set of beams as a reference beam according to beam measurements performed for the first set of beams; identifying one or more target Rx beams based on the reference beam and based on the first ephemeris information or the second ephemeris information; and reporting the one or more target Rx beams to the network to receive downlink information via the second network access point.

This invention provides a real-time ranging and positioning system and method based on an extended light source and a fast coincidence measurement algorithm. The real-time ranging system includes: an entangled light source, a first single-photon detector, a time-to-digital converter, a coincidence measurement module, a quantum transceiver module, and a corner mirror. The coincidence measurement module performs real-time coincidence measurement using a fast coincidence measurement algorithm based on the arrival time sequence of the signal beam and the arrival time sequence of the reference beam, obtaining the time difference corresponding to the peak position of the coincidence measurement curve. The distance between the target point and the real-time ranging system is then obtained based on this time difference. Furthermore, this invention splits the signal beam emitted by the light source into multiple signal sub-beams to form an extended light source, effectively reducing the cost of the measurement device while still satisfying quantum positioning measurement requirements.

This application relates to a method, apparatus, and computer-readable storage medium for determining beam distribution. For a beam to be modeled, at least two reference directions are determined based on a measured dose distribution; and a target beam distribution of the beam is determined based on at least two reference beam distributions corresponding to the at least two reference directions. This solves the problem of low beam modeling efficiency, improves the speed of modeling calculation, and is applicable to a wider range of application scenarios.

A method for improving OCT imaging accuracy. The present invention relates to the field of processing detection technology, and specifically to the field of a method for improving OCT imaging accuracy. The present invention introduces an electrically controlled crystal in the propagation direction of a reference beam, and controls the electrically controlled crystal by applying an external electric field to change its refractive index, thereby changing the light intensity of the reference beam, making its light intensity equal to the light intensity of a test beam reflected from the surface of the inspected material, thereby improving the OCT imaging accuracy. The method for improving OCT imaging accuracy comprises: a reference beam and a test beam; an electrically controlled crystal is provided in the propagation direction of the reference beam; the electrically controlled crystal is used to adjust the light intensity of the reference beam to obtain a reference beam with adjusted light intensity; the test beam is reflected from the surface of the inspected material to obtain a returned test beam; when the light intensity of the reference beam with adjusted light intensity is equal to the light intensity of the returned test beam, the OCT imaging accuracy is improved.

A system includes an illumination system, an optical system, a detector system, and a processor. The illumination system directs a first illumination beam and a second illumination beam toward the target structure, and directs a first reference beam toward the detector system. The optical system directs the first scattered beam and the second scattered beam from the target structure to the detector system. A detector system captures the interference pattern and outputs a measurement signal. The first scattered beam, the second scattered beam, and the first reference beam generate an interference pattern. The processor analyzes the measurement signal to determine a characteristic of the target structure.