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35 results about "Absolute phase" patented technology

Absolute phase refers to the phase of a waveform relative to some standard (strictly speaking, phase is always relative). To the extent that this standard is accepted by all parties, one can speak of an absolute phase in a particular field of application.

Three-dimensional reconstruction method and device based on multi-frequency stripe synchronous optimization and medium

The invention belongs to the technical field of computer vision and optical measurement, and discloses a three-dimensional reconstruction method and device based on multi-frequency fringe synchronous optimization and a medium, and the method comprises the following steps: based on a monocular structured light system, projecting a plurality of groups of sine fringe images with different frequencies to the surface of an object to be measured through a projector, and carrying out the stepping of a plurality of phases, acquiring a corresponding image sequence by using a camera; using a structured light phase shift method to obtain a relative phase value of a pixel point; obtaining an initial absolute phase value and modulation intensity based on a structured light phase shift method and a multi-frequency heterodyne method; and carrying out joint optimization on the absolute phase and modulation intensity parameters of the multi-frequency fringes through a Gaussian-Newton iteration method. According to the method, the anti-noise capability and the reconstruction precision are improved, a parameter adjustment and threshold recovery mechanism is introduced in the optimization process, the convergence stability and abnormal value elimination are ensured, and the method is suitable for high-precision structured light application scenes such as industrial vision measurement and complex surface detection.
Owner:GREATER BAY AREA INST FOR INNOVATION HUNAN UNIV +1

Beam bunch signal aliasing calibration method based on cavity probe

The invention provides an inter-beam bunch signal aliasing calibration method based on a cavity probe. The inter-beam bunch signal aliasing calibration method comprises the following steps: acquiring a non-aliasing reference signal from a high repetition frequency free electron laser device; extracting a signal waveform of each beam bunch and a measurement result thereof from the aliasing-free reference signal; modeling to obtain a residual signal formula; obtaining a calibration result of the beam bunch based on a residual signal formula and a vector calibration algorithm according to the measurement result of the aliasing signal waveform and the standard waveform of the previous beam bunch; taking the next beam bunch as the current beam bunch, and returning to the step of obtaining the calibration result; and obtaining calibration results of all the beam bunches until all the beam bunches are calibrated. According to the method, the amplitude-phase characteristics of the attenuation wake of the adjacent beam bunches are modeled and compensated through the vector calibration algorithm, the time domain aliasing effect in the high-repetition-frequency free electron laser device is effectively eliminated, and the phase absolute deviation measured by the beam arrival time of the cavity probe is reduced to the femtosecond magnitude.
Owner:SHANGHAI ADVANCED RES INST CHINESE ACADEMY OF SCI

A phase unwrapping method and apparatus, system, storage medium

The application discloses a phase unwrapping method and device, system and storage medium, comprising: constructing a U-NetHD absolute phase generation network for directly mapping the wrapped phase to the unwrapped phase; constructing a wrapped phase dataset; training the U-NetHD network by using an unwrapped dataset, unwrapping the interference phase through the absolute phase generation network to obtain an initial unwrapped phase; re-wrapping the initial unwrapped phase and performing conjugate multiplication with the original interference phase to obtain a residual phase; unwrapping the residual phase through an L1 norm unwrapping method to obtain a residual unwrapped phase; and finally, summing the initial unwrapped phase and the residual unwrapped phase to obtain the final unwrapped phase. The technical scheme of the application can solve the problem of low unwrapping precision in low coherence and large gradient regions, and effectively improve the phase unwrapping precision.
Owner:CHINA UNIV OF MINING & TECH

A method for calculating the absolute phase of phase without phase shift in multi-frequency fringes for dynamic three-dimensional measurement.

