Acoustic imaging system and method for underwater targets

Abstract

The present application provides an acoustic imaging system and method for underwater targets, comprising: a transducer for emitting a first acoustic wave signal toward an underwater target object, which is reflected at a first position and forms an echo signal; a laser sensor for emitting a laser beam and determining echo wave vector information of the echo signal based on first phase information of the laser beam under the influence of the echo signal; and determining normal information at the first position based on the first acoustic wave wave vector information and the echo wave vector information of the first acoustic wave signal, so as to form an acoustic image of the underwater target object. The present application integrates vector information of the normal vector into acoustic imaging, achieving high-quality imaging. The accuracy of the wave vector information of the echo signal also meets the requirements of high-resolution acoustic imaging, especially in underwater long-distance and small target imaging detection scenarios, which can effectively meet the acoustic imaging effect.

Description

Technical Field

[0001] The present application relates to the field of acoustic imaging technology, and in particular to an acoustic imaging system and method for underwater targets. Background Art

[0002] Underwater target imaging is a key development direction for underwater information technology and a crucial technology for underwater national defense and security. Related underwater target imaging technologies rely on target characteristics (the interaction between underwater sound and the target) such as the target's reflection or scattering intensity. The received sound pressure distribution is then used to inversely calculate the sound pressure (intensity) distribution on the target surface for target imaging.

[0003] However, this method has theoretical limitations in terms of resolution improvement. Due to the limitations of wavelength and receiving aperture, the resolution will be significantly reduced in underwater long-distance and small target imaging detection scenarios. Summary of the Invention

[0004] Based on this, it is necessary to provide an acoustic imaging system and method for underwater targets in response to the above technical problems, aiming to solve the technical problem that the imaging effect of acoustic imaging in related technologies is not ideal.

[0005] In a first aspect, the present application provides an acoustic imaging system for underwater targets, comprising a transducer, a laser sensor device, and a processor;

[0006] The transducer is configured to transmit at least one first acoustic wave signal toward an underwater target object, so as to reflect at a first position on the underwater target object and form an echo signal corresponding to the first acoustic wave signal;

[0007] The laser sensing device is arranged on a propagation path of the echo signal, and is used to emit at least two mutually orthogonal laser beams, and determine the echo wave vector information of the echo signal based on first phase information of the laser beams under the influence of the echo signal;

[0008] The processor is configured to determine normal information at a first position on the underwater target object based on the first acoustic wave wave vector information of the first acoustic wave signal and the echo wave vector information, so as to form an acoustic imaging of the underwater target object based on the normal information at multiple positions of the underwater target object;

[0009] Wherein, determining the echo wave vector information of the echo signal based on the first phase information of the laser beam under the influence of the echo signal includes:

[0010] For a target orthogonal direction, performing Fourier transform on laser signals of at least two laser beams affected by the echo signal in the target orthogonal direction to obtain a phase spectrum of the laser beam;

[0011] determining, based on the frequency of the echo signal, a phase difference between the at least two laser beams at the frequency from the phase spectra of the at least two laser beams, and determining echo wave vector information of the echo signal in an orthogonal direction of the target based on the phase difference and a distance between the at least two laser beams;

[0012] The echo vector information of the echo signal in the target orthogonal direction is calculated by the following formula:

[0013] ;

[0014] in, is the echo angle in the echo wave vector information of the echo signal in the orthogonal direction of the target, represents a function, d is the distance between the laser beams, n is an integer fuzzy number, is the phase difference of the first phase information of the plurality of laser beams under the influence of the echo signal, is the echo signal wavelength, is the echo signal frequency, is the echo signal speed.

[0015] In one embodiment of the present application, the echo wave vector information of the echo signal includes at least wave vector information in two orthogonal directions, and the laser beam generated by the laser sensing device includes at least a first laser beam and a second laser beam in the two orthogonal directions, wherein the first laser beam includes at least two parallel laser beams in the first orthogonal direction, and the second laser beam includes at least two parallel laser beams in the second orthogonal direction.

[0016] In one embodiment of the present application, the laser sensing device includes at least two layers of laser arrays, wherein each layer of the laser array is configured to emit at least two mutually orthogonal laser beams;

[0017] The laser sensing device is also used to determine the echo wave vector information of the echo signal based on the phase information of the laser beam in each layer of the laser array under the influence of the echo signal, and the response time difference of the at least two layers of laser arrays under the influence of the echo signal.

