A rotating enhanced non-uniform electrode capto tomography system and method
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XI AN JIAOTONG UNIV
- Filing Date
- 2026-04-10
- Publication Date
- 2026-06-09
Smart Images
Figure CN122171633A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of capacitance tomography technology, and relates to a rotation-enhanced non-uniform electrode capacitance tomography system and method, and more particularly to a system and method that improves the amount of observation information and reconstruction effect of capacitance tomography by combining non-uniform electrode structure with rotational multi-view acquisition. Background Technology
[0002] Electrical Capacitance Tomography (ECT) measures the capacitance changes between different electrode pairs by arranging multiple electrodes circumferentially in the measured area, and then inverts the dielectric constant distribution or equivalent permittivity distribution of the measured area based on this. This technique has advantages such as being non-invasive, having a fast response speed, and being suitable for monitoring multiphase flow or particulate processes.
[0003] Existing ECT sensors typically employ uniform electrode arrays with equal arc lengths and equal gaps. This type of structure offers advantages such as ease of manufacturing, well-defined channels, and good azimuth consistency. However, it still has shortcomings in central region resolution, specific target shape recognition capabilities, and underdeterminacy suppression. Especially when the target is close to a local location or has a complex structure, the observational information obtained from a single viewpoint is limited, easily leading to blurred reconstruction results, sensitivity to noise, and insufficient detail recovery.
[0004] To improve imaging performance, existing technologies have employed methods such as increasing the number of electrodes, altering electrode structures, employing rotational scanning, or introducing complex reconstruction algorithms to enhance reconstruction quality. However, simply using a uniform electrode structure limits the adjustability of the observation sensitivity distribution; and relying solely on mechanical rotation to increase the viewing angle will also restrict the gain if a design matching the electrode structure is lacking.
[0005] Therefore, an ECT scheme that balances sensor structure design and multi-view acquisition mechanism is needed. While maintaining a clear definition of the single-view measurement channel, the scheme can increase effective observation information, improve the reconstruction quality of the measured area, and provide a more stable data foundation for subsequent joint reconstruction by combining non-uniform electrode structure with rotating multi-view acquisition. Summary of the Invention
[0006] The purpose of this invention is to provide a rotation-enhanced non-uniform electrode capacitance tomography system and method. By setting a non-uniform electrode array with different arc lengths on the inner circumference of the sensor, and performing rotational multi-view acquisition under the condition that the target under test is relatively fixed, more effective observation information can be obtained without changing the definition of the measurement channels of each viewpoint, thereby improving the quality and applicability of ECT reconstruction.
[0007] To achieve the above objectives, the present invention adopts the following technical solution.
[0008] This invention provides a rotation-enhanced non-uniform electrode capacitance tomography system, including a capacitance tomography sensor, a rotation and positioning mechanism, a capacitance switching acquisition circuit, a microcontroller unit, and a host computer.
[0009] The capacitance tomography sensor includes a substrate or insulating cylinder and components arranged along the inner circumference of the substrate or insulating cylinder. Each electrode has a gap between adjacent electrodes, and the arc lengths of each electrode are not all the same, forming a non-uniform electrode array. This non-uniform electrode array can produce different sensitivity distribution characteristics at different orientations under the same substrate circumference conditions.
[0010] The rotation and positioning mechanism is connected to the capacitance tomography sensor and is used to rotate the capacitance tomography sensor around the axis of the measured area or the measured target when the measured target is relatively fixed, and to complete positioning at multiple preset viewing angles. In some embodiments, the rotation and positioning mechanism rotates angularly in preset angular steps so that the same set of electrode arrays can repeatedly perform measurements at different angular positions.
[0011] The capacitance switching acquisition circuit is electrically connected to the electrode array and is used to switch the measurement channels between the electrodes according to the same measurement channel definition under each positioning angle and acquire capacitance observation data to form multi-view capacitance observation data.