This invention relates to the field of dynamic three-dimensional measurement technology for irregular surfaces or contours, and provides a phase-shift-free multi-frequency fringe absolute phase calculation method for dynamic three-dimensional measurement. The method includes two processes: initial phase calculation and phase result optimization. The initial phase calculation process processes the acquired multi-frequency fringe pattern and calculates the absolute phase information of the corresponding pixels. The phase result optimization process uses the constraint of the absolute phase on the multi-frequency fringe pattern equation as a data fidelity term and the modulation degree of the fringe pattern as a smoothing constraint term. Through joint optimization of phase fidelity and modulation degree smoothness, the optimal absolute phase is solved. This invention introduces a multi-frequency fringe pattern combination that satisfies the uniqueness of the optimal phase. While maintaining high measurement efficiency, it comprehensively utilizes its information constraints to improve phase accuracy, thus contributing to high-efficiency and high-precision dynamic three-dimensional measurement.
Owner:SHANDONG UNIV

A radar detection method for active electromagnetic regulation target

The application discloses a radar detection method for active electromagnetic regulation and control targets, comprising the following steps: modeling a radar receiving echo signal after a radar transmitting signal is reflected by an electromagnetic super surface arranged on a target to be detected; performing pretreatment on the echo signal to remove a carrier frequency and a frequency modulation, and then performing phase unwrapping processing to obtain an absolute phase; performing window segmentation processing on the absolute phase, estimating a slope of each segmented phase, and taking an average value of the slope of the segmented phase as a slope estimation result of the absolute phase; constructing a phase distribution first-order function by using the slope estimation result of the absolute phase, and subtracting the absolute phase from the phase distribution first-order function to obtain an estimated value of a jump phase term of the electromagnetic super surface; constructing a time-domain phase compensation function according to the estimated value of the jump phase term, multiplying the time-domain phase compensation function with the radar receiving echo signal to obtain a reconstructed signal; and performing matched filtering processing on the reconstructed signal to obtain an output signal.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

Wavefront aberration compensation method based on nonlinear response cascade model

The present invention discloses a wavefront aberration compensation method based on a nonlinear response cascade model, which uses the frequency reconstruction technology in the process of establishing a Bouc-Wen hysteresis model of a fast steering mirror (FSM). The frequency reconstruction technology can overcome the zero-point drift characteristics of piezoelectric ceramic materials and improve the accuracy and robustness of Bouc-Wen hysteresis modeling. Subsequently, the present invention uses the hysteresis model of FSM for a wavefront corrector with a cascade structure of FSM and a deformable mirror (DM), and proposes a wavefront closed-loop compensation method based on absolute phase distortion based on the model structure of the nonlinear response cascade of the wavefront corrector. Taking absolute phase distortion as the fitting target avoids the accumulation of model errors and hardware noise, so that the wavefront corrector of the FSM and DM cascade can complete the correction of the wavefront with only one closed-loop feedback, thereby improving the compensation capability range, accuracy and efficiency.
Owner:ZHEJIANG UNIV

Decoding three-dimensional reconstruction method based on DCT

The invention relates to a three-dimensional reconstruction method based on DCT (Discrete Cosine Transform) decoding. The method comprises the following steps: projecting a four-step phase shift stripe of a specific code to an object and collecting a deformed stripe; calculating a wrapped phase; the key improvement lies in that after a least square unwrapping model is constructed, improved divergence calculation based on a cosine function is adopted, nonlinear transformation is carried out on a multi-direction wrapped phase gradient so as to suppress noise errors, and an improved divergence field is generated; secondly, performing two-dimensional DCT (Discrete Cosine Transform) forward transformation on the divergence field, and solving an absolute phase field through inverse transformation after operation with a transfer function in a frequency domain; and finally completing three-dimensional reconstruction. The system comprises a projection module, an acquisition module and a processing module. According to the method, non-linear divergence calculation is introduced to be combined with DCT frequency domain solving, the defect that a traditional method is sensitive to noise is effectively overcome, and the reconstruction speed and robustness are improved while precision is guaranteed.
Owner:XIAMEN WEIZHU INTELLIGENT EQUIP CO LTD

A three-dimensional reconstruction method, device and medium based on multi-frequency fringe synchronous optimization

