A multi-channel hydrophone channel sequence correctness automatic detection method

Abstract

The present application relates to a kind of multi-channel hydrophone channel sequence correctness automation detection method, the following steps are executed using computer, step 1, time delay matrix is solved;Step 2, judge channel sequence correctness;Wherein, the time delay matrix of step 1 is specifically operated as follows, step 1.1: sound source emits periodic T, the duty cycle of sinusoidal pulse signal is h, and the response waveform of each channel is recorded, for the i only hydrophone, record positive output signal p i,+ [n] and negative output signal p i,‑ [n], n is the sampling time sequence of digital signal.The present application avoids tedious manual detection, reduces the burden of workers;Greatly reduce the time required for detection, improve detection efficiency;Detection threshold can be adjusted according to test environment and condition.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrophone, and particularly relates to a multi-channel hydrophone channel sequence correctness automatic detection method. BACKGROUND

[0002] In the production process of the multi-channel hydrophone, the phase consistency and other indexes of responses of each channel need to be detected. Since the hydrophone is not completed encapsulation, the detection can only be carried out in the air. At present, the detection is completed by manual, and there are problems such as heavy burden of workers, slow detection speed, and inconsistent detection standards.

[0003] Taking a certain type of multi-channel hydrophone as an example, each channel is arranged in a matrix form on a panel, and a panel includes N=AB channels in total, which are arranged in A rows and B columns, and each channel has two output paths of positive (+) and negative (-). When wiring, 2N output paths are connected in the order of 1+, 1-, 2+, 2-, 3+, 3-, … Before encapsulation, the channel sequence correctness needs to be tested and checked. If the channel sequence of each hydrophone is consistent with the serial number (1, 2, 3, 4, …), it is determined to be qualified, otherwise it is determined to be unqualified (for example, 1, 4, 2, 3, …). In the current production process, the detection is mainly completed by manual, and there are problems such as low production efficiency and heavy burden of workers. SUMMARY

[0004] The technical problem to be solved by the application is to provide a multi-channel hydrophone channel sequence correctness automatic detection method, which avoids tedious manual detection and reduces the burden of workers, greatly reduces the time required for detection, and improves the detection efficiency.

[0005] The technical solution of the application is to provide a multi-channel hydrophone channel sequence correctness automatic detection method, which uses a computer to execute the following steps,

[0006] Step 1, calculating a time delay matrix;

[0007] Step 2, judging the channel sequence correctness; wherein,

[0008] The specific operation of step 1 for calculating the time delay matrix is as follows,

[0009] Step 1.1: a sound source emits a sinusoidal pulse signal with a period of T and a duty cycle of h, and records the response waveform of each channel. For the i-th hydrophone, the positive output signal p i,+ [n] and the negative output signal p i,- [n] are recorded, n is the sampling time sequence of the digital signal;

[0010] Step 1.2: Calculate the cross-correlation coefficient of the positive output of the remaining (N-1) channels relative to the first channel, using the positive output of the first channel as the standard. The specific method is as follows: for any -Tf s / 2 < m < Tf s / 2, T is the period of the sinusoidal pulse signal, f s is the sampling rate, and the cross-correlation coefficient r 1i [m] = r{p 1,+ [n], p i,+ [n+m]},

[0011]

[0012] Step 1.3: Find the maximum value of the cross-correlation coefficient , and the corresponding time delay is M 1i , which is the time delay of the signal reaching the two channels (the first and the i-th). 1i

[0013] Step 1.4: Take the positive output of the second, third, …, Nth channel as the standard, repeat steps 1.2 to 1.3, and obtain the N-row N-column cross-correlation coefficient matrix R = [R ij ] N×N and the time delay matrix M = [M ij ] N×N ;

[0014] The specific operation of step 2 to determine the correctness of the channel order is as follows,

[0015] Step 2.1: Establish a plane rectangular coordinate system xOy, let the number of channels in the x and y directions be A and B respectively, let the coordinates of the a-th row b-th column channel be (x ab , y ab ), and the spatial coordinates of the sound source be (x s , y s ), the distance from the sound source to the channel is

[0016]

[0017] The time delay of the channel receiving the sound source emitted signal is

[0018]

[0019] where c is the speed of sound, M ab is the time delay obtained in step 1, and the spatial position of the excitation source is specified,

[0020] (1) If the sound source position satisfies x s < 0, then the time delay should satisfy

[0021] M​1b <M 2b <…<M Ab (5)

[0022] (2)If the sound source position satisfies y s <0, then the time delay should satisfy

[0023] M a1 <M a2 <…<M aB (6)

[0024] If not, it means that the channel order is wrong, and the position of the abnormal channel is determined by the index of the size exception time delay;

[0025] Step 2.2: In order to measure the channel order of a one-dimensional channel array, a waveform is transmitted and the response is recorded at one position, which should be located on one side of the array; in order to measure the channel order of a two-dimensional channel array, at least two positions should be used to transmit waveforms and record responses, and the two positions should be on the same side of the array;

[0026] Step 2.3: In actual measurement, set the detection pass rate threshold ξ, for the ith channel, if M i1 ,M i2 ,…M iN of the N time delays satisfy the condition of step 2.1, then it is determined that the channel order is correct, otherwise it is determined that the channel order is wrong.

