525 results about "Echo time" patented technology

An imaging marker comprised of glass and iron-containing aluminum microspheres in a gel matrix which shows uniformly good contrast with MR, US and X-Ray imaging. The marker is small and can be easily introduced into tissue through a 12-gauge biopsy needle. The concentration of glass microspheres and the size dictate the contrast for US imaging. The contrast seen in MRI resulting from susceptibility losses is dictated by the number of iron-containing aluminum microspheres; while the artifact of the marker also depends on its shape, orientation and echo time. By optimizing the size, iron concentration and gel binding, an implantable tissue marker is created which is clearly visible with all three imaging modalities.

The invention discloses a partial echo compressed sensing-based quick magnetic resonance imaging (MRI) method. The conventional imaging method has low speed and high hardware cost. The method comprises the following steps of: acquiring echo data of a random variable density part, namely intensively acquiring data in a central area of a k-space and acquiring the data around the k-space randomly and sparsely to generate a two-dimensional random mask, adding the two-dimensional random mask into every data point which needs to be acquired on a frequency coding shaft to form a three-dimensional random mask, and acquiring the data of the k-space according to the generated three-dimensional random mask; re-establishing by projection onto convex sets based on a wavelet domain which is de-noised by soft thresholding; and nonlinearly re-establishing a minimum L1 normal number based on finite difference transformation, namely sparsely transforming an image space signal x, determining an optimization objective and solving the optimization objective. By the method of the invention, partial echo technology and compressed sensing technology are combined and applied to data acquisition of MRI, sothat echo time is shortened, and data acquisition time is shortened at the same time.

A method and apparatus for enhancing the spectral resolution of magnetic resonance spectroscopic (MRS) measurements include receiving time domain echo data from an MRS measurement for an MRS volume in a subject. Also received are high spatial resolution complex signal values within the MRS volume based on magnetic resonance imaging (MRI) measurements. Frequency-domain content is determined for the echo data based at least in part on the complex signal values. For example, in some embodiments, receiving complex signal values includes receiving high spatial resolution complex signal values within the MRS volume for each of two different echo time settings. The frequency-domain content of the echo data is corrected for a lineshape profile based on high resolution frequency dispersion values for the MRS volume determined from differences in the complex signal values for the two different echo time settings.

The invention discloses an echo eliminating device, comprising: an acoustic echo eliminator which receives an echo time-delay value and determine parameters according to the echo time-delay value to eliminate the echo; a downlink voice detecting module which detects whether energy of a received downlink voice signal reaches the prearranged threshold value, if so, an identifier is output; a time-delay computing module which collects the uplink, downlink voice signals, computes correlative coefficient of the uplink, downlink voice signals at the time of receiving the identifier, determines the echo time-delay value corresponding to the maximum value of the correlative coefficient, and sends the echo time-delay value to the acoustic echo eliminator. The invention not only can configure appropriate parameters for terminal by the time of leaving factory, but also can be integrated to update relevant parameters in real time for a part of the acoustic echo eliminator, thereby the invention is apt for variation of the echo time-delay owing to change of the terminal's circumstance and improves effect of echo elimination as well as reduces expenditure of system resource. Meanwhile, the invention also discloses a communication terminal including the echo eliminating device, and a method for determining the echo time-dealy.

A multi-point chemical species (e.g., water, fat) separation process which is compatible with rapid gradient echo imaging such as SSFP uses an iterative least squares method that decomposes water and fat images from source images acquired at short echo time increments. The single coil algorithm extends to multi-coil reconstruction with minimal additional complexity.

The invention discloses a method for accurately measuring shale porosity by adopting the low-field nuclear magnetic resonance. The method comprises the following steps: as for a saturated water column-shaped shale sample, conducting nuclear magnetic porosity measurement in different echo time and waiting time; conducting helium porosity measurement; comprehensively comparing and analyzing the porosity results of the two methods; optimizing the optimal echo time and waiting time for testing to facilitate the accurate testing of follow-up samples. The method solves the problems of how to set reasonable parameters to measure the shale porosity by adopting the low-field nuclear magnetic resonance, and solves the problem that in the actual testing, the nuclear magnetic porosity obtained in different echo time and waiting time is in great disparity, and the comparability of the nuclear magnetic porosity and the helium porosity is relatively poor; compared with the prior art, by adopting the method, the shale porosity can be quickly and nondestructively measured, the accuracy and precision of the shale porosity measurement can be improved, and the operation is convenient.

