103 results about "Pulsed doppler" patented technology

A pulse Doppler ultrasound system and associated methods are described for monitoring blood flow and hemodynamics. The Doppler ultrasound system includes an ultrasound probe to emit ultrasound signals and detect reflected signals therefrom and further includes a processor coupled to the ultrasound probe and operable to process the detected reflected signals and calculate therefrom blood flow data for a plurality of locations at time intervals, the processor further operable to identify locations at which blood flow having a hemodynamic characteristic is present based on the blood flow data calculated for a plurality of the time intervals. A user interface coupled to the processor provides blood flow information based on the blood flow data, the blood flow information representative of detected blood flow and the presence of the hemodynamic characteristic.

The invention discloses an in-orbit moving target detecting method with space-based radar and infrared data fusion. The method includes the steps that when an infrared detecting system is used for detection, background suppression is carried out on each frame in an infrared image sequence by adopting a filtering method based on the morphology, self-adaptive threshold segmentation is carried out on images obtained after background suppression, a single frame detection result is extracted, a multi-frame target is determined through a tracking algorithm, and whether the detection result is a real target or not is judged to obtain the detection result of the multi-frame target; during radar detection, pulse doppler (PD) is adopted for processing. After time calibration and space calibration are carried out on the obtained infrared and radar target information, data fusion is carried out on the information by adopting a measurement fusion method, and track prediction is carried out on fused data to obtain the estimated position of the target.

A pulse Doppler ultrasound system and associated methods are described for monitoring blood flow and hemodynamics. The Doppler ultrasound system includes an ultrasound probe to emit ultrasound signals and detect reflected signals therefrom and further includes a processor coupled to the ultrasound probe and operable to process the detected reflected signals and calculate therefrom blood flow data for a plurality of locations at time intervals, the processor further operable to identify locations at which blood flow having a hemodynamic characteristic is present based on the blood flow data calculated for a plurality of the time intervals. A user interface coupled to the processor provides blood flow information based on the blood flow data, the blood flow information representative of detected blood flow and the presence of the hemodynamic characteristic.

A pulse Doppler ultrasound system and associated methods are described for monitoring blood flow. A graphical information display includes simultaneously displayed depth-mode and spectrogram displays. The depth-mode display indicates the various positions along the ultrasound beam axis at which blood flow is detected. These positions are indicated as one or more colored regions, with the color indicating direction of blood flow and varying in intensity as a function of detected Doppler ultrasound signal amplitude or detected blood flow velocity. The depth-mode display also includes a pointer whose position may be selected by a user. The spectrogram displayed corresponds to the location identified by the pointer. Embolus detection and characterization are also provided.

Pulsed or mutual interference in a pulse radar system is ameliorated by a process that includes a pulse-Doppler filter, some frequency bins of which correlate with clutter. Pulsed interference is identified, and the corresponding column vectors of a pulse-Doppler-filter-equivalent matrix are identified. The row values of the corresponding interference-affected column vectors that correlate with clutter are nulled. The vectors are orthogonalized, and then converted to measurement and correction signal vectors for application to the pulse-Doppler received signals. Vector dot products of the measurement signal vectors with the received signals are calculated, to produce pulsed interference measurements that are nominally free of clutter. The pulsed interference measurements are combined with the correction signals which are then subtracted from the received signals to produce signals that are nominally free of pulsed interference. In one embodiment, the pulsed interference-free received signals are applied to a pulse-Doppler filter to suppress the clutter signals.

The invention discloses a distance-speed synchronous pull-off deception jamming recognition algorithm based on gradient projection, and belongs to the field of radar anti-jamming. According to a PD radar, the radar is generally jammed through distance-speed synchronous pull-off jamming, the deception jamming can conduct pull-off jamming on distance information and speed information at the same time, and thus the difficulty for accurately choosing and tracking a target of the PD radar is increased. The method comprises the following steps that (1) signals received by the radar are sampled, and a complete atom library is established according to the time-variant characteristic of a distance-speed synchronous jamming echo; (2) when the AGC voltages and the target number of a receiver are suddenly changed, it is judged that the target is jammed; (3) the Doppler frequency of the target is obtained through a gradient projection method, then the target speed is figured out, and accordingly anti-jamming is performed according to the target speed. The distance-speed synchronous pull-off deception jamming recognition algorithm based on gradient projection is high in jamming recognition capability, easy in engineering realization, high in engineering application value and large in popularization prospect.

