141 results about "Echo time" patented technology

The invention provides an electromagnetic ultrasonic bolt stress detection system based on a space-time complementation algorithm, and the system comprises the steps: carrying out the multi-channel ultrasonic signal collection of a to-be-detected bolt, and obtaining a multi-channel echo signal group; performing time-varying attenuation compensation and adaptive entropy weight denoising on the multi-channel echo signal group to obtain a denoised echo signal group; extracting echo time-domain features from the de-noised echo signal group, performing segmented time-frequency feature extraction on the de-noised echo signal group based on a short-time sliding window to obtain echo time-frequency features, and fusing the echo time-domain features and the echo time-frequency features into ultrasonic time-frequency features; performing wave field reconstruction on the de-noised echo signal group to obtain a spatial ultrasonic energy diagram, and extracting ultrasonic spatial features of the spatial ultrasonic energy diagram based on a self-attention map convolutional network; performing correlation detection and space-time complementary modeling on the ultrasonic time-frequency features and the ultrasonic space features to obtain ultrasonic space-time joint features, and performing stress analysis on the ultrasonic space-time joint features to obtain bolt stress data.

The invention discloses a current transformer oil level monitoring system based on ultrasonic echo detection, which relates to the technical field of electric power monitoring and comprises the following steps: acquiring original echo time sequence data; calculating the distance between the transmitting end and the top of the metal expander by combining the propagation velocity of the ultrasonic waves in the air; and when the oil level height value is lower than a set threshold value, an alarm signal is triggered. According to the invention, the problems of easy clamping stagnation, complex installation, large temperature drift and environmental interference and the like of the traditional float-type, pressure-type and window observation methods are effectively overcome, remote uploading and local acousto-optic prompt are supported, and intelligent inspection and fault pre-warning identification under unattended operation are realized; and the operation safety, the monitoring reliability and the operation and maintenance intelligent level of the oil-immersed current transformer are remarkably improved.

The invention discloses a sonar target motion identification method based on a low-frame-rate bright spot structure sequence. The sonar target motion identification method comprises the steps of 1, roughly intercepting a bright spot structure; 2, accumulating a bright spot structure, sonar platform information and tracking information; step 3, motion compensation of the sonar platform; 4, accurately intercepting a bright spot structure; and 5, searching the optimal radial speed. According to the method, target radial motion parameters are extracted by means of distance steep motion of a sonar target among multiple frames of echoes, and a speed estimation loss function based on bright spot structure global optimal estimation is innovatively designed for the problems that the time interval between adjacent echoes of a low-frame-rate sonar target is long and the bright spot structure fluctuates greatly. According to the method, the global similarity between input period bright spot structures is fully utilized, the distance steep motion measurement precision is improved, the radial speed of the sonar target can be given at the same time, and the motion identification precision and stability of the sonar target are improved.

The invention provides a method and a system for identifying environment abnormity in a direct-current battery swap station. The method comprises the following steps: fusing multi-source images acquired by the direct-current battery swap station; determining at least one suspected abnormal region based on the fused image; constructing a three-dimensional structure model of an object in the suspected abnormal area based on reflection deformation information of structured light projected into the suspected abnormal area for multiple times; determining reflection change information of the object in the suspected abnormal area based on reflection echo intensity and reflection echo time of the obtained ultrasonic wave on the surface of the object in the suspected abnormal area; and performing logic correlation analysis based on the three-dimensional structure model and the reflection change information, and determining a target abnormal region in the to-be-identified direct-current battery swap station. According to the method and the system, the capability of identifying tiny and hidden abnormal objects of the direct-current battery swap station is greatly improved, missed judgment is effectively reduced, the accuracy and the reliability of environment abnormity identification in the direct-current battery swap station are improved, and stable operation of the battery swap station is guaranteed.

The invention provides a water quality pollution tracing method and system applied to a wave radar sea area, and the method comprises the steps: firstly obtaining a sea area polarization echo time sequence set captured by a wave radar and a sea area pollutant characteristic set measured synchronously, and then carrying out the polarization characteristic deconstruction processing of the sea area polarization echo time sequence set; a polarization characteristic parameter set of each sea area block is obtained, then a pollutant molecular structure and a polarization reflection coefficient in the sea area pollutant characteristic set are associated and adapted with the polarization characteristic parameter set to generate a pollution polarization association map, and a polarization-driven pollution traceability model is constructed based on the pollution polarization association map. The method comprises the steps of inputting a pollution polarization correlation map and preset sea area ocean current parameters, outputting a traceability path set of pollutants and an initial pollution area boundary, finally analyzing an original diffusion starting point of the pollutants according to a polarization-driven pollution traceability model, and generating a pollution traceability report containing information such as coordinates of the initial pollution area. Therefore, a sea water quality pollution source can be accurately positioned.

