287 results about "Absolute phase" patented technology

A new measurement system, with two receiver channels per measurement port, has been developed that provides absolute magnitude and absolute phase relationship measurements over wide bandwidths. Gain ranging is used at RF to provide optimum noise performance and a swept YIG preselector filter is used to avoid spurious signals. A new absolute vector error correction method is used to calibrate the measurement system in order to allow for absolute vector measurements, and it also removes the time-varying responses caused by the swept YIG preselector filters. A quasi-reciprocal mixer with a characterized non-reciprocal ratio is used to provide the absolute calibration standard. The two receiver channels can be adapted to a wide variety of applications, including wide bandwidth vector signal analyzer measurements, mixer measurements, and harmonic measurements. The two-channels can also be used as an absolute calibrated transmitter/reflectometer.

Disclosed is a non-equal probability constellation labeling method based on an absolute phase shift keying (APSK) constellation diagram. The non-equal probability constellation labeling method based on the APSK constellation diagram is characterized by comprising the steps that: the APSK constellation diagram is constructed, number of steps of the constellation labeling is M, M=2m, and m is a positive integer, numbers of constellation points on each ring is the same, phase deviations of each ring are also the same; a constellation labeling mode of the APSK constellation diagram is designed, and the constellation labeling mode is enabled to be a gray labeling; the constellation points are grouped, and constellation points on the same ring are combined to be a new constellation point; labeling bits of the prior constellation points on the same ring are distributed to the new constellation point in sequence. According to the non-equal probability constellation labeling method based on the APSK constellation diagram, the inhomogeneous constellation diagram and a non-equal probability labeling technology are adopted, distribution of output signals of the constellation labeling is enabled to be close to Gaussian distribution, shaping gain is achieved, performance of a coded modulation system is improved, and signal to noise ratio in a modulation process is reduced.

An electrostatic trap such as an orbitrap is disclosed, with an electrode structure. An electrostatic trapping field of the form U′(r,φ,z) is generated to trap ions within the trap so that they undergo isochronous oscillations. The trapping field U′(r, φ,z) is the result of a perturbation W to an ideal field U(r, φ,z) which, for example, is hyperlogarithmic in the case of an orbitrap. The perturbation W may be introduced in various ways, such as by distorting the geometry of the trap so that it no longer follows an equipotential of the ideal field U(r, φ,z), or by adding a distortion field (either electric or magnetic). The magnitude of the perturbation is such that at least some of the trapped ions have an absolute phase spread of more than zero but less than about 2π radians over an ion detection period T_m.

The invention discloses a phase error compensation method applied to grating three-dimensional projection measurement. The method includes the following steps: generating sine grating stripes; collecting grating stripes that are modulated by the surface of an object; pre-processing images; carrying out phase unwrapping through a phase shift method on the basis of the pre-processed stripe images; projecting a grey-scale image with a single gray value onto the surface of a standard white board; mapping regional results in the step (5) onto a target surface of a projector through an obtained ideal phase; establishing regional correction models for different regions according to the regional results; projecting the sine grating stripes onto the object; solving an initial phase through a phaseshift method, compensating the phase on the basis of established regional error compensation, and solving an actual phase; and through calibrated camera parameters and a solved absolute phase, calculating three-dimensional coordinate information of a to-be-measured object through a spatial intersection method. The method overcomes phase errors and measurement errors caused by Gamma non-linearity.

The invention discloses a dualistic structure optical optimization method suitable to rapid three dimensional profilometry. The method is characterized by comprising the steps of conducting inverted Y-shape correction to a camera and a projector, calibrating the camera, revising distortion, projecting phase shift grating fringe, projecting a dualistic structure optical coded graph, using the phase shift method to solve a grating wrapped phase, using the coded fringe to solve the grating orders, solving an absolute phase, completing the phase un-wrapping, mapping the phase to real heights to reconstruct a three dimensional profile. According to the dualistic structure optical optimization method suitable to rapid three dimensional profilometry, the optimized dualistic structure optical coding method is used for achieving the reconstruction of the three dimensional profile of an object. The method can be used for precisely determining a cycle order of the projection grating fringe, avoiding the non-linear projection problem of the multilevel gray value, and the color aliasing problem of multi-channel projection, the measuring speed is fast, and the method has a good adaptability to different measured objects, and a substantial and obvious technological effect.

The invention discloses a method for calibrating a three-dimensional imaging system, which comprises the following steps of: 1, designing a calibration flat plate to be white and have a diffuse reflection surface and designing black annular identifiers in a square matrix arrangement mode on the calibration flat plate simultaneously, wherein the center distance between adjacent identifiers is equal; 2, placing the calibration flat plate at different positions in a measurement field, projecting non-uniform sinusoidal grating stripes with the optimal number of stripes at each placement position onto the surface of the calibration flat plate, and acquiring and calculating the absolute phase of each white pixel point inside the black annular identifiers; 3, extracting the central point position of each identifier from a corresponding absolute phase diagram to solve the relative depths of the identifiers when the calibration flat plate is at each placement position; 4, establishing a high-order polynomial (A) to express the relationship between the absolute phases and the relative depths; and 5, converting the absolute phases into actual depth data by using the calibrated polynomial coefficients so as to finish the calibration of the three-dimensional imaging system.

