194 results about "Electrical 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 invention discloses a device and a method capable of preferably reconstructing three-dimensional electrical impedance distribution in an object and improving electric field space distribution nonuniformity through obtaining object surface voltage information in particular relating to human organ tissues such as heads and breasts. Through the adoption of the scheme, voltage information can be obtained from both a horizontal section and a vertical section and images on the sections are respectively combined to form a space three-dimensional graphic; and voltages between the rest positions can be also obtained through exciting any contact point on the surface and then a plurality of combined measuring methods are achieved to realize multi-algorithm extension and improve image accuracy. The design mainly comprises 65 special electrodes distributed on a hemispherical surface; with a high-performance FPAG (Field Programmable Gate Array) as core, functions such as exciting source control, digital frequency synthesis, multiplex control, high speed phase-sensitive detection, fast Fourier transformation and measuring signal demodulation are integrated in a single chip; and a circuit design capable of self-adaptively adjusting output impedance of a detected object is achieved.

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.

The invention requests to protect a bio-electrical impedance imaging hardware system and relates to medical equipment. The bio-electrical impedance imaging hardware system comprises an upper computer 1, a USB interface chip 2, a D/A converter, a filter and pressure flow switching circuit 3, multiplex switches 4 and 6, a tested object 5, an amplifying, filter and A/D switching circuit 7 and an FPGA controller 8. The core component of the system is the FPGA controller and comprises a constant flow source control module, a multiplex switch selecting control module, an A/D converting sampling control module, a digital phase sensitive detection module, a USB transmission control module and a master control module. The system uses the FPGA technology to realize the functional modules and improves integrated level, expandability and upgradability of the circuit so as to greatly reduce the volume and power consumption of the imaging hardware system, reduce the cost and improve the anti-interference performance.

The invention relates to a PXI-bus-based respiration process three-dimensional electrical impedance imaging system and an imaging method thereof. According to the PXI-bus-based respiration process three-dimensional electrical impedance imaging system and the imaging method thereof, the three-dimensional electrical impedance imaging system which is in three layers and comprises 48 electrodes is constructed by means of highly integrated hardware and software tool kits of the PXI bus; a pair of adjacent exciting electrodes is selected sequentially through a gating switch; safe alternating currents are injected into a thoracic cavity, voltage signals on the other electrodes are collected synchronously; a distribution image of sensitive areas of electrical impedances inside the thoracic cavity during a respiration process is obtained on a computer through filtration, amplification, analog-digital conversion, demodulation and transmission and finally through an image reconstruction algorithm. Compared with the existing electric resistance imaging system, the PXI-bus-based respiration process three-dimensional electrical impedance imaging system has the advantages of being high in measuring accuracy, rapid in speed and high in reliability, having no damage to human bodies, achieving continuous real-time bedside monitoring and continuously monitoring respiration variations of human lungs clinically in real time.

The invention discloses an electrical impedance imaging method and system based on a generative adversarial network. The method comprises the following steps: applying an excitation signal on the boundary of an object field, and measuring an electrical response signal voltage value on the boundary; on the basis of the voltage value, carrying out preliminary imaging to obtain a preliminary imagingpicture; inputting the preliminary imaging picture into a pre-trained generative adversarial network to obtain a final imaging picture. The electrical impedance imaging method provided by the invention has a wide applicable range, and can be combined with any preliminary imaging algorithm. On the basis of preliminary imaging, the generative adversarial network is used for further reconstructing animage, and imaging accuracy is improved. Compared with the prior art, the electrical impedance imaging method is characterized in that imaging can be quickly carried out with high accuracy.