The invention discloses a DIXON water-fat separation method in magnetic resonance imaging. The method comprises the following steps: a) in the magnetic resonance scanning process, three different echo signals including the first echo signal S1, the second echo signal S2 and the third echo signal S3 are acquired, wherein the water-fat signal procession phase difference of the first echo signal S1 and the third echo signal S3 is 2npi, and n is a natural number; b) the acquired k space signals are converted into image signals through Fourier transform; c) effective image signal pixels are extracted in a image domain, the phase diagram of the effective image signal pixel composite signal is extracted, and phase unwrapping is performed on the phase diagram to obtain a static magnetic field distribution diagram delta B0; d) and the water image and the fat image in the echo signals are separated by utilizing the static magnetic field distribution diagram delta B0. According to the DIXON water-fat separation method provided in the invention, the echo time can be set flexibly according to a magnetic resonance imaging sequence and application requirements, so not only data can be processed by applying the conventional DIXON algorithm, and but also the limitation on imaging sequence parameter setting can be reduced at the same time.

In a method described for generating magnetic resonance exposures in which diffusion-coded raw data are acquired with of a diffusion gradient measurement sequence having a number of partial diffusion gradient sequences, at least one diffusion coding gradient pulse is emitted in each partial data set, and raw data of a k-space region are acquired during a first echo after a defined first echo time the k-space regions in total covering a complete k-space. Raw data of an established navigator k-space region are acquired during a second echo after a second echo time the navigator k-space region being identical for different partial diffusion gradient sequences. Reference raw data are acquired by a reference measurement sequence with multiple partial reference sequences.

The invention provides a method and a device for tracking echo time delay. The method comprises steps that, an echo reference signal and a sound input signal are acquired, and echo time delay of the echo reference signal at a present frame is determined by utilizing peak values of cross-correlation functions of the echo reference signal and the sound input signal at the present frame. According to the method and the device, in the process of acquiring the echo reference signal, the echo time delay of the echo reference signal at the present frame is determined by utilizing the peak values of the cross-correlation functions of the echo reference signal and the sound input signal at the present frame, so echo time delay of the echo reference signal at each frame is tracked, and bases are provided for eliminating time delay jittering and improving long-term stability of the echo elimination performance.

An ultrasonic liquid level detector includes clamp-on transducers for a liquid level measurement by the clamp-on transducers instead of insertion type transducers. The ultrasonic liquid level detector measures a height of a liquid-liquid interface or a gas-liquid interface based on an acoustic attenuation of an acoustic pulse or a transit-time of the acoustic pulse using a pulse echo technique or a combination thereof.

The invention discloses a multi-channel laser echo time measurement system based on an FPGA (Field Programmable Gate Array) chip, and relates to the field of photoelectric measurement. The system solves the problems that the existing single-point detector cannot meet requirements of multiple channels, high accuracy, wide measurement range, rapid measurement and the like. The system comprises an array detector used for converting a received laser echo signal into a weak current signal, a plurality of preamplifiers with the same quantity as array detector pixels, a plurality of threshold comparators with the same quantity as the preamplifiers, and the FPGA chip of a plurality of channels with the same quantity as the threshold comparators, wherein the preamplifiers are used for amplifying the weak current signal to a voltage signal; the threshold comparators are used for comparing the voltage signal with reference voltage, and generating a timing stop pulse signal used for marking the laser echo signal; and the FPGA chip is used for measuring a time difference between the received timing stop pulse signal and a timing start pulse signal, and obtaining the pulse flight time. The system realizes high-accuracy, wide-range and high-speed array signal measurement through multi-channel signal processing.

The invention relates to a multi-sending and multi-receiving acoustic measurement method for oceanic internal waves. According to the method, sound wave signals with frequency bands are sent through an internal wave measurement device, travel time of the sound wave signals with the frequency bands in the vertical direction in seawater is measured, after influences of a factor of background environmental is removed, echo time disturbance is obtained and combined with dynamics property of the internal waves, the relation between the echo time disturbance and the amplitude of the internal waves is built, so that change of crucial hydrology parameters such as temperature, salinity and flow rate of whole water depth caused by the internal waves is obtained, and therefore the purpose of observation on the oceanic internal waves is achieved. The multi-sending and multi-receiving acoustic measurement method for the oceanic internal waves can be widely used for the observation on the oceanic internal waves, particularly for the observation on internal waves in a deep sea.

