Direct image reconstruction method based on capacitance tomography of round sensor

Abstract

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.

Description

(1) Technical field [0001] The invention relates to an image reconstruction method, in particular to a direct method of image reconstruction based on electric capacitance tomography of a circular sensor. The invention belongs to the technical field of image reconstruction. (2) Background technology [0002] Electrical capacitance tomography (ECT) is based on the measured capacitance data to reconstruct the distribution of the space permittivity of insulating materials. ECT has several advantages over other tomographic techniques such as: low cost, fast response, portability, non-invasiveness and robustness. It has broad application prospects in many industrial fields. The core technology of ECT is to use the image reconstruction method to reconstruct the variation of the internal permittivity distribution according to the variation of a set of measured values ​​of boundary capacitance. [0003] In the past, most image reconstruction algorithms were based on the sensitivity...

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Problems solved by technology

[0006] However, due to the existence of a shielding layer in the ECT sensor, and the electrical resistance tomography in the literature uses an excitation measurement strategy of current excitation and voltage measurement, while ECT uses an excitation measurement mode of voltage excitation and current measurement, Calderon’s algorithm cannot be directly used. in ECT

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