The application belongs to the technical field of computer vision and optical measurement, and discloses a three-dimensional reconstruction method based on multi-frequency stripe synchronous optimization, equipment and medium, which comprises the following steps: based on a monocular structured light system, a plurality of groups of sinusoidal stripe images with different frequencies are projected onto the surface of an object to be measured by a projector, and a plurality of phase steps are performed respectively, and corresponding image sequences are collected by using a camera; the relative phase value of a pixel point is obtained by using a structured light phase shift method; initial absolute phase values and modulation intensities are obtained based on the structured light phase shift method and a multi-frequency heterodyne method; and the absolute phase and modulation intensity parameters of the multi-frequency stripe are jointly optimized by using a Gauss-Newton iteration method. By using the above method, the anti-noise capability and reconstruction precision are improved, the parameter adjustment and threshold recovery mechanism are introduced in the optimization process, the convergence stability and abnormal value elimination are ensured, and the method is suitable for high-precision structured light application scenarios such as industrial vision measurement and complex surface detection.
Owner:GREATER BAY AREA INST FOR INNOVATION HUNAN UNIV +1

A phase denoising method based on noise feature classification

The present invention discloses a phase denoising method based on noise feature classification. The method reads a fringe image and uses the N-step phase shift method to calculate the corresponding absolute phase, modulation index, and background based on the fringe phase shift frequency and the number of phase shift steps. The calculated data is then used to determine the initial denoising phase. The phase after initial denoising is then used to calculate a phase difference map, and a determination is made as to whether the values ​​in the phase difference map reach the threshold for forming isolated noise to generate a denoising mask 4. The area of ​​each connected domain in the mask 4 is then calculated, and regions with excessively large areas are removed to generate a final denoising mask, which is then used to denoise the phase. The present invention avoids the problem of inaccurate noise removal in traditional phase denoising algorithms, thereby improving the accuracy of phase measurement.
Owner:NANJING UNIV OF SCI & TECH

Variable frequency fringe encoding and decoding method and device for fast three-dimensional measurement and medium

The application discloses a variable-frequency fringe encoding and decoding method and device for rapid three-dimensional measurement and a medium, and belongs to the technical field of computer vision. The method comprises the following steps: in the fringe encoding stage, the optimal encoding pixel offset is obtained according to the target depth range, the fringe frequency and the corresponding phase are determined, the optimal fringe encoding is obtained, and the phase is stored in a lookup table; in the fringe decoding stage, the encoded fringe pattern is emitted to the surface of the object to be measured, the fringe is deformed, the deformed fringe sequence is obtained, the absolute phase is obtained by using a geometric constraint phase unwrapping method, pixel matching is performed through the lookup table established in the fringe encoding stage, and the three-dimensional shape of the object to be measured is restored. The fringe encoding method has the advantages of high precision, high speed, large range and the like.
Owner:SOUTH CHINA UNIV OF TECH

A three-dimensional measurement method based on nonlinear cosine coding

The application discloses a three-dimensional measurement method based on nonlinear cosine coding, and comprises the following steps: step one, generating N-step phase shift coding, constructing a wavelength-De Bruijn element mapping table, generating nonlinear cosine coding and nonlinear cosine component coding; step two, projecting phase shift stripes and nonlinear cosine coding stripes to a measured object frame by frame, acquiring a modulation pattern and decoding to obtain wrapped phase and nonlinear cosine components; step three, constructing an approximate phase, performing phase unwrapping on the wrapped phase to obtain a local continuous phase, and dividing the local continuous phase into local phases; step four, minimizing cosine component errors of the local phase regions to retrieve phase orders, thereby realizing phase unwrapping and obtaining error absolute phase; and step five, performing phase repair on the error absolute phase to obtain error-free absolute phase, and combining with structural light system parameters to reconstruct a three-dimensional model of an object. The application can realize high-precision phase unwrapping by using only a single frame pattern, and greatly improves the three-dimensional measurement efficiency.
Owner:HUNAN UNIV

