Area increment based resistive tomography sensitivity coefficient in high conductivity flow field

Abstract

This invention relates to a resistivity tomography sensitivity coefficient based on area increment in a high-conductivity flow field. The key feature is that the area increment of a pixel is defined as the sum of the areas of all its neighboring pixels. Under any excitation and measurement mode, the area increment of a pixel in the flow field inevitably produces an increment in the boundary measurement value. The ratio of the measurement value increment to the area increment is used to calculate the area increment-based sensitivity coefficient in a high-conductivity flow field, which characterizes the boundary measurement response corresponding to a unit increment in pixel area. This invention also provides a method for object reconstruction and parameter detection using this sensitivity.

Description

Technical Field

[0001] This invention belongs to the field of application technology based on resistance tomography, specifically involving the definition of a novel electrical tomography sensitivity coefficient based on area increment in a high conductivity flow field. It is a method for obtaining prior information in applications of visual reconstruction of the detection object and parameter detection. Background Technology

[0002] Electrical resistance chromatography (ORC) is an advanced, visual measurement technique with advantages such as being radiation-free, non-invasive, having a fast response time, and being practical and economical. Currently, ORC technology is widely used in testing fields such as chemical, petroleum, biological, and medical fields.

[0003] The application of electrical resistivity tomography relies on various reconstruction algorithms. In the reconstruction algorithm, the sensitivity coefficient is an important type of prior information. The sensitivity matrix composed of all the sensitivity coefficients and the measured values ​​are used to achieve the visual reconstruction of the detected target according to a specific algorithm.

[0004] However, the sensitivity coefficients currently used, based on conductivity increments, exhibit a non-linear trend in the relationship between pixel conductivity changes and boundary responses within the detection field. Particularly in high-conductivity flow fields, the boundary measurement response to pixel conductivity tends to be infinitesimal, thus negating the fundamental role of the sensitivity coefficient. High-conductivity flow fields are prevalent, such as seawater (32.5 μS / cm) and the average conductivity of a mixture of river water and seawater at ports (12.3 μS / cm). In these applications, the failure of the sensitivity coefficient renders resistivity tomography unusable. Summary of the Invention

[0005] Considering that in high-conductivity flow fields, the boundary response caused by pixel area changes is higher than that caused by conductivity changes, this invention proposes a novel electrical tomography sensitivity coefficient based on area increments. This overcomes the limitations of existing sensitivity coefficients based on conductivity increments in high-conductivity flow field applications, providing a new calculation method and means to improve the spatial resolution of resistance tomography. The technical solution is as follows:

[0006] A resistivity tomography sensitivity coefficient based on area increment in a high conductivity flow field is characterized by defining the area increment of a pixel as the sum of the areas of all its neighboring pixels; under any excitation and measurement mode, the area increment of a pixel in the flow field will necessarily produce a boundary measurement increment; the ratio of the measurement increment to the area increment is used to calculate the area increment-based sensitivity coefficient in a high conductivity flow field, which is used to characterize the boundary measurement response when the pixel area has a unit increment.

[0007] Further, let Ω represent the detected flow field, and n be the total number of pixels in Ω; under a given excitation mode, the sensitivity coefficient of the j-th pixel in Ω based on the area increment is defined as:

[0008]

[0009] In the formula, σ j (k) represents the conductivity increment corresponding to the k-th neighboring pixel of the j-th pixel, k = 1, ..., T j ,T j σ(j) represents the conductivity increment of the j-th pixel; v(j,k) represents the measurement increment caused by the conductivity increment of the k-th neighboring pixel in the excitation mode; u(j) represents the measurement increment caused by the conductivity increment of the j-th pixel in the excitation mode.

[0010] The method for reconstructing the detection object and detecting parameters using the aforementioned resistance tomography sensitivity coefficient, applied to high conductivity flow fields, is characterized by comprising the following steps:

[0011] ① Under a given excitation mode, ensure that all pixels in Ω have a uniform conductivity, i.e., an empty field;

[0012] ② Let the conductivity of the j-th pixel have an increment σ(j), and obtain the boundary measurement value u(j) in the excitation mode;

[0013] ③ Let the T of the j-th pixel j The conductivity of adjacent pixels has an increment σ j (k), in the excitation mode, the boundary measurement value v(j,k) is obtained;

[0014] ④ Calculate the sensitivity coefficient;

[0015] ⑤ Traverse all pixels in Ω and execute steps ②, ③, and ④;

[0016] ⑥ Traverse all excitation electrodes and execute steps ②, ③, ④, and ⑤.

[0017] For each excitation mode, a sensitivity coefficient matrix S is obtained. S is used to replace the current sensitivity coefficient matrix based on conductivity increment, and the detection object is visualized, reconstructed, and its parameters are detected. Attached Figure Description

[0018] Figure 1 Schematic diagram of electrode distribution in electrical resistivity tomography.

[0019] Figure descriptions: 1. The j-th pixel; 2. Neighboring pixels of the j-th pixel; 3. Measurement electrode. Detailed Implementation

[0020] This invention addresses the application of high conductivity flow fields by proposing a novel definition, measurement, and application of the electrical tomography sensitivity coefficient based on area increment.

