In-bore scanning error correction and yin-yang line identification method

Abstract

The invention discloses an in-bore scanning error correction and yin-yang line identification method, and belongs to the technical field of in-bore scanning, and the method comprises the steps: firstly obtaining multi-path measurement data of a rifling, carrying out the ellipse fitting of single-path data, the correction of an eccentric error, and the correction of an installation inclination angle error of a rotating platform after the ellipse rotation; performing preliminary alignment on the multi-path data according to the installation angle interval, setting single-frequency measurement according to the number of negative and positive lines of the barrel, calculating the phase difference among the data through the single-frequency measurement to obtain the number of offset sampling points among the four groups of data, correcting the installation angle error of the multi-path data after alignment, and performing fusion processing on the multi-path data; and finally, solving inflection points of contours of the fused data in a differential or sliding window mode to obtain contours of the yin and yang lines. According to the invention, the installation error can be corrected by processing the data of the plurality of sensors, the detection accuracy is improved, and the negative and positive lines of the artillery bore can be effectively identified.

Description

Technical Field

[0001] The present invention relates to the technical field of in-bore scanning, and particularly to a method for correcting in-bore scanning errors and identifying yin-yang lines. Background Art

[0002] After long-term use of a cannon, defects such as ablation, wear, cracks, fracture of the lands, severe copper fouling, and corrosion will appear in the inner bore, directly affecting the shooting accuracy, service life, and shooting safety of the cannon. Therefore, the inner bore of the cannon must be inspected before and after shooting. In practical applications, sensor data is often affected by various errors, especially installation errors. Therefore, developing effective data processing algorithms to correct these errors is the key to improving measurement accuracy. By processing the data, installation errors can be effectively corrected, including the eccentricity error of the rotation center, the installation inclination error of the sensor, and the radial angle deviation between multiple sensors, thereby improving the measurement accuracy. Summary of the Invention

[0003] The purpose of the present invention is to solve the disadvantages existing in the prior art, and to propose a method for correcting in-bore scanning errors and identifying yin-yang lines. This method can correct installation errors by processing data from multiple sensors, improve the accuracy of detection, and can effectively identify the yin-yang lines of the inner bore of the cannon. This method uses a correction algorithm based on an error model to achieve automatic detection and quantitative analysis of the defects in the inner bore of the cannon, thereby improving the reliability and safety of the use of the cannon.

[0004] The present invention achieves the above object through the following technical solutions:

[0005] A method for correcting in-bore scanning errors and identifying yin-yang lines, comprising the following steps:

[0006] First, use a multi-channel in-bore scanning device to obtain multi-channel data, and its data size is m×n:

[0007]

[0008] Assume that the in-bore scanning device is equipped with n channels of sensors. In formula (1), d1, d2, d n respectively represent the outputs of n channels of sensors, and m is the number of data points obtained by a single channel rotating one week;

[0009] Let the installation angle difference between the nth group and the 1st group of sensors be θ i , then the first i data of the nth group need to be moved to the end of the data of this channel to preliminarily align the data of each sensor;

[0010] l n =[d i+1,n d i+2,n …d m,n d1,n … d i,n T (13)

[0011] Among them, d i,n represents the i-th point of the n-th group of data, and l n is the sensor data after preliminary alignment;

[0012] D1 = [l1 l2 … l n (14)

[0013] Convert the data into Cartesian coordinate data. The single-channel data of the n-th group is:

[0014]

[0015] In formula (4), (x k,n , y k,n ) represents the Cartesian coordinates of the k-th data in the n-th group of data.

[0016] Preferably, perform ellipse fitting on each single-channel data obtained from formula (4) to obtain the ellipse center position (x0, y0), the angle of the major axis relative to the positive x direction is θ0, and the ratio of the major and minor axes is A. After subtracting the center coordinates from the Cartesian coordinate data, use the rotation matrix to rotate the Cartesian coordinate data so that the ellipse center is located at the origin of the Cartesian coordinate system and the ellipse major axis is located on the x-axis. Accordingly, the test error caused by the eccentricity of the rotation center of the in-bore scanning device can be corrected:

[0017]

[0018] In formula (5), (x' k,n , y' k,n ) represents the coordinates of the k-th sampling point after correcting the eccentricity error of the n-th group of data.

