47 results about "Principal value" patented technology

The invention discloses a three-dimensional measuring method based on binary grating out-of-focus projection.The method comprises the steps that 1, a binary grating image is designed and generated by a computer; 2, the grating image is projected to a measured target in an out-of-focus mode through a projector; 3, a deformed grating image is collected with a camera and transmitted to the computer; 4, a principal value phase is obtained through a four-step phase-shifting method; 5, phase unwrapping is conducted on the principal value phase through a gray code method; 6, calibration is conducted on the camera and the projector, and three-dimensional coordinate information of the measured target is calculated according to a space intersection method.According to the three-dimensional measuring method based on binary grating out-of-focus projection, a binary grating needed by measurement is generated based on design of symmetry and periodicity of sine fringes, in different degrees of out-of-focus projection environments of the projector, the quality of phase information can be improved, and the three-dimensional measuring method is more suitable for out-of-focus projection three-dimensional measurement.

A defocusing projection grating measurement method based on a Sierra Lite dithering algorithm mainly aims to generate a two-value dithering grating through the Sierra Lite dithering algorithm, improve the sine performance of the grating after defocusing and then improve the quality of a phase position. The defocusing projection grating measurement method includes the implement steps of generating a sine grating by a computer, calculating dithering output starting from the pixel at the top left corner of an image of the grating, calculating a quantization error of the pixel according to a gray value of the dithering output, selecting an S-shaped scanning direction and a corresponding kernel function coefficient to diffuse the error according to the fact that whether the pixel is in an odd-numbered line or an even-numbered line or not, overlapping the error to a corresponding next pixel until the image of the whole grating is processed completely, obtaining a needed measured grating by defocusing and projecting the finally obtained dithering grating through a projector, obtaining a principal value phase position through a classic four-step phase shift method, unfolding the principal value phase position to obtain an absolute phase position, and finally obtaining three-dimensional information of a measured object according to a conversion formula between the phase position and height.

A phase principal value extraction method based on a full convolutional neural network comprises the following steps: 1) projecting a fringe pattern which is distributed according to sine and is required by pre-coding and a pre-coded fringe pattern on a computer to a to-be-detected object, and collecting the fringe pattern of the to-be-detected object by using an industrial camera; 2) constructinga full convolutional neural network model, setting a training parameter and a loss function, inputting the picture obtained in the step 1) into the neural network, and operating the neural network toobtain a required phase principal value; and (3) unwrapping the phase main value obtained in the step (2) by using a method based on quality map guidance to obtain an accurate phase value. The invention provides the phase main value extraction method based on the full convolutional neural network, which has the advantages that the image acquisition quantity is small, a training data set and a training process are not needed, and the precision is relatively high.

The invention discloses a water resource bearing capacity evaluation method. The method comprises the following six steps of: firstly, determining an evaluation index weight by utilizing an information entropy principle; secondly, constructing a set pair model of an evaluation region and water resource bearing capacity evolution, introducing a concept of contact numbers, and contacting the identical discrepancy contrary of the set pair model; thirdly, based on an evaluation index system, calculating the contact numbers of each layer respectively from the bottom to the top, obtaining the contact number of the last layer in turn by combining a weight vector, and analogizing one by one by obtain the contact numbers of the overall system; fourthly, determining the values of the contact numbers of the systems at each level and a principal value of an n-component contact number by utilizing an equipartition principle; fifthly, equally dividing an interval [-1,1] into n levels by utilizing the equipartition principle according to the concept of the contact numbers to obtain n level intervals; and finally, comparing the values of the contact numbers of each level in the fourth step and the n level intervals divided equally in the fifth step, and analyzing the average mu is positioned in which interval, wherein the level corresponding to the interval in which the average mu is positioned is the evaluation level of the water resource bearing capacity.