[0027] The method of the present application uses a computer program to detect the process of a multi-channel hydrophone, and the detection content is the correctness of the order of each channel. The detection method is that the sound source transmits an excitation signal, records the response of each channel, and judges whether the channel order is correct according to the response waveform. Moreover, the signal transmitted by the sound source should be a sine pulse signal with a certain duty cycle, otherwise it may affect the accuracy of time delay calculation, resulting in incorrect judgment. By calculating the cross-correlation coefficient and time delay matrix of each channel relative to each channel, and setting a detection pass rate threshold, the program is not sensitive to false positives in a single measurement, and the correct judgment rate is improved.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] The present application avoids tedious manual detection and reduces the burden on workers; greatly reduces the time required for detection and improves the detection efficiency; the detection threshold can be adjusted according to the test environment and conditions. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The program block diagram for step 1 of the present application to calculate the time delay matrix.

[0031] Figure 2The block diagram for judging the correctness of the channel sequence in step 2 of the present application. DETAILED DESCRIPTION

[0032] The present application will be further described in the specific embodiments in combination with the accompanying drawings:

[0033] A multi-channel hydrophone channel sequence correctness automatic detection method, which utilizes a computer to execute the following steps,

[0034] Step 1, time delay matrix is obtained;

[0035] Step 2, judging the correctness of the channel sequence; wherein,

[0036] As shown in the following, Figure 1 the specific operation of step 1 of obtaining the time delay matrix is as follows,

[0037] Step 1.1: a sine pulse signal with a period of T and a duty cycle of h is emitted by the sound source, and the response waveform of each channel is recorded. For the i-th hydrophone, the positive output signal p i,+ [n] and the negative output signal p i,- [n] (n is the sampling time sequence of the digital signal) are recorded.

[0038] Step 1.2: taking the positive output of the first channel as the standard, the cross-correlation coefficient of the positive output of the remaining (N-1) channels relative to the first channel is calculated. The specific method is as follows: for any -Tf s / 2 < m < Tf s / 2 (T is the period of the sine pulse signal, f s is the sampling rate), the cross-correlation coefficient r 1i [m] = r{p 1,+ [n], p i,+ [n+m]} is calculated according to the following formula (1).

[0039]

[0040] Step 1.3: the maximum value of the cross-correlation coefficient corresponding to the time delay is recorded as M 1i , and M 1i is the time delay of the signal reaching two channels (the first and the i-th).

[0041] Step 1.4: taking the positive output of the second, third, …, N-th channel as the standard, repeating steps 1.2 to 1.3, obtaining an N-row and N-column cross-correlation coefficient matrix R = [R ij ] N×N and a time delay matrix M = [M ij ] N×N .

[0042] As shown in the following, Figure 2The judgment of the correct sequence of the channels in step 2 is shown in the following,

[0043] Step 2.1: Establish a plane rectangular coordinate system xOy. Let the channel numbers in x and y directions be A and B respectively, as shown in Figure 2 Let the coordinate of the ath row bth channel be (x ab ,y ab ), the spatial coordinate of the sound source be (x s ,y s ), and the distance from the sound source to the channel be

[0044]

[0045] The time delay of the channel receiving the signal emitted by the sound source is

[0046]

[0047] where c is the sound speed, and M ab is the time delay obtained in step 1. Now a spatial position of the excitation source is defined,

[0048] (1) If the position of the sound source satisfies x s < 0, then The time delay should satisfy

[0049] M 1b < M 2b < … < M Ab (5)

[0050] (2) If the position of the sound source satisfies y s < 0, then The time delay should satisfy

[0051] M a1 < M a2 < … < M aB (6)

[0052] If the above conditions are not satisfied, it means that the sequence of the channels is incorrect, and the position of the abnormal channel can be determined by the index of the abnormal time delay. For example, for the hydrophone shown in Figure 2 , A = 4, B = 2, and the three-dimensional coordinates of each channel are respectively Now assume that the channel with coordinate (3, 2) and the channel with coordinate (4, 1) are exchanged in sequence, then

[0053] (1) When the position of the excitation source satisfies x s < 0, y s < 0, the error in the sequence of the channels cannot be detected by the time delay;

[0054] (2) When the position of the excitation source satisfies x s < 0, y s > 0,

[0055] ① The time delay of hydrophone with correct channel order should satisfy

[0056] 0 = M 11 < M 21 < M 31 < M 41

[0057] M 12 < M 22 < M 32 < M 42

[0058] M 11 > M 12

[0059] M 21 > M 22

[0060] M 31 > M 32

[0061] M 41 > M 42

[0062] ② The time delay of hydrophone with incorrect channel order will appear

[0063] M 11 < M 21 < M 41 < M 31 or M 11 < M 41 < M 21 < M 31

[0064] M 12 < M 22 < M 42 < M 32

[0065] M 31 < M 32

[0066] M 41 < M 42

[0067] The time delay of channels with coordinates (4, 1) and (3, 2) is abnormal. According to this, the positions of channels with incorrect order can be determined.