[0018] In one embodiment of the present application, the laser sensing device is further used to determine the sound speed information of the echo signal based on the phase information of the laser beam in each layer of the laser array under the influence of the echo signal, and the response time difference of the at least two layers of laser arrays affected by the echo signal, wherein the sound speed information is used to assist in achieving acoustic imaging of the underwater target object.

[0019] In one embodiment of the present application, the transducer is further configured to transmit at least one second acoustic wave signal to the laser sensor device;

[0020] The laser sensing device is further configured to determine second acoustic wave vector information of the second acoustic wave signal based on second phase information of the laser beam under the influence of the second acoustic wave signal;

[0021] The laser sensing device is further configured to determine a first propagation time for the first acoustic wave signal to reach the laser sensing device after being reflected by the underwater target object, and a second propagation time for the second acoustic wave signal to reach the laser sensing device;

[0022] The processor is used to determine the positioning information at the first position based on the first propagation time, the second propagation time, the first acoustic wave vector information, the second acoustic wave vector information and the echo wave vector information, so as to obtain the tangent plane at the first position according to the positioning information and the normal information, so that the tangent planes at multiple positions of the underwater target object form an acoustic imaging of the underwater target object.

[0023] In one embodiment of the present application, when the underwater target object is a curved structure object in a moving state, the transducer is further configured to transmit at least one first acoustic wave signal to the underwater target object at multiple moments, and collect corresponding echo signals at multiple moments;

[0024] The processor is further configured to determine the echo wave vector information corresponding to the echo signal based on the Doppler frequencies of the echo signals corresponding to the multiple moments, or based on the echo signals corresponding to the multiple moments and the moving speed of the underwater target object.

[0025] In one embodiment of the present application, the transducer is disposed on a moving mechanism, and the moving mechanism is used to control the movement of the transducer so that the transducer transmits a first acoustic wave signal to the underwater target object at a plurality of different positions to form a plurality of echo signals corresponding to the plurality of first acoustic wave signals;

[0026] The laser sensor device is further used to determine echo wave vector information of the multiple echo signals;

[0027] The processor is further configured to determine normal information at a first position on the underwater target object based on the displacement information of the transducer and the echo wave vector information of the multiple echo signals.

[0028] In one embodiment of the present application, the transducer is composed of a plurality of array element sound sources, and the plurality of array element sound sources control sound emission through a phased array model to transmit at least one beam of first sound wave signals to the underwater target object, wherein the first sound wave signal is a plane wave signal.

[0029] In a second aspect, the present application provides an underwater target acoustic imaging method, which is applied to an underwater target acoustic imaging system as described in any one of the above items, and the method comprises:

[0030] Transmitting at least one first acoustic wave signal toward an underwater target object through a transducer, so as to reflect at a first position on the underwater target object and form an echo signal corresponding to the first acoustic wave signal;

[0031] emitting at least two mutually orthogonal laser beams through a laser sensor device disposed on a propagation path of the echo signal, and determining echo wave vector information of the echo signal based on first phase information of the laser beams under the influence of the echo signal;

[0032] determining normal information at a first position on the underwater target object based on the first acoustic wave wave vector information of the first acoustic wave signal and the echo wave vector information, so as to form an acoustic imaging of the underwater target object based on the normal information at multiple positions of the underwater target object;

[0033] Wherein, determining the echo wave vector information of the echo signal based on the first phase information of the laser beam under the influence of the echo signal includes:

[0034] For a target orthogonal direction, performing Fourier transform on laser signals of at least two laser beams affected by the echo signal in the target orthogonal direction to obtain a phase spectrum of the laser beam;

[0035] determining, based on the frequency of the echo signal, a phase difference between the at least two laser beams at the frequency from the phase spectra of the at least two laser beams, and determining echo wave vector information of the echo signal in an orthogonal direction of the target based on the phase difference and a distance between the at least two laser beams;

[0036] The echo vector information of the echo signal in the target orthogonal direction is calculated by the following formula:

[0037] ;

[0038] in, is the echo angle in the echo wave vector information of the echo signal in the orthogonal direction of the target, represents a function, d is the distance between the laser beams, n is an integer fuzzy number, is the phase difference of the first phase information of the plurality of laser beams under the influence of the echo signal, is the echo signal wavelength, is the echo signal frequency, is the echo signal speed.