[0021] This patent application presents a resistivity tomography sensitivity coefficient based on area increment in a high-conductivity flow field, comprising three parts:

[0022] (1) Definition: In a high conductivity flow field, given any excitation and measurement mode, the sensitivity coefficient of any pixel is the increment of the corresponding boundary measurement value when the pixel area has a unit increment under the excitation and measurement mode.

[0023] The above "definition" specifically includes the following scope:

[0024] ① "High conductivity flow field" refers to a current field with an average conductivity greater than 10 μS / cm, and the current field has a current loop when excited from any position to another.

[0025] ② The "high conductivity flow field" has arbitrary boundary shape;

[0026] ③ "Excitation and measurement mode" in this embodiment means: using the currently commonly used single-electrode excitation and adjacent electrode mode, the corresponding measurements are all adjacent electrode measurement modes.

[0027] (2) Measurement: The area increment of a pixel is the sum of the areas of all its neighboring pixels; under any excitation and measurement mode, the area increment of a pixel in the flow field will inevitably produce the boundary measurement increment; the ratio of the measurement increment to the area increment is used to calculate the "sensitivity coefficient based on area increment" in the "definition".

[0028] The "Measurement" section above specifically includes the following range:

[0029] ① "Neighboring pixels" refers to all pixels that intersect with a given pixel;

[0030] ② "Area increment" refers to the increase in area caused by expanding from one pixel to its neighboring pixels;

[0031] (3) Application: In a high conductivity flow field, all pixels form a sensitivity coefficient matrix based on the area increment sensitivity coefficients; use this sensitivity coefficient matrix to replace the current electrical tomography algorithm based on conductivity increment sensitivity coefficient matrix to reconstruct the detection object and detect parameters.

[0032] Assuming a given detected flow field is excited using either a single-electrode excitation or adjacent-electrode excitation, the present invention uses the following symbols to denote specific meanings:

[0033]

[0034] The specific technical solution is as follows:

[0035] (1) Definition: Under a given excitation mode, the sensitivity coefficient of the j-th pixel in Ω based on the area increment is defined as:

[0036]

[0037] This definition represents the response of boundary measurements when the pixel area has a unit increment.

[0038] (2) Measurement and Implementation:

[0039] ① Ensure that all pixels in Ω have a uniform electrical conductivity (i.e., an empty field) under a given excitation mode;

[0040] ② Let the conductivity of the j-th pixel have an increment σ(j), and obtain the boundary measurement value u(j) in the excitation mode;

[0041] ③ Let the T of the j-th pixel j The conductivity of adjacent pixels has an increment σ j (k) is obtained under the excitation mode.

[0042] Measured value v(j,k);

[0043] ④ Calculate the sensitivity coefficient according to the definition in (1);

[0044] ⑤ Traverse all pixels in Ω and execute steps ②, ③, and ④;

[0045] ⑥ Iterate through all excitation electrodes and execute steps ②, ③, ④, and ⑤;

[0046] (3) Application: Based on all the obtained "sensitivity coefficients based on area increment", a sensitivity coefficient matrix S is formed. S is used to replace the currently common sensitivity coefficient matrix based on conductivity increment, and the detection object is visualized, reconstructed and its parameters are detected.

Claims

1. A method for reconstruction of a detection object and parameter detection based on an area increment-based resistive tomography sensitivity coefficient implementation for a high conductivity flow field, characterized by, comprising the following steps: ①Ω represents the detected flow field, n N is the total number of pixels in Ω, and all pixels in Ω have the same conductivity under the given excitation mode, i.e. the empty field. ii) let the first pixel conductivity have an increment j σ j u j ​​​​​ ③ let the conductivity of the first pixel have an increment j T j of the second adjacent pixel, in the excitation mode to obtain the boundary measurement value σ j ( k ) v ( j, k )​ IV. Calculate the sensitivity coefficients according to the following method: The area increment of a pixel is defined as the sum of the areas of all its neighboring pixels. Under any excitation and measurement mode, the area increment of a pixel in the flow field necessarily produces an increment in the boundary measurement value. The ratio of the measurement increment to the area increment is used to calculate the area increment-based sensitivity coefficient in high-conductivity flow fields, characterizing the boundary measurement response corresponding to a unit increment in pixel area. Under a given excitation mode, the th... j The sensitivity coefficient based on area increment for each pixel is defined as follows: In the formula, σ j ( k ) indicates the first j The first pixel k Each neighboring pixel corresponds to an increase in conductivity. k =1,…, T j , T j The number of neighboring pixels; σ ( j ) indicates the first j The increase in conductivity per pixel; v ( j, k ) indicates the first in the incentive mode k The increase in measured value caused by the increase in conductivity of a neighboring pixel; u ( j ) indicates the first in the incentive mode j The increase in measured value caused by the increase in conductivity of each pixel; V. Execute steps II, III, IV for all pixels in Ω; VI. Execute steps II, III, IV and V for all excitation electrodes; For each excitation mode, a sensitivity coefficient matrix is obtained S Instead of the current incremental conductivity-based sensitivity coefficient matrix, the detection object is visualized reconstructed and parameter detected using S Instead of the current incremental conductivity-based sensitivity coefficient matrix, the detection object is visualized reconstructed and parameter detected using

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