[0012] The microcontroller unit is communicatively connected to the rotation and positioning mechanism, the capacitance switching acquisition circuit, and the host computer, respectively, and is used to coordinate the working timing of the rotation and positioning mechanism and the capacitance switching acquisition circuit. The host computer is used to receive multi-view capacitance observation data, reconstruct the measured area or the measured target, and output the reconstructed image or reconstruction result parameters.
[0013] This invention also provides a rotation-enhanced non-uniform electrode capacitance tomography method, comprising: arranging an electrode array with different arc lengths on the inner circumference of a substrate or insulating cylinder; driving the electrode array to rotate to multiple viewing angles according to a preset angle step size, under the condition that the measured area or the measured target is relatively fixed; switching the measurement channels between the electrodes and acquiring capacitance observation data according to the same measurement channel definition at each viewing angle to obtain multi-view capacitance observation data; sending the multi-view capacitance observation data to a host computer, and completing the reconstruction of the measured area or the measured target based on the multi-view capacitance observation data, and outputting the reconstructed image or reconstruction result parameters.
[0014] In some embodiments, the number of electrodes Based on the size of the object being measured, the target resolution requirements, and the design of the acquisition channel, all electrodes are arranged around the circumference of the substrate or insulating cylinder without overlapping, forming multiple discrete entities with independent acquisition channels.
[0015] In some embodiments, the gap angle between adjacent electrodes is the same, and the sum of the arc lengths of all electrodes is less than the total circumference of the inner circumference of the substrate or insulating cylinder, in order to maintain an insulating isolation gap. Total electrode coverage. This is a preset value. The total electrode coverage can be expressed as: in, Indicates the first The arc length angle corresponding to each electrode.
[0016] In some embodiments, the non-uniform electrode array includes large-arc-length electrodes and small-arc-length electrodes distributed at different positions on the inner circumference of the substrate or insulating cylinder. The non-uniform electrode array forms a structural size difference so that the electrodes on the substrate or insulating cylinder have different geometric shapes at different circumferential positions, forming local dense areas and local sparse areas with asymmetrical electrode coverage.
[0017] In embodiments where the angle between adjacent electrodes is the same, if the angle between adjacent electrodes is... Then we have: In some implementations, the ratio of the maximum electrode arc length to the minimum electrode arc length... The default value is greater than 1, that is: In some embodiments, the arc lengths of the electrodes can be arranged according to an arithmetic progression; in other embodiments, the arc lengths of the electrodes can be arranged according to a cosine-weighted distribution. Taking the cosine-weighted distribution as an example, it can be: in, For the first The arc length corresponding to each electrode For the weighting coefficients, satisfying Furthermore, the arc length angle of each electrode can be determined as follows: In some implementations, the preset angle step size and total number of viewing angles of the rotation and positioning mechanism are... The viewpoint set is preset according to imaging requirements. The viewpoint set can be represented as: in, This represents the rotation angle step size.
[0018] In some implementations, the capacitance observation data collected from various viewpoints are the... The mutual capacitance observation data between the electrodes are used, and the same channel definition is used for each viewpoint.
[0019] In some implementations, multi-view reconstruction can be achieved by obtaining the corresponding sensitivity matrix for each viewpoint separately, and then normalizing and stacking the multi-view capacitance observation data and the multi-view sensitivity matrix to form a joint multi-view reconstruction solution. The multi-view sensitivity matrix can be obtained through calibration measurements, numerical simulation, or by transforming the base sensitivity matrix through viewpoint transformation. This part represents an optional reconstruction processing method used to further improve reconstruction quality, and is not intended to limit the invention to employing a specific algorithm.
[0020] Compared with the prior art, the present invention has at least the following beneficial effects.
[0021] First, by setting up a non-uniform electrode array with different arc lengths, compared with a traditional uniform electrode array, the sensitivity distribution of different orientations of the measured area can be adjusted, thereby improving the observation and discrimination capabilities of specific target scenarios.