A rotating shaft rotating speed and radial runout amount detection method and system based on radar phase reconstruction

PendingCN122386287ARotational axisRadar
The application discloses a rotating shaft rotating speed and radial runout detection method and system based on radar phase reconstruction, relates to the technical field of precision measurement, and comprises the following steps: obtaining a radar echo signal reflected by a target rotating shaft; performing signal processing based on the radar echo signal to obtain complex characteristic data in the distance dimension, performing angle separation, and obtaining a complex signal sequence after spatial separation; performing geometric circle fitting on the complex signal sequence on a complex plane to obtain a biased circle center; performing centering decoupling on the complex signal sequence to obtain a pure complex signal; performing phase extraction on the pure complex signal to obtain a naturally continuous absolute phase sequence under the Nyquist constraint condition of f_frame>2*f_rot; and performing spatial displacement mapping and parameter multi-dimensional calculation based on the absolute phase sequence to obtain the rotating speed and radial runout of the target rotating shaft. The application can realize the precision measurement of the absolute geometric quantity of the industrial rotating shaft rotating speed and radial runout.
Owner:SHANGHAI FEIXIONG ELECTRONIC TECHNOLOGY CO LTD

PS-InSAR multi-baseline time sequence phase unwrapping method based on uniform variable speed deformation hypothesis

The invention belongs to the technical field of synthetic aperture radar interferometry, and particularly relates to a PS-InSAR multi-baseline time sequence phase unwrapping method based on uniform variable speed deformation assumption, which comprises the following steps of: preprocessing multi-temporal SAR data to obtain a time sequence difference interferogram, selecting a permanent scatterer PS point on the time sequence interferogram, and performing uniform variable speed deformation assumption on the selected permanent scatterer PS point; a second-order phase gradient constraint model is constructed on the time dimension under the assumption of uniform variable speed deformation, the integer fuzzy number gradient of the second-order phase gradient constraint model is solved by adopting a bidirectional time marching algorithm, and a global weighted L1 norm optimization problem about an absolute phase vector is constructed and solved based on the integer fuzzy number gradient. According to the method, the acceleration component in the earth surface deformation process is effectively described by establishing the second-order phase gradient constraint model, and the adaptability to complex time sequence deformation is improved.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

A high-precision projector calibration method and system

The present application provides a kind of high-precision calibration method of projector overcoming nonlinear error, the present application adopts phase encoding technique, obtains absolute phase value by projecting gray code and sinusoidal stripe pattern.Hilbert transform is used to compensate phase error, reduce the error introduced by nonlinear factors of projector and camera.The feature points of calibration board are converted from camera pixel coordinate system to projector coordinate system by local homography matrix, further reduce the influence of nonlinear error on calibration accuracy.Finally, Zhang Zhengyou calibration method is used to calibrate the projector, and its internal and external parameters are obtained.This method can effectively improve the calibration accuracy and reduce the calibration difficulty.
Owner:HEFEI INSTITUTE OF PHYSICAL SCIENCE CHINESE ACADEMY OF SCIENCES

An artificial intelligence-based single-exposure absolute step-type error measurement method

PendingCN122360276AAlgorithmSingle exposure
This application relates to the interdisciplinary fields of optical precision measurement and artificial intelligence, and in particular to an artificial intelligence-based method for measuring absolute step error in a single exposure. By constructing a physical-guided artificial intelligence algorithm model, a virtual interferogram sequence of another wavelength is generated based on the interferogram sequence obtained by a single wavelength and a single exposure. The absolute phase of the surface under test is calculated by combining the principle of synthetic wavelength, and then the absolute step height is calculated. This solves the 2π phase ambiguity problem in traditional interferometry and realizes large-scale, high-precision measurement of absolute step height.
Owner:CHONGQING UNIV OF POSTS & TELECOMM

High-precision phase decoding method and system of structured light three-dimensional measurement system

