394 results about "Interferometry" patented technology

The invention relates to the field of cable fault detection, in particular to a distribution cable fault positioning method based on electric signal analysis, which comprises the following steps of: determining a cable analysis state of each abnormal response point according to an interval monitoring execution index; determining whether to perform initial interference analysis or execute evaluation analysis according to the cable analysis state of the abnormal response point location; when initial interference analysis is carried out, whether interference compensation processing and range optimization processing are carried out on each abnormal response point location or not is determined according to the reference feature matching index; determining whether to perform channel filtering or not according to the interference effect evaluation index, and determining whether to perform compensation acquisition processing on each cable monitoring interval or not according to the interference compensation coefficient; and when the execution evaluation analysis is carried out, determining whether to carry out redundancy distribution prompt for each abnormal response point location according to the execution redundancy parameters. According to the method, the cable fault positioning efficiency is guaranteed, and meanwhile, the requirement for monitoring point arrangement is lowered.

The invention relates to the technical field of geological engineering, and discloses a geological safety risk dynamic assessment method based on multi-source data fusion, which comprises the following specific steps: step 1, collecting and standardizing multi-source geological data; 2, performing semantic fusion and conflict resolution on the geologic features; 3, constructing a dynamic risk assessment model; 4, risk situation real-time updating and early warning are carried out; the satellite remote sensing system in the first step adopts the synthetic aperture radar interference measurement technology, the spatial resolution is better than 3 meters, the revisit period is shorter than 7 days, and the earth surface deformation monitoring precision reaches the millimeter level. Through standardized processing and semantic fusion of the multi-source geological data, the problem of heterogeneous data integration is effectively solved, the data basic quality of risk assessment is improved, a space-time coupling neural network model is adopted, nonlinear features and space-time correlation characteristics of geological risk evolution are accurately captured, and prediction precision and timeliness are improved.

The invention discloses a space-air-ground collaborative rock-soil landslide monitoring and early warning system, which relates to the technical field of disaster monitoring and early warning and comprises an air remote sensing monitoring module, a ground sensing module, a data communication module, a multi-source information fusion module and an intelligent early warning decision module. The aerial remote sensing monitoring module is used for collecting aerial image data based on the unmanned aerial vehicle; the ground sensing module is used for collecting ground sensing data; the multi-source information fusion module is used for fusing and aligning aerial image data, ground sensing data and geological model multi-dimensional information, extracting surface crack morphological characteristics by adopting a deep learning algorithm, analyzing a deformation time sequence generated by radar interferometry and identifying an abnormal motion mode; the intelligent early warning decision module is used for analyzing the landslide evolution stage and simulating the geologic body deformation process and conducting early warning decision, the problem of signal blind areas of a traditional monitoring system in extreme landforms can be effectively solved, and total factor analysis and advanced early warning of the disaster evolution process are achieved.

The invention provides a three-dimensional flow velocity field inversion method and system based on coherence-assisted SAR adaptive offset tracking, and a storage medium, so as to improve the problem of decoherence caused by time heterogeneity in a synthetic aperture radar interferometry (InSAR) technology, and relates to the technical field of electric power engineering geological disaster monitoring. The method comprises the following steps: establishing a space-time baseline network between SAR images; obtaining coherence data after geocoding; selecting a pair of SAR images from the space-time baseline network as a reference unit, calculating an offset result through a pixel offset tracking technology for the reference unit, and determining an optimal matching window parameter of the reference unit; establishing a mapping function between coherence and optimal matching window parameters; according to the established mapping function, calculating an optimal matching window parameter of each remaining SAR image pair; and in combination with the line-of-sight average deformation rate fields of the ascending and descending rails, inverting a surface three-dimensional flow velocity deformation field of the target area through a geometric vector decomposition model.

The invention relates to the technical field of optical detection, and discloses an object surface three-dimensional topography measurement method based on optical interference, which comprises the following steps: acquiring a mixed time domain interference signal sequence in an axial scanning process; extracting seed pixels and constructing a spatial topology connectivity feature matrix; introducing fractional Fourier transform, and constructing a joint decoupling objective function containing a frequency domain nonlinear phase distortion evaluation index and a time domain physical invariant evaluation index; executing multi-stage optimization for the seed pixels, and locking a global optimal rotation angle; array self-adaptive decoupling is executed in combination with the spatial topology connectivity feature matrix, and an optimal rotation angle matrix is generated; and performing signal decoupling and reconstruction on the mixed signal, and extracting the absolute surface height of each pixel point to generate three-dimensional shape data. According to the invention, through multi-dimensional joint decoupling and spatial prior constraint, the problem of phase decoupling caused by film interference aliasing is solved, and the calculation overhead of a large-pixel array is reduced while the measurement precision is improved.