[0022] Second, by rotating the same capacitance tomography sensor to acquire data from multiple perspectives under the condition that the target being measured is relatively fixed, effective observation information can be increased while maintaining the consistency of the measurement channel definition for each perspective, thus alleviating the problem of insufficient single-view observation.
[0023] Third, by combining the non-uniform electrode structure with rotating multi-view acquisition, both structural gain and view gain can be taken into account, thereby improving the quality, stability, and applicability of the reconstructed image of the measured area.
[0024] Fourth, in some implementations, the reconstruction effect can be further improved by combining multi-view joint reconstruction processing, but the protection focus of this invention is primarily on the synergistic scheme of non-uniform electrode structure and rotating multi-view acquisition. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of an electrode arrangement with non-uniform arc length and uniform gap in one embodiment of the present invention.
[0026] Figure 2 This is a schematic diagram of a system in which a capacitance tomography sensor rotates at a preset step size to form multi-view acquisition in one embodiment of the present invention.
[0027] Figure 3 This is a schematic diagram of the sensitivity matrix being rotated, normalized, and stacked to form a joint operator according to a viewpoint in one embodiment of the present invention.
[0028] Figure 4 This is a schematic diagram of a multi-view stacked joint reconstruction process according to an embodiment of the present invention.
[0029] Explanation of reference numerals in the attached figures 1-1. Matrix or insulating cylinder; 1-2, Electrodes; 1-3. Gap between adjacent electrodes; 1-4. Example of a maximum arc length electrode; 1-5. Examples of electrodes with minimum arc length; 1-6. Angle between adjacent electrodes ; 1-7. Electrode arc length angle ; 1-8. Rotation and positioning mechanism; 1-9. Capacitor switching acquisition circuit; 1-10. Microcontroller Unit; 1-11. Host computer; 1-12. The area or target being measured; 1-13. Direction of rotation; 1-14, Angle Step ; 1-15. Change of perspective; 1-16. Stacking operations. Detailed Implementation
[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Various modifications or substitutions can be made by those skilled in the art without departing from the concept of the present invention, and all such modifications or substitutions should fall within the scope of protection of the present invention.
[0031] (I) Overall System Structure This embodiment provides a rotation-enhanced non-uniform electrode capacitance tomography system, such as Figure 1 and Figure 2 As shown, the sensor includes a substrate or insulating cylinder (1-1), multiple electrodes (1-2) arranged on the inner circumference of the substrate or insulating cylinder (1-1), a rotation and positioning mechanism (1-8), a capacitance switching acquisition circuit (1-9), a microcontroller unit (1-10), and a host computer (1-11). The area to be measured or the target to be measured (1-12) is located within the detection area enclosed by the electrodes. The substrate or insulating cylinder (1-1) and the multiple electrodes (1-2) arranged on the inner circumference of the substrate or insulating cylinder (1-1) constitute a capacitance tomography sensor.
[0032] In this embodiment, electrodes (1-2) are arranged along the inner circumference of the substrate (1-1), and adjacent electrodes (1-2) form adjacent electrode gaps (1-3). Unlike traditional uniform electrode arrays, in this embodiment, the arc lengths of each electrode (1-2) are not all the same, thus forming a non-uniform electrode array. This non-uniform arrangement can create differences in the electric field sensitive areas in different orientations, thereby providing a richer information basis for subsequent multi-view acquisition.
[0033] The rotation and positioning mechanism (1-8) is connected to the substrate or insulating cylinder (1-1) and is used to drive the capacitance tomography sensor to rotate around the axis of the measured area or the measured target (1-12). The rotation and positioning mechanism (1-8) may include components such as a motor, coupling, support, bearing, encoder, or angle sensor to achieve stable rotation and viewing angle positioning. The microcontroller unit (1-10) is used to issue rotation control commands to the rotation and positioning mechanism (1-8) and determine whether the target viewing angle has been reached based on feedback information from the encoder or angle sensor.
