99 results about "Impedance imaging" patented technology

A system and a method of magnetosonic impedance imaging based on a lorentz force mechanic effect comprise an ultrasonic driving excitation source, an ultrasonic probe array, a control system, a magnet system, a direct current power supply and a signal detecting processing system. The ultrasonic probe array is in an emitting or measuring mode through the control system. The direct current power supply is in a connected or disconnected state through the control system so as to achieve two modes of exerting a magnetic field or withdrawing a magnetic field. Mass point vibration speed ratio under a magnetic field condition or a non-magnetic field condition is measured, and a conductivity image is rebuilt according to a square root of the vibration speed ratio. The imaging method does not require electric field measurement, only sound wave signals are required to be measured, a corresponding relation between measured signals and conductivity is simple and clear, and fast image rebuilding is facilitated.

The resolution and contrast of impedance measurements and scans are improved by using a non-contact impedance probe comprising an inner conductor configured to bear a measurement signal and an outer conductor configured to bear a shielding signal. The measurement signal and shielding signal are selected to increase the directionality of the flux emitted from the impedance probe. In one embodiment, the measurement signal and the shielding signal are phase locked signals. A sample may be placed in a basin having a conductive surface that receives the flux emitted from the impedance probe. By filling the basin with a conductive solution, direct contact between the probe and the sample may be avoided along with the associated variability in contact resistance. The small highly-directional flux emitting area achievable with the present invention enables high resolution high contrast non-contact scanning of biological and non-biological materials.

Multi-element impedance probe apparatus (40), adapted to produce an image of a body tissue, having a structure, comprising: a raster of sensors (43), comprised of a substantially radiolucent, conductive material; substantially radiolucent conductive wiring (44), forming conductive connections with the sensors; and a substantially radiolucent substrate (46), on which the sensors are mounted.

The present invention relates to an increment amplifying type signal detecting device used in resistance imaging. The invention comprises an electrode array (1), a switch array (2), a signal generating circuit (3), an analog and digital transferring circuit (4), a voltage and current converting circuit (5), a voltage scale adjusting circuit (6), a voltage filtering and amplifying circuit (7), a difference computing circuit (8) and a central control processing circuit(9). Additionally, the invention has a probe case containing combined electrode and detecting circuit, which greatly shortens distance between the detecting circuit and the electrode, reduces unfavorable effects to signal detecting caused by capacitance on lead, distributed inductance and various electromagnetic interference. By amplifying increment during measurement, one can acquire high measuring accuracy with analog and digital converter of lower resolution.

A method for non-invasive mapping (imaging) of the electrical impedance of an object. The present invention provides a method, current density impedance imaging (CDII) which produces an impedance image of object by measuring current density distributions and directly calculating the local impedance values. The method includes making measurements of at least two current density vector fields, J1 and J2, within a region of interest in an object and then calculating the logarithmic gradient of local conductivity, ∇ ln σ(x,y,z), using a formula∇ln⁢⁢σ=⁢(∇×J2)·(J1×J2)J1×J22⁢J1+⁢(∇×J1)·(J2×J1)J1×J22⁢J2+⁢(∇×J1)·J2J1×J22⁢J1×J2(1)where {right arrow over (J)}1(x,y,z) and {right arrow over (J)}2(x,y,z), are the pair of measured nonparallel current densities at point (x,y,z) and ∇ denotes the gradient operator.

This invention relates to a method and apparatus for concrete damage detection based on impedance imaging, which comprises the following steps: (1) setting multiple electrodes on target; (2) connecting the excitation input ports of former electrodes to the multi-way input switch; (3) forcing the drive sine current to every two electrodes by turns, measuring the current amplitudes and phases; (4) computing resistance distribution in the concrete; (5) acquiring and storing computation data to compare with given data for analysis.

The invention discloses an electrode contact state detecting method for electrical impedance detection based on measurement precision, and belongs to the technology and application field of bioelectrical impedance imaging. The method comprises the steps that original transmission impedance data collected by an imaging system within a period of time is utilized for acquiring the relative measurement precision of all measurement channels through statistic analysis; the related average measurement precision of all measuring and exciting electrode pairs is acquired through further operational analysis, and the contact state of an electrode and skin is detected according to the range of the average measurement precision. The method can be used for detecting the electrode contact quality fast and accurately in real time, therefore, it is possible for operators to fast eliminate electrode connecting anomaly in time, and reference bases are provided for evaluation of continuous electrical impedance data collecting quality.

