190 results about "Electrical capacitance tomography" patented technology

An impedance model of tissue is useful for describing conductivity reconstruction in tissue. Techniques for determining and mapping conductivity distribution in tissue supply useful information of anatomical and physiological status in various medical applications. Electrical Impedance Tomography (EIT) techniques are highly suitable for analyzing conductivity distribution. Electrical characteristics of tissue include resistive elements and capacitive elements. EIT techniques involve passing a low frequency current through the body to monitor various anatomical and physiological characteristics. The system can interrogate at multiple frequencies to map impedance. Analytical techniques involve forward and inverse solutions to boundary value analysis to tissue characteristics.

A magnetic resonance-electrical impedance tomography (MREIT) technique for determining the local conductivity of an object. The MREIT technique combines magnetic resonance current density imaging (MRCDI) with electrical impedance tomography (EIT) in order to obtain the benefits of both procedures. The MREIT technique includes the step of current density imaging by performing the steps of placing a series of electrodes around the patient or object to be imaged for the application of current, placing the patient or object in a strong magnetic field, and applying an MR imaging sequence which is synchronized with the application of current through the electrodes. Next, the electric potentials of the surface of the object or patient are measured simultaneously with the MR imaging sequence, as in EIT. Then, the MR imaging signal containing information about the current and the measured potential are processed to calculate the internal conductivity (impedance) of the object or patient.

The present teachings relate to the application of electrical impedance tomography (EIT) to demonstrate the multifunctionality of carbon nanocomposite thin films under various types of environmental stimuli. Carbon nanotube (CNT) thin films are fabricated by a layer-by-layer (LbL) technique or other techniques and mounted with electrodes along their boundaries. The response of the thin films to various stimuli determined by relying on electric current excitation and corresponding boundary potential measurements. The spatial conductivity variations are reconstructed based on a mathematical model for the EIT technique. Here, the ability of the EIT method to provide two-dimensional mapping of the conductivity of CNT thin films is validated by (1) electrically imaging intentional structural defects in the thin films and (2) mapping the film's response to various pH environments.

A method based on capacitance chromatographic imaging system for measuring the two-phase oil-gas stream features that a reverse projection algorithm is used to reconfigure the oil-gas stream's medium distribution image to real-time show the stream type in pipeline, a fuzzy pattern recognization is used for in-line automatic recognization of stream type, a combined image rebuilding algorithm is used to rebuild the image for showing oil and gas distribution, and the image is processed to obtain the porosity of the oil-gas stream. Its equipment is composed of array-type capacitance sensor, data acquisition unit and computer. Its advantages are high speed and high precision.

The invention discloses a high temperature electrical capacitance tomography sensor and a production method thereof. The sensor can be applied to a 300 DEG C high temperature environment. The sensor includes high temperature-resistant array-distributed measuring electrodes, a shaft end shielding electrode, an insulation and isolation layer, an outer shield cover and a signal transmission line, wherein the array distribution electrodes comprise N measuring electrodes; and the signal transmission line comprises a high temperature section and a normal temperature section and comprises a cable core, an insulating layer and a shield silk screen. In the invention, the defect of no resistance of traditional sensors to a high temperature is improved, the problem of difficulty in arrangement of electrodes in the high temperature environment is solved, the electrodes and the outer shield cover are isolated and fixed by a high temperature-resistant insulating material, and signals of the measuring electrodes are led out through the high temperature signal transmission line, so an effective means is provided for researching gas and solid two-phase distribution, the fluidization characteristics and relevant reaction monitoring in the high temperature environment, and the application field of an electrical capacitance tomography technology is widened.

