19 results about "Absolute phase" patented technology

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

The invention provides an anisotropic substrate-based interdigital transducer and a design method and a preparation method thereof. The design method comprises the following steps: acquiring phase velocity distribution of an anisotropic substrate, determining a direction in which a maximum velocity is located as a zero-degree propagation direction according to the phase velocity distribution, determining a phase velocity in the zero-degree propagation direction as an absolute phase velocity, and acquiring the phase velocity of each sound wave propagation angle of the anisotropic substrate, and calculating the speed difference between the phase speed of each sound wave propagation angle and the absolute phase speed, calculating the difference quantity according to the resonant frequency of the interdigital transducer and each speed difference, and optimizing the concentric circle-shaped finger strip electrode according to each difference quantity to obtain the optimized structure of the interdigital electrode. According to the method, the Rayleigh wave sound conversion efficiency can be improved, and sound field distribution with high spatial resolution is realized.

The invention discloses a spectral domain quantitative phase absolute phase recovery method based on a safe working band, and the method comprises the steps: obtaining an interference spectrum sampled by a camera, and re-sampling the interference spectrum to a uniform wave number k axis; performing Hilbert transformation on the resampled interference spectrum along the k axis to obtain an analysis signal, and extracting a spectral domain wrapped phase and a wrapped phase sequence corresponding to each wavenumber sampling point; performing phase unwrapping on the spectral domain wrapped phase to obtain a spectral domain phase function; constructing an endpoint sensitivity function, and determining the range of a safe working zone; the spectral domain phase function of each A-scan is cut off, only data in a safe working band range are reserved, and the slope of a reference phase is obtained through linear fitting; calculating an offset phase to complete phase circle judgment; and unwrapping the wrapped phase of each A-scan at the wavenumber anchor point by using the offset phase, and outputting an absolute phase result. By utilizing the method, the misjudgment probability of the number of turns can be remarkably reduced, the local 2pi jump error can be inhibited, and the continuity and reliability of absolute phase reconstruction can be improved.

The application discloses a three-dimensional measurement method based on amplitude modulation segmented phase encoding, which comprises the following steps: firstly, four computer-generated sinusoidal fringe patterns and four amplitude-modulated segmented phase encoding fringe patterns are generated; secondly, the wrapped phase can be solved from the four computer-generated sinusoidal fringe patterns, two sets of fringe orders can be respectively solved from the four amplitude-modulated phase encoding fringe patterns, and the plane and the absolute phase of the object can be solved together with the wrapped phase; finally, the real three-dimensional information of the object can be obtained through a phase-height model conversion formula; the method can obtain two sets of fringe order information through one set of amplitude-modulated segmented phase encoding fringe patterns without adding an additional set of phase encoding projection patterns, thereby performing relationship matching to obtain complete fringe orders, more code words can be obtained, and the measurement speed and precision are improved.