A method for measuring and displaying flow and flow volume in the vessel of a subject. The method includes acquiring ultrasound data from a subject and producing a color Doppler m-mode image depicting the vessel. A 3D representation of the color Doppler m-mode image is then generated to enable an operator to identify the blood vessel and window the ultrasound data accordingly to a selected range of heart beats. Blood vessel walls are automatically identified from the windowed ultrasound data and blood flow through the vessel lumen is measured using pulsed Doppler ultrasound, which is gated to substantially exclude data from outside the lumen. Volume flow through the vessel is determined by multiplying the measured blood flow with a calculated cross-sectional area of the vessel and an image indicative of the volume is then generated and displayed.

An ultrasound method and medical devices using same provide for various techniques of sampling blood flow velocity, e.g., at several sampling rates. To minimize the energy required for ultrasound monitoring, pulsed Doppler signal packages provided by a pulsed ultrasound circuit are switched in such a way that the repetition rate is the lowest possible and yet sufficiently high to be able to record the blood flow velocity within the heart. For example, an ultrasound circuit may be activated only within a part of the cardiac cycle designated as the Doppler Measurement Interval (DMI); the ultrasound circuit may be switched between an on state and an off state during the DMI; and / or the ultrasound circuit may also be switched on and off in different sampling modes: detection mode and measurement mode (e.g., using different sampling rates).

The invention provides an ultrasonic imaging device, comprising a central processing unit, a storage cell, an ultrasonic probe, a display module and an operating module, wherein the operating module comprises an artery and vein distinguishing button, a B / pulse wave Doppler (B / PWD) dual-mode scanning program, a pulse wave Doppler (PWD) frequency spectrum wave analysis program and / or B / colour flow mapping / pulse wave Doppler (B / CFM / PWD) three-mode scanning program are stored in the storage cell. When the artery and vein distinguishing button is pressed down, the central processing unit receives an artery and vein distinguishing instruction, the display module is controlled to display a tracking range, the tracking range is moved to select a blood vessel to be captured, the central processing unit calls a corresponding frequency spectrum wave analysis program from the storage cell to analyze the captured blood vessel according to the received artery and vein distinguishing instruction and a captured blood vessel echo signal, whether the capture blood vessel is an artery or vein is judged, an identification is marked on the capture blood vessel according to the judging result, and the identification is displayed by virtue of the display module.

An ultrasound method and medical devices using same provide for various techniques of sampling blood flow velocity, e.g., at several sampling rates. To minimize the energy required for ultrasound monitoring, pulsed Doppler signal packages provided by a pulsed ultrasound circuit are switched in such a way that the repetition rate is the lowest possible and yet sufficiently high to be able to record the blood flow velocity within the heart. For example, an ultrasound circuit may be activated only within a part of the cardiac cycle designated as the Doppler Measurement Interval (DMI); the ultrasound circuit may be switched between an on state and an off state during the DMI; and / or the ultrasound circuit may also be switched on and off in different sampling modes: detection mode and measurement mode (e.g., using different sampling rates).

Methods and systems are described that provide for measuring flow properties of multiphase mixtures within a pipe carrying gas-liquid hydrocarbons and water produced from oil-gas wells. The methods and systems may provide for a combination of a clamp-on ultrasonic gas flow meter to measure flow characteristics of a gas phase in a pipeline and a pulsed ultrasonic Doppler sensor(s) and / or an RF / microwave electromagnetic sensor(s) to measure flow characteristics of a liquid phase. The combination of sensors may provide for multiphase flow measurements under certain flow conditions, such as when the gas-liquid is flowing in a substantially horizontal pipeline, when the flow is stratified or is caused to be stratified and / or the like.