The invention discloses an ultrasonic imaging system and method based on a heart surface, a medium and a product, the system comprises an ultrasonic detection assembly and an imaging terminal which are in communication connection, an ultrasonic transducer is packaged at the head end of an attached ultrasonic probe in the ultrasonic detection assembly, and an acoustic window on the ultrasonic transducer is planar; the ultrasonic transducer is used for being attached to the surface of the heart or the aorta, and the plane of the ultrasonic transducer is parallel to the plane of the acoustic window; and the imaging terminal is used for generating a sound velocity mask pattern according to the reference ultrasonic image, determining echo time delay data according to the sound velocity mask pattern, synthesizing and reconstructing the radio frequency signal data according to the echo time delay data to obtain an ultrasonic image, performing motion compensation on the image sequence, performing multi-modal fusion on the ultrasonic image subjected to motion compensation, and obtaining a final ultrasonic image. The problem of acoustic interference of anatomical structures such as the chest wall and the esophagus in a traditional echocardiography technology is solved, and real-time and high-quality image support is provided for cardiac surgery.

The invention relates to a magnetic resonance imaging electromagnetic parameter distribution scanning and calculation method, which comprises the following steps that a fast spin echo sequence I is adopted to scan a target body, parameters are (alpha1, TE0, TR0 and Bw1), alpha is a deflection angle, TE is echo time, TR repetition time and Bw receiving bandwidth; scanning a target body by adopting a fast spin echo sequence II, wherein parameters are (alpha2, TE0, TR0 and Bw1); scanning a target body by adopting a fast spin echo sequence III, wherein parameters are (alpha2, TE0, TR0 and Bw2); and scanning the homogeneous water model by adopting the fast spin echo sequences I, II and III. And under the condition that the magnetic vector precession meets the conditions that the amplitudes are comparable when the phases are the same and the phases are differentiable when the amplitudes are the same, each magnetic field and electric field parameter is calculated based on the homogeneous water model data. According to the invention, decoupling of the proton density and the sensitive field of the signal is realized, so that magnetic resonance weighted quantization imaging becomes possible.

The invention discloses a radar target detection method based on graph node dual-channel feature attention fusion, and belongs to the technical field of radar signal detection, and the method comprises the following steps: 1, carrying out the graph node division of received frame radar echo data; 2, respectively extracting time domain amplitude and time frequency characteristics from echo time sequence data corresponding to each graph node; step 3, establishing a feature preprocessing sub-network; step 4, constructing a node feature fusion sub-network; 5, constructing a signal classification graph neural sub-network; 6, connecting the feature preprocessing sub-network, the node feature fusion sub-network and the signal classification graph neural sub-network in series to form a radar target detection neural network; and 7, inputting the test set into the trained radar target detection neural network, and outputting a dichotomy result of which the corresponding node is a target or clutter signal. Through the scheme, the target detection capability of the radar in the clutter environment can be improved.

The invention belongs to the technical field of sonar echo processing, and discloses an underwater active sonar echo time-frequency tensor feature fusion method based on sub-beam filling. According to the method, firstly, a receiving array element is divided into a plurality of sub-beams, each sub-beam is independently subjected to beam forming, and the delay difference between the sub-beams is calculated to achieve time alignment. Then, short-time Fourier transform, continuous wavelet transform and smooth pseudo Wigner-Ville distribution analysis are respectively carried out on the echo signal of each sub-beam, and a corresponding time-frequency feature tensor is generated; thirdly, performing frequency domain weighting on the time-frequency characteristics by adopting a Gaussian distribution weighting function so as to highlight target frequency band characteristics; and finally, performing normalization processing on the weighted time-frequency features, and splicing feature tensors of different time-frequency transformations in a frequency dimension to form a fused feature tensor. The method effectively solves the problem of spatial information loss of a traditional method, and has a wide application prospect.

A polyacrylic acid (salt)-based super absorbent polymer has a T2 relaxation time of 1.85×10−5 seconds or less, as derived by exponential fitting of the TD-NMR measurement results of the super absorbent polymer through regression analysis using the following Equation 1:y=y⁢0+A×e-(xt)wherein, y represents a signal intensity obtained through TD-NMR analysis, x represents an echo time determined from specified experimental parameters: first duration; last duration; and a data point, t represents a T2 relaxation time derived by exponential fitting, A represents a signal intensity value derived by exponential fitting, and y0 represents an offset constant derived through regression analysis.