In a method of electrical impedance tomography (EIT), a mediating fluid provides electrical contact between the electrodes of an EIT device and the skin of a body part to be examined. The height of the fluid is raised or lowered between impedance measurements, enabling tomographic images of the tissue under examination to be resolved mathematically for subsequent viewing. Tomographic planes are isolated by calculating differences between Cartesian models generated from impedance values measured at the plane of interest and at an adjacent plane.

A method for producing a computationally efficient system that reduces the number of iterations required to generate a conductivity image pattern of a subsurface object, and its attendant conductivity distribution, through a solution to the system of field equations that simultaneously satisfies all of the boundary conditions and conserves internal current flux densities.

The invention discloses a biological impedance imaging device. The biological impedance imaging device comprises a single-chip microcomputer (1), an upper computer (2), a DDS signal source (3), an A / D conversion circuit (4), a low-pass filtering circuit (5), a voltage-current conversion circuit (6), a signal amplifying circuit (7), a phase-sensitive demodulation circuit (8), multi-way switches (9), a plurality of electrode sets (10) and a physical model (11). The biological impedance imaging device has the advantages that a generated current source has high output resistance, and therefore the independence between output current and load voltage can be guaranteed; each set of switches needs eight-digit IO ports for controlling, the control end of an analog switch is connected with a latch circuit, in this way, two sets of switches can be controlled through an 8+2 digital address line, the number of the IO ports for controlling the single-chip microcomputer is reduced, and then the circuit is simpler and optimized; besides, real part information and imaginary part information of impedance can be obtained through the phase-sensitive demodulation circuit, so that the impedance information obtained through the biological impedance imaging device is more accurate compared with a method for taking the real part information of the impedance only.

The invention provides a hybrid variation bioelectrical impedance imaging method, relating to the measurement on the conductivity of the pleural cavity of the body. According to the method, the potential spatial distribution condition is simulated by adopting a finite element method, a numerical model of the bioelectrical impedance imaging technology is established, a numerical model with large size is dispersed into small units, certain boundary conditions are applied and boundary voltage is calculated, a two-dimensional thoracic cavity numerical model and a three-dimensional thoracic cavity numerical model are respectively established, after the objective function of the hybrid variation algorithm is determined, the inverse problem solving is carried out by adopting the steepest descent method, the electrical impedance image reconstruction of the thoracic cavity is carried out, so that the resolution ratio of the reconstructed image is improved, therefore, the problems in the existing bioelectrical impedance imaging technology, the influences of noises and errors exist during the process of reestablishing the image with high resolution ratio, consequently, the excessive smooth and staircase effect are caused, and the accurate electrical impedance reconstructed image of the lung can not be obtained are solved.

The invention discloses an abnormal electrode connection detecting method for impedance detection. The abnormal electrode connection detecting method includes utilizing acquired original data of an impedance imaging system to calculate relevancy of acquired data of various electrode channels, acquiring electrode variable coefficient according to the relevancy, and judging whether electrode connection is abnormal or poor in contact when variable coefficient of a certain electrode is larger than the set threshold value. The abnormal electrode connection detecting method is an automatic, quick and accurate electrode connection state detection method, and can provide reliable basis for clinical staff to adjust electrode connection in time and guarantee continuity and completeness of impedance image monitoring.

This invention relates to an impedance image forming method, which uses exciting coil to generate alternating field and generate inductance current in the target according to the magnetoelectric induction principles and influence the exciting alternating field distribution and adopts the magnetic resonance image forming technique to measure the field distribution in target. The image forming device comprises the exciting coil, magnetic resonance magnetism, radio frequency coil and step coil, magnetic resonance signal receiving coil, magnetic resonance image forming system and exciting current power and computer, wherein the exciting coil is a pair of Helmholtz coil fixed on the upper and down electrode plates of the open magnetic resonance image forming system radio frequency coil.

The invention relates to a data acquiring device for bioelectrical impedance imaging. The data acquiring device comprises a control unit, wherein the control unit is in parallel connection with a signal generator; the signal generator is connected with a voltage-controlled current source circuit; the voltage-controlled current source circuit is connected with a multi-way switch; the multi-way switch is connected with an electrode array and a signal conditioning module; voltage is transmitted into a DSP module through the signal conditioning module; the DSP module comprises an analog to digital converter and a digital demodulator; the DSP module is connected with a host computer; the control unit is used for transmitting data to the DSP module; an excitation current is injected to the electrode array by the voltage-controlled current source through the multi-way switch; the multi-way switch is used for acquiring the voltage on the electrode array; the voltage is transmitted to the DSP module through the signal conditioning module; the DSP module is used for performing modulus transformation on a voltage signal and then performing digital demodulation; and the data is transmitted to the host machine for image reconstruction. According to the data acquiring device disclosed by the invention, the data processing speed is accelerated, the speed and the precision of bioelectrical impedance data acquisition can be effectively increased, and the image reconstruction quality is guaranteed.