A plateau mountain area road slope geological disaster automatic identification method fusing multiple data comprises the following steps: S1, acquiring multi-source heterogeneous data of a target slope area, including a time sequence satellite optical image, synthetic aperture radar interferometry (InSAR) deformation data, laser radar (LiDAR) point cloud data, meteorological and hydrological data and basic geological data, and generating fusion data; s2, constructing a space-time registration module, unifying the multi-source data obtained in the S1, establishing a unified space-time coordinate system for the multi-source data, and generating fusion data; and S3, processing synthetic aperture radar interferometry (InSAR) deformation data through a freeze-thaw cycle noise compensation model, and eliminating deformation noise caused by seasonal frost heaving and thaw collapse. According to the plateau slope disaster identification method, the plateau freeze-thaw compensation model is combined with a multi-modal dynamic decision-making mechanism, and physical mechanism complementation of InSAR and LiDAR is adopted, so that'earth surface deformation-rock mass structure 'two-dimensional verification is realized, and multi-data fusion is realized, and therefore, the automatic identification precision of plateau slope disasters is improved.

The invention discloses a spectral interference system resolution improving method and system, and the method comprises the steps: building an ISE-Net end-to-end deep neural network model, enabling the convolution kernel size of an efficient channel attention module of the ISE-Net end-to-end deep neural network model to be adaptively determined according to the number of input channels, and constructing a mapping relation between narrowband and broadband interference signals; and generating an ideal narrowband signal and a double-bandwidth target signal according to a spectral interference physical formula, defining a loss function by minimizing deviation between model output and the target signal, updating parameters and dynamically adjusting a learning rate by using an AdamW optimizer until model loss is converged, and completing data generation and training. An input narrowband signal horizontal axis is converted to a corresponding frequency domain axis, and is subjected to time shifting and intensity scaling preprocessing to adapt to the model. A signal processing flow suitable for a single / multi-layer structure is constructed, a bandwidth expansion signal is obtained through decomposition, expansion and reconstruction, and the resolution of a spectrum interference system is improved. The method has the advantages of high calculation efficiency, high generalization and flexible deployment.

The invention relates to the technical field of synthetic aperture radar interferometry (InSAR) and deep learning, and discloses a CNN-BiGRU landslide displacement prediction method based on InSAR deformation spatial-temporal feature fusion. The method comprises the following steps: firstly, acquiring landslide area time sequence deformation displacement by utilizing an SBAS-InSAR technology, decomposing the displacement into a trend term, a season term and a noise component by adopting variational mode decomposition (VMD), fitting and predicting the trend term and a segmented polynomial through RNN, converting a one-dimensional time sequence into a time-frequency image by the season term through a Gramb angle field (GADF), extracting spatial features by combining the CNN and extracting time sequence features by a BiGRU, and calculating the landslide area time sequence deformation displacement according to the time-frequency image. Multi-modal fusion prediction is realized; and finally combining the trend term and the season term to obtain total displacement prediction. Experiments prove that RMSE, MAE and Rindexes of the method in seasonal item and total displacement prediction are all superior to those of comparison models such as BiGRU and BiLSTM, and prediction precision and reliability are remarkably improved.

The invention relates to a high-precision multi-surface wavelength tuning interference measurement signal processing method. The core of the method is to solve the problem of dissociation of superposed interference signals and overcome the frequency spectrum fence effect. The patent process comprises the following steps: constructing a dissociation framework based on an iteration vector and a time delay virtual detection point; optimizing an iteration process by using an approximate Newton method; designing a double judgment dissociation criterion and orthogonally outputting a dissociation result; performing frequency spectrum fine segmentation analysis and phase demodulation function extraction on the dissociation signal to realize high-precision solution of harmonic frequency and phase; and the dissociation quality can be evaluated by using a correlation coefficient quantification method. The method can effectively separate multi-surface interference superposition signals and accurately reconstruct key parameters, is obviously superior to a traditional method (such as FFT), and improves the performance by about two orders of magnitude. Experiments prove that the surface shape error is controlled to be 10e <-3 > magnitude, the frequency precision reaches 10e <-4 > magnitude, and the method has excellent robustness and wide applicability and is suitable for high-precision optical element detection.