The invention discloses a method for testing anisotropic permeability tension. The method for testing the anisotropic permeability tension, which mainly takes invariance of permeability tension as theoretical basis, is provided, and a method for treatment of experimental data and principal value and direction of each anisotropic permeability is provided. The method for testing the anisotropic permeability tension comprises the following main steps: (1) making a rock sample, (2) testing, (3) measuring, and (4) calculating. The method for testing the anisotropic permeability tension has the advantages that tension invariance theory is taken as basis, the principle and the method are combined together; meanwhile, permeability tension can be determined only by determining permeation in three different directions, workload is small, and calculated amount is small.

The invention discloses a three-dimensional measurement method and system based on single grating projection. The three-dimensional measurement method comprises the steps that a physical grating is projected to an object to be tested in an out-of-focus manner so as to form a sinusoidal fringe pattern, and a deformed fringe pattern of the object to be tested is collected; the deformed fringe pattern is processed by using an S-transform method to obtain the principal value phase Phi(x, y); unwrapping is performed based on a wrapping elimination method to obtain the absolute phase phi(x, y), and a three-dimensional measurement system for telecentric imaging is calibrated so as to build an imaging model, and three-dimensional coordinate information of the tested object is calculated. The three-dimensional measurement system is used for executing the method. The three-dimensional measurement method is based on the single fringe pattern, zero padding is performed on both ends of the principal value phase after the principal value phase is obtained according to the S-transform method so as to acquire up-sampling in the frequency domain, the frequency spectrum of the phase is shifted to the original position according to frequency shift characteristics of Fourier transform, a phase component of carriers is eliminated, the height-phase mapping relationship is fitted by adopting the telecentric imaging model, the three-dimensional measurement system is calibrated, the three-dimensional coordinate information of the tested object is obtained, the steps are simple, and the measurement speed is higher.

The invention relates to a permeability tensor test method and anisotropy quantification assessment method for columnar jointed rock. The permeability tensor test method includes: simulating actual columnar jointed rock to be measured to prepare similar materials with different cylinder inclination angles; measuring the permeability of similar materials; and according to the measured the permeability of similar materials, presenting the method for calculation of columnar jointed rock permeability tensor and permeability anisotropy quantification assessment. Based on the principle of tensor invariance, the method measures the permeability of similar materials with different cylinder inclination angles to obtain permeability tensor, permeability principal direction and osmotic principal value of the columnar jointed rock; and according to different types of actual columnar jointed rocks, corresponding similar materials can be prepred. The method solves the problem of indoor test for the measurement of natural rock permeability tensor and the problem of discreteness of testing results caused by the difference of natural rock, and has the advantages of low measurement cost, strong operability, accurate results and wide scope of application.

The invention provides a three-dimensional reconstruction accuracy improvement method and device based on laser grating scanning. The method includes the steps: encoding needed double-frequency stripes, loading the encoded double-frequency stripes into an MEMS (micro-electro mechanical system) micro vibration mirror control panel, scanning the panel by an X-ray machine according to the double-frequency stripes, and triggering the binocular stereoscopic camera to shoot the double-frequency stripes changed by an object surface shape by scanning of the X-ray machine; performing phase unwrapping on grating stripe images containing object surface shape information, and stereoscopically matching the left images and the right images by the aid of phase information to obtain parallax maps; calculating point cloud data for describing target object surfaces based on three-dimensional measurement principles according to binocular calibration results. Principal value phase image noise or discontinuous conditions are decreased, accuracy of an unwrapped phase is improved, the difference between two groups of initial phases is designed into 45 degrees by projecting two groups of four sinusoidal grating stripe images, a four-step phase shift algorithm is executed twice to obtain two principal value phase images, measuring errors can be greatly reduced, and the method can be effectively used for actual measurement.

The invention discloses a quality map weighting based multi-baseline least-square phase unwinding method. According to the method, a first-order phase gradient principal value in the winding phase ofa multi-baseline InSAR is calculated, and is extended in mirror symmetry, a second-order phase gradient is calculated, a quality map is used to determine the quality of the winding phase, the windingphase as prior information is used to carry out phase compensation on residual error points in the winding phase, the second-order phase gradient of the winding phase is optimized and weighted on thebasis of the quality map, and multi-baseline least square phase unwinding is carried out to obtain the unwinding phase. Multi-baseline measurement enriches interference phase information of the targetscene, the problem in transferring the phase error of a residual error point in a traditional single-baseline least square phase unwinding algorithm is solved, and the phase unwinding precision is improved.