[0039] An embodiment of the present application provides an acoustic imaging system for underwater targets, which transmits at least one first acoustic wave signal to the underwater target object through a transducer to reflect at a first position on the underwater target object and form an echo signal corresponding to the first acoustic wave signal, and uses a laser sensor device to generate a laser beam to accurately obtain the wave vector information of the echo signal by utilizing the acousto-optic effect, thereby detecting the normal vector at the first position on the underwater target object in combination with the wave vector information of the first acoustic wave signal, and integrating the vector information into the acoustic imaging process of the underwater target object, thereby achieving high-quality imaging of the underwater target object, and the accuracy of the wave vector information of the echo signal determined by the above method also meets the requirements of high-resolution acoustic imaging, especially in the imaging detection scenario of long-distance and small targets underwater, which can effectively meet the effect of acoustic imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 A schematic structural diagram of an underwater target acoustic imaging system provided in an embodiment of the present application;

[0042] Figure 2a A schematic diagram of the effect of an echo generation process on a target object provided by an embodiment of the present application;

[0043] Figure 2b A schematic diagram of the effect of multiple laser beams in orthogonal directions being affected by acoustic signals provided by an embodiment of the present application;

[0044] Figure 2c A schematic diagram showing the effect of multiple laser beams in a multi-layer laser array in orthogonal directions being affected by an acoustic wave signal provided in an embodiment of the present application;

[0045] Figure 3 A schematic diagram of the effect of an imaging model of an underwater target object provided in an embodiment of the present application;

[0046] Figure 4A schematic diagram of an application scenario of an acoustic imaging system for underwater targets provided in an embodiment of the present application;

[0047] Figure 5 A schematic flow chart of the steps of an acoustic imaging method for underwater targets provided in an embodiment of the present application;

[0048] Figure 6 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0050] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of this application, "plurality" means two or more, unless otherwise specifically specified.

[0051] In the description of this application, the word "for example" is used to mean "used as an example, illustration or illustration". Any embodiment described in this application as "for example" is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is given to enable any person skilled in the art to implement and use the present invention. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present invention can be implemented without using these specific details. In other examples, well-known structures and processes are not elaborated in detail to avoid obscuring the description of the present invention with unnecessary details. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in this application.

[0052] To facilitate understanding of the acoustic imaging system and method for underwater targets provided in the embodiments of the present application, the application scenarios of the acoustic imaging of underwater targets provided in the present application will be described below. Specifically, underwater target imaging is an important development direction of underwater information technology and an important development technology for underwater national defense security. At present, acoustic imaging usually relies on the reflection or scattering intensity information of water sound (underwater sound waves) and the target object, and then uses the received sound pressure distribution to inversely calculate the sound pressure (intensity) distribution on the target surface to perform target imaging. However, the target imaging obtained by this method has theoretical limitations, that is, it depends on the wavelength and the receiving aperture, which results in a significant decrease in resolution in some underwater long-distance, small target imaging detection scenarios, affecting the imaging effect.

[0053] It is precisely to solve the above problems that the present application provides an acoustic imaging system based on vector information. By detecting the wave vector information of the sound wave before and after the reflection of the target object, the normal information at a specific position is determined, and the normal information is integrated into the acoustic imaging process to achieve high-precision acoustic imaging. In addition, through the acousto-optic effect, the influence of the laser beam and the acoustic wave signal can meet the requirements of determining high-precision wave vector information, thereby effectively improving the resolution of acoustic imaging. It is especially suitable for imaging and detection scenarios of long-distance and small targets underwater, and can effectively improve the effect of acoustic imaging. Specifically, the acoustic imaging system for underwater targets will be described in detail below.

[0054] For details, please refer to Figure 1 , Figure 1 A schematic structural diagram of an acoustic imaging system for underwater targets provided in an embodiment of the present application, specifically including a transducer 110, a laser sensor device 120 and a processor 130.

[0055] The transducer 110 is configured to transmit at least one first acoustic wave signal to an underwater target object, so as to be reflected at a first position on the underwater target object and form an echo signal corresponding to the first acoustic wave signal.

[0056] The laser sensor device 120 is arranged on the propagation path of the echo signal, and is used to emit at least two mutually orthogonal laser beams, and determine the echo wave vector information of the echo signal based on the first phase information of the laser beam under the influence of the echo signal;

[0057] The processor 130 is used to determine the normal information at a first position on the underwater target object based on the first acoustic wave vector information of the first acoustic wave signal and the echo wave vector information, so as to form an acoustic imaging of the underwater target object based on the normal information at multiple positions of the underwater target object.