[0019] Preferably, use the scaling matrix of affine transformation for the data (x' k , y' k ) obtained after correcting the eccentricity error of the n-th group of data obtained from formula (5). Construct a matrix according to the ratio of the major and minor axes A of the ellipse, and the contour of the obtained data in the Cartesian coordinate system is close to a perfect circle, and sequentially correct the measurement error caused by the sensor inclination of the in-bore scanning device:

[0020]

[0021] In formula (6), represents the coordinates of the k-th sampling point after correcting the inclination error of the n-th group of data.

[0022] Preferably, convert the coordinates in formula (6) into polar coordinate data: ​

[0023]

[0024] l' n = [l 1,n l 2,n … l k,n T (19)

[0025] D2 = [l'1 l'2l' n [] (20)

[0026] The [l k,n θ k,n in Equation (7) represents the k-th data of the n-th group of data converted to polar coordinates, and l' n in Equation (8) is the n-th group of data after being converted to polar coordinates, and D2 in Equation (9) is all channel data after being converted to polar coordinates.

[0027] Preferably, according to the number of male and female threads of the gun barrel, single-frequency measurement is set for the data D2 after being converted to polar coordinates. Let the number of male and female threads be j and the sampling time be t, then the main frequency is j / t, and the phase φ n between the calculated data of the n-th group of single-frequency measurements is obtained, and the number of offset points of the n-th group of data relative to the first group of data is obtained. The formula is:

[0028]

[0029] where Δt n is the number of offset points of the n-th group of data relative to the first group of data, then

[0030]

[0031] D3 = [l1”l2” … l n ”] (21)

[0032] where l' k,n represents the n-th data point of l' k , and l n ” is the n-th group of data obtained after processing the phase deviation, and the full-channel data is D3.

[0033] Preferably, a multi-channel data fusion method is used for the data D3, including but not limited to methods such as calculating the mean value and screening out abnormal points, to obtain:

[0034]

[0035] R = [a1 a2…a m T

[0036] where a m ​​It represents the fusion processing result of the m-th sampling point in all channels, f represents the fusion processing method, and R represents a set of data with a length of m for the final output.

[0037] For the data R, use the method of difference or sliding window to obtain the inflection points of its contour, and take the data between the inflection points to obtain the contour of the positive line.

[0038] Compared with the prior art, the present invention has the following beneficial technical effects:

[0039] 1) The in-bore scanning error correction method proposed by the present invention is based on an error geometric model, considering eccentricity, inclination, and radial angle error, and provides a highly interpretable error correction method.

[0040] 2) The present invention separately corrects and then fuses multi-channel data, greatly improving the credibility of the data, facilitating the elimination of abnormal points, and at the same time reducing the influence of the installation error of the sensor in the radial position. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0042] Figure 1 It is the original waveform diagram of the embodiment in the present invention;

[0043] Figure 2 It is the original waveform polar coordinate diagram with eccentricity and inclination error in the embodiment of the present invention;

[0044] Figure 3 It is the rectangular coordinate contour diagram with eccentricity and inclination error in the embodiment of the present invention;

[0045] Figure 4 It is the rectangular coordinate contour diagram after correcting eccentricity and inclination error in the embodiment of the present invention;

[0046] Figure 5 It is the waveform diagram of four channels with phase difference in the embodiment of the present invention;

[0047] Figure 6 It is the waveform diagram after aligning four channels in the embodiment of the present invention;

[0048] Figure 7 It is the contour diagram after correction in the embodiment of the present invention;

[0049] Figure 8 It is the contour diagram of positive and negative lines in the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0050] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0051] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0052] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, method or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive with other embodiments, either individually or selectively.

[0053] Secondly, the present invention is described in detail in conjunction with schematic diagrams. When describing the embodiments of the present invention in detail, for the convenience of explanation, the schematic diagrams are only examples and should not limit the scope of protection of the present invention.