The invention discloses a cross-sensor long-time-sequence InSAR deformation monitoring method and device, a medium and a product, and relates to the field of synthetic aperture radar interferometry, the method comprises the following steps: obtaining image data sets of a plurality of SAR sensors in a monitoring area, and sequentially carrying out differential interference and time sequence deformation calculation to obtain an LOS direction deformation result; geocoding all results to unify a coordinate system; screening high-coherence point targets and constructing an observation geometry unified analysis model; time information is obtained by combining the images, and a long-time-sequence earth surface deformation resolving function model after observation geometric correction is established; and further introducing a truncated singular value decomposition operator, constructing a cross-sensor long-time-sequence deformation resolving analysis model, and finally resolving to obtain a high-precision and long-time-span earth surface deformation product in the monitoring area. According to the method, the problems of rank deficiency and solution failure caused by time shortage and observation geometric difference in multi-platform InSAR data joint solution are effectively solved, and the precision and applicability of long-time-sequence deformation monitoring are remarkably improved.

A system for automatically focusing ("autofocusing") a microscope during an inner limiting membrane (ILM) peeling maneuver is configured to output low-coherence infrared (IR) light toward the eye during the maneuver. The system includes an interferometer that senses an axial distance between the microscope and ILM and outputs distance signals indicative of the sensed axial distance. An electronic control unit (ECU) is in communication with motor-driven lenses of the microscope and with an IR light source of the interferometer. Execution of the instructions causes the ECU to receive the distance signals from the interferometer. In response to the distance signals, the ECU transmits a focus control signal to the lens(es) to thereby resolve the ILM with a desired depth-of-field. The ECU automatically adjusts a focus level of the microscope on the ILM to accommodate for respiration-related movements of the patient.

The invention provides a forest vertical structure information inversion method and system based on radar interferometry, and the method comprises the steps: carrying out the small-view processing of high-resolution SAR interferometry data with a space baseline, calculating the small-view InSAR phase height, extracting the statistical distribution of the small-view interferometry phase height in a set space window, and carrying out the calculation of the small-view interferometry phase height. Generating a small-looks interferometric phase height histogram; establishing an under-forest ground elevation regression estimation model based on the statistical characteristics of the small-looks interferometric phase height histogram, and determining model parameters to invert the terrain; and two canopy top indexes are extracted, two index results are fused by setting a threshold value, and final forest vertical structure information is generated. The method has the advantages that more canopy internal and under-forest information can be captured only by using single-baseline and single-polarization radar interference data, and the sensitivity to a forest vertical structure is improved; and the forest vertical section, the tree height and the terrain can be synchronously inverted.

Provided are a silicon-based tunable filter, laser and an optical module. The tunable laser comprises a semiconductor optical amplifier and a silicon photonic integrated chip, wherein a first coupler, a phase regulator and a tunable filter are provided on the silicon photonic integrated chip; the tunable filter comprises a flat-top band-pass filter structure, a Mach-Zehnder interferometry (MZI) structure and a micro ring resonation (MRR) structure, which are cascaded; gain light emitted by the semiconductor optical amplifier is coupled to the silicon photonic integrated chip by means of the first coupler, and a narrowband filtered optical signal is output by means of the tunable filter; and the phase of the gain light is regulated by means of the phase regulator so as to output single-peak narrowband laser light with a tunable target wavelength.

A surface deformation monitoring method and systems based on time-series InSAR (TS-InSAR) are provided. The method includes acquiring Synthetic Aperture Radar (SAR) data; performing differential interferometry; performing a robust two-tier multi-temporal InSAR method for detection of Persistent Scatterer (PS) and Distributed Scatterer (DS) candidates to acquire time series data for surface deformation monitoring; performing a variational mode decomposition (VMD) method to decompose TS-InSAR data into a plurality of components; reconstructing time series data; performing a gated recurrent unit (GRU) method; extracting trend of surface deformation; and performing continuous large-scale deformation monitoring. The InSAR-based deformation monitoring method integrates VMD and GRU, offering significant improvements in robustness and accuracy over the existing methods.