The invention discloses an interface pressure distribution testing sensing element. The interface pressure distribution testing sensing element comprises a sensing film, electrodes uniformly arranged around the sensing film at intervals, a lead connected with the electrodes and an upper and lower insulating paint layer. The sensing film is made from a conductive polymer composite material provided with a piezo-resistive sensitivity characteristic, and the electrodes and the lead are used for outputting resistivity information of the sensing film in different positions. When in testing, the lead is connected with a testing instrument, the electrical impedance imaging technology is used for acquiring, testing and computing so as to obtain the resistivity distribution of the sensing film in different positions, and then the pressure distribution can be obtained through the relationship between the sensing film pressure and the resistivity. The interface pressure distribution testing sensing element can be used for measuring the interface pressure distribution and change, and has the advantages of simple structure, ultra-thin film, strong flexibility, high resolution and precision, large measuring range and low cost.

The invention discloses a lung respiration monitoring system based on magnetic detection electrical impedance imaging. By means of an excitation source module, excitation signals are introduced to the chest cavity of an imaging body through a plurality of pairs of excitation electrodes bonded to the measured imaging body; a measurement module is composed of a series of measurement coils and used for measuring the magnetic induction intensity of an induced magnetic field caused by exciting current around the chest cavity; a control module is used for controlling the signal excitation and magnetic field measurement process during the whole respiration monitoring; an image reconstructing module obtains the image change of electrical inductance distribution of the chest cavity in the respiration process according to an electrical impedance image reconstruction algorithm on the basis of magnetic field distribution data. According to the system, the measurement coils of any number can be placed in the space around the chest cavity of the imaging body, limitation of a traditional electrical impedance imaging system on measurement information is changed, the system has the advantages of being high in measurement precision, high in speed and reliability and free of injuries to a human body, more importantly, information amount is increased by means of a magnetic field measurement mode, and therefore the electrical impedance reconstructing ill conditioning is changed, the resolution ratio of electrical impedance (or impedance spectrum) images is increased, and the image reconstruction quality is improved.

The invention discloses an electrical impedance imaging device. The electrical impedance imaging device is composed of a signal generator, an amplitude frequency adjustment circuit, a voltage control current source circuit, a multiway switch, an electrode plate set, a physical model, a signal amplification circuit, a band-pass filter, a phase-sensitive demodulator circuit, an A/D conversion circuit, a single-chip microcomputer and an upper computer. The electrical impedance imaging device has the advantages that first, the signal generator can generate a high-precision voltage signal without an extra filter; second, a stable and multi-frequency alternating-current source signal with the amplitude value adjustable can be generated by a voltage signal through the amplitude frequency adjustment circuit and the voltage control current source circuit; third, because electrode plates are made of stainless steel materials, the electrode plates are not prone to rusting corrosion and stable and reliable in performance, and because the electrode plates are connected with stainless steel alligator clips, disassembly and replacement are facilitated, and good electrical conductivity is achieved; fourth, in the phase-sensitive demodulator circuit, a sinusoidal signal is adopted for replacing a square signal to serve as a reference signal for on-off demodulation, and therefore the demodulation effect is better compared with square wave demodulation.

The invention discloses an electrical impedance imaging method of an ultrasonic-synergy biological tissue. The electrical impedance imaging method comprises that a plurality of electric excitation leads and detection guide leads are arranged on the surface of the biological tissue, and an ultrasonic excitation source is adopted to generate ultrasonic waves and the ultrasonic waves are focused in the biological tissue through ultrasonic drive; the ultrasonic waves focused in the biological tissue are located in a continuous mode, and integral or partial scanning to the biological tissue is finished; signals are collected, the ultrasonic waves are focused at a certain spatial position, and a high-frequency signal corresponding to electrical impedance of the spatial position is generated, the signals are collected through the multi-channel detection leads, amplified, filtered, and then output; after focusing and scanning of the ultrasonic waves are finished, a voltage signal after being collected is guided in a computer, and a signal is obtained according to the collected integral scanning and partial scanning to the biological tissue, and electrical impedance distribution of the biological tissue is calculated and rebuilt. Through the electrical impedance imaging method of the ultrasonic-synergy biological tissue, a high-precision and high-resolution electrical impedance image can be obtained.