Methods and compositions are provided for magnetic resonance imaging of biological tissue, particularly methods and compositions for 23Na and 39K magnetic resonance imaging of cardiac tissue. In particular, methods of 23Na magnetic resonance imaging (MRI) cardiac imaging is presented for attenuating 23Na signals corresponding to ventricular cavity blood and viable well-perfused tissue and for visualizing myocardial infarction. Cardiac tissue is imaged using 23Na MRI after the introduction of an intravascular paramagnetic contrast agent. Optimally, the intravascular paramagnetic contrast agent is MION-46. The MION-46 suppresses the blood signal intensity in sodium images of ventricular cavities and signal for viable cardiac tissue. The quantity of MION-46 and the echo time (TE) for 23Na MRI of cardiac tissue may be selected to minimize signal intensity differences between ventricular cavity blood and well-perfused viable myocardium; maximize signal intensity differences between non-viable myocardium and ventricular cavity blood in myocardial infarction; and maximize signal intensity differences between non-viable myocardium and well-perfused viable myocardium in myocardial infarction.

A device for measuring a fill level of a liquid includes an ultrasonic sensor with two sensor elements. One of the sensor elements determines the echo time of an ultrasonic wave to a float which follows the liquid level. The other of the sensor elements determines the echo time of the ultrasonic wave up to a measuring reflector arranged at a known distance from the other of the sensor elements. An evaluation unit compares the echo times and determines the fill level of the liquid from the ratio of echo times and from the known distance to the measuring reflector.

The invention provides a transverse relaxation time measuring method. The method comprises the following steps of: acquiring an echo signal; fitting the echo signal to acquire a prior estimate value of the relaxation time; and calculating echo time interval according to the prior estimate value, and feeding the echo time interval to the fitting calculation to acquire a measurement value of the relaxation time. Through rough estimation on the relaxation by the fitting calculation, the transverse relaxation time measuring method and system realize optimization on the signal to noise ratio of the relaxation time in the echo signal, so that the accuracy of relaxation time measurement is effectively improved.

In a method for calculating a one-dimensional map of the base magnetic field B0 and subsequent correction, based on this map, of image artifacts due to B0 field changes, in the examination of a subject with a magnetic resonance tomography apparatus, data for a slice of the subject to be examined are obtained with a sequence of a fast MRT imaging method that includes at least three phase correction scans and measurement signals of the respective phase correction scans as well as of the slice are obtained, the phase difference of the data points (respectively pertaining to one another) of two phase correction scans, in the form of the acquired measurement signals of the respective phase correction scans, are calculated point-by-point, the average phase difference between the phase correction scans is evaluated, and the frequency offset between the actual resonance frequency relative to the adjusted resonance frequency is calculated based on the average phase difference and the echo time difference between the phase correction scans used, a B0 field map is calculated dependent on the frequency offset and, the measurement data for the slice are corrected using the calculated B0 field map.

The invention relates to a multi-scale convolutional neural network-based heavy rainfall and thunderstorm prediction method and system. The method of the invention includes the following steps that: original radar echo data are acquired; the original radar echo data are preprocessed, so that radar echo time series images can be obtained; any three frames of radar echo time series images which aregenerated consecutively are selected, a radar echo convolutional neural network is constructed, and the next frame of radar echo image can be inferred; and radar echo change within one minute is inferred by means of an optical flow field method and a linear interpolation method. With the method adopted, thunderstorm weather in one hour can be predicted, and the space range of thunderstorm weatherprediction can be narrowed to be a range within 1 km.