PendingCN120820067AUsing optical meansSinusoidal gratingDecoding methods
The invention provides a high-precision phase decoding method of a structured light three-dimensional measurement system, which belongs to the field of three-dimensional measurement, and comprises the following steps: constructing m groups of structured light patterns: constructing m groups of n-step phase shift sinusoidal grating coding patterns and corresponding Gray code grating coding patterns; the method comprises the following steps: respectively projecting m groups of n-step phase-shift sine structured light patterns to a measured object, projecting a Gray code structured light pattern, and shooting a scene after each projection to obtain a corresponding structured light projection image; performing one-time phase decoding calculation on each group of structured light projection images to obtain an absolute phase; performing probability consistent averaging on the m groups of absolute phases to obtain an optimized phase decoding result; the invention also provides a phase decoding system. Phase shift sine coding and Gray code structured light are adopted, and through grouping dislocation measurement and probability error compensation, phase errors caused by nonlinear response of each component, random dark current and the like are suppressed, and high-precision periodic phase decoding is obtained.
Owner:HEFEI INSTITUTE OF PHYSICAL SCIENCE CHINESE ACADEMY OF SCIENCES

A dual-frequency phase expansion method and measuring device for coded succession

The application relates to the field of structured light three-dimensional measurement, and discloses a dual-frequency phase unwrapping method for encoding continuation, which cyclically projects absolute phase fringe sequence groups to an object, each absolute phase fringe sequence group comprises high-frequency three-step phase shift fringe images and first-step low-frequency phase shift fringe images and second-step low-frequency phase shift fringe images in low-frequency three-step phase shift fringe images, and absolute phase is calculated once per 1 or 2 phase shift fringe images corresponding to image signals. The total fringe number (N abs ) of the absolute phase fringe sequence group is 5, the absolute phase acquisition rate (f aacq ) is reduced from every 6 of the standard dual-frequency three-step phase shift method to an average of every 1.5, and the absolute phase acquisition rate is improved. In each fringe sequence group used for acquiring absolute phase, the high-frequency fringe group used for finally unwrapping absolute phase has a fringe number (N afspan ) of 4, and only two high-frequency phase shift fringe images are separated by one low-frequency phase shift fringe image, so that the measurement precision is maximally maintained.
Owner:HUAZHONG UNIV OF SCI & TECH

Rotational phase multi-cycle absolute solution method and device

ActiveCN120372128BComplex mathematical operationsAlgorithmComplex representation
The present invention provides a method and device for multi-cycle absolute phase calculation. The method collects first and second phase signals with different periods and processes them into non-orthogonal oblique trajectories. These trajectories are converted into complex form and then rotated and aligned by a set rotation angle. The rotated complex trajectories are then processed into discrete segments and interpolated to obtain the absolute phase. This method utilizes multi-cycle modulo phase signals to form non-orthogonal oblique trajectories, which are aligned with the rotation angle using complex representations. This achieves structural normalization, eliminates table lookup and inverse solution modules, and enables real-time angle recovery. The method is applicable to any period combination (including both coprime and non-coprime cases), offers high computational efficiency and accuracy, and can be directly deployed in an MCU / FPGA for real-time absolute phase calculation.
Owner:SHANGHAI INDASENS SEMICONDUCTOR TECHNOLOGY CO LTD

A method, system, medium, and equipment for measuring the surface shape of a freeform surface mirror.

This application discloses a method, system, medium, and device for measuring the surface shape of a freeform surface mirror, relating to the field of optical precision measurement technology. It aims to solve the problem of poor accuracy in measuring the surface shape of freeform surface mirrors for head-up displays in existing technologies. This application first acquires fringe images reflected by the primary and secondary mirrors to obtain an absolute phase map for ray tracing. Next, it uses stereo matching of corresponding points to calculate initial depth data to eliminate ambiguity in normal-height coupling. Then, it constructs a variational fusion model for solving. The model introduces a depth fidelity term to suppress low-frequency surface distortion caused by the traditional gradient integral method, while introducing a gradient constraint term to smooth quantization noise in binocular vision, preserving the mirror's subtle features. Finally, by solving the model, high-precision three-dimensional surface shape data of the primary and secondary mirrors are obtained, improving the measurement accuracy of the surface shape.
Owner:SICHUAN VISENSING TECH CO LTD

