CN101178382B

CN101178382B - Peak value width polymerization filtering methods using circumference coordinates system

Info

Publication number: CN101178382B
Application number: CN2007100938958A
Authority: CN
Inventors: 金根顺; 李瑞忠
Original assignee: Shanghai Baosight Software Co Ltd
Current assignee: Shanghai Baosight Software Co Ltd
Priority date: 2007-06-26
Filing date: 2007-06-26
Publication date: 2011-02-09
Anticipated expiration: 2027-06-26
Also published as: CN101178382A

Abstract

The invention provides a peak value edge width polymerization filtering method which adopts a circumference coordinate system, including the following steps: step 1. two lines of signals which are obtained by comparison of a sensor are carried out the coordinate transformation, an X axis and a Y axis of a rectangular coordinate system are transformed into a r axis and a Theta axis of the circumference coordinate system; step 2. the r value sequence is carried out the smooth processing to remove the small interference burrs, so as to ensure the accurate seeking of the peak value; step 3. the wave peak, the wave trough and the demarcation point are sought in the r value sequence; step 4. the polymerization of the peak value is completed; step 5. the differentiation is carried out on the phase angle Theta of the circumference coordinate system. The peak value edge width polymerization filtering method which adopts the circumference coordinate system that is provided by the invention can solve the problem that the differentiation can not be carried out as the noise signal on the same phase angle is stronger than the defect signal in the eddy current or magnetic leakage flaw detection equipments.

Description

Adopt the peak value not care about one's appearance polymerization filtering methods of circumferential coordinates system

Technical field

The present invention relates in the signal analysis and processing a kind of filtering method, particularly a kind ofly be used for the peak value not care about one's appearance polymerization filtering methods that eddy current, magnetic leakage detection adopt circumferential coordinates system.

Background technology

In eddy current and magnetic leakage detection equipment, pumping signal is a standard sine wave, and sensor feedback signal is because of having comprised flaw indication slightly distortion on the basis of sine wave.Sensor signal and pumping signal comparison back form two paths of signals, and wherein the relative amplitude of one tunnel characterization feedback signal changes the phase change of another road characterization feedback signal.Directly be drawn in rectangular coordinate system as X, Y value this two paths of signals, form " 8 " word figure, can see that flaw indication is different with the angle of the dynamic vibration of surface noise signal on two dimensional surface, this also is usually in order to distinguish the method for surface noise signal and flaw indication.

But in the carrying out flaw detection process, no matter be surface noise signal or flaw indication, fastening in circumferential coordinates all has the phase angular breadth, and the peak value not care about one's appearance of the surface noise signal that intensity is bigger may opacifying strength smaller defect signal, makes it can not be by identification.Original domestic and international eddy current or leakage field equipment did not all carry out special disposal to the signal peak not care about one's appearance, caused the trickle defective of some degree of depth to be detected.

Summary of the invention

Technical matters to be solved by this invention is to fasten in circumferential coordinates, and the peak value not care about one's appearance of surface noise signal and flaw indication is carried out polymerization, and " 8 " font or the polymerization of " 0 " font peak value are become

" 1 " font peak value makes noise signal and flaw indication On phase angle theta, separate fully, no longer

Hide mutually, thereby improve the detection sensitivity of little flaw indication.

In order to solve the problems of the technologies described above, the invention provides a kind of peak value not care about one's appearance polymerization filtering methods that adopts circumferential coordinates system, comprise the steps:

Step 1 is handled the 2D signal that obtains with comparison and is carried out coordinate conversion, and originally the X of rectangular coordinate system, Y-axis are converted into r, the θ axle of circumferential coordinates;

Step 2 is carried out smoothing processing to the r value sequence, removes small size interference burr;

Step 3 is sought crest, trough and separation thereof in the r value sequence;

Step 4 is finished the polymerization to peak value;

Step 5 is differentiated on the phase angle theta of circumferential coordinates system.

Beneficial effect

Bigger raising defect-detecting equipment detection sensitivity, and can be applicable to other similar flaw indication detection processing.

Description of drawings

Fig. 1 is the process flow diagram of the peak value not care about one's appearance polymerization filtering of phase field;

Fig. 2 is the signal schematic representation that does not use the peak value not care about one's appearance polymerization filtering of phase field;

Fig. 3 is to use the peak value not care about one's appearance polymerization filtering signal schematic representation (representing with diffusing point mode) afterwards of phase field;

Fig. 4 is to use the peak value not care about one's appearance polymerization filtering signal schematic representation (representing with the single line mode) afterwards of phase field.