The invention provides a runner chamber wall thickness and void synchronous detection method, and relates to the technical field of hydro-power engineering nondestructive testing, S1, modular calibration: preparing a combined simulation block of a metal standard plate and an organic material plate, establishing a concrete water content inversion model and a void depth model segmented according to the thickness of a steel lining, and outputting calibration parameters; s2, field data acquisition: arranging measuring lines along a vertical welding seam and a longitudinal rib plate of the runner chamber, acquiring ultrasonic echo time and a thermal neutron counting rate, correcting the wall thickness in combination with the temperature of a steel lining, performing secondary verification on an abnormal measuring point, and outputting an original data set S = {}; and S3, machine learning signal processing: performing wavelet packet decomposition to extract energy ratio characteristics, and calculating thermal neutron counting rate fluctuation characteristics. Precise collaborative detection of the wall thickness and the void is realized through a link-by-link process of modular calibration, field data acquisition, machine learning signal processing, segmented collaborative modeling and Internet of Things data management.

The invention discloses a waveform feature extraction method and system for irregular waveforms of a hyperspectral laser radar, and aims at solving the problem that asymmetric waveforms, weak echoes and overlapped echoes in multi-channel full-waveform laser radar signals are difficult to accurately decompose, modeling full-waveform signals collected by multiple spectral channels into superposition of echo components and background noise. A multi-channel waveform is preprocessed through noise threshold and pulse width combined constraint, the waveform position is determined by adopting a gravity center discrimination method, and time synchronization calibration of each channel signal is realized in combination with a multi-echo quality index. The method further utilizes a cubic B-spline function to carry out modeling on transmitted waveforms of all spectrum channels, carries out weighted accumulation on multi-channel echo signals to enhance weak echo signals, and adopts a multi-channel interconnection decomposition optimization strategy to realize accurate extraction of irregular waveform features under the constraint condition of keeping time parameters of sub-echoes of all the channels consistent.

The invention provides a radar data processing method and device, electronic equipment and a vehicle, and the method comprises the steps: comparing the echo time corresponding to an echo signal of a reversing radar with the pre-obtained echo time of a license plate after the vehicle is powered on, and when the echo time corresponding to the echo signal of the reversing radar is smaller than or equal to the echo time of the license plate, starting the reversing radar; and discarding the echo signal of the reversing radar corresponding to the echo time. When the echo time corresponding to the echo signal of the reversing radar of the vehicle is smaller than or equal to the echo time of the license plate, the echo signal of the reversing radar corresponding to the echo time is discarded, so that the echo signal generated by the license plate can be effectively filtered, and the influence of the echo signal generated by the license plate on the detection result of the reversing radar is avoided; in addition, a radar data processing strategy does not need to be changed along with the change of the size of the license plate, and therefore the development cost is prevented from being increased, and a large amount of manpower and material resources are prevented from being consumed.

The invention discloses a gynaecology and obstetrics intelligent visual midwifery system based on an ultrasonic technology, and relates to the technical field of ultrasonic midwifery, the system constructs a two-dimensional coordinate system and extracts ultrasonic echo total time and respiratory phase data, and fetal membrane structure data and fetal physiological data are generated through dimensionless processing and data analysis. And constructing an amniotic sac thickness gradient index dyn according to the thickness gradient change to evaluate the structural stability of the amniotic sac. And if the fetal respiratory phase drift index psh is evaluated to be unstable, calculating the fetal respiratory phase drift index psh, and jointly constructing a comprehensive parturition risk index Rco with the amniotic sac thickness gradient index dyn to reflect the potential parturition risk of coupling of the fetal stress level and the membrane structure variation. And the system generates different types of intervention instructions according to the evaluation result of the comprehensive parturition risk index Rco. Multi-dimensional data mapping and layer display are achieved, linkage display of a risk thermodynamic diagram and a breathing phase curve is supported, and a visual and traceable dynamic midwifery decision basis is provided for medical staff.

Described are various embodiments of a system and method for minimizing a storage mode dephasing error caused by a reset of the auxiliary qubit. In one embodiment, the method comprises the steps of performing on the auxiliary qubit a first ηge pulse causing a |g↔|e transition in said auxiliary qubit, waiting for a designated echo time duration; and performing on the auxiliary qubit a second ηge pulse. The method may further comprise performing a f0g1 reset on the auxiliary qubit.