[0058] The following will provide a detailed description of the specific structure and related principles of each component in the system in combination with the above content.

[0059] In one embodiment, the transducer 110 is typically an underwater acoustic transducer that can be controlled to generate a specific acoustic wave signal. For example, the transducer can be controlled to transmit an acoustic wave signal with specific wave vector information toward an underwater target object. Alternatively, the transducer can be controlled to transmit a specific acoustic wave signal toward another target, such as a laser sensor device. This embodiment of the present application does not limit the function of the transducer.

[0060] On the basis of the above, in order to further improve the subsequent acoustic imaging effect, in one embodiment of the present application, the transducer 110 is generally used to transmit an acoustic wave signal similar to a plane wave to maintain the consistency of the wave vector information. Specifically, the wave vector information of the plane wave k Is a constant vector, and the direction of the wave vector is always consistent with the propagation direction of the wave, and does not change with the spatial position in a homogeneous medium, which can effectively simplify subsequent calculations. Specifically, the wave vector information usually includes the direction of wave propagation and the spatial frequency of the wave. In the embodiment of the present application, the calculation of the normal information on the underwater target object is mainly based on the direction of wave propagation, that is, the direction of the wave vector. Specifically, in three-dimensional space, the direction of the wave vector can usually be expressed by the direction cosine. To describe, among them, It can be regarded as the angle between the x, y, and z axes in the three-dimensional space of the unit vector. Therefore, under normal circumstances, only two of the components need to be considered during the detection process. For example, For the convenience of description, Slightly change:

[0061] ;

[0062] Understandably, because With symmetric properties, similarly, It also has a symmetrical property. Therefore, in the subsequent embodiments of this application, one of the components, such as the angle component relative to the x-axis (positive direction) will be used. As an example, for another component, such as the angle component relative to the z axis You can refer to the angle component The description of the embodiments of the present application will not be repeated here.

[0063] Of course, in order for the transducer to achieve the effect of emitting a sound wave signal that is approximately a plane wave, in one embodiment, the transducer can be configured to be composed of multiple array element sound sources, wherein the multiple array element sound sources are controlled by a phased array model to form a specific sound emission function under the phased array model, thereby being controlled to emit a sound wave signal that is approximately a plane wave, that is, the first sound wave signal, to the underwater target object.

[0064] Of course, in addition to the solutions provided above, it is also feasible to implement solutions in other forms to enable the transducer to transmit at least one beam of first sound wave signals to the underwater target object, which will not be described in detail in the embodiments of the present application.

[0065] It can be understood that when the first acoustic wave signal emitted by the transducer to the underwater target object reaches the first position on the underwater target object, it will be reflected and form an echo signal corresponding to the first acoustic wave signal. Based on the wave vector information of the first acoustic wave signal, if the wave vector information of the echo signal can be accurately determined, the normal information at the specific first position can be calculated, thereby introducing the normal information in the subsequent acoustic imaging process to improve the imaging quality. For details, for easier understanding, please refer to Figure 2a , Figure 2a A schematic diagram of the effect of an echo generation process on a target object provided in an embodiment of the present application is described in detail as follows.

[0066] For details, please refer to Figure 2a , the effect diagram is to project the whole process onto the xoy plane, that is, the angle component relative to the z-axis is regarded as 0 (perpendicular to the z-axis). At this time, the angle between the wave vector direction of the emitted plane wave and the x-axis is , the wave vector direction of the echo vector is , since the propagation property of sound waves is water and the target object is a solid object with a greater impedance than water, only the case where the acoustic boundary is a hard boundary is considered. In this case, the action process conforms to Snell's law of sound wave reflection, so , , The size relationship is:

[0067] ;

[0068] Similarly, for the angle between the wave vector direction of the emitted plane wave and the z-axis, that is, the other angle component (perpendicular to the x-axis, is considered as 0), we can also get , , Relationship:

[0069] ;

[0070] Therefore, under ideal conditions, such as good synchronization, by emitting a series of plane waves modulated by acoustic wave vectors and recording their corresponding parameters Then, by collecting the high-precision arrival angle of the echo signal, the corresponding wave vector information is obtained. , we can get the normal vector of the tangent plane at the target action point.