A Fringe Phase Retrieval Method Based on Untangling Theory and Deep Learning

This invention discloses a fringe phase retrieval method based on untangling theory-driven deep learning, belonging to the field of optical detection. The method includes: generating absolute phase labels based on a random number sequence; obtaining the original speckle image, wrapped phase labels, and wrapped count labels based on the absolute phase labels; constructing training and validation datasets; constructing a dual-task coupled network model based on a convolutional neural network and a composite loss function; training the dual-task coupled network model using the training dataset, validation dataset, and composite loss function; inputting the original fringe image to be processed into the trained dual-task coupled network model, and outputting the absolute phase result after fringe phase retrieval. This invention achieves unified end-to-end processing of speckle removal, fringe analysis, phase unwrapping, and phase retrieval, significantly improving the accuracy, robustness, and interpretability of the phase retrieval results under scenarios with noise, uneven illumination, complex backgrounds, and varying fringe density.
Owner:TIANJIN NORMAL UNIVERSITY

Phase unwrapping method and system based on double-phase signal

The invention relates to a phase unwrapping method and system based on double-phase signals, and the method comprises the steps: determining the phase difference between an original signal and an auxiliary signal, and achieving the purpose that in all pixels, when one signal is likely to be wound, the other signal is not likely to be wound; adding an auxiliary signal according to the phase difference between the original signal and the auxiliary signal; setting an upper limit and a lower limit of a winding early-warning phase; and when the original signal and the auxiliary signal exceed the winding early warning phase upper limit or lower limit, updating the value of the current pixel absolute phase through a difference algorithm to realize phase unwrapping. According to the method, due to the fact that an extra signal source is used, the influence of noise interference on winding point judgment is greatly reduced, and a certain recognition capability is achieved for signal mutation; secondly, real-time unwrapping can be realized without storing a large amount of historical data; finally, the algorithm does not need to store a large amount of historical data for judgment, the equation is simple, the requirement for computing power is very small, and the method can be operated in some small equipment.
Owner:BEIJING XIQING WEIXIN TECHNOLOGY CO LTD +1

A method for calibrating inter-bunch signal aliasing based on cavity probe

The present invention provides a method for calibrating signal aliasing between bunches based on a cavity probe, comprising: obtaining an alias-free reference signal from a high-repetition-rate free electron laser device; extracting the signal waveform of each bunch and its measurement result from the alias-free reference signal; modeling a formula for the residual signal; obtaining a calibration result for the bunch based on the residual signal formula and a vector calibration algorithm according to the measurement result of the aliased signal waveform and the standard waveform of the previous bunch; using the next bunch as the current bunch and returning to the step of obtaining the calibration result; and continuing until all bunches are calibrated, at which point the calibration results for all bunches are obtained. The method of the present invention models and compensates for the amplitude and phase characteristics of the decay tails of adjacent bunches through a vector calibration algorithm, effectively eliminating the time-domain aliasing effect in the high-repetition-rate free electron laser device and reducing the absolute phase deviation of the beam arrival time measurement of the cavity probe to the femtosecond level.
Owner:SHANGHAI ADVANCED RES INST CHINESE ACADEMY OF SCI

High-low frequency mutual verification absolute phase noise standard uncertainty verification method and system

ActiveCN114421932BPulse automatic controlPulse descriminationPhase noiseStandard uncertainty
This application discloses a method and system for verifying the uncertainty of an absolute phase noise standard using high- and low-frequency cross-verification. The method includes: determining the source of the maximum permissible error between a millimeter-wave relative noise standard and a low-frequency absolute phase noise standard; testing the low-frequency absolute phase noise standard and the millimeter-wave absolute phase noise standard based on the source of the maximum permissible error; and verifying the uncertainty of the millimeter-wave absolute phase noise standard based on the parameters obtained from the tests. This application solves the problem of the inability to verify the uncertainty of millimeter-wave absolute phase noise standard devices, thereby verifying the uncertainty of the millimeter-wave absolute phase noise standard.
Owner:BEIJING INST OF RADIO METROLOGY & MEASUREMENT