A digital missile warning system comprising a distributed pulse doppler radar having a plurality of antennas, each being coupled to a transmit / receive (T / R) module located adjacent to the antenna, and parallel signal processing channels including an A / D converter, FFT processor and a range / velocity track file processor in each channel for each antenna resulting in enhanced detection range, reduced False Alarm Rate (FAR), faster response time, reduced size, weight and installation requirements, improved reliability and reduced acquisition and life cycle costs. An optional optical missile warning system can provide azimuth and elevation data to the track file processors which enables a three (3) dimensional track of a missile, with azimuth and elevation angles provided by the optical system and range, velocity and acceleration data provided by the pulse doppler radar. The combination of Pulse Doppler Radar MWS and the Optical MWS produces close to a zero False Alarm Rate (FAR). Further, means to extract a threat IR missiles' roll rate and its seeker spin rate and phase angle are provided.

A flowmeter includes: a propagation time difference method unit having a sensor and a reception signal amplification control unit and a flow rate calculation unit which are connected to the sensor via a sensor selector switch; a pulse Doppler method unit having a reception signal amplification control unit and an integration calculation unit which are connected to the sensor; a transmission / reception timing control unit common to them; a measurement method selection control unit for controlling switching between the propagation time difference method unit and the pulse Doppler method unit and parallel operation; and a measurement value output selector switch for selecting the output of the propagation time difference method unit and the pulse Doppler method unit. That is, the single flowmeter can perform flow rate measurement by the propagation time difference method having no restriction on the measurement range as well as the pulse Doppler method having an upper limit of the measurement range but enabling a highly accurate measurement.

The invention discloses a radar signal simulation system for generating signals through data files and belongs to the field of communication. The system comprises a computer unit, a USB (Universal Serial Bus) to high-speed serial port circuit, an FPGA (Field Programmable Gate Array) unit, a DA (Digital-Analog) circuit and a microwave circuit, wherein the computer unit is used for transmitting a PDW (Parallel Data Warehouse) pulse description word file to the FPGA unit; the PFGA unit is used for analyzing PDW pulse description words in real time to control the DA circuit and a microwave controlchain to generate simulation radar signals. By adopting the system, radar signal simulation functions are achieved, various system radar signals and anti-interference radar signals, including commonpulse, common continuous waves, repeated frequency jittering, repeated frequency diversity, pulse Doppler, pulse groups, frequency agility, frequency diversity, linear frequency modulation, waveform modulation, phase encoding and the like, can be simulated through man-machine interaction by using a radar signal simulator, and the system can be applied to radar equipment testing.

The invention discloses a pulsed Doppler radar ambiguity-resolving ranging method based on jitter repetitive frequency. The implementation steps of the pulsed Doppler radar ambiguity-resolving rangingmethod based on the jitter repetitive frequency are as follows: (1) obtaining a radar echo signal under the jitter repetitive frequency; (2) performing pulse compression on two pulse group echo signals; (3) performing Doppler filtering on the pulse compression results of the two pulse groups; (4) performing periodic extension on the Doppler filtering results of the two pulse groups in the distance dimension according to the maximum range ambiguity number; (5) performing coherent accumulation on the periodic extension results; (6) performing threshold detection, and performing target discrimination to determine a distance unit corresponding to the true distance of the target; and (7) calculating the true distance of the target and completing the ambiguity-resolving ranging. The pulsed Doppler radar ambiguity-resolving ranging method based on the jitter repetitive frequency can accumulate all the pulses of the two jitter repetitive frequency pulse groups, can improve the detection probability while resolving ambiguity, and can also perform the ambiguity-resolving ranging for the target with small signal-to-noise ratio.

A method and system for SNR enhancement in pulse-Doppler coherent target detection. In accordance with the method of the invention, complex signals are obtained for each of two or more sub-intervals of the time-on-target interval, allowing simultaneous rang and Doppler measurements. A coherent integration is then performed on the signals to generate complex-valued folded matrices. The folded matrices are unfolded and target detection is then performed in a process involving one or more of the unfolded matrices. A pulse-Doppler coherent system is also provided configured for target detection by the method of the invention.