[0071] It is understood that the accuracy of the echo signal's wave vector information affects the acoustic imaging effect to a certain extent. Specifically, the higher the accuracy of the wave vector information, the better the acoustic imaging effect, for example, improving the resolution of acoustic imaging. Therefore, in an embodiment of the present application, a solution is provided for accurately determining the echo wave vector information of an echo signal based on the principle of the acousto-optic effect. The details are as follows.

[0072] In the embodiments of the present application, the calculation of the echo wave vector information of the echo signal is performed based on a laser sensor device. Specifically, for ease of understanding, the laser sensor device can be configured to consist of a laser emitting unit and a laser receiving unit. Under normal circumstances, in the absence of external environmental interference, the laser beam emitted by the laser emitting unit will propagate in a straight line and be received by the laser receiving unit. However, when there is external environmental interference, the laser beam emitted by the laser emitting unit will be interfered with by the acoustic signal due to the acousto-optic interference effect, causing a certain deflection, thereby affecting the laser signal received by the laser receiving unit. Therefore, in some embodiments, the echo wave vector information of the echo signal, that is, the echo direction, can be determined based on the characteristic information of the received laser signal. For example, in the embodiments of the present application, the echo wave vector information of the echo signal can be determined based on the first phase information of the laser beam under the influence of the echo signal. Of course, in combination with the above-mentioned relevant description, it can be seen that since it is generally necessary to determine the echo wave vector information of the echo signal in multiple directions, in some embodiments, the laser sensor device is configured to emit at least two mutually orthogonal laser beams to more accurately determine the echo wave vector information of the echo signal. For example, in one embodiment, the laser sensor device can adopt a structure that is approximately circular, and a laser emitting unit and a laser receiving unit are respectively arranged on opposite sides of the circular structure. Since the echo wave vector information of the echo signal includes at least wave vector information in two orthogonal directions, that is, for example, the angle component provided above , . Therefore, correspondingly, the laser beam generated by the laser sensor device also includes at least the first laser beam and the second laser beam in the two orthogonal directions, wherein the first laser beam includes at least two parallel laser beams in the first orthogonal direction, and the second laser beam includes at least two parallel laser beams in the second orthogonal direction, that is, at least two parallel laser beams are included in each orthogonal direction, so that the echo wave vector information in the corresponding orthogonal direction is realized based on the laser signals of the at least two laser beams, which can be understood as the angle between the wave arrival direction and the corresponding orthogonal direction, that is, a grid-like laser beam will be formed on the inner side of the circular structure of the laser sensor device to realize the measurement of the echo wave vector information. That is to say, in one embodiment, the step of determining the echo wave vector information of the echo signal based on the first phase information of the laser beam under the influence of the echo signal in the laser sensor device includes:

[0073] For a target orthogonal direction, receiving laser signals of at least two laser beams in the target orthogonal direction affected by the echo signal, and performing Fourier transform on the laser signals to obtain a phase spectrum of the laser beam;

[0074] Based on the frequency of the echo signal, the phase difference between the at least two laser beams at the frequency is determined from the phase spectrum of the at least two laser beams, so as to determine the echo wave vector information of the echo signal in the orthogonal direction of the target based on the phase difference and the distance between the at least two laser beams.

[0075] Specifically, to understand the above content, please refer to Figure 2b , Figure 2b This is a schematic diagram of the effect of multiple laser beams in orthogonal directions being affected by acoustic signals, as provided in an embodiment of the present application. Detailed description is as follows.

[0076] In the embodiment of the present application, it can be understood that due to the symmetry of the laser beam, that is, the signal processing methods in multiple orthogonal directions are the same, therefore, the embodiment of the present application takes the data processing process of the laser array in one orthogonal direction as an example to illustrate. , the wavelength of the echo signal is , the distance between the two laser beams is d. Among them, similar to the traditional two-dimensional planar dual array element, the wave vector direction angle Satisfies the following formula:

[0077] ;

[0078] Therefore, the average value of the spot deviation angle of at least two laser beams can be used as a rough estimate of the wave vector direction angle and substituted into the left side of the equation to determine the value of the integer ambiguity number n. Then, the laser signals of the two laser beams received are Fourier transformed to obtain the phase spectrum. The phases at the corresponding sound wave frequency points are taken and the difference is taken to obtain the fractional part of the phase difference. At this point, the angle of arrival can be estimated by roughly estimating the value and eliminating spatial aliasing using the phase difference. That is, in one embodiment, the echo angle in the echo vector information in the orthogonal direction of the target can be obtained, that is, the direction of arrival angle in the orthogonal direction of the target. The specific calculation formula is:

[0079] ;

[0080] in, is the echo angle in the echo wave vector information of the echo signal in the orthogonal direction of the target, which represents the function, d is the distance between the laser beams, n is an integer fuzzy number, is the phase difference of the first phase information of the plurality of laser beams under the influence of the echo signal, is the echo signal wavelength, is the echo signal frequency, is the sound velocity of the echo signal, which can be a preset value or determined by other means.