This invention discloses a phased array ultrasonic defect intelligent identification and data analysis system, relating to the field of PAUT (Polymerization and Angiography). It includes: an acquisition module for driving a phased array ultrasonic sensor array to perform weld seam scanning according to preset scanning rules, simultaneously acquiring and outputting ultrasonic echo time-series data across the entire depth range of the weld seam; and a preprocessing module for receiving the ultrasonic echo time-series data, performing data correction, noise filtering, and initial screening of effective signals, while simultaneously receiving feature anchoring parameters output by a mapping module, refining the signals in the corresponding regions, and outputting the results. This invention enables continuous, blind-zone-free scanning across the entire thickness and width range of the weld seam, simultaneously completing accurate echo signal correction and defect feature extraction, improving defect identification accuracy through closed-loop adaptive processing, accurately determining defect types and calculating their spatial location, size, and other core parameters, and simultaneously completing defect data statistical analysis and welding process correlation.

This specification describes systems and methods for using Zero Echo Time (ZTE) magnetic resonance imaging (MRI) sequences for applications to functional MRI (fMRI). In some examples, a system for functional magnetic resonance imaging includes a magnetic resonance imaging (MRI) scanner and a control console implemented on at least one processor. The control console is configured for executing, using the MRI scanner, a zero echo time (ZTE) pulse sequence; acquiring, using the MRI scanner, magnetic resonance data in response to the ZTE pulse sequence; and constructing at least one MRI image using the magnetic resonance data and measuring tissue oxygenation (PtO2)-related T1 changes as a proxy of neural activity changes of a subject using the at least one MRI image.

Disclosed are a compatible system and a compatible method for synchronize working of magnetic resonance imaging and focused ultrasound thermal ablation. The compatible system for synchronize working includes a magnetic resonance device and a focused ultrasound device, further includes a signal collector and a control circuit connected to the signal collector. In an imaging process of the magnetic resonance device, the signal collector is configured to detect a radio frequency (RF) signal of the magnetic resonance device, and the control circuit is configured for recording a trigger time of the RF signal, generating an enable signal triggering the focused ultrasound device to start heating based on the trigger time of the RF signal, and controlling a heating duration of the focused ultrasound device according to an echo time.

This invention discloses a multi-node collaborative electromagnetic ultrasonic online monitoring method and system. The invention relates to the technical field of online monitoring, introducing orthogonal code demodulation into multiple electromagnetic ultrasonic probes to ensure complementary interference between the probes and the same object under test. It collects detection data output from each monitoring node and extracts the echo timestamp of the object under test. Clock drift of each monitoring node is compensated in reverse along this echo timestamp to trigger spatiotemporal alignment of the detection data. An attention mechanism is then used to construct a corresponding multi-node collaborative detection system, improving its accuracy. Based on the dynamic identification of multiple electromagnetic ultrasonic online monitoring contents, corresponding suspected defect data is determined. This suspected defect data is loaded into the online monitoring finite element module, and the corresponding online monitoring defect path is determined by combining the corresponding multi-physics coupling relationship, improving the accuracy of the online monitoring defect path.

The present invention provides a method and apparatus for generating an echo time-dependent magnetic resonance diffusion imaging signal, which includes the steps of acquiring a magnetic resonance non-diffusion-weighted image and a magnetic resonance multi-b-value diffusion-weighted image, calculating a magnetic resonance diffusion signal without T2 value weighting corresponding to various water components in the human tissue for each voxel using the magnetic resonance non-diffusion-weighted image and quantitative T2 values ​​of various water components in the human tissue, calculating a diffusion coefficient corresponding to various water components in the human tissue for each voxel using the magnetic resonance multi-b-value diffusion-weighted image, the magnetic resonance diffusion signal, and the quantitative T2 values, and calculating a magnetic resonance diffusion imaging signal acquired using an arbitrary echo time for each voxel using the magnetic resonance multi-b-value diffusion-weighted image, the magnetic resonance diffusion signal, the quantitative T2 values, and the diffusion coefficients.

The application discloses a low-complexity rough road echo time delay estimation method based on sparse frequency sampling, and is used for solving the problems of high calculation complexity and poor estimation accuracy of existing ground penetrating radar echo time delay estimation technology. In the application, a grouping sparse frequency sampling method is adopted, the data dimension is reduced through sparse sampling, and the calculation complexity is greatly reduced. Meanwhile, cross-correlation detection is adopted to solve the time domain ambiguity caused by sparse sampling. In addition, a time delay iteration screening method is adopted, the preliminary time delay estimation value result is further iterated and screened, false time delay estimation values can be effectively avoided from being mistaken for real values, and higher estimation accuracy can be obtained.