[0054] Embodiment 1

[0055] like Figure 1-8 As shown, the present invention proposes a method for correcting scanning errors in a chamber and identifying positive and negative lines, comprising the following steps:

[0056] First, obtain multiple channels of measurement data, four channels in this embodiment. Due to inaccurate centering, the data curve presents a sinusoidal form, such as Figure 1 As shown, the data is converted to polar coordinates as Figure 2 As shown;

[0057] In this embodiment, the in-bore scanning device is equipped with 4 sensors, the sampling time is 288 seconds, the sampling rate is 100 Hz, and the data size is 28800×4;

[0058] Assume that the installation angle difference between the nth group of sensors and the first group of sensors is θ i , It is necessary to move the first i sampling points of the nth group to the end of the channel data to preliminarily align the sensor data.

[0059] Convert the single-channel data after preliminary alignment into rectangular coordinate system data, such as Figure 3 As shown;

[0060] For each single-channel data, perform elliptical fitting to obtain the elliptical center position, the angle of the major axis relative to the positive x-direction, and the ratio of the major and minor axes. After subtracting the center coordinates from the rectangular coordinate data, use the rotation matrix to rotate the rectangular coordinate data so that the elliptical center is located at the origin of the rectangular coordinates and the major axis of the ellipse is on the x-axis. In this way, the test error caused by the eccentricity of the rotation center of the in-bore scanning device can be corrected, as Figure 4 shown.

[0061] Convert the data back to polar coordinates again, with the abscissa being the sampling time and the ordinate being the distance, to obtain a waveform at the envelope level. Its main frequency is the frequency of the yin and yang lines. At this point, the error caused by the installation inclination has been corrected, but there is still a phase difference in the four-channel data, which is mainly due to the deviation of the installation angle of the ranging sensor, as Figure 5 shown.

[0062] According to the number of yin and yang lines of the gun barrel, set single-frequency measurement for the data converted to polar coordinates, as Figure 5 in the data. If the number of yin and yang lines is 48, then the main frequency is 48 / 288 = 0.1666 hz. Calculate the phase difference between the data through single-frequency measurement to obtain the sampling points of the offset between the four groups of data.

[0063] Align the four groups of data and use the method of averaging or removing outliers to obtain the data A after phase alignment, as Figure 6 shown.

[0064] Convert it to polar coordinates to obtain a contour map, as Figure 7 shown.

[0065] Use the method of difference or sliding window for the data again to obtain the inflection points of the contour and get the contour of the yin and yang lines.

[0066] Transfer it to polar coordinates to obtain the contour map of the yin and yang lines, as Figure 8 shown; at this point, all the data of the yin and yang lines can be obtained.

[0067] In this embodiment, the wear amount can be obtained by calculating the average value of the yin and yang lines. Compare the data of the yin and yang lines with the data at each position in the gun barrel to obtain the wear amounts at different positions. Through the present invention, it can be measured whether there is ablation in the gun barrel. When there are abnormal protrusions or abnormal defects on the yang line, or the measured radius exceeds the normal range, it can be determined that the wear amount here is too large, there is a missing part or ablation attachment, and the gun barrel needs to be repaired or replaced.

[0068] The present invention uses multiple laser sensors to be able to exclude error points from each other, thereby ensuring the integrity of the data. Even if one laser sensor does not measure data at a certain place, the data can still be measured and corrected through the other three laser sensors, improving the measurement accuracy.

[0069] Due to installation errors during installation, i.e., the installation problem of the laser sensor, this problem will cause the data to contain an overall error. By averaging the data from four laser sensors, this problem can be solved and the influence of the installation error can be reduced; the centering problem is corrected by ellipse fitting, and the inclination problem is solved by correcting the ellipse back to a circular shape, so as to reduce the influence brought by the installation error and improve the measurement accuracy.

[0070] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited thereto. Various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those skilled in the art.