[0034] The capacitance switching acquisition circuit (1-9) is connected to each electrode (1-2) and is used to sequentially switch different electrode pairs and acquire mutual capacitance observation data according to the same measurement channel definition at each viewing angle. The microcontroller unit (1-10) is also used to control the acquisition timing of the capacitance switching acquisition circuit (1-9) so that it performs channel switching and data acquisition after each viewing angle is positioned. The host computer (1-11) is used to receive the multi-view observation data uploaded by the microcontroller unit (1-10) and perform subsequent reconstruction processing.
[0035] (II) Design of Non-Uniform Electrode Array This embodiment mainly describes the geometric design method of non-uniform electrode arrays, such as... Figure 1 As shown, One electrode (1-2) is arranged along the inner circumference of the substrate or insulating cylinder (1-1), and an adjacent electrode gap (1-3) is formed between adjacent electrodes. Figure 1 (1-4) shows an example of an electrode with the maximum arc length, (1-5) shows an example of an electrode with the minimum arc length, and (1-6) represents the angle between adjacent electrodes. (1-7) represents the electrode arc length angle. Let the first... The arc length angle of each electrode is ,but: That is, not all electrodes have the same arc length.
[0036] In one embodiment, the angle between adjacent electrodes Same. If the total coverage is Then the following condition is met: Indicates the first The arc length angle corresponding to each electrode.
[0037] Correspondingly, the angle of the gap between adjacent electrodes It can be represented as: In one implementation, the ratio of the maximum electrode arc length to the minimum electrode arc length satisfies: in, This is a preset value greater than 1. In specific applications, an appropriate value can be selected based on the type of object being measured, the target's azimuth characteristics, and the required sensitivity distribution. value.
[0038] In one specific arrangement, the arc lengths of the electrodes are arranged in an arithmetic progression and then normalized according to the total coverage. Let the original sequence be: in, The arc length of the smallest measurable electrode. For tolerance, and all Since it is a positive value, after normalization we get: In another specific arrangement, the arc lengths of the electrodes are arranged in a cosine-weighted manner. This can be defined as: in, For the first The arc length corresponding to each electrode For the weighting coefficients, satisfying Then, normalization is performed based on the total coverage to obtain: The above design allows the electrode array to exhibit the desired non-uniformity while maintaining the overall manufacturability of the structure.
[0039] (III) Rotational Multi-view Acquisition This implementation method mainly describes the rotating multi-view acquisition process, such as... Figure 2 As shown, under the condition that the measured area or the measured target (1-12) is relatively fixed, the capacitance tomography sensor is driven by the rotation and positioning mechanism (1-8) to rotate around the axis in the rotation direction (1-13), and the angular step size is represented by (1-14). Let the angular step size be... The number of viewpoints is Then the set of viewpoints can be defined as: From every perspective At this point, the microcontroller unit (1-10) controls the rotation and positioning mechanism (1-8) to complete the positioning, and then controls the capacitance switching acquisition circuit (1-9) to switch and measure the electrode pairs according to the preset channel sequence, acquiring mutual capacitance observation data from this perspective. .
[0040] In some implementations, the same channel definition and measurement sequence are used for each viewpoint. Taking mutual capacitance measurement as an example, when using... With one electrode, the number of observation channels can be expressed as: Therefore, a length of [length] can be obtained from each perspective. Observation vector: The above method allows for the acquisition of multiple sets of capacitance observation data from different perspectives. Compared to a single static perspective, multi-view acquisition effectively increases the sources of observational information and improves the quality of subsequent reconstruction.
[0041] (iv) Examples of multi-perspective joint reconstruction methods This section explains how to further improve reconstruction results based on multi-view capacitance observation data. For example... Figure 3 As shown, the basic sensitivity matrix The multi-view sensitivity matrix is obtained after viewpoint transformation (1-15). Then, after stacking operations (1-16), the stacked joint sensitivity matrix is obtained. .like Figure 4 As shown, the joint reconstruction process corresponds to steps S1 to S5. It should be noted that this section is used to fully explain the present invention. The following mathematical expressions are only examples for ease of understanding. The present invention is not limited to adopting the following specific mathematical forms.