The invention relates to a non-conformal measurement near field acoustic holography sound field rebuilding method, and relates to the technical field of acoustics. The method includes the steps that spherical wave function q(x,y) in a common wave superposition method (see the formula in the description) is replaced by a compound ray wave function with principal value directivity, by means of the method, when the holographic plane and a sound source shape are under the non-conformal condition, namely a planar array, a spherical array, a cylindrical surface array and other regular shape arrays are adopted in a holographic measurement plane, and a sound source is in an any shape, a system matrix is still in the good state of main diagonal domination, magnitude equivalence and approximate symmetry, numerical value inversion can be directly conducted on the system matrix efficiently and accurately, approximate solutions of ill-posedness problems can be obtained without using a regularization method or using the regularization method less, some variables of virtual equivalent sources are analyzed and prolongated to a complex space from a traditional real space, appropriate virtual damp is added, and therefore unique solution is obtained in the full wave number field.

The invention discloses a dynamic object three-dimension measuring method comprising the following steps: 1, using a two-dimension wavelet transformation wavelet ridge extraction algorithm based on animproved value function to solve a phase principal value; 2, using the improved value function to adjust a weight factor; 3, unwrapping the three dimensional phases, and unwrapping the phases in a time axis direction t; Pk refers to certain pixel point of a wrapped phase of the kth frame striped image; when the Pk is wrapped by red enclosing branch-cuts and the phase cannot be unwrapped in the two-dimension direction, the phase of Pk can be calculated by using the wrapping phase of Pk-1 of the k-1th frame striped image. The dynamic object three-dimension measuring method has a better three dimensional phase unwrapping result, and has a better noise inhibition capability.

An interferometric sensor and related methods are provided, with a sensing element whereby a measurand induces a relative phase shift between two waves, at least one detector measuring an interference signal between the two waves, and further including a phase shift detection unit having as input the interference signal and determining a first measure representative of the principal value of the relative phase shift, and a contrast detection unit having as input the interference signal for determining a second measure representative of the cross-correlation between the two waves, and a further a processing unit for converting the first and second measures to a measurand value.

A method for performing verification includes receiving a design and building for the design an intermediate binary decision diagram set containing one or more nodes representing one or more variables. A first case-splitting is performed upon a first fattest variable from among the one or more variables represented by the one or more nodes by setting the first fattest variable to a primary value, and a first cofactoring is performed upon the intermediate binary decision diagram set with respect to the one or more nodes using an inverse of the primary value to generate a first cofactored binary decision diagram set. A second cofactoring is performed upon the intermediate binary decision diagram set with respect to the one or more nodes using the primary value to generate a second cofactored binary decision diagram set, and verification of the design is performed by evaluating a property of the second cofactored binary decision diagram set.

A computer readable storage medium includes executable instructions to order a binary tree using primary values and selected secondary values required to resolve a position in the binary tree. The remaining secondary values are in a do not care state. A new primary value is compared to the primary value at the root node of the binary tree. If necessary, a new secondary value is compared to the secondary value at the root node to determine whether the new primary value and the new secondary value or the value at the root node should be placed in a sorted list.

An interferometric sensor is provided, with one or more wave generators (20, 20') generating at least a first set of two waves both centered at a first wavelength and a second set of two waves both centered at a different second wavelength, and a sensing element (22) whereby a measurand induces a first relative phase shift between the first set of waves and a second relative phase shift between the second set of waves, respectively, at least one detector (26, 26') measuring a first interference signal between the first set of waves and a second interference signal between the second set of waves, and further including a signal processing unit (31) adapted to determine from the first and second interference signals two quantities representative of the principal values of the first and the second relative phase shifts unambiguously within a 2[pi] range, respectively, and to derive a measurand value from their combination.