An acoustically-active catheter (AAC) for use with an ultrasound imaging system and a method for tracking the AAC with respect to anatomic target chosen within a body using the interference ultrasonography. A tip of the AAC is equipped with a crystal transmitting an acoustic wave with parameters similar to those of an acoustic wave generated by a transducer of the imaging system so as to produce acoustic interference the strength of which depends on a position of the AAC tip with respect to at least one Doppler scan plane, formed by the imaging transducer, and a distance from a pulsed-wave Doppler sample that is overlapped with the anatomic target. The ultrasound imaging system detects the interference signal and produces a visual and / or audible interference output that indicates the strength of the acoustic interference. Based on the intensity of the interference output, the user can navigate the AAC tip towards the anatomic target. An anatomic target can be chosen within a cardiovascular system.

The invention relates to an electromagnetic pulse radar echo simulation method in an offshore area. A sea spectrum of an offshore area is established; an ocean surface grid region under a pulse Doppler system is determined and calculated; a scattering field vector of a rough surface element in the ocean surface grid region is calculated by using an electromagnetic algorithm; weighted calculation and simulation of influences on scattering conditions of all parts of the rough surface by a transceiver antenna gain are carried out; and with consideration of the antenna gain, a radar beam back-scattering echo radar equation is established, superposition calculation of scattering field vectors of rough surface elements in the ocean surface grid region is carried out, and thus a radar Doppler echo simulation signal is obtained. Therefore, the need for the electromagnetic property of the coastal environment by the offshore radar system design can be met; lots of manpower and materials are saved by compared with the practical marine measurement; and the reference can be provided for radar detection and anti-jamming algorithm design, parameter selection and performance evaluation. Therefore, the method not only can be used for different sea situation prototype dynamic meeting virtual experiment in an offshore area but also can be used for developing electromagnetic pulse echo scattering mechanism study of the offshore surface.

A method and diagnostic apparatus for determining the condition of a patient's artery or arteries by the use of an ultrasound imaging system which operates in the triplex mode, with a B-mode image of a selected artery location, an A-mode perpendicular to the plane of the artery, at the selected location and a pulsed doppler, at the selected location at an angle to the plane of the artery, with the signals combined, the artery physically or chemical stimulated, the percent dilation of the artery is determined after stimulation, and therefore the condition of the artery is obtained.

The invention provides a method of monitoring blood flow in a vertebrate animal subject. Unfocussed plane-wave ultrasound pulses are transmitted into the subject, along a transmission axis, from a single-element ultrasound transducer (2) fastened to the subject (5). Reflections of the ultrasound pulses are received, generating a succession of pulse-Doppler response signals over time. Each pulse-Doppler response signal is processed to determine a first respective spatial-maximum velocity value for blood flowing towards the single transducer element (2), and a second respective spatial-maximum velocity value for blood flowing away. Heartbeats are identified from said spatial-maximum velocity values and a quality metric is assigned to each identified heartbeat. A subset of the spatial-maximum velocity values is identified for which the assigned quality metric exceeds a threshold level. The values from the subset are monitored, and, when a set of values from the subset satisfies a predetermined alert criterion an audible or visual alert is signalled.

A method and system for SNR enhancement in pulse-Doppler coherent target detection for applications in the fields of radar and ultrasound. In accordance with the method of the invention, complex signals are obtained for each of two or more sub-intervals of the time-on-target interval, allowing simultaneous range and Doppler measurements. A coherent integration is the performed on the signals to generate complex-valued folded matrices. The folded matrices are unfolded and target detection is then performed in a process involving one or more of the unfolded matrices. A pulse-Doppler coherent system is also provided configured for target detection by the method of the invention.

The invention discloses a radar signal detection method based on a convolutional neural network. According to the method, a distance-Doppler frequency spectrum obtained after pulse Doppler processingis used as an image sample, different characteristics of a time-frequency spectrum with or without a target are taken as identification characteristics, radar signal detection is realized by utilizingthe classification capability of a convolutional neural network, existence of a target signal is judged, the convolutional neural network is applied to radar signal processing, and signal detection is realized from the perspective of image processing. Compared with a traditional CFAR detector, the method of the inventiom has the advantages that the detection probability is improved, the influencecaused by the correlation of background clutters when the CFAR detector is used is avoided, and the limitation that the fixed CFAR detector is suitable for a specific environment is improved.