The invention provides a method for accurately measuring the nuclear magnetic resonance porosity of oil-containing shale. According to the method, nuclear magnetic resonance T2 spectral distribution and porosity of kerosene shale different in waiting time and echo interval are measured, the oil-containing shale porosity is compared with the helium porosity with respect to calibration waiting time and echo intervals, and the nuclear magnetic resonance T2 spectral distribution obtained at the time of the optimum echo time and the echo interval can represent reservoir physical property traits of the oil-containing shale. According to the method, factors influencing the measuring accuracy of the nuclear magnetic resonance porosity of the oil-containing shale are ascribed to the type and measurement parameters (waiting time and echo intervals) of sample saturated fluid, and the hydration influence of a shale sample is eliminated through saturated kerosene; the optimum waiting time and echo intervals are calibrated by analyzing T2 spectral distribution variation and the helium porosity; by means of the method, nuclear magnetic resonance T2 spectral distribution and porosity of the kerosene shale different in waiting time and echo interval are measured, thus the optimum measurement parameters which can accurately represent the porosity of the oil-containing shale can be obtained, test operation is simple and easy to conduct, and operability is great.

Methods and systems are providing for improving engine coolant level estimation to reduce engine overheating. The level of fluid in a coolant overflow reservoir is inferred based on the fluid level in a hollow vertical standpipe fluidically coupled to the reservoir at top and bottom locations, while the fluid level in the standpipe is estimated based on output from an ultrasonic signal transmitted by a sensor positioned in a recess at the bottom of the vertical standpipe. The sensor uses a combination of raw echo times and processed fluid level data to estimate the fluid level accurately and reliably.

Mapping of myelin water content in white matter may provide important information for early diagnosis of multiple sclerosis and the detection of white matter abnormality in other diseases. It is disclosed here that free induction decay (FID) of each voxel at multiple slice locations is acquired in the brain using an echo-planar spectroscopic imaging (EPSI) pulse sequence. The multi-slice EPSI acquisition is designed to have a short first echo time (˜2 ms) and echo-spacing (˜1 ms) in order to acquire multiple sampling points during the fast decay of the myelin water signal. Multi-compartment analysis is then applied to the FID in each pixel using a 3-pool model of white matter to obtain quantitative maps of the myelin water fraction. Using this technique, the MR data for whole brain mapping of the myelin water can be acquired in less than 10 minutes, making this technique feasible for routine clinical applications.

The invention provides a multibeam depth measuring method based on a roll stabilization strategy and a system thereof. The multibeam depth measuring method comprises the steps of: a step 101), forming a receiving wavebeam according to a phase control angle beta after rolling stabilization; a step 102) estimating an echo arriving time T0 by means of amplitude phase information of a signal after wave beam formation; a step 103) determining a synthetic wavebeam angle-of-spread gamma of an echo arriving time according to an emitting surface equation and a receiving surface equation; and a step 104) using the synthetic wavebeam angle-of-spread gamma as an initial incidence angle alpha0 of a sound ray, and utilizing echo time T0 for performing sound speed correction and coordinate homing. The step 101) further comprises steps of: step 101-1) receiving a relative gesture yawing phi, a pitch P and a roll R through a sensor in system operation period; and a step 101-2) operating a receiving phase control angle betan=thetan+R according to the roll angle R, and performing time shift wavebeam forming according to the obtained phase control angle.

The invention discloses a direct locating method based on external radiation source time delay and Doppler frequency, and overcomes the problem of insufficient utilization of external radiation source direct wave signal information of the existing direct locating method. The direct locating method comprises the following steps that time synchronization of the dual-channel receiving systems of L observation stations is performed; the Fourier coefficient of the dual-channel receiving data of each station is calculated; each observation station transmits the acquired array signal frequency domain data to a central station; a Gaussian maximum likelihood function is constructed for the data of the conversion value frequency domain at the central station and an information matrix including echo time delay and Doppler and direct wave time delay information is extracted; a grid search scope is set and the maximum eigenvalue corresponding to the data information matrix on geographical grid points is calculated; and accurate locating of a target can be obtained by searching the coordinates corresponding to the maximum value within the grid scope. Compared with the conventional two-step locating algorithm, loss of locating information can be reduced and locating precision can be obviously enhanced.

A method for performing ultrasonic testing comprising, in one embodiment, the steps of firing an ultrasonic transducer to generate an ultrasonic pulse that passes through a delay line, measuring a delay echo time of flight, and determining the temperature of the delay line using the delay echo time of flight, thereby eliminating the need for additional temperature measuring devices. Other embodiments further comprise the step of using the temperature of the delay line to determine the temperature of a test object, and using the temperature of the test object to determine a thickness of the test object that is compensated for thermal expansion and temperature dependent ultrasonic velocity.