An electrical impedance imaging apparatus and method are provided. The electrical impedance imaging device (100) is generally composed of a sensing module (101), a data acquisition module (102), a communication module (103), a data processing module (104), an imaging display module (105) and a power supply module (106). The electrical impedance imaging device (100) of the invention is applied to medical imaging, an in-vivo electrode can be used for carrying out simultaneous multi-frequency excitation and measurement on a to-be-measured organism tissue; three-dimensional image reconstruction iscarried out by using a measured complex voltage signal, and ventilation and perfusion images can be displayed in real time at the same time, so that the number of acquired data is increased, the dataacquisition speed is increased, the sensitivity of the measurement signal to the conductivity of in-vivo tissues is improved, and image analysis comparison and disease detection and diagnosis are facilitated.

The invention discloses a brain magnetic detection electrical impedance tomography system. The brain magnetic detection electrical impedance tomography system comprises electromagnetic detection caps,excitation acquisition and control modules and image processing and display devices. Each electromagnetic detection cap has inner and outer layers and can be worn by the head of a human body. An excitation signal is put on the above inner-layer cap. A magnetic field sensor is disposed on the above outer-layer cap. The above electrode and the above magnetic field sensor are connected with the excitation acquisition and control modules through wires. The excitation acquisition and control modules have effects of controlling excitation signals and collecting information on magnetic fields. According to needs, parameters are adjusted in order to output and process signals with different intensity and frequencies. By filtering, amplifying and performing analog-to-digital conversion to collection signals, the signals are finally transmitted to the image processing and display devices. The image processing and display devices are integrated with a micro-processor and a display screen and used for reconstructing brain electrical impedance distribution images of imaging bodies according to obtained information on brain electromagnetic fields. The brain magnetic detection electrical impedance tomography system overcomes the influence of contact resistance of contact measurement in conventional electrical impedance tomography. Through a non-contact magnetic-field detection mode, magneticinduction intensity information around a brain under excitation signals can be obtained. Additionally, electrical impedance distribution images inside the brain can be reconstructed according to an image reconstruction algorithm so that doctors can make diagnoses about the physiological and pathological states of the brain.

The invention discloses a composite material strength prediction method based on electrical impedance imaging damage monitoring. The composite material strength prediction method based on electrical impedance imaging damage monitoring comprises the following steps: 1. the electrical impedance imaging damage detection step builds an electrode array for current excitation and voltage measurement tothe outer boundary of the tested structure; the measured data are used to reconstruct the resistivity distribution image and display it graphically, and the mapping relationship between the damage condition and the resistivity distribution is used to detect the structural damage in real time; 2, the damage real-time detection result obtained by the damage detection step of the electrical impedanceimage is combined with the theory of the finite element progressive damage strength analysis to realize the structural strength prediction. Fusion of damage detection information which is close to the unknown real damage status of structural parts can accurately predict the residual strength of structural parts under the condition of damage.

The invention discloses a spectroscopic imaging method for multi-frequency electrical impedance tomography which can be used for early detection of cerebral stroke and belongs to the technical field of electrical impedance tomography. The spectroscopic imaging method includes firstly, using data at all frequency positions in a frequency band for imaging, and reconstructing electrical impedance tomography spectral images reflecting tissue impedance change along with frequencies according to impedance spectral characteristics of tissues; secondly, according to impedance spectral specificity of the tissues, obtaining independent electrical impedance images from the electrical impedance tomography spectral images so as to separate cerebral stroke tissues from normal tissues; finally, selecting the electrical impedance images capable of reflecting the cerebral stroke tissues according to spatial information and position information of the cerebral stroke tissues. The spectroscopic imaging method is capable of detecting focuses of the cerebral stroke from experiments which are based on a real cranium brain structure so as to lay the foundation for applying the multi-frequency electrical impedance tomography to rapid early detection of the cerebral stroke.