The invention discloses an improved two-dimension constant false alarm method. According to the method, FFT (fast Fourier transform) calculation is carried out N pulse Doppler signals in each distance unit, the maximum value is found out, in addition, the maximum value is stored into a buffer memory unit according to the address of the corresponding distance unit, then, M maximum values Xi stored in the buffer memory are subjected to one-dimension constant false alarm processing, and the target detection is completed. According to the method, only the maximum values of each distance unit after the FFT operation are stored, so the requirement can be met only through the small buffer unit, a half of memory requirement and operation complexity can be reduced, and in addition, the effect similar to the existing two-dimension constant false alarm method is reached.

The invention discloses a pulse repetition frequency adjustment method and a high pulse Doppler imaging device. The pulse repetition frequency adjustment method includes the steps: A, calculating a sampling gate number N needed for performing HPRF (high pulse repetition frequency) emission by an alternative PRF (pulse repetition frequency) parameter at a depth of a current sampling gate; B, when the sampling gate number N is larger than 1 and smaller than a preset value, calculating a location of a dead zone according to the sampling gate number N; and C, judging whether sampling gates are located in the dead zone or not, if yes, increasing the alternative PRF parameter in a PRF list into a next level and shifting into the step A, and otherwise, using the alternative PRF for performing HPRF emission. Complexity and robustness of algorithms are considered comprehensively, an implementation method is simple, and a spectrogram effect is good.

The invention discloses an ultrasonic pulse Doppler imaging method and device. The method comprises the steps that an energy matrix is established for echo signals of a received transmitting sequence; a speed sequence for scanning a target is established according to pulse repetition frequency and the central frequency of a probe; energy values corresponding to all speed elements in the speed sequence are obtained according to the energy matrix; an energy spectrum of the speed sequence is generated according to the energy values; an ultrasonic image is generated according to the energy spectrum. The order of a coding compression filter can be effectively reduced, and Doppler imaging can be achieved without a large calculation amount.

The reliability of a reception wave from a transducer is checked and when the reliability is determined to be insufficient, a method different from the current method is selected. The reliability is judged by calculating a value serving as an index of the reliability of the reception wave and checking whether the value is smaller than a predetermined set value. When the value is smaller than the set value, the reliability is judged to be insufficient. The values serving as an index of the reliability of the reception wave may be the amplitude of the reception wave, the ratio of the amplitude of the reception wave against a predetermined measurable amplitude value, the ratio of the power spectrum against a predetermined power value, the ratio of the transmission wave amplitude against the maximum amplitude of the reception wave, the ratio of the power spectrum of the transmission frequency included in the reception wave and obtained by Fourier transform of the reception wave against a predetermined power value, and the like.

A method for the coherent integration of Fill Pulses in Pulse Doppler Radar sensors is disclosed. The present invention uses a pre- and a post-coherent waveform transmission and reception period to collect transient signals from reflections of Fill Pulses throughout the range extent. It then reassembles these signals to produce additional coherently integrable pulses of interval returns that are input to the filter and coherently integrated along with normally coherently integrated pulses. The result is an improved Signal To Noise Ratio (SNR) and Signal To Clutter Ratio (SCR) which is related to the total number of pulses emitted, including the Fill Pulses. This improvement can be obtained almost solely by signal processing in a digitally controlled Radar, and requires few if any hardware modifications.

The reliability of a reception wave from a transducer is checked and when the reliability is determined to be insufficient, a method different from the current method is selected. The reliability is judged by calculating a value serving as an index of the reliability of the reception wave and checking whether the value is smaller than a predetermined set value. When the value is smaller than the set value, the reliability is judged to be insufficient. The values serving as an index of the reliability of the reception wave may be the amplitude of the reception wave, the ratio of the amplitude of the reception wave against a predetermined measurable amplitude value, the ratio of the power spectrum against a predetermined power value, the ratio of transmission wave amplitude against the maximum amplitude of the reception wave, the ratio of the power spectrum of the transmission frequency included in the reception wave and obtained by Fourier transform of the reception wave against a predetermined power value, and the like.