[0042] Let the linearized model under a single perspective be: in, For the observation vector, Based on the basic sensitivity matrix, The distribution vector to be reconstructed is denoted as .
[0043] For the From each perspective, corresponding capacitance observation data can be obtained. and viewpoint sensitivity matrix The viewpoint sensitivity matrix It can be achieved through direct calibration, numerical simulation, or from a basic sensitivity matrix. Obtained through viewpoint transformation. If the fundamental sensitivity matrix is used... After transformation, it can be expressed as: in, For perspective The corresponding rotation mapping operator.
[0044] In one implementation, the observation vectors and viewpoint sensitivity matrices under each viewpoint are normalized and then stacked to obtain: This leads to a multi-perspective joint reconstruction model: in, This is multi-view capacitance observation data.
[0045] In one implementation, the joint model can be solved using an iterative reconstruction method with non-negativity constraints. For example, the following update method can be used: in, This represents the nonnegative projection operator. This represents the reconstruction result of the t-th iteration. Indicates the step size parameter. This is the transpose symbol. Furthermore, the linear backprojection result can be used as the initial value for iteration.
[0046] The aforementioned joint reconstruction processing method can fully utilize multi-view observation information and further improve the quality of reconstructed images in some application scenarios. Correspondingly, such as... Figure 4 As shown, the joint reconstruction process can be summarized as follows: Step S1, input the basic sensitivity matrix and mask and set the view set; Step S2, collect observation data from each view; Step S3, construct the sensitivity matrix of each view and normalize it; Step S4, stack them to form a joint model; Step S5, perform joint reconstruction solution and output the results. (V) Specific Implementation Examples In one specific embodiment, the number of electrodes is taken as... The total electrode coverage is taken as The ratio of the maximum electrode arc length to the minimum electrode arc length is taken as The angle between adjacent electrodes remains the same, and the arc length of each electrode is arranged using a cosine-weighted allocation method.
[0048] During the data acquisition process, the rotation and positioning mechanism (1-8) uses... The angle step size drives the rotation of the capacitance tomography sensor to select... Data is collected from multiple perspectives. Under each perspective, the capacitance switching acquisition circuit (1-9) performs mutual capacitance measurement according to the same measurement channel definition and sends the obtained multi-view observation data to the host computer (1-11).
[0049] The host computer (1-11) performs reconstruction processing on the multi-view observation data. Compared with the case of using only single-view observation, this embodiment can obtain more effective observation information and improve the quality of reconstructed images by combining non-uniform electrode structure and rotating multi-view acquisition.
[0050] It should be noted that the number of electrodes, total coverage, arc length ratio, angle step size, number of viewing angles, and specific reconstruction processing methods can all be adjusted according to different test objects and application environments, and should not be construed as limiting the scope of protection of this invention.
Claims
1. A rotation-enhanced non-uniform electrode capacitance tomography system, characterized in that, It includes a capacitance tomography sensor, a rotation and positioning mechanism, a capacitance switching acquisition circuit, a microcontroller unit, and a host computer; among which: The capacitance tomography sensor includes a substrate or insulating cylinder and components arranged along the inner circumference of the substrate or insulating cylinder. Each electrode has a gap between adjacent electrodes, and the arc lengths of each electrode are not all the same, so as to form a non-uniform electrode array. The rotation and positioning mechanism is connected to the capacitance tomography sensor and is used to drive the capacitance tomography sensor to rotate around the axis of the measured area or the measured target at preset angle steps and to position it at multiple viewpoints when the measured area or the measured target is relatively fixed. The capacitor switching acquisition circuit and the Each electrode is electrically connected to switch the measurement channels between the electrodes according to the same measurement channel definition under each positioning view and to collect capacitance observation data to form multi-view capacitance observation data. The microcontroller unit is communicatively connected to the rotation and positioning mechanism, the capacitor switching acquisition circuit, and the host computer, and is used to control the execution timing of rotation positioning and channel switching acquisition. The host computer is used to receive the multi-view capacitance observation data and output the reconstructed image or reconstruction result parameters of the measured area or the measured target based on the multi-view capacitance observation data.