The invention provides an exciting current source for bioelectrical impedance imaging. The exciting current source for bioelectrical impedance imaging comprises a DDS module, an amplitude control module, a D / A conversion module, a differential amplification module, a lowpass filtering module, a voltage control current source module and a universal impedance conversion module, wherein the universal impedance conversion module comprises an analog multiplexer (16) and multi-channel universal impedance converters, the on-off state is controlled through an FPGA, and gating is performed on the universal impedance converter matched with exciting frequency; the multi-channel universal impedance converters can be applicable to four frequency ranges of 0-100k Hz, 100-500k Hz, 500-800k Hz and 800k Hz-1M Hz, and there are different equivalent inductance values in each frequency range. By means of the exciting current source for bioelectrical impedance imaging, imaging precision of an electrical impedance imaging system can be improved.

The invention provides a three-dimensional hemoperfusion image generation method and device based on electric impedance imaging. The method (100) comprises the following steps: performing electric impedance testing on human body areas to be tested by using electrode arrays distributed in a three-dimensional space so as to obtain electric impedance testing signals (110); and on the basis of hemoperfusion signals in the electric impedance testing signals, reconstructing a three-dimensional hemoperfusion image (120) by using an image reconstruction algorithm. Therefore, three-dimensional images of electric impedance variation caused by hemoperfusion can be generated, compared with two-dimensional images of the prior art, the three-dimensional images are capable of visibly reflecting hemoperfusion situations of one volume area in a three-dimensional space of a human body area, and image analysis and comparison and disease detection and diagnosis can be facilitated.

The invention relates to a high-precision multi-frequency distributed medical impedance imaging measuring system and method.The system comprises a main control panel and at least three front end measurement collection panels.The main control panel is connected with an upper computer and the front end measurement collection panels.The front end measurement collection panels are connected with an electrode.The main control panel comprises a first communication module, a drive signal generation module, a second communication module, a first handshaking signal module, a synchronizing signal generation module and a main control chip.The main control chip is provided with the drive signal generation module, controls the synchronizing signal generation module to generate a clock synchronizing signal, and conducts communication with the front end measurement collection panels through the second communication module and the first handshaking signal module.Each front end measurement collection panel comprises an excitation switch selection module, a data collection module, a third communication module, a second handshaking signal module, a measurement controller and an interface module.Compared with the prior art, the high-precision multi-frequency distributed medical impedance imaging measuring system and method have the advantages that quick and accurate collection and safe isolation of impedance information under multiple frequencies are realized.

The invention relates to an electrical impedance tomography device of electrodes 32. Channel 32 multi-way switches are adopted for constructing an electrical impedance tomography system of an electrode 32 physical model, in this way, the complexity of obtaining channels 32 through connecting channel 16 multi-way switches in parallel is lowered, control is easier compared with simulation matrix switches, performance is better, and the collection precision of the system is improved. For a control module, a processor ARM9 is adopted according to the design, serves as an embedded microprocessor of the electrical impedance tomography system, has high control capacity and data processing capacity, and improves the collection speed and real-time performance of the system, and many interfaces facilitate expanding of more functions of the system. In addition, for a high-precision instrument amplifier, a variable gain amplifying circuit is further introduced, the high-precision instrument amplifier and the variable gain amplifying circuit form a two-stage amplifying circuit, in this way, changes of gains can be controlled in a programmed mode, the amplification factor of collected voltage signals is increased, the flexibility of the collected voltage signals is improved, and follow-up processing of the signals is facilitated.

The invention discloses an electric impedance imaging system with an open electrode scanning mode. Exciting electrodes introduce an excitation signal emitted from an excitation source into an imaging body; a first measurement electrode and a second measurement electrode carry out one-dimensional or two-dimensional scanning along the surface of the imaging body between the exciting electrodes; a measurement device collects measurement information of the imaging body through the first measurement electrode and the second measurement electrode, and transmits the measurement information to a microprocessor, and the microprocessor processes the measurement information and rebuilds an electric impedance distribution image of the imaging body. According to the electric impedance imaging system disclosed by the invention, limitation of the surface area of the imaging body to the mounting quantity of the first measurement electrode and the second measurement electrode is overcome, the density of arranged measurement electrodes is greatly improved by arrangement of the first measurement electrode and the second measurement electrode; useful information is increased; the ill-condition of rebuilding the electric impedance is improved; the imaging resolution ratio of the electric impedance (or impedance spectroscopy) is improved and the rebuilding quality of the image is also improved.