Absolute photoelectric encoder system and alignment calibration method

The invention discloses an absolute photoelectric encoder system and an alignment calibration method. The system comprises a light source (1), a coded disc (2), a photoelectric detector (3) and a signal processing and adjusting system (4). The code disc (2) is integrated with an incremental code channel (210) and an absolute code channel (220); the photoelectric detector is correspondingly provided with an incremental signal detection module (310) and an absolute signal detection module (320). According to the method, an incremental signal (311) and an absolute signal (321) are synchronously processed through the signal processing and adjusting system (4), incremental phase information and absolute phase information are obtained respectively, and the phase deviation between the incremental phase information and the absolute phase information is calculated. According to the system, the relative position of the photoelectric detector (3) and the coded disc (2) is calibrated and adjusted based on the phase deviation, so that the alignment deviation between an incremental code channel and an absolute code channel is eliminated or compensated, and the long-term consistency and high precision of output signals of the encoder are ensured. The method effectively solves the problem of relative offset between an increment signal (311) and an absolute signal (321) caused by assembly tolerance, temperature drift or long-term mechanical stress, remarkably improves the reliability and precision of absolute position calculation, and can be widely applied to the fields of high-precision servo control, precision measurement instruments, aerospace and the like with strict requirements on position detection performance.
Owner:TIME VISION TECH (SHANGHAI) CO LTD

Device and method for controlling the relative phase in pairs of ultrashort electromagnetic pulses, interferometry system with said device and interferometry method with said method

Device for controlling the relative phase in pairs of ultrashort electromagnetic pulses, in particular light pulses, comprising an input port configured to receive an ultrashort input pulse of electromagnetic radiation, wherein the input pulse is to propagate along a propagation direction and has a first linear polarization that is distinct from both a first direction orthogonal to the propagation direction and a second direction orthogonal to the first direction and the propagation direction;An adjustable single- or dual-beam interferometer for generating a pair of ultrashort electromagnetic pulses, optically coupled to or comprising the input port, wherein the interferometer has a rotatable achromatic delay plate, in particular a quarter-wave plate, in the single beam or in at least one of the dual beams, wherein the interferometer is structured to generate from the input pulse a first pulse polarized along the first direction and a second pulse polarized collinearly to the first pulse and along the second direction, and to introduce an adjustable relative linear phase as well as an adjustable relative absolute phase between the first pulse and the second pulse.
Owner:CARL VON OSSIETZKY UNIV OLDENBURG KORPERSCHAFT DES OFFENTLICHEN RECHTS

Multi-layer multi-frequency radial stripe coding and decoding method and device

ActiveCN120489008AUsing optical meansPhase shiftedPhase mapping
The invention discloses a multilayer multi-frequency radial fringe coding and decoding method and device, which are used for solving the technical problem of high projection cost caused by the fact that the conventional fringe coding and decoding mostly adopt the traditional unidirectional modulation fringe coding and decoding technology. The method comprises the following steps: acquiring a fringe image basic parameter and a preset frequency band range, and generating a multi-frequency-band fringe geometric parameter; after a stripe coding pattern is constructed based on a preset radius and an angle condition, a signal code and a phase shift zero point signal are extracted respectively, and the zero point signal is used to carry out zeroing calibration on a main pattern. And projecting the processed pattern to a measured object, acquiring a plurality of stripe images, and decoding according to the stripe frequency of each frequency band to obtain a target absolute phase. And finally outputting three-dimensional information through the depth phase mapping model.
Owner:GUANGDONG UNIV OF TECH

Phase decoding method and device for dynamic object three-dimensional structured light imaging