Claims

1. A method for correcting in-bore scanning errors and identifying yin and yang lines, characterized in that It includes the following steps: First, use a multi-channel in-bore scanning device to obtain multi-channel data with a data size of m×n: Suppose the in-bore scanning device is equipped with n sensors. In Equation (1), d1, d2, …, d n respectively represent the outputs of the n sensors, and m is the number of data points obtained by a single channel rotating one week; Let the installation angle difference between the nth group and the first group of sensors be θ i , then it is necessary to move the first i data of the nth group to the end of the data of this channel to preliminarily align the data of each sensor; l n = [d i+1,n d i+2,n … d m,n d 1,n d i,n T (2)​ where d i,n represents the i-th point of the n-th group of data, and l n is the sensor data after preliminary alignment; D1＝[l1 l2 … l n ] (3) Convert the data into Cartesian coordinate data, and the single-channel data of the nth group is; In formula (4), (x k,n , y k,n ) represents the rectangular coordinates of the k-th data in the n-th group of data; l k,n represents the k-th sensor data of the n-th group of data l n in D1.

2. The method for correcting in-bore scanning error and identifying yin-yang lines according to claim 1, wherein Perform ellipse fitting on each single-channel data obtained from Equation (4) to obtain the ellipse center position (x0, y0), the angle of the major axis relative to the positive x direction is θ0, and the ratio of the major and minor axes of the ellipse is A. After subtracting the center coordinates from the Cartesian coordinate data, use a rotation matrix to rotate the Cartesian coordinate data so that the ellipse center is located at the origin of the Cartesian coordinate system and the major axis of the ellipse is on the x-axis. In this way, the test error caused by the eccentricity of the rotation center of the in-bore scanning device can be corrected; In formula (5), (x' k,n , y' k,n ) represents the coordinates of the k-th data after correcting the eccentric error of the n-th group of data.

3. The method for correcting in-bore scanning error and identifying yin-yang lines according to claim 2, characterized in that After correcting the eccentric error of the nth group of data obtained from Equation (5), the data (x' k , y' k ) uses the scaling matrix of the affine transformation to construct a matrix according to the major and minor axis ratio A of the ellipse, and the contour of the obtained data in the rectangular coordinate system is close to a perfect circle. The measurement error caused by the sensor inclination of the in-bore scanning device is corrected sequentially: In formula (6), represents the coordinates of the k-th data after correcting the inclination error of the n-th group of data.

4. A method for correcting in-bore scanning errors and identifying yin-yang lines according to claim 3, characterized in that, Convert the data in Equation (6) into polar coordinate data: l' n ＝[l 1,n l 2,n …l k,n ] T (8) D2＝[l'1 l'2…l' n ] (9) [l in Equation (7) k,n θ k,n represents the k-th data after the n-th group of data is transformed into polar coordinates. l' in Equation (8) n is the n-th group of data after being transformed into polar coordinates. D2 in Equation (9) is all the channel data after being transformed into polar coordinates.

5. A method for correcting in-bore scanning errors and identifying yin-yang lines according to claim 4, characterized in that According to the number of yin and yang lines of the gun barrel, single-frequency measurement is set for the data D2 after being converted to polar coordinates. Let the number of yin and yang lines be j and the sampling time be t, then the main frequency is j / t, and the phase φ between the calculation data of the nth group of single-frequency measurements is obtained. n , and the number of offset points of the nth group of data relative to the first group of data is obtained. The formula is: where Δt n is the number of offset points of the nth group of data relative to the first group of data, then where l' k,n represents the nth data point of l k , and l n ” is the nth group of data obtained after processing the phase deviation, and the full-channel data is D3.

6. A method for correcting in-bore scanning errors and identifying yin-yang lines according to claim 5, characterized in that Use a multi-channel data fusion method for the data D3, including but not limited to calculating the mean value and anomaly point screening method, to obtain: Among them, a m represents the fusion processing result of the m-th sampling point in all channels, f represents the fusion processing method, and R represents a set of data with a length of m finally output; Use the difference or sliding window method for the data R again to obtain the inflection points of its contour, and take the data between the inflection points to obtain the contour of the raised line.

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