The invention relates to the technical field of optical interference measurement, in particular to a synchronous wavelength phase-shifting interference measurement system. According to the scheme, a laser set outputs multiple narrow-linewidth light beams with nm-level wavelength spacing, and the multiple narrow-linewidth light beams are combined through a wavelength division multiplexer and then enter an interference light path to generate multi-wavelength interference fringes. The metasurface achieves separation of interference fringes of all wavelengths through a sub-wavelength structure array, a detector synchronously captures light intensity data of the interference fringes of all the wavelengths in a single frame mode, and then phase distribution can be directly calculated through single-frame multi-wavelength light intensity. According to the system, mechanical phase shifting and polarization control assemblies are eliminated, the defects that a traditional wavelength phase shifting interference measurement technology is poor in environmental adaptability and a traditional synchronous phase shifting technology has polarization errors are overcome, and a high-precision and high-environmental-adaptability dynamic measurement scheme is provided for optical manufacturing.

Quantum Mechanics Instruction Production (QMIP) systems, methods, and computer-readable media are described. In some implementations, the QMIP system may comprise an input / output module, a database library module, a tradeoff module, a printer module, a samples analyzer module, and a test bench module. Some implementations can include a Nosanow Fermion and Boson Wave Module (or Nosanow Fermion Wave Module), a Grand Free Energy Module, an artificial intelligence module, a chemical bench module, a simulation module, and a metrology and interferometry module. The QMIP system can be programmed and configured to implement a quantum computer and algorithms that are executed on the quantum computer system, which notably, benefit from improved coherence and stability. In some implementations, the QMIP system may be programmed and configured to design new materials such as superconductors, superfluids, photovoltaics, and new drug therapies to treat disease.

The invention provides an overall design method and system for a double-satellite double-frequency-point InSAR satellite system. The overall design method comprises the steps that the specification of a surveying and mapping product of the double-satellite double-frequency-point InSAR satellite system is determined; determining a target positioning equation of the double-satellite double-frequency-point InSAR satellite system; determining a resolving strategy of the absolute phase of the double-satellite double-frequency-point InSAR satellite system; designing double frequency points and working bandwidth of the SAR of the satellite system; distributing surveying and mapping indexes of the double-satellite double-frequency-point InSAR satellite system; designing a dual-frequency cooperative working mode of the SAR system; and designing an on-orbit working process of the double-satellite double-frequency-point InSAR satellite system. Through double-frequency cooperative imaging and full-link index distribution design under double-satellite formation, the problems of dependence of absolute phase ambiguity of traditional InSAR surveying and mapping calculation on ground control points and time decoherence of heavy-orbit interference are solved, and single-flight-pass, high-precision and uncontrolled global topographic surveying and mapping are realized. The method has the technical effects of greatly improving the self-positioning capability of the system, the surveying and mapping product quality and the development reliability.

The present invention provides an interference measurement method and apparatus that can appropriately measure the physical properties of a sample in a non-contact manner. [Solution] The interference measurement method using the interference measurement device 1 includes: a first step of obtaining a first interference waveform W1 for each optical path length difference in the first state by performing measurements while changing the optical path length difference between the first optical path P1 and the second optical path P2 in a first state in which no sample S is placed in the second optical path P2; a second step of converting the first interference waveform W1 into a first electric field amplitude waveform WE1; a third step of obtaining a second interference waveform W2 for each optical path length difference in the second state by performing measurements while changing the optical path length difference in a second state in which a sample S is placed in the second optical path P2; a fourth step of converting the second interference waveform W2 into a second electric field amplitude waveform WE2; and a fifth step of obtaining measured values ​​regarding the physical properties of the sample S based on the electric field amplitudes corresponding to the peaks of the first electric field amplitude waveform WE1 and the second electric field amplitude waveform WE2, respectively.

Provided herein is a method comprising: binding α-synuclein to a biolayer interferometry (BLI) microprobe, contacting the BLI microprobe with a biological sample, contacting the BLI microprobe with α-synuclein, and measuring an optical signal from the BLI microprobe, wherein the optical signal indicates whether α-synuclein aggregates have formed on the microprobe.