[0068] Step 2.2: To measure the channel order of a one-dimensional channel array, only need to emit a waveform at one position and record the response, which should be located at one side of the array (for example, x s<0); in order to measure the channel order of a two-dimensional channel array, at least two positions should be used to emit waveforms and record responses, and the two positions should be on the same side of the array (for example, x s <0,y s <0 and x s <0,y s >0, or x s <0,y s <0 and x s >0,y s <0, but not x s <0,y s <0 and x s >0,y x >0).

[0069] Step 2.3: Considering that the correct rate of time delay is not always 100% due to the interference such as reverberation and noise in the environment, a detection pass rate threshold value ξ can be set during actual measurement. For the ith channel, if more than ξ proportion of the N time delays satisfy the condition of step 2.1, it is determined that the channel order is correct, otherwise, it is determined that the channel order is incorrect. i1 i2 iN

[0070] The present application avoids tedious manual detection, reduces the burden of workers, greatly reduces the time required for detection, and improves the detection efficiency. The detection threshold value can be adjusted according to the test environment and conditions.

[0071] The above only describes the preferred embodiments of the present application, but should not be understood as limiting the claims. Any equivalent process transformation made by using the present application specification is included in the patent protection range of the present application.​​​

Claims

1. A method for automatically detecting the correctness of the channel sequence of a multi-channel hydrophone, characterized by: The following steps are included: Step 1, calculate the delay matrix; Step 2: Determine the correctness of the channel sequence; The specific operation of finding the delay matrix in step 1 is as follows: Step 1.1: The sound source emits a sinusoidal pulse signal with a period of T and a duty cycle of h, and records the response waveform of each channel. For the i-th hydrophone, record the positive output signal p i,+ [n] and negative output signal p i,- [n], n is the sampling timing of the digital signal; Step 1.2: Taking the positive output of channel 1 as the standard, calculate the correlation coefficient of the positive outputs of the remaining (N-1) channels relative to channel 1; the specific method is to calculate the correlation coefficient of the positive outputs of the remaining (N-1) channels relative to channel 1 for any -Tf s / 2<m<Tf s / 2, T is the period of the sinusoidal pulse signal, f s is the sampling rate, and the correlation coefficient r is calculated according to formula (1) 1i [m]=r{p 1,+ [n],p i,+ [n+m]}, Step 1.3: Find the maximum value of the cross-correlation coefficient The corresponding delay is recorded as M 1i , M 1i It is the time delay for the signal to reach the two channels (the 1st and the i-th); Step 1.4: Using the positive output of the second, third, ..., Nth channel as the standard, repeat steps 1.2 to 1.3 to obtain the N-row and N-column cross-correlation coefficient matrix R = [R ij ] N×N and the delay matrix M = [M ij ] N×N ; The specific operations for judging the correctness of the channel sequence in step 2 are as follows: Step 2.1: Establish a plane rectangular coordinate system xOy, let the number of channels in the x and y directions be A and B respectively, let the coordinates of the channel in row a and column b be (x ab ,y ab ), the spatial coordinate of the sound source is (x s ,y s ), the distance from the sound source to the channel is The time delay of the channel receiving the signal transmitted by the sound source is Where c is the speed of sound, M ab is the time delay obtained in step 1, and specifies the spatial position of the excitation source. (1) If the sound source position satisfies x s <0, then The delay should meet M 1b <M 2b <…<M Ab (5) (2) If the sound source position satisfies y s <0, then The delay should meet M a1 <M a2 <…<M aB (6) If it is not satisfied, it means that the channel sequence is wrong, and the position of the abnormal channel is determined by the subscript of the abnormal delay; Step 2.2: To determine the channel order of a one-dimensional channel array, transmit the waveform at one location and record the response. This location should be on one side of the array. To determine the channel order of a two-dimensional channel array, transmit the waveform at least two locations and record the response. These two locations should be on the same side of the array. Step 2.3: Set the detection pass rate threshold ξ during actual measurement. For the i-th channel, if M i1 ,M i2 ,…M iN If a proportion greater than ξ among the total N time delays satisfies the conditions in step 2.1, the channel sequence is determined to be correct; otherwise, the channel sequence is determined to be incorrect.

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