Vertex C scanning imaging detection method

Abstract

The invention relates to a vertex C scanning imaging detection method. The method comprises steps of collecting impedance change waveform of a defect comparison test block; performing high-pass filtering on a solid part and a virtual part of the impedance change waveform, performing noise statistics on the filtered solid part and virtual part separately, and extracting a defect signal area; separating a lift-off signal from the defect signal area; then, calculating impedance amplitude, phase angle and impedance increment of the filtered impedance change waveform in the defect signal area, andextracting and envelop diagram of an impedance amplitude spectrum in the same defect after area fusion, so as to obtain corrected defect amplitude spectrum; performing threshold segmentation through the corrected defect amplitude spectrum, extracting a defect trend in an initial vertex C scanning imaging map, and establishing a relationship curve of different deflection angles and a defect maximumamplitude; and performing amplitude correction on defect trend and the initial vertex C scanning imaging map by using the relationship curve. The method can determine a defect position, length and direction accurately, and can quantify defect size accurately.

Description

technical field [0001] The invention relates to the field of image detection, in particular to an eddy current C-scan imaging detection method. Background technique [0002] Eddy current testing is a non-destructive testing method based on the principle of electromagnetic induction and is suitable for conductive materials. The basic principle is that when a conductor is placed in an alternating magnetic field, an induced current exists in the conductor, that is, an eddy current is generated. Due to the change of various factors of the conductor itself (such as electrical conductivity, magnetic permeability, shape, size and defect, etc.), the change of eddy current will be caused, and this phenomenon is used to determine the detection method of the nature and state of the conductor. Combining computer technology and digital signal processing technology, it can realize fast and effective detection of materials and parts. [0003] Combining eddy current testing with an automa...

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Problems solved by technology

[0004] However, the eddy current C-scan imaging has the following problems: 1) Impedance variation imaging is generally used in the eddy current C-scan imaging method, and the impedance presents a fluctuating law, and the size of the defect corresponds to the gray value of the image non-linearly, so that the inspectors cannot be more accurate. Judging the length, size and other information of the defect; 2) Due to the interference of the lift-off noise and the electrical noise of the automatic scanning device, there are false defects in the C-scan image

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