The invention provides 16-step dual-frequency grating phase shift profilometry capable of absolute phase unwrapping in the three-dimensional sensor technology. The invention is characterized by usingcomputers to design codes to generate 16 dual-frequency grating patterns, using a digital light projector to image the grating patterns on the surface of an object instantaneously in sequence, using apick-up device to record the deforming fringe pattern of the object, subsequently using the functional relationship between the gratings with two frequencies, using the absolute phase unwrapping method to directly realize phase unwrapping of point to point in the whole field range and having no relation with the path for phase unwrapping, effectively inhibiting accumulative error diffusion, usingphase measuring profilometry to process the deforming fringes, accurately restoring the three-dimensional shape of the object and obtaining such digital information as deformation of the object and the like by further analyzing the data processing results. The method can be used for measurement study of the characteristics of the object surface with the characteristic of diffuse reflection. The method has the advantages of high measurement precision and strong adaptability to the surface topography of the object, etc.

A DPSK demodulator demodulates DPSK signals in a computationally efficient manner to reduce the power requirements of the DPSK demodulator. A DPSK signal is received, digitized, converted to its in-phase (I) and quadrature (Q) components and filtered to remove noise. The I and Q components are processed to determine a relative phase and frequency offset. The phase is adjusted using the frequency offset. The adjusted phase is converted to an absolute phase, which is then mapped to a symbol representative of one or more bits of data.

The invention provides a digital beam forming and phase fitting method, and aims to provide a method capable of suppressing interference, improving the signal to interference and noise ratio and accurately controlling the phase of a beam forming signal. The method is implemented according to the technical scheme that a steering vector model obtains relative steering vectors by using online calibration, accurate absolute steering vectors are acquired by combining absolute phase responses, which are measured in a darkroom, of a reference array element, model parameters of the steering vector are fitted out by combining the existing absolute steering vectors, and an accurate spare steering vector of an antenna array in any direction is acquired; the second-order statistic of the array signal is iteratively calculated through an array signal statistic hardware calculation module, and sent to an array signal processing algorithm module together with an antenna array steering vector and a channel response to calculate an optimal beam weight; and finally, the array signal processing algorithm module imbeds the optimal beam weight into the digital beam forming module to perform real-time digital beam forming and phase fitting and process multi-channel array data and beam output in real time.

A first frequency synchronization unit (103) corresponds to the frequency synchronization apparatus of the present invention. A higher apparatus that is, for example, a wireless receiver supplies a reception signal to the first frequency synchronization unit (103) via an A/D converter (101) and an orthogonal detector (102). A synchronization symbol that includes a predetermined waveform at least twice is incorporated into the reception signal. A correlation estimator (104) generates a reference signal expressing the same waveform as the synchronization symbol, and successively finds correlation vectors between the reception signal and the reference signal. A first signal error detector (106) finds a frequency error based on an average phase difference of predetermined correlation vectors, and finds an absolute phase error based on transition of absolute phase of predetermined correlation vectors. A first frequency corrector (108) simultaneously gives the reception signal a frequency shift and phase rotation that cancel the errors.

The invention discloses a calibration method of a projector. The calibration method comprises steps of providing a calibration plate; providing a structure optical three-dimensional detection system; using a first type of circle to right the calibration plate; in an effective range of the calibration plate, shooting pictures on the calibration plate, projecting coding strips to the calibration plate and shooting through the projector, and repeating the step for at least twice; carrying out phase position calculation on each group of images with strips to obtain horizontal and longitudinal absolution phase position values of centre point positions of each group of the calibration plate images, using a circular point extraction algorithm to calculate center point pixel coordinates on the calibration plate images and combining the horizontal and longitudinal absolution phase position values and the center point pixel coordinates to obtain an absolute phase position value of each centre point; and converting the absolute phase position value of each centre point of the calibration plate into pixels of the projector from pixels of a camera, thereby achieving calibration of the projector. According to the invention, the three-dimensional structure optical scanning measurement system is enabled to achieve measurement of workpieces in different sizes with no need to change various kinds of calibration plates, and the calibration method is suitable for three-dimensional detection of micro elements in different sizes.

The present invention provides measuring apparatus and method for three-dimensional profilometry of an object, wherein a random-speckle beam and a structured fringe beam are projected onto the object and reflected therefrom for forming deformed random-speckle beam and structured fringe beams that are separately acquired by an image acquiring device thereby obtaining a random-speckle image utilized to determine an absolute phase information of each position on the surface of the object, and a structured fringe image utilized to determine a relative phase information for each position of the surface of the object. Each absolute phase information and each relative phase information corresponding to each position are converted into an absolute depth and a relative depth, respectively. Finally, the depth information of each position on the surface of the object is calculated by combining the corresponding absolute depth and the relative depth whereby the surface profile of the object can be established.