Embodiment

Obtain two-way rectangular coordinate system signal X, Y after step 1, signal of sensor and pumping signal are compared, X, Y are carried out coordinate conversion, with the X of original rectangular coordinate system, r, the θ that Y is converted into circumferential coordinates, the mould and the phase angle of difference characterization data point.

Its conversion formula is:

R＝sqr(X*X+Y*Y)；

θ＝arctan(Y/X)；

Step 2, utilize mathematical methods such as discrete Fourier transform (DFT), wavelet transformation or FIR that the r value sequence is carried out smoothing processing, remove small size interference burr, guarantee correct searching r value sequence peak value.

Various mathematical methods respectively have its characteristics, select for use according to actual conditions.Application of principle can not surpass certain threshold value for interference is beated to the influence of crest when removing.

Step 3, obtain the differential sequence D of r value, seek each limit of r value sequence.

The differential sequence is asked method: D (N)=r (N+1)-r (N);

Think in principle, represent that when the differential sequence is 0 the r sequence is in flex point.Owing to there is 0 continuous problem among the D (N), also need to add corresponding fuzzy Judgment, finish cutting apart of each border.

Step 4, finish polymerization to peak value.There has been each limit to assist, just obtained separatrix, corresponding border, in r value sequence upthrow cambered surface, found typical value (generally get maximal value, also can average or integrated value), the crest signal pcl has been combined into single line.

Step 5, manually be provided with the sorting scope (only allowing flaw indication pass through) of θ after, because the not care about one's appearance of peak value has obtained polymerization, flaw indication no longer is subjected to the covering of noise signal not care about one's appearance, and surface noise and flaw indication are separated on the phase angle theta of circumferential coordinates system fully.

Embodiment

Describe the present invention in detail below in conjunction with Fig. 2, Fig. 3, Fig. 4 synoptic diagram and how to reach raising defect-detecting equipment detection sensitivity purpose.

Fig. 2 is the pattern of original signal.Though the vibration phase angle of surface noise and flaw indication is different, the not care about one's appearance of surface noise is bigger, has hidden flaw indication.Only rely on the phase place sorting can't avoid the influence of noise signal, cause and to differentiate noise signal and flaw indication flaw indication.

Fig. 3, Fig. 4 are to use the peak value not care about one's appearance polymerization filtering signal hint pattern afterwards of phase field, and Fig. 3 represents crest with diffusing point mode, and Fig. 4 represents crest with the single line mode.After carrying out the peak value not care about one's appearance polymerization of phase field, the crest not care about one's appearance all is aggregated, and surface noise and flaw indication is carried out the sorting of mutually noninterfere on phase place.

Claims

1. a peak value not care about one's appearance polymerization filtering methods that adopts circumferential coordinates system is used in the analyzing and processing of flaw detection signal, it is characterized in that, comprises the following steps:

Step 1 is carried out coordinate conversion with sensor output signal and pumping signal through the two paths of signals that the comparison processing obtains, and is converted into r, the θ axle of circumferential coordinates system by X, the Y-axis of rectangular coordinate system;

Step 3 is sought crest, trough and separation thereof in the r value sequence, be to ask method with the differential sequence: D (N)=r (N+1)-r (N) obtains the differential sequence D of r value, seeks each limit of r value sequence; Step 4 has had each limit to assist, and has just obtained separatrix, corresponding border, in r value sequence upthrow cambered surface, find typical value, typical value comprises maximal value, mean value or integrated value, and the crest signal pcl is combined into loose point or single line, finishes the polymerization to peak value;

2. the peak value not care about one's appearance polymerization filtering methods that employing circumferential coordinates according to claim 1 is, it is characterized in that, two paths of signals is aggregated into single-point or single line respectively on dynamic phase angle direction of vibration, on phase angle, thoroughly separated, no longer interfere with each other, thoroughly eliminated the mutual covering of not care about one's appearance between signal.

3. the peak value not care about one's appearance polymerization filtering methods that employing circumferential coordinates according to claim 1 is is characterized in that, is used in eddy current or the magnetic leakage detection.

4. the peak value not care about one's appearance polymerization filtering methods that employing circumferential coordinates according to claim 3 is, it is characterized in that, when this method is used in eddy current or the magnetic leakage detection, solved the problem that the jamtosignal flaw indication can't be differentiated by force on the same phase angle.