The application provides a celestial body orientation parameter solving method and system based on inverse VLBI interferometry and a medium. The method comprises the following steps: firstly, a rotation orientation physical model of a celestial body and an inverse VLBI differential measurement model are established, a lander coordinate and a celestial body orientation parameter are introduced into the model by combining the conversion between a non-inertial system and an inertial system coordinate. High-precision differential measurement tracking data of inverse VLBI are obtained, and based on the principle of the least square method, a lander position and a celestial body orientation model parameter are determined, so that the residual square sum between the calculated theoretical observation value of inverse VLBI and the ground observation value is minimum, and high-precision extraterrestrial celestial body orientation parameters are obtained. The application can realize precise positioning of a lander and solving of celestial body orientation parameters, the obtained data are high in precision, high-precision inverse VLBI differential measurement data can significantly improve the solving precision of the celestial body orientation model parameters, and then information about the internal structure and surface mass distribution change of the celestial body is provided, and additional constraints for the improvement of the celestial body physical model are provided.

This invention discloses a phase-shifting interferometry measurement device and testing method based on a liquid crystal retarder. The device includes a short-coherence light source module and a Fizeau interferometry measurement module. In the light source module, the short-coherence light source is split into p-beams and s-beams by a polarizing beam splitter, and the linearly polarized light is phase-modulated by a liquid crystal variable retarder. The modulated polarized light is coupled into the interferometry module via a fiber coupler, where interference occurs in the interferometry cavity. Finally, the interferogram is acquired by a CCD camera for calculation. This invention solves the problem of complex assembly and adjustment in traditional interferometer devices that integrate the light source and the interferometric system, avoids the environmental instability caused by the movement of mechanical parts in traditional phase-shifting methods, and suppresses the influence of parasitic fringes by utilizing the characteristics of the short-coherence light source. This device utilizes the characteristics of the liquid crystal variable retarder to achieve phase modulation to realize phase-shifting interferometry and surface shape detection. The phase-shifting interferometry surface shape measurement device can obtain high-precision surface shape measurement results.

The present application relates to the field of optical interferometry, and aims at the phase distortion problem in off-axis interferometric quantitative phase imaging, and provides an interferometric microscopic phase distortion elimination method based on PACUNeXt3+ network. The method comprises the following steps: 1. using Zernike polynomials and test target pictures to simulate and generate a data set; 2. establishing and training a PACUNeXt3+ neural network model; 3. inputting the interference graph I or of the sample to be measured into the trained neural network, and outputting the background interference graph I' r corresponding to the sample without sample information; 4. using the two interference graphs I or and I' r to reconstruct the sample phase distribution φ o (x, y) without phase distortion. The present application has high precision and speed, can eliminate the secondary or high-order phase distortion in interferometric quantitative phase imaging, and has great application prospect in the field of phase imaging.

This invention relates to the fields of optical interferometry and artificial intelligence image processing, specifically to a high-precision phase extraction method for orthogonal transverse shearing interferograms based on generative multimodal AI. This method integrates the spatial texture of the interferogram with the constraints of the orthogonal shearing mathematical model through a multimodal feature fusion module, constructing a hybrid architecture of Generative Adversarial Network (GAN) and U-Net with a physical prior loss function. This achieves an end-to-end nonlinear mapping from the interferogram to the wrapped phase, and combines differential Zernike polynomial (DZF) to complete high-precision reconstruction of the absolute phase. Experimental results show that in low signal-to-noise ratio orthogonal transverse shearing interferograms, the proposed method reduces the root mean square error (RMSE) of phase extraction by 42.7% compared to the traditional DZF method, and improves the spatial resolution to λ / 100, providing an efficient and high-precision phase extraction scheme for optical wavefront detection.

This invention relates to the field of underwater acoustic signal processing and target recognition technology, and in particular to an intelligent classification method for surface and underwater targets based on a grazing angle-range domain interferometric structure. The method first constructs a standardized sample set of vertical time-recorded maps containing depth features of both surface and underwater targets through acoustic field simulation. Then, it designs and trains a multi-scale, cross-stage feature fusion classification model. This model uses multi-scale convolution operators to extract features from different receptive fields and integrates shallow and deep-layer features through a cross-stage fusion module, achieving deep mining of depth information in the interferometric structure. Finally, the trained model is used to classify unknown target data. This invention avoids the limitations of manual feature design, realizes end-to-end mapping from raw data to category decisions, and improves the accuracy and robustness of surface and underwater target classification in complex deep-sea environments.

