109 results about "Impedance distribution" patented technology

An electroimpedance tomograph with a plurality of electrodes (1) is provided, which can be placed on the body of a patient and are connected via a selector switch (60) with a control and evaluating unit (20). The control and evaluating unit (20) cooperates with the selector switch (60) such that two electrodes each are supplied with an alternating current from an AC power source (22) and the detected analog voltage signals of the other electrodes are processed in order to reconstruct therefrom the impedance distribution of the body in the plane of the electrodes, wherein a symmetrical AC power source is used to reduce common-mode signals. To further suppress interferences due to common-mode signals, provisions are made for the control and evaluating unit (20) to be set up, furthermore, for detuning the common-mode signal of the alternating current on the body against the ground by means of a common-mode signal measuring electrode (4) and, based on this, the symmetry of the symmetrical AC power source such that the common-mode signal on the body is minimized, and the corresponding detuning parameters are stored for each electrode pair.

An apparatus for determining functional lung characteristics of a patient includes an electrical impedance tomography (EIT) imaging device adapted to record the impedance distribution within a plane of the thorax of the patient. The EIT imaging device includes a control and analysis unit for performing the impedance measurement and deriving the impedance distribution within the plane of the thorax. The control and analysis unit automatically performs steps including determining a global impedance change, defined as the impedance change with respect to an earlier measured reference impedance distribution integrated over the electrode plane, and recording the global impedance change curve as a function of time, performing breath detection in order to identify a breathing cycle, subdividing each breathing cycle to define a plurality of intratidal intervals, subdividing an EIT image from each interval into a plurality of regions of interest and calculating for each region of interest the ratio of the integrated impedance change within this region of interest to the global impedance change of this EIT image, for each intratidal interval presenting indications of the ratios determined for the regions of interest to provide an intratidal gas distribution representation for each interval.

The disclosure describes a wearable, low-cost and low-power Electrical Impedance Tomography system for gesture recognition. The system measures cross-sectional bio-impedance using electrodes on wearers' skin. Using all-pairs measurements, the interior impedance distribution is recovered, which is then fed to a hand gesture classifier. This system also solves the problem of poor accuracy of gesture recognition often observed with other gesture recognition approaches.

An EIT device has a plurality of electrodes (4) that can be arranged on a body in order to reconstruct the impedance distribution of the body with a reconstruction algorithm. The control unit (10) of the EIT device is set up by suitable programming to continuously determine at least one property (e1, . . . , eM) each from the measured signals (U1, . . . , UM) of all measuring channels and to correct measured signals of the measuring channels on the basis of the properties or to adapt the reconstruction algorithm on the basis of the properties.

Two grooves are provided on a rear face of the remote control transmission apparatus and a plurality of electrodes are arranged in the grooves in substantially the same direction as an extension direction thereof. The plurality of the electrodes are connected to a conversion device. The conversion device measures an impedance between each of the electrodes and the finger placed in the groove, codes that impedance distribution pattern and transmits it to a recognition device. The recognition device determines whether or not he is a particular registered person by verifying with a preliminarily stored registration pattern and controls availability of a pay channel according to the determination result.

An electroimpedance tomograph is provided with a plurality of electrodes placed on a body, measuring circuits that process the voltage signals recorded by the electrodes, and a control unit that supplies two, preferably adjacent electrodes each with an alternating current. The control unit has a preset feed frequency performed in different states and different preset feed frequencies performed at different frequencies. The control unit processes the processed voltage signals of all other electrodes to reconstruct the impedance distribution of the body in the electrode plane. To make the EIT more insensitive to electromagnetic interferences, the control unit provides for an automatic setting of the current feed frequency/frequencies to record a background frequency spectrum by detecting the electrode voltage signals over a preset period of time and record them as a voltage time series and transform them into a frequency spectrum. The control unit searches in the background frequency spectrum for a frequency (different states) or frequencies (different frequencies) that leads to a useful signal to background ratio above a preset threshold value when used as a feed frequency.