2. The system according to claim 1, characterized in that, The number of electrodes As a pre-set integer according to imaging requirements, all electrodes are arranged around the circumference of the substrate or insulating cylinder, and are arranged without overlap to form multiple discrete entities with independent acquisition channels; The corresponding gap angles between adjacent electrodes are all the same, and the sum of the arc lengths of all electrodes is less than the total circumference of the inner circumference of the substrate or insulating cylinder, so as to retain the insulating isolation gap.
3. The system according to claim 1, characterized in that, The non-uniform electrode array includes large-arc-length electrodes and small-arc-length electrodes distributed at different positions on the inner circumference of the substrate or insulating cylinder. The non-uniform electrode array forms a structural size difference so that the electrodes on the substrate or insulating cylinder are geometrically different at different circumferential positions, forming local dense areas and local sparse areas with asymmetrical electrode coverage. The arc lengths of each electrode in the non-uniform electrode array are arranged in a regular, gradual manner along the inner circumference of the substrate or insulating cylinder. The physical spatial arrangement includes any of the following: Arrangement method 1: The arc lengths of each electrode increase or decrease sequentially in a step-like manner with a fixed size difference along the inner circumference of the substrate or insulating cylinder; Arrangement method 2: The arc lengths of each electrode are smoothly transitioned to both sides along the circumference with the largest arc length electrode at a certain circumferential position as the center of symmetry, until the smallest arc length electrode is located at the opposite circumferential position.
4. The system according to claim 1, characterized in that, The preset angle step size and total number of angles Based on imaging requirements, a preset angle step size is defined as a non-zero deflection angle that causes the non-uniform electrode array to misalign with its initial spatial position after rotation. The total number of viewing angles is... To enable multiple samplings that can cover the circumference or part of the circumferential features of the measured area or the measured target.
5. The system according to claim 1, characterized in that, The rotation and positioning mechanism includes a motor, a transmission assembly, and an encoder or angle sensor, used to position and provide feedback on the rotation angle at each viewing angle.
6. The capacitance tomography method of the system according to any one of claims 1 to 5, characterized in that, Includes the following steps: Arranged on the inner circumference of the substrate or insulating cylinder The electrodes form an electrode array, with gaps between adjacent electrodes, and the arc lengths of each electrode are not all the same, so as to form a non-uniform electrode array. Under the condition that the area or target being measured is relatively fixed, the electrode array is driven to rotate around the axis to multiple viewing angles by a rotation and positioning mechanism at preset angle steps. From each perspective, the measurement channels between electrodes are switched according to the same measurement channel definition, and capacitance observation data are collected to obtain multi-view capacitance observation data. The multi-view capacitance observation data is sent to the host computer, which then reconstructs the measured area or target based on the multi-view observation data and outputs the reconstructed image or reconstruction result parameters.
7. The method according to claim 6, characterized in that, The capacitance observation data collected from various perspectives are as described above. The mutual capacitance observation data between the electrodes are used, and the same channel definition is used for each viewpoint.
8. The method according to claim 6, characterized in that, The reconstruction of the measured area or target based on multi-view observation data includes: obtaining the corresponding sensitivity matrix for each viewpoint, and stacking the capacitance observation data and sensitivity matrix under each viewpoint after normalization to form a multi-view joint reconstruction model.
9. The method according to claim 8, characterized in that, The sensitivity matrix is obtained through calibration measurement, numerical simulation, or by perspective transformation from the basic sensitivity matrix; the multi-view joint reconstruction model is solved using an iterative reconstruction method with non-negative constraints.
10. The method according to claim 9, characterized in that, The iterative reconstruction uses the linear backprojection result as the initial value for the iteration.