The invention discloses a distributed vessel and acupoint multi-parameter tester and testing method. The tester is composed of a combined sensor A, a combined sensor B, sensor connection lines, a measuring and data processing system and a comprehensive data analyzing system. Twenty-five electrodes are distributed according to shape rules of a circle center, an inner ring and an outer ring. By means of a gate circuit, parameters and parameter distribution of impedance spectroscopy, impedance imaging and oxygen partial pressure of gates of the electrodes are measured. Temperature and temperature distribution are measured through an infrared measuring mode. The measured parameters are measured and collected through the measuring and data processing system, the comprehensive data analyzing system carries out data analysis, and the testing process is controlled through a computer. By means of the tester, four kinds of parameters and parameter distribution of a vessel and acupoint area can be detected, and is a research device used for physicochemical property research of acupoints through parameter comparison. Modern technologies are used for analyzing and sorting a large quantity of data and researching mutual relations of the parameters and parameter distribution and distribution rules, and a basic instrument is provided for theoretical research of traditional Chinese medicine vessels and acupoints.

The invention discloses a device and measuring method for measuring multi-channel electrode / scalp contact impedance in real time, and belongs to the technical and application field of bioelectrical impedance imaging. The device includes a host computer, a main control unit, an excitation current signal generating unit, a boundary voltage signal measuring unit, an excitation channel, a measuring channel and a contact impedance measuring module. On the basis of an original imaging electrode, the device introduces a distal reference electrode. During the contact impedance measurement, a plurality of imaging electrodes are switched to contact impedance measurement circuits in order through an electrode channel control unit, and real-time synchronous measurement of boundary voltage data and contact impedance data can be realized through the electrode channel control unit. According to the method, accuracy measurement can be carried out to obtain information of the contact impedance in thefollowing two dimensions: 1, spatial consistency of the multi-channel contact impedance; and 2, time stability of single-channel contact impedance. Compared with a conventional measuring method, the measuring method of the invention is simple in operation and can carry out measurement in real time.

A microcosmic electrical impedance imaging device based on a diamond NV color center comprises a magnetic field imaging module adopting a diamond ensemble NV as a weak magnetic field detector; a microwave radiation structure module which adopts an omega-shaped radiation structure as a microwave antenna to radiate a microwave magnetic field to the diamond NV color center; a microelectrode module which is used for injecting alternating current into the buffer solution by adopting a cross-shaped iridium-iridium oxide metal electrode with two pairs of electrode arms. According to the invention, the spatial resolution of the existing magnetic resonance electrical impedance imaging is expanded, and the spatial resolution of the electrical impedance imaging is improved to a micron scale to a submicron scale, so an electrical impedance imaging method on a microcosmic scale is realized, and the method is suitable for conductivity imaging of a cell biological sample.

The invention provides an injection current type thermoacoustic imaging method. The injection current type thermoacoustic imaging method is characterized by: through an electrode, injecting a current into an imaging target, generating Joule heat in the imaging target body, causing thermal expansion, generating an ultrasonic signal, utilizing an ultrasonic probe to detect the ultrasonic signal, and reconstructing conductivity distribution of a sound source and a target body according to the detected ultrasonic signal. The injection current type thermoacoustic imaging method can be used for electric impedance imaging with high-resolution, and is used for early diagnosis of diseases.

The invention provides an electrical impedance imaging method and a device based on a supervised descent method. The electrical impedance imaging method (100) based on the supervised descent method comprises the following steps: obtaining a descent direction (110) for inverting new electrical impedance imaging measurement data through iteration based on electrical impedance distribution and electrical impedance imaging measurement data of a group of training samples; setting an initial model (120) of the electrical impedance distribution; and based on the initial model, the descending direction, an electrical impedance imaging forward model and actually measured electrical impedance imaging data, performing image reconstruction (130) of electrical impedance imaging through iteration. Compared with a traditional iterative method based on optimization, the image reconstruction method can flexibly introduce prior information in the inversion process. In addition, the image reconstructionmethod provided by the invention has good anti-noise performance and high image reconstruction speed.