The invention discloses an electrical capacitance tomography sensor used in a submerged environment, which belongs to the field of designing of sensors. The sensor comprises a two-phase flow distribution measurement electrode array, an annular-electrode tip shielding electrode, inter-electrode isolation electrodes, a sensor water isolating layer and signal transmission cables, wherein the two-phase flow distribution measurement electrode array comprises N measurement electrodes, and each of the signal transmission cables comprises a cable core and a shielding silk screen. According to the invention, a shielding case structure out of the a traditional electrical capacitance tomography sensor is discarded, an insulating heat-conduction material is used to enclose the measurement electrode array in the outer wall surface of a measurement pipe section, so the electrical capacitance tomography sensor can be placed in the submerged environment, an effective detection means is provided for two-phase distribution of steam and liquid in a heat convection area, formation and development of a liquid film, flow pattern monitoring, etc., and the application field of electrical capacitance tomography technology is effectively broadened.

The invention relates to a direct image reconstruction method based on the capacitance tomography of a round sensor. The method comprises the following operation steps: 1. N electrodes of an ECT sensor, which are arranged on the same cross section, are counterclockwise marked as electrodes i (i is larger than or equal to 1 and is smaller than or equal to N) and a traditional 1-by-1 excitation measuring mode is adopted, i.e. a scanning process comprises N-1 actions; 2. measured capacitance values are firstly pre-treated by linear transform to obtain N*(N-1)/2 independent measured charge change values; 3. the scattering transformation t(s) of discrete electrodes is calculated; and 4. the specific inductive capacity variation of any point is rebuilt. The invention aims at a round measuring region, overcomes the defects that a traditional algorithm needs to calculate a sensitivity matrix and can not independently calculate the rebuilding result of a subregion, directly rebuilds images according to capacitance measuring values and can directly rebuild images in the subregion. The method has high real-time performance, can be popularized to ECT and has important practical values and application prospects.

The invention discloses an eddy flow concentration sparse gas-solid two-phase flow capacitance chromatography imaging measurement method and device which belong to gas-solid two-phase flow measurement technology. The device includes an eddy flow concentration apparatus connected with a sparse gas-solid two-phase flow channel, the eddy flow concentration apparatus is connected with a control valve and an air pump, an outlet of the air pump is connected to the sparse gas-solid two-phase flow channel. The method includes that after eddy flow concentration of the sparse gas-solid two-phase flow, solid particle is concentrated at wall surface, solid particle concentration is measured by single-layer capacitance sensor, speed is measured by double-layer capacitance sensor, and mass flow of the solid particle can be calculated by combining the solid particle concentration and the speed. Capacitance chromatography imaging technology is used to measure improved measurement precision. The measurement method and sensor provided by the present invention integrate concentration, speed and mass flow measurement, have advantages of simple structure and convenient calibration, solve problem of measuring the sparse gas-solid two-phase flow in large-diameter pipeline by using the capacitance chromatography imaging technology, and have wide application field.

In the capacitance tomography system composed of the capacitance sensor array, the electronic measurement circuit and the computer for image formation, the method of principal component analysis is introduced to analyze the normalized value of capacitance measured. These components with contribution rate less than mu are removed from the principal components. The data of principal components withcontribution rate larger than mu are as the input for the forwarding neuron network. The output of the neuron network is the phase concentration. The substance of the principal component analysis is that the normalized sample matrix of the capacitance values measured is transformed to the correlation matrix, from which each eigenvalue and related principal component is obtained.

A control system and data acquisition system for an electrical capacitance tomography sensor comprised of a sensor having a plurality of electrodes, where each electrode is further comprised of a plurality of capacitance segments. Each of the capacitance segments of each electrode can be individually addressed to focus the electric field intensity or sensitivity to desired regions of the electrodes and the sensor.

A control system and data acquisition system for an electrical capacitance tomography sensor comprised of a sensor having a plurality of electrodes, where each electrode is further comprised of a plurality of capacitance segments. Each of the capacitance segments of each electrode can be individually addressed to focus the electric field intensity or sensitivity to desired regions of the electrodes and the sensor.

The invention discloses a double helix electrode capacitance tomography sensor for measuring an annular space that belongs to the field of an electrical process tomography device. The sensor comprises a main structure part and a capacitance measurement part. The main structure part is composed of concentric inner and outer tubes and a connection bracket used for fixing position. An annular space between the inner and outer tubes is a measured space. The capacitance measurement part comprises detection electrodes, electrode end shields, shielding cases, a signal transmission cable, ECT signal acquisition equipment and connection wires. By the utilization of electrode sensor parts which are respectively spirally arranged on the inner and outer tube walls, three-dimensional imaging of the measured annular space is truly realized. Due to the sensor structure with electrodes uniformly distributed on the two tube walls, imaging of the annular space is realized, and the problem of weak capacitance signal is also improved. The invention is a big breakthrough of the ECT technology.