The invention discloses an image reconstruction method in quasi-static electrical impedance imaging. The image reconstruction method utilizes an electrical impedance imaging method. A to-be-tested object is excited under current excitation with frequency, namely f (omega1) and f (omega2) respective, boundary voltages, namely V' (omega1) and V' (omega 2) under the two times of current excitation are collected, and collected data undergo the process of weighting and difference calculating. A boundary voltage variation delta V caused by difference of impedance change of a target area excited by different frequency is calculated, and impedance distribution change delta Rho of the target area excited by different frequency is calculated. The impedance distribution change delta Rho of the target area excited by different frequency is utilized to reconstruct an electrical impedance tomography (EIT) image. According to the image reconstruction method in quasi-static electrical impedance imaging, before two groups of measured data with different frequency are used for imaging, affection of non-target information on a reconstruction result in an imaging area is considered, and a data processing manner of weighting and difference calculating is raised. Artifacts produced in a reconstructed image by the non-target information are effectively removed, target identification is improved, and quality of the reconstructed image is improved.

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 electrical impedance imaging method, and belongs to the technical field of electrical impedance scanning and imaging. The method disclosed by the invention comprises: step 1, respectively arranging a first electrode device and a second electrode device contacting with the surface of an object to be imaged at the two opposite sides of the object to be imaged, and enabling the first electrode device and the second electrode device to apply a constant clamp force onto the object to be imaged; step 2, applying an input electric signal via the first electrode device, acquiring the output electric signal of the second electrode device, and obtaining the current distribution of the object to be imaged under the clamp force; step 3, changing the clamping forced applied on the object to be imaged by the first electrode device and the second electrode device, and repeating the step 2; and step 4, constructing the impedance image of the object to be imaged according to the current distribution difference value of the object to be imaged between two different clamp forces. Compared with the prior art, the method disclosed by the invention has the advantages of higher sensitivity, good electrode contact antifact inhibition effect, and low implementation cost.

The invention relates to an electrical impedance tomography-based gel conductivity measurement method, which comprises the following steps of (1) placing gel into an impedance experiment tank filled with conducting solution; (2) performing current excitation and voltage acquisition by an electrical impedance tomography data acquisition system, and reestablishing a conductivity image utilizing the sensitivity algorithm; (3) according to an obtained imaging result, judging whether the conductivity of the gel is equal to that of the solution, is not, performing the step (4), and otherwise, measuring the conductivity of the solution by a liquid conductivity meter to obtain the conductivity of the gel; (4) adjusting the conductivity of the solution, and returning to the step (3). Compared with the prior art, the electrical impedance tomography-based gel conductivity measurement method has the advantage that the conductivity value of the gel of any shape under the excitation of a current of a certain frequency can be measured conveniently as long as the conductivity is uniformly distributed and measuring electrodes are not in contact with the gel.

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 an electrical impedance imaging method based on tissue space distribution characteristics and frequency-dependent impedance characteristics. The method comprises the followingsteps: constructing frequency difference EIT positive problem mathematical description by utilizing boundary measurement voltages of multiple different frequencies at the same moment; solving a frequency difference EIT inverse problem by adopting a one-step linear Gaussian Newton method to obtain a frequency difference EIT sequence image; according to the spatial independent distribution characteristics of the tissues in the imaging area, extracting the electrical impedance images of different types of tissues at one moment and the change characteristics of the electrical impedance along withthe frequency from the frequency difference EIT sequence image by adopting a high-order statistical magnitude signal extraction method; repeating the operation, respectively reconstructing N target tissues with representative positions and sizes, and constructing an electrical impedance identification model of the target tissues by taking the obtained electrical impedance change characteristics ofthe N target tissues along with the frequency as a training set by adopting a machine learning method. According to the method, the electrical impedance distribution image of the selected target in the measured body at one moment can be reconstructed according to the data of multiple frequencies.