Provided is an electrode fixing and locating device for breast impedance imaging. The electrode fixing and locating device comprises main rods 2, pull rods 4, a lifting plate 6, a bottom plate 7, and a linear guide rail module 8. The lifting plate 6 is provided with a main rod radial motion groove 9, the main rods 2 penetrate through the main rod radial motion groove 9, one end of each main rod 2 is hinged to the bottom plate 7 in a rotating mode, and the other ends of the main rods 2 are connected with electrodes 1. One end of each pull rod 4 is hinged to the main rods 2 and the other ends of the pull rods 4 are hinged to the lifting plate 6 in a rotating mode. The linear guide rail module 8 is connected with the lifting plate 6 and the bottom plate 7, and the lifting plate 6 is parallel with the bottom plate 7. A detected target is placed in the space formed by enclosure of the electrodes 1. The external force enables the lifting plate 6 and / or the bottom plate 7 to slide in the vertical direction under the guide of the linear guide rail module 8. The pull rods 4 are matched with the main rods 2 through rotation and push the main rods 2 to drive the electrodes 1 to be closed, and therefore the electrodes 1 make contact with the detected target according to an established mode, uniformity of contact between each detection electrode and the breast tissue can be guaranteed, model errors of remodeling imaging can be reduced, and the detection effect can be improved.

The invention discloses a temperature measurement method of a ceramic-based composite material high-temperature component based on electric impedance imaging. The measurement method comprises the following steps: manufacturing an electrode; constructing a multi-channel testing measurement hardware system; designing electric impedance real-time imaging software; determining a function relation of the resistivity changed along with the temperature; and acquiring a temperature distribution condition through a resistivity distribution computation result. Through the method disclosed by the invention, the temperature distribution of the high-temperature component can be synchronously, accurately and indirectly measured by combining the real-time computation result on the resistivity distribution of the ceramic-based composite material high-temperature component by the electric impedance imaging technology with the relation of the resistivity changed along with the temperature change.

The invention discloses a dynamic resistance electrical impedance tomography method based on electrode sampling verification. The method comprises the steps of sequencing EIT measurement electrodes into a group of all electrodes, a group of odd-number electrodes and a group of even-number electrodes; separately acquiring boundary measuring potential of the three groups of electrodes, and separately calculating boundary potential change of the three groups of electrodes; separately calculating reestablishment results under the three groups of electrode measurement data according to the boundarypotential change of the three groups of electrode, and drawing EIT reestablishment images which separately correspond to the reestablishment results; separately calculating the coefficient of association between the reestablishment results according to the reestablishment results under the measurement data of the three groups of electrodes; and judging the credibility of the reestablishment results and the credibility of the EIT reestablishment images which separately correspond to the three reestablishment results according to the coefficient of association. According to the method, an extraeffective imaging judgment standard is provided for EIT in a measurement environment with noises and interference, and the imaging credibility is improved.

The invention discloses a multi-frequency impedance imaging system. The system mainly performs imaging according to different impedances displayed by biological tissue under various frequencies. The system comprises a data collecting card, a voltage to current circuit, a multi-way switch circuit, a to-be-tested object, a signal amplification circuit and a computer. The system is of a virtual instrument structure and is formed by combining a LabVIEW platform with the data collecting card and pheripheral hardware, the data collecting card with the high precision is used, the system testing precision and stability are improved, the advantages of flexibility and convenience of the virtual instrument technology building system are brought into full play, and the system is convenient to expand. Drive signals adopt mixing signals stacked by multiple frequency sinusoidal signals, the multi-frequency signals are injection into a physical model at a time, measured voltage signals are processed to obtain voltage information under each frequency, and therefore the system imaging speed is increased.

The resolution and contrast of impedance measurements and scans are improved by using a non-contact impedance probe comprising an inner conductor configured to bear a measurement signal and an outer conductor configured to bear a shielding signal. The measurement signal and shielding signal are selected to increase the directionality of the flux emitted from the impedance probe. In one embodiment, the measurement signal and the shielding signal are phase locked signals. A sample may be placed in a basin having a conductive surface that receives the flux emitted from the impedance probe. By filling the basin with a conductive solution, direct contact between the probe and the sample may be avoided along with the associated variability in contact resistance. The small highly-directional flux emitting area achievable with the present invention enables high resolution high contrast non-contact scanning of biological and non-biological materials.

The invention discloses a three-dimensional dual-mode electrical impedance imaging sensor and a manufacturing method thereof. The sensor includes a hemispherical sensor support, a capacitance sensor and a resistance sensor, the capacitance sensor is arranged on the hemispherical support, and the resistance sensor and the Capacitive sensor snap-in. The sensor provided by the invention is combined with the electrical impedance measurement system to obtain the three-dimensional surface capacitance and resistance information of the hemispherical measurement area, which is used for the reconstruction of the permittivity and conductivity distribution of the three-dimensional hemispheric area. Utilizing the difference in electrical properties between breast tissue and cancer tissue, the sensor provided by the invention can be applied to early screening of female breast cancer, and has the advantages of low cost, easy portability, and no harm to the human body.