The invention discloses a high-temperature-resistant electrical capacitance tomography sensor applicable to room temperature to a 600 DEG C high-temperature environment. The sensor comprises an array distribution electrode, a shaft end shielding electrode, an electric-insulation isolating layer, a shaft end shielding electrode connecting layer, a fixing layer, a shielding cover and a signal transmission line, wherein the array distribution electrode is made by an etching hollowing technique, and composed of a measuring end and a fixing end which are respectively used for measuring the capacitance and wrapping and fixing the electrode measuring end and transmission cable; the measuring end is attached to the outer wall of a high-temperature-resistant electric-insulation pipeline through a high-temperature-resistant electric-insulation rubber overall locating sleeve; the signal transmission line comprises a hot temperature section and a normal temperature section which are respectively a double-shelding line composed of a cable core, an electric-insulation layer and a shielding silk net; and the shaft end shielding electrode connecting layer directly contacts the shaft end shielding electrode, and is connected with the shielding cover. The sensor can be normally used at room temperature to a 600-DEG C high-temperature environment, thereby effectively widening the application range of the electrical capacitance tomography technique in the field of high-temperature thermal state.

The invention discloses a three-dimensional electrical capacitance tomography (ECT) imaging image reconstruction method which employs the measuring capacitance value obtained by a three-dimensional ECT imaging sensor as the projection data for image reconstruction. In an iteration reconstruction process, a threshold filtering mode is employed to perform artifact inhibition on an obtained reconstruction image; a filtering threshold regularly performs adaptive adjustment, and is selected to minimize the fuzzy measurement of a current image. The method effectively reduces reconstruction image artifacts, improves complexly distributed three-dimensional imaging effects, and realizes real three-dimensional ECT imaging image reconstruction.

The embodiment of the invention discloses an electrical impedance tomography measuring method, which is characterized in that: in an annular array of N electrodes arranged in the body surface of a human body, every two adjacent electrodes form a pair of exciting electrode pairs to perform excitation once, and the excitation is performed for N times; in one of the excitation, other N-2 electrodes expect the exciting electrode pairs are used as measuring electrodes, two electrodes adjacent to the excited electrodes in the current excitation are used as reference electrodes and form measuring electrode pairs with other measuring electrodes, and the measuring electrode pairs and a measuring electrode pair is formed by the two reference electrodes, and 2N-7 measuring electrode pairs are formed; and after exciting current is inputted by the exciting electrode pairs, the voltage data of the 2N-7 measuring electrode pairs are measured, and electrical impedance distribution images in the human body are acquired according to N(2N-7) voltage data obtained by exciting and measuring for N times, wherein N is an integral number which is more than or equal to 8. The embodiment of the invention also discloses the other electrical impedance tomography measuring method. By the method, the reliability and effectiveness of measuring integral the data can be improved, independent measuring numbers are enough, redundant measuring is less, and the real time of the measuring is good. Particularly the imaging effect is better under the condition of lower measuring sensitivity and lower signal to noise ratio in an electrical impedance tomography (EIT) system.

This invention discloses biphase current mesh capacitor tomography. The one pole of the insert mesh capacitor is a metal core in the insulation wire and the other pole is formed by the contact surface of conduct phase and mesh or wet surface in the biphase current and its surface insulation layer serves as dielectric between electrodes and identifies the capacitor value. The insert mesh capacitor sensor high-speed scan the biphase current in the pipe driven by electric or self rotation apparatus and gets the project information to different directions on the pipe section of biphase current and gets real time image of the biphase current. The insert capacitor sensor identifies local distribution information of the biphase current on whole pipe or container section and directly gets the real time image of the biphase current.