The application discloses a kind of phase decoding method and device for dynamic object three-dimensional structured light imaging, and the method steps include: capturing the image of two groups of modulation stripes projected on the measured object, two groups of modulation stripes are projected on the measured object after being generated in advance according to different frequencies, each group of modulation stripes includes multiple longitudinal stripes and a horizontal stripe, or includes multiple horizontal stripes and a longitudinal stripe;According to the captured modulation stripe image, solve longitudinal wrapped phase using n' step phase shift method, and calculate average light intensity and modulation light intensity, to solve horizontal wrapped phase, finally, difference method is used to unwrap longitudinal wrapped phase and horizontal wrapped phase to obtain longitudinal absolute phase and horizontal absolute phase.The application has the advantages of simple implementation method, low cost, high decoding efficiency and high precision.
Owner:SPEEDBOT ROBOTICS CO LTD

Bottle cap quality intelligent detection method and system based on machine vision

The invention provides a bottle cap quality intelligent detection method and system based on machine vision. According to the method, multi-frequency fringes are projected and a deformation modulation phase diagram sequence is collected, first, the absolute phase of a first frequency is utilized to analyze wrapped phases of a second frequency and a third frequency, phase offset is transmitted step by step to correct periodic jump, first three-dimensional point cloud data are generated, and then a continuity constraint condition is constructed in combination with a thread trend; eliminating isolated point cloud fragments through topological reconstruction to obtain a second three-dimensional point cloud, then performing axial registration on multi-frequency point clouds, fusing curvature mutation features, constructing a three-dimensional shape of the sealing surface, constructing a neighborhood node network in a meshing region based on curvature gradient distribution in a thread screwing-in direction, and detecting and identifying a fitting degree abnormal section through gradient direction consistency. And finally outputting a quality detection result. According to the invention, through multi-frequency phase fusion and curvature gradient analysis, accurate reconstruction and fitting degree anomaly detection of the three-dimensional shape of the thread sealing surface of the bottle cap are realized.
Owner:ZHEJIANG ZHOUQING COVER IND

A superimposed coding phase unwrapping method based on phase quantization

ActiveCN115790451BUsing optical meansSuperposition codingAlgorithm
The application discloses a kind of superimposed coding phase unwrapping method based on phase quantization in the field of optical measurement, comprising the following steps: confirming the pixel width W1 of each period in image, generating N-step phase shift fringe;Design the superimposed coding fringe of auxiliary phase unwrapping, uniformly assign to each period, generate black and white fringe image;Acquisition modulated projection fringe is transmitted into computer;Extract wrapped phase, extract order fringe k1;Determine another group of fringe order k2 by order k1 superimposed binary fringe;Phase unwrapping operation is carried out to wrapped phase, and the absolute phase of measured object is obtained.The method of the application in the process of obtaining order, coding fringe can obtain ladder order by digital superposition operation, algorithm is simple, and it is not necessary to carry out tedious calculation such as radix operation, mapping array or phase calculation, and jump error is modified using the method of wrapped phase binaryzation, improve wrapped phase utilization, reduce additional coding projection.
Owner:NANJING UNIV OF INFORMATION SCI & TECH

Wave plate absolute phase delay measurement method and device, equipment and storage medium

The invention discloses a wave plate absolute phase delay measurement method, device and equipment and a storage medium, and relates to the field of wave plate measurement, and the method comprises the steps: obtaining the apparent phase delay and birefringence of a to-be-measured wave plate at at least three target wavelengths; according to the apparent phase delay and the birefringence of the to-be-measured wave plate at each target wavelength, calculating to obtain the delay level of the absolute phase delay of the to-be-measured wave plate at each target wavelength; and according to the delay level of the absolute phase delay of the to-be-measured wave plate at each target wavelength and the apparent phase delay, calculating to obtain the absolute phase delay of the to-be-measured wave plate at each target wavelength. According to the invention, the absolute phase delay measurement precision is improved.
Owner:CHENGDU METROLOGY TESTING INST