The invention relates to a storage battery impedance detection device excited by a SPWM signal generated by a single-chip microcomputer, and relates to a four-wire detection device for the internal resistance of a sealed valve-regulated lead-acid battery. One wire is connected to the voltage detection device to form a voltage sampling circuit, and the other two wires are connected to a current constant current source to form a current injection circuit. The excitation signal comes from the SPWM signal generated by the microcontroller through programming, and the modulation frequency of the SPWM excitation signal It can be adjusted according to the actual measurement situation. The invention obtains sinusoidal excitation signals of different frequencies through the SPWM modulation method to measure the internal impedance distribution of the sealed valve-regulated lead-acid battery VRLA, and can comprehensively grasp the internal resistance of the sealed valve-regulated lead-acid battery VRLA in the working state of the sealed valve-regulated lead-acid battery. line detection device.

This invention supplies a squareness double mode self-standardization sensor. Cross section of this sensor embody three-layer: outer layer is metallic conduit layer used for structure fixing and shielding effect; intermediate layer is insulant layer; inner layer structure is multi- pole attach at insulating layer; the poles dispersed over identity section to a certainty order, interval of neighbor pole is not equidistant. These inventions also supply two kinds of image reconstruction method base on this sensor. Aim at squareness measuring region, this double mode electricity imaging system sensor spread measuring range. The invention can measure object of different section and stimulation nonsynchronous, possess self-standardization property. The invention adopts multifold stimulation mode, realize synchronization and coordination measuring, make real part and imaginary part information of measuring sectional impedance distribution each other merge, and simplify the design and realization of soft and hard ware of bimodal measuring system.

The invention provides an electrochemical detection method through partial morphology scanning by using an electrochemical detection device. The method comprises the following steps: performing rapid and long-distance control on a probe through a three-dimensional stepper motor, performing short-distance precise control through a piezoelectric ceramic sensor, keeping constant potential on a tested sample through a double-constant potential rectifier, meanwhile externally exerting an alternating current potential signal onto the testing probe, acquiring imaging information of three-dimensional spatial distribution of the electrochemical signal such as real part Zre, imaginary part -Zim, an absolute module value Z and a phase angle -Phase of a sample partial area through a data acquisition module, and acquiring element parameter information of an equivalent circuit. By adopting the method, the defects that a conventional scanning electrochemical microscope is weak in signal, hard in obtaining a feedback current density signal, single in detection signal and the like are overcome, partial microcosmic impedance distribution characteristics of the surface of a sample can be obtained, the information is rich, and the real characteristics of the sample can be studied and analyzed.

An electroimpedance tomograph is provided with a plurality of electrodes (1), which can be placed on the body of a patient and are connected to a control and evaluating unit (20) via a selector switch (60). The control and evaluating unit (20) cooperates with the selector switch (60) such that two electrodes each are supplied with alternating current from an AC power source (22). The detected analog voltage signals of the other electrodes are sent into the control and evaluating unit (20) via a measuring amplifier (62) and AD converter (64) and are processed there in order to reconstruct the impedance distribution of the body in the plane of the electrodes therefrom. A symmetrical AC power source (22) is used to reduce common-mode signals. To make it possible to suppress errors due to common-mode signals, provisions are made for the control and evaluating unit (20) to be set up for making available an additional common-mode signal at an output during an adjusting mode of operation and to send it to the body via common-mode signal electrodes (4, 90) that can be placed on the body. The control and evaluating unit (20) is prepared, furthermore, to adjust the measuring amplifier (62) according to value and phase for each electrode pair connected by the selector switch (60) such that the common-mode signal at the output of the measuring amplifier (62) is minimized, and the adjusted parameters are stored for each electrode pair.

An electrical impedance sensing device which integrates multielectrode automated impedance spectroscopy capability with automatic parameter extraction and data analysis to create an automated cell behavior monitoring system. The device comprises radial electrodes and an out-of-plane counter electrode. Quantitative impedance data provided information on cell adhesion, spreading, proliferation and detachment due to cell cycle processes as well as cell-drug interaction, with spatio-temporal resolution. The resulting dataset is processed for impedance distribution and used to characterize cellular motion, morphology, electrochemical and dielectric properties. Also, a method is described for studying cell-cell and cell-matrix interactions, determining electrical characteristics of cell layers, and identifying specific impedance parameters for cancer screening, drug screening, bacterial growth monitoring, organ transplant compatibility, and cell-drug interaction among other applications.