The invention discloses a planar array electrical capacitance tomography method and a system thereof, and relates to the technical field of image reconstruction. In the invention, the planar array electrical capacitance tomography system comprises a capacitance sensor, a data measurement and acquisition module and a computer. The capacitance sensor converts the distribution of the substance-fieldmedium of the object detected to a capacitance value; the data measurement and acquisition module is used for measuring and acquiring the capacitance value between any two electrode plates, and transmitting the measured capacitance data to the computer; the computer optimizes the capacitance data through fuzzy C-mean clustering algorithm, uses the optimized capacitance value as an image reconstruction value, reconstructs the defect image in combination with a non-iterative image processing algorithm or an iterative image processing algorithm, and obtains a reconstructed image. Compared to conventional imaging methods, the planar array electrical capacitance tomography method and the system thereof can solve the problem that the capacitance data is influenced by the position of the electrode plates and the noise interference of the detection environment, and obtain more stable and high-quality image of the measured field.

The invention provides a high-precision ECT (Electrical Capacitance Tomography) intelligent sensor. The intelligent sensor comprises a sensitive capacitance polar plate and a signal processing circuit board, wherein the surface of the sensitive capacitance polar plate can directly get in contact with detected fluid after being subjected to Teflon spray processing. A Teflon coating has higher heatresistance and corrosion resistance, smooth surface and stable dielectric constant, and thereby the measuring result is more stable, the application field is wider, the maintenance period of cleaningdeposited dirt is expected to be prolonged, and the recycling is possible. The signal processing circuit board is fixed on a stud provided by the sensitive capacitance polar plate and used for collecting an analog signal derived from the sensitive capacitance polar plate in the neighbourhood; and the analog signal is converted into a digital signal by processing for being transmitted to an imaging computer by a CAN (Controller Area Network) bus; and the transmission distance of the analog signal is effectively shortened, the influence of stray capacitance on the imaging effect is reduced, andthe current exciting and data acquiring task can be automatically finished after a command is received. An industrial CAN bus interface has the characteristics of strong interference resistant capability, remote transmission distance, and the like so that the imaging computer can be arranged far away from the industrial field.

The invention discloses a dynamic supervising method for gas-solid fluidized bed and the system. The method is: using wavelet analysis technology to analyze the pressure vibration signal, judging its flow state, displaying the flow state with capacitance chromatography imaging technology, measuring the aperture rate and its vibration of the fluidized bed, extracts the character value and carries on flow state judgment, using multi-sensor information melting technology to carry on flow state judgment, upgrading the accuracy of the judgment. The supervising system has a fluidized bed main body, under which there has a gas distribution board, gas chamber, on the external wall in the middle of the main body there arranges a capacitance chromatography imaging sensor, pressure sensor, the capacitance chromatography imaging sensor is connected to the tiny capacitance measuring model, data collecting system, and computer, the pressure sensor is connected to A/D converting card, and computer.

The invention provides a flexible combination type electric capacitance tomography data obtaining system for a sensor electrode. The flexible combination type electric capacitance tomography data obtaining system consists of a hardware system and control software; the hardware system comprises six parts, namely a capacitance sensor, a microcontroller, a combination array switch, an excitation source, a capacitance-to-voltage and digital-to-analogue conversion circuit and an upper computer; the excitation source is used for generating a sinusoidal signal with a high precision; the combination array switch receives a control instruction sent by the microcontroller so as to realize flexible combination of working modes of the sensor electrode; the capacitance-to-voltage and digital-to-analogue conversion circuit realizes conversion between a capacitance value and a voltage value of a sensor, data conditioning, and conversion between an analogue signal and a digital signal; and the control software is mounted on the upper computer, sets the data obtaining system by controlling a software interface, and sends information to the microcontroller. The flexible combination type electric capacitance tomography data obtaining system is matched with the control software by adopting a modularized design, and carries out modularized assembly according to actual working demands, so that the random flexible combination of the excitation source and a measurement polar plate is realized; and the environment adaptive capacity, the generality and the measurement precision of the data obtaining system are improved, and the cost is saved.