The invention discloses a decoding algorithm for n-frequency coding structured light, and belongs to the technical field of structured light three-dimensional measurement. The decoding algorithm comprises the following steps: firstly, computing the periodicity of the n-frequency coding structured light within a measurement range, and then computing a phase principal value corresponding to a space position x; secondly, structuring an array and computing the values of the array in all situations; on such basis, searching for an array value of which all elements have the same numerical value, and recording the corresponding periodicity; finally, computing the value of the space position x. The decoding algorithm is applicable to the decoding of not only double-frequency coding structured light but also multiple-frequency coding structured light.

The invention provides an artificial grid making geometric phase analysis method based on local high-resolution Fourier transformation. The method comprises the following steps of firstly collecting an undeformed raster image and a deformed raster image; respectively performing fast Fourier transformation on a reference image and a deforming image; acquiring a reference spatial frequency spectrum and a deformation spatial frequency spectrum, and selecting the interval where a spatial frequency main value is positioned to perform the local high-resolution Fourier transformation to obtain a local high-resolution spatial frequency spectrum; determining the spatial frequency main value in the local high-resolution spatial frequency spectrum and taking the spatial frequency main value as a center to select a spatial frequency value; filtering on the spatial frequency spectrum formed by the selected spatial frequency value so as to obtain a filtering reference spectrum and a filtering deformation spectrum, and then performing Fourier inversion and solving a reference phase and a deformation phase; and solving a phase difference by using the reference phase and the deformation phase, and calculating displacement and strain. The displacement and strain result calculated by the method is high in precision and short in calculation time.

The invention relates to an interferometric synthetic aperture sonar complex image registration method based on piecewise curved surface fitting. The method comprises the steps that an effective control point is selected on a main image according to the principle of maximum correlation coefficient, and the azimuthal coordinates, the distance coordinates and the offset of the control point are recorded; the whole image is divided into multiple segments along the distance direction, polynomial curved surface fitting is performed for each segment through the least square method by using the coordinates and the offset of the control point in the segment so as to obtain the offset curved surface of each segment; the offset curved surfaces of all the segments are spliced into an entire offset curved surface; interpolation resampling is performed on an auxiliary image by using the offset so as to obtain the registered complex image; the main image and the registered auxiliary image are multiplied in a conjugated way, and the phase principal value is taken so as to obtain an interferometric phase image and complete the registration process. According to the method, piecewise curved surface fitting is closer to the real landform so that the distance space variation characteristics of the landform can be further reflected and the registration accuracy is high.

The invention discloses a narrow band interference detection method based on principal value interval analysis. The narrow band interference detection method based on the principal value interval analysis comprises the following steps of obtaining preprocessed signal frequency spectrums from a front end frequency spectrum generation device, a signal detection device and a signal preprocessing device; computing to obtain a frequency spectrum distributed column diagram according to signal frequency spectrums; computing to obtain a signal main value interval according to the column diagram distribution; iterating the frequency spectrums and finding the narrow band interference according to the principal value interval. The narrow band detection method based on the principal value interval analysis has the advantages of being strong in adaptability, high in accuracy and good in stability.

The invention discloses a scene classification method based on interferometric synthetic aperture radar images. The scene classification method comprises the steps of 1) reading a to-be-classified interferometric synthetic aperture radar image pair including a main image and an auxiliary image, dividing the image pair into a plurality of sub-image pairs, and recording coordinates of the center positions of sub-images in the original images; 2) quickly obtaining a sub-pixel-level-precision offset and a coherence coefficient between the sub-image pairs through a fast coherence coefficient method; 3) establishing a scattered point relation graph between the offset and the center positions, and estimating an offset principal value interval based on the scattered point distribution density; 4)establishing a scattered point relation graph between the coherence coefficient and the offset on the basis of the estimated offset and coherence coefficient, and determining a coherence coefficient judgment threshold based on the scattered point distribution; and 5) based on the offset principal value interval and the coherence coefficient judgment threshold, dividing target scattering of sub-image blocks of the main image into four different types, and performing marking by using different marks to form a final classification diagram.