The invention discloses a calibration device for an electric impedance tomography system. The calibration device comprises basic impedance units for simulating impedance distribution or the disturbance of the impedance distribution and electrode/skin contact units for simulating electrode/skin contact characteristics, wherein the basic impedance units are distributed to form a calibration network with a known conductivity; at least four layers of basic impedance units are arranged from the central point to the edges of the calibration network; and the electrode/skin contact units are formed by electrode/skin contact impedance modules and electrode polarization potential simulation modules, distributed around the calibration network at equal interval and connected with the basic impedance units on the outermost layer of the calibration network. The device provided by the invention can meet the evaluating requirements of performance and an image reconstruction effect of an electric impedance tomography data acquisition system.

The invention discloses a voltage optimizing point sorting method for a 10KV overhead line reactive compensation device. The method comprises the following steps: a. obtaining the load rate and the power factor in maximum load according to data of line load curves and reactive and active sampling; b. initially determining the compensation capacity range; c. calculating and drawing a line load and impedance distribution diagram according to the load rate, the power factor and a circuit electric wiring diagram as well as the span and the diameter of an overhead line, and counting the reaction value of a main circuit or branches; d. calculating the voltage drop percentage of each load point relative to an original point or a branch point; e. determining compensation point quantity and capacity according to the conditions of line voltage drop and line reactive capacity in an allowable compensation range, and verifying; and f. determining the position of the compensation point. By adopting the method, the quantity and position of the compensation points can be analyzed and calculated according to actual conditions, the compensation efficiency to the lines can be improved maximally, and meanwhile, the conditions of overcompensation and under-compensation can be avoided.

The invention discloses a device and a method for non-contact magnetic induction impedance plane projection imaging. An alternating current magnetic field is generated in an excitation coil by introducing alternating sinusoidal current, a measured object with certain conductivity is arranged in the alternating current magnetic field, the inside of the measured object generates same-frequency alternating eddy current due to electromagnetic induction, measuring coils which are arranged into a plane in a matrix way are used for respectively detecting magnetic filed signals caused by the alternating current eddy current, according to the relationship of the measuring signals and the impedance distribution of the measured object, the impedance distribution condition of the part of the measured object corresponding to each measuring coil is respectively calculated, and all calculating results form an impedance plane projection image according to the positions of the measuring coils.

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 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 capacitor-carried power supply ground plane modeling and capacitor decoupling radius simulating method. The method includes the steps of recording coordinates of an input/output port and a decoupling capacitor port, calculating port coefficients and frequency domain responses of all resonance modes according to a resonant cavity formula or based on a double-frequency-point approximation algorithm resonant cavity formula, obtaining all capacitor division schemes according to the port coefficients, the frequency domain responses of all the resonance modes, the number of the modes, the capacitor frequency domain responses and the number of capacitors, converting the divided capacitors into a power supply ground plane resonant cavity model to obtain a capacitor-carried power supply ground plane resonant cavity formula, calculating power supply ground plane actual frequency domain impedance distribution through the resonant cavity formula, and extracting the capacitor decoupling radius on the basis of the impedance distribution. By means of the method, the problem that capacitor-carried power supply ground plane modeling can not be conducted through a resonant cavity algorithm is solved, a rapid, easy and convenient method is provided for load-carried power supply ground plane modeling, and reliable guidance is provided for selection and placement of the decoupling capacitors in power supply integrity design through the decoupling radius.

The invention relates to a brain resistance distribution diagram dynamic measurer and relative method, wherein said measurer comprises 16 driving measuring electrodes, digit synthesize sine signal source, sine constant current source, voltage/phase detecting circuit, high-speed A/D collector, high-speed microprocessor, and PC. Said method uses network topology, to treat the brain resistance data via mark value, to be shown at PC. The invention will not hurt detected user, to get the condition of brain.

The invention discloses a breast rheid model applied to mammary gland impedance scanning detection technique training, and a preparation method of the model. The model mainly consists of a conductive rubber film layer, sepharose gel and an electrolyte solution, wherein the sepharose gel and the electrolyte solution are wrapped by the conductive rubber film layer in a sealed manner so as to form an overall hemispherical breast rheid model. The model is capable of vividly simulating form and impedance distribution state of a breast and has the characteristics of high form simulation degree, approximation to real impedance parameters, simplicity in preparation process and the like, different model phantoms can be prepared according to structural types and lesion types of the breast, and meanwhile the model can be repeatedly used for a long time and is beneficial for long-term operation training.