Disclosed herein, among other things, are systems and methods for sound pressure level measurement for hearing devices. Various aspects include a method for sound pressure level measurement using self-mixing interferometry. The method includes directing a coherent light signal towards an eardrum of a user using an optical generation device, directing an audio signal towards the eardrum of the user using an audio generation device, and sensing a reflected light signal from the eardrum of the user using an optical sensor device. Displacement of the eardrum caused by the audio signal is computed using the reflected light signal, and real ear sound pressure level (SPL) at the eardrum is computed based on the displacement of the eardrum.

The invention provides an InSAR orbit phase fine modeling method combining a frequency domain and a space domain, and the method comprises the steps: 1, obtaining a synthetic aperture radar image data set of a target region, carrying out the preprocessing, and carrying out the pairwise interference, and obtaining an initial interferogram; 2, a flat ground winding phase and a terrain winding phase in the interferogram are reserved, and an orbit phase influenced by a baseline is obtained; thirdly, the azimuth fringe frequency and the distance fringe frequency of the interferogram are obtained through Fourier transform and linear frequency modulation transform, and the azimuth phase gradient and the distance phase gradient are calculated; fourthly, an orbit fine phase model is established according to the phase gradient and the space polynomial model; according to the method, the track accurate phase model combining the frequency domain and the space domain is established, linear and non-linear track phases caused by inaccurate base lines are removed at the same time under the condition that InSAR interference diagram unwrapping is not needed, and the precision of track phase error removal is improved.

This application provides an inertial measurement method and system based on atomic interferometry. The method includes: controlling a first atomic beam and a second atomic beam to exit into an interference region, and sequentially interacting with three pulse beams in the interference region to detect the corresponding momentum transfer probability signals. The exit directions of the first and second atomic beams intersect and are symmetrical about the quantization axis. The effective pulse vector directions of the three pulse beams are adjusted so that the adjusted effective pulse vector directions are opposite to those of the original three pulse beams. The first and second atomic beams are then controlled to exit into the interference region, and sequentially interact with the adjusted three pulse beams in the interference region to detect the corresponding momentum transfer probability signals. Based on the four momentum transfer probability signals, the inertial measurement result is determined. Thus, by reversing the effective pulse vector direction, the interference area is reversed, effectively suppressing noise and drift terms unrelated to the effective pulse vector direction.

State of art techniques for measurement of blood viscosity, RBC concentration and the like are in vitro methods. Embodiments of the present disclosure provide a method and system for in vivo non-invasive measurement of blood parameters using Laser Enabled Swept Frequency Acoustic Interferometry (LE-SFAI) principle. A Continuous Wave Laser diode based Photo Acoustic (CWPA) signal in frequency domain generated from laser excitation incident on a biological tissue of a subject carrying blood vessel is acquired by the ultrasound sensor and converted to a windowed time domain CWPA signal limited to two peaks. The signal characteristics such as risetime, amplitude, and time difference between first peak and the second peak are obtained to derive blood viscosity, Red Blood Corpuscles (RBC) concentration, and blood vessel diameter.

Asymmetric interferometry is used with various embodiments of an optical photo-thermal infrared (OPTIR) system to suppress thin film interference effects. Systems and methods for operating a photo-thermal infrared microscope to achieve these purposes are described herein. These may include illuminating a sample region with an infrared pump beam, splitting a probe beam into two paths (one towards the sample and the other towards a reference reflector), directing the probe beam towards the sample to produce interference radiation, collecting the interference radiation as collected probe light, recombining the collected probe light with the reflected probe radiation, and recombining the recombined probe light with the reflected probe radiation. The recombined light is separated between the two detectors, and the signals from the detectors are used to generate a composite photo-thermal signal that suppresses thin film interference effects caused by interference radiation.

Method (100) for detecting at least one object (2) in a region (4), comprising: providing (102) at least one laser feedback interferometry sensor device (202); aligning (104) the at least one laser feedback interferometry sensor device (202) such that the region (4) is illuminated by at least one laser beam (204) of the at least one laser feedback interferometry sensor device (202); operating (106) the at least one laser feedback interferometry sensor device (202) by means of a periodic modulation signal (208) such that a wavelength of the laser beam (204) of the laser feedback interferometry sensor device (202) is modulated in a pattern depending on the modulation signal (208); Detection (108) of an interference signal (16) generated by rays (206) of the laser beam (204) backscattered by the at least one object (2) in the laser feedback interferometry sensor device (202);Transforming (110) at least part of the interference signal (16) into at least one frequency spectrum (18) of a frequency range; detecting (112) the presence of the at least one object (2) in the range (4).;