The present invention is suitable for the image processing technology field. The present invention provides a three-dimensional face reconstruction method and system. The method and system comprise: a three-dimensional imaging units are respectively arranged at left and right two sides of face in the same mode; the multi-mode relation between the 3D cloud coordinates collected by the 3D imaging units and the corresponding phase according to the result of the binocular calibration, and the transformation relation between the 3D cloud coordinates collected by the 3D imaging units is determined; the 3D imaging unit collects the image sequences at two sides of the face, and the absolute phase of the image sequence is obtained; by employing the multi-mode relation, the absolute phase of the image sequences is mapped to the 3D point cloud coordinates; and according to the transformation relation, the 3D point cloud coordinates of the 3D imaging units are uniformed in the whole coordinate system. The rapid face 3D reconstruction is realized, the processing efficiency of the face 3D reconstruction is improved.

The invention belongs to the technical field of an optical three-dimensional sensor technology, particularly relating to an optical three-dimensional measurement method with absolute phase measurement. The invention provides a method which adopts a single assistant coding pattern, which combines the intercepting phase distributing characteristic with the coding pattern deforming characteristic ina phase coding project, and uses 3-value gray level coding, thereby improving the decoding reliability and simplifying the decoding algorithm. By adding a sine optical grating or a logic optical grating pattern with a space gray level coding pattern, the method realizes the absolute phase measurement to compute the three-dimensional feature and the space room of an object.

The invention belongs to the fields of antenna measuring technique and satellite navigation and positioning, and relates to a correction method for the absolute antenna phase center of an outdoor GNSS (Global Navigation Satellite System) receiver based on a precision mechanical arm. In view of the problem that conventional outdoor GNSS observation cannot obtain a high-precision correction model for the absolute antenna phase center of a receiver, a majority of common errors are eliminated through ultra-short baseline observation, the absolute phase center offset (PCO) of a receiver antenna and the separation of phase center variation (PCV) are realized through rapid rotation and inclination of the high-precision mechanical arm, finally the PCO is resolved through a least squares algorithm, and fitting calculation of the PCV is carried out for observation residual. According to the correction method, outdoor operation can be carried out, the correction precision of 1mm for the PCO and PCV can be reached, the correction method is suitable for accurate calibration of the PCO and PCV of the receiver capable of tracking the signals of satellite navigation systems such as a GPS (Global Positioning System), a BDS (Beidou Navigation System), a GLONASS (Global Navigation Satellite System) and Galileo, and thus the systematic measuring error caused by imprecision of the PCO and PCV of the receiver can be eliminated, and the user positioning precision is further improved.

A motor drive controller includes a position detector that detects and outputs positional signals representing rotational positions of the magnetic rotor at first resolution, a position change detector that detects and outputs position change signals representing rotational positions of the magnetic rotor at second resolution higher than the first resolution, a phase synchronizing circuit that generates and outputs low resolution absolute phase information based on the positional and position change signals. The phase synchronizing circuit generates and outputs high-resolution absolute phase information based on the position change signals. A drive voltage signal outputting device outputs a drive voltage signal causing the current to flow through the coils in accordance with the absolute phase information.

The invention discloses a high-dynamic performance three-dimensional measurement method based on adaptive grating projection, and the method comprises the steps: setting a saturation threshold value of an image; carrying out the projection of an all-white image for a to-be-measured object, collecting the image through a camera, changing the gray scale of the projection image, generating a proper grating, and enabling the camera image not to be saturate; enabling the projection to sequentially pass through the gratings adjusted for the first time, collecting an image, solving an absolute phase through a phase shift method and a Gray code method, and completing the matching of the camera image coordinates and the projection grating image coordinates of an excessively bright region through the phase; projecting the image, collecting the image through the camera, adjusting the gray scale of the projection image pixel by pixel based on a coordinate matching result, and generating a final adaptive grating map; projecting a finally generated grating map, collecting the image, and solving an absolute phase through the phase shift method and the Gray code method; and calculating the three-dimensional coordinate information of the measured object according to a space intersection method through the calibrated camera parameters and the solved absolute phase. The method finally achieves the precise three-dimensional measurement with the high dynamic performances.

A digital frequency synthesizer provides absolute phase lock and shorter settling time through the use of a digital filter with a phase and frequency path. Control logic control disables the frequency path during the frequency acquisition and sets a wide bandwidth. After frequency acquisition, a counter with digital phase information is reset using the input clock signal to bring the output phase closer to lock with the input signal and the control logic enables the phase path in the digital loop filter to achieve phase lock with a narrower bandwidth than the initial bandwidth.