The invention discloses a photographic image enhancement method based on a low-altitude economic unmanned aerial vehicle, and the method comprises the steps: transmitting a laser pulse, obtaining an echo signal of the laser pulse, and obtaining echo power data changing along with the echo time; acquiring a first image of active illumination and a second image of passive illumination in the same observation period; calculating atmospheric extinction coefficient distribution on a path from an observation point to a scenic spot according to the echo power data, and constructing a three-dimensional atmospheric particle field based on the atmospheric extinction coefficient distribution; calculating a target direct illumination component of the scene, and acquiring a spectral signal of the second image as a target spectral signal; obtaining a target intrinsic material parameter under passive illumination and a target illumination parameter after interference removal; and synthesizing and outputting an enhanced image through a graphic renderer. According to the method, the final enhanced image is established on the real atmospheric physical model, the problem of scene information loss in the prior art is solved, and the quality of the enhanced image is improved.

The invention discloses an ultra-short echo sequence magnetic resonance image processing method and device and a medium. The processing method comprises the following steps: performing magnetic resonance scanning on a to-be-imaged part of a patient by adopting a UTE sequence, acquiring N (N is greater than or equal to 4) magnetic resonance images of echo time, and storing the magnetic resonance images as image data in a DICOM format; converting the magnetic resonance image data from a DICOM format to an NIFTI format for storage; and performing analytic calculation on the long and short values by using a four-point analytic model based on piecewise exponential decay hypothesis, and finally obtaining a three-dimensional parameter distribution diagram of the rapid relaxation time, the slow relaxation time and the proportion (f) of rapid relaxation time protons in the ultra-short echo signal. According to the method, the processing time of the three-dimensional UTE image data is remarkably shortened to about 10 seconds from 10 hours of a traditional method by adopting an analytical algorithm, and meanwhile, the proportion of the number of slow relaxation protons and the number of fast relaxation protons can be effectively distinguished.

The invention provides a distance measuring method applied to reducing an ultrasonic detection blind area, which is a technical scheme for correcting the distance of an obstacle in the blind area by using a theoretical relationship between a short-distance echo time ratio or difference and a real echo frequency and combining a software algorithm. According to the distance measurement method applied to reducing the ultrasonic detection blind area, the accuracy of the distance measurement distance can be effectively corrected, the obstacle in the blind area can be accurately judged, the distance measurement is performed on the obstacle by changing the number of the sent waves, the detection capability of the sensor on the obstacle in the blind area is effectively improved, and the detection efficiency is improved. And meanwhile, the result is comprehensively judged by using the confidence coefficient, so that the risk of misjudgment is reduced.

Provided in the present invention is a relaxation exchange magnetic resonance imaging (REXI) sequence, comprising: a filtering module, consisting of a 90° excitation radio frequency pulse and a 180° refocusing radio frequency pulse; an exchange module, consisting of a 90° excitation radio frequency pulse and an exchange delay; and a detection module, consisting of a 90° excitation radio frequency pulse and a plurality of 180° refocusing radio frequency pulses. Paired crusher gradient pulses are applied to the filtering module and the detection module, and a spoiler gradient pulse is applied to the exchange module. Further disclosed in the present invention is an acquisition and analysis method for the REXI sequence: during REXI acquisition, the echo time of the filtering module is fixed, and only the exchange delay time of the exchange module and the echo time of the detection module are changed; and during REXI analysis, a dual-chamber exchange model is used for fitting data. Further disclosed in the present invention is the use of the REXI sequence and the acquisition and analysis method thereof in measuring transmembrane transport of cerebrospinal fluid by magnetic resonance imaging, which is especially suitable for magnetic resonance imaging for rapidly measuring the speed of molecular exchange between a short T2 component and a long T2 component in a dual-component system.

The invention discloses a tunnel lining thickness real-time detection system and a tunnel lining thickness real-time detection method, particularly relates to the technical field of water conservancy and hydropower engineering tunnel construction quality nondestructive detection, and is used for solving the problem that a real thickness signal cannot be accurately identified due to the fact that a water film dielectric mutation effect is not included in an existing detection method. The method comprises the following steps: synchronously transmitting first-frequency and second-frequency electromagnetic waves to a lining surface, and obtaining a concrete-water film interface reflected wave intensity difference value; calculating a water film dielectric constant gradient change rate according to the difference value; determining an electromagnetic wave penetration energy compensation coefficient; calculating an electromagnetic wave emission angle offset value by combining the tunnel axis inclination angle and the water film gravity flow direction, and adjusting the orientation of an emission device; correcting the received signal by using the compensation coefficient and the offset value, and extracting the effective echo time of the lining-surrounding rock interface; and finally, calculating the actual thickness of the lining based on the effective echo time and the reference propagation velocity of the electromagnetic wave in the concrete. The interference of a water seepage environment is effectively overcome, and the real-time high-precision detection of the lining thickness is realized.

The present application belongs to the field of underwater acoustic signal processing, and particularly relates to a method for simulating echo of active sonar target. Firstly, the sonar transmitting signal is generated according to the sonar transmitting parameters. By setting the initial azimuth and distance of the target and the speed and course of the target and the ship, the azimuth and distance of the target relative to the ship, the attitude angle and the radial velocity at the echo time are calculated. Then, the echo intensity of the target received by the sonar is analyzed through the sonar transmitting mode, the transmitting power, the underwater acoustic propagation loss and the target type, and the echo signal amplitude is calculated according to the element sensitivity, the attenuator attenuation multiple and the DA bit number. Then, the multi-bright-point target model is established according to the target type and the azimuth, distance and attitude information of the target. The present application realizes the echo simulation of various target types of active sonar, and can effectively carry out the training and verification work of underwater target detection and target identification, and has certain practical and economic value.

The invention relates to the technical field of shale oil development, in particular to a shale oil two-dimensional nuclear magnetism online mobility evaluation method and device, and the method comprises the steps: firstly, determining low-frequency phase redundancy on a frequency domain dimension based on the energy distribution condition on an energy spectrum and the phase distribution condition on a phase spectrum of an echo time row vector; determining echo invalidity on the time domain dimension based on the data fluctuation stability condition in the echo time row vector; then, integrating the low-frequency phase redundancy and the echo invalidity, and determining the mobility interference degree which represents redundancy characteristics more accurately; further decomposing and reconstructing the redundant row vector screened based on the mobility interference degree, and determining a reconstructed row vector of which redundant ineffective components are more accurately removed, so as to determine a two-dimensional nuclear magnetic resonance T1-T2 spectrogram of which the redundant ineffective components are more accurately removed; and the accuracy of shale oil two-dimensional nuclear magnetic resonance online mobility evaluation according to the two-dimensional nuclear magnetic resonance T1-T2 spectrogram is improved.

The invention relates to the technical field of radar three-dimensional imaging, in particular to a TDM-MIMO radar signal processing method based on an improved sparse array and related equipment. The TDM-MIMO radar signal processing method based on the improved sparse array comprises the following steps: acquiring first echo data of a moving target based on a first MIMO array; exchanging the positions of a transmitting channel and a receiving channel in the first MIMO array to obtain a second MIMO array, and determining an equivalent reference channel from the second MIMO array; determining a delay increase rate based on the equivalent reference channel; wherein the time delay increase rate represents the increase rate of the echo time delay generated by the moving target due to displacement in the process of switching the adjacent communication channels; and correcting the first echo data based on the delay increase rate.

A method according to the invention for acquiring T2*-weighted measurement data of a test object using a magnetic resonance system comprises the steps: - irradiating a first RF excitation pulse to excite spins in a first layer in the test object, - switching gradients to generate at least one gradient echo signal, - after an echo time following the irradiation of the first RF excitation pulse, acquiring a first gradient echo signal from the first layer, - after the irradiation of the first RF excitation pulse and before the elapsed echo time following the first RF excitation pulse, irradiating at least one further RF excitation pulse to excite spins in a further layer,wherein, before the application of a further RF excitation pulse and after each RF excitation pulse preceding the further RF excitation pulse, a pre-rephasing gradient of a moment corresponding to the further RF excitation pulse following the pre-rephasing gradient is switched, - recording generated further gradient echo signals from further layers. By switching the pre-rephasing gradients according to the invention, gradient echo signals of the spins of different layers excited by the first RF excitation pulse and the at least one further RF excitation pulse can be separated. Thus, the echo time TE, which elapses until a first gradient echo signal is measured after the first RF excitation pulse, can be used to generate and measure further gradient echo signals in further layers after the first gradient echo signal, which increases the readout efficiency.