[0081] Furthermore, based on the above-mentioned solution, due to the complexity and variability of the underwater environment and the fact that seawater is not a uniform medium with fixed properties, the speed of sound is not a constant. In the above-mentioned solution, since the error caused by the difference between the actual sound speed and the theoretical sound speed cannot be avoided, a method is needed to reduce or even eliminate the influence of the sound speed on the angle of arrival.

[0082] Considering that the acoustic field information in the measurement area will not change due to the laser measurement, in addition to the laser sensor device provided above, this application also provides a multi-layer laser array to improve the angle of arrival, that is, the accuracy of the echo wave vector information of the echo signal. Specifically, the laser sensor device includes at least two layers of laser arrays, wherein each layer of the laser array is used to emit at least two mutually orthogonal laser beams. At this time, please refer to Figure 2c , Figure 2c Schematic diagram of the effect of multiple laser beams of a multi-layer laser array in orthogonal directions being affected by acoustic signals provided in an embodiment of the present application.

[0083] In the embodiment of the present application, Figure 2bCompared with the effect diagram shown in FIG, an additional layer of laser array is set below most of the laser beams in the first layer of laser array. The distance between the laser beams in this laser array and the corresponding laser beams in the first layer of laser array is h. The arrangement of the second layer of laser array can not only increase a series of laser detection points, but also increase the equivalent aperture of the array. The enlarged equivalent aperture is Furthermore, and more importantly, it can help eliminate the influence of the speed of sound c on the angle of arrival measurement. The details are as follows.

[0084] Similar to the formula provided above, the arrival angle of the laser array of each layer satisfies the following formula:

[0085] ;

[0086] At the same time, if the second layer of laser is aligned with the first layer of laser and the distance between the two laser beams is , then the angle of arrival and the speed of sound also satisfy:

[0087] ;

[0088] in, It is the time difference between the two corresponding laser beams in the first layer and the second layer of laser in response to the acoustic signal, that is, the response time difference of at least two layers of laser arrays affected by the echo signal.

[0089] Therefore, in combination with the aforementioned relationship, the direction of arrival (DOA) can be determined based on phase information and response time difference. That is, in one embodiment, the laser sensor device is further configured to determine the echo wave vector information of the echo signal based on the phase information of the laser beam in each layer of the laser array under the influence of the echo signal, and the response time difference between the at least two layers of laser arrays under the influence of the echo signal. In this case, the final calculation formula for the DOA is as follows:

[0090] ;

[0091] Among them, the definitions of various parameters in the above formula have been explained above and will not be repeated here in the embodiments of the present application.

[0092] It should be noted that the above process eliminates the influence of the speed of sound c on angle of arrival measurement. Of course, in one embodiment, the above scheme can also be used to determine the speed of sound information of the echo signal, which can be used to assist in acoustic imaging of underwater targets. That is, in one embodiment, the laser sensor device is further used to determine the speed of sound information of the echo signal based on the phase information of the laser beam in each layer of the laser array under the influence of the echo signal, as well as the response time difference between the at least two layers of laser arrays under the influence of the echo signal. This speed of sound information is used to assist in acoustic imaging of the underwater target object.

[0093] Specifically, the specific calculation formula for the sound velocity information c of the echo signal is:

[0094] ;

[0095] By analyzing the error of the two schemes mentioned above, such as comparing the error terms in the calculation formulas of the two schemes, it can be found that the angle error terms of the two schemes have cycle number errors. , the distance error between adjacent lasers in the same layer , and frequency error The three error terms in the formula of multi-layer laser array are smaller than those of single-layer laser array. In addition, the sound velocity error term unique to single-layer laser array is Greater than the error of the distance between two layers of laser in a multi-layer laser array The time difference between the two layers of laser response Therefore, by deploying a multi-layer laser array to utilize the distance between two layers of lasers, the influence of the speed of sound on the angle of arrival measurement can be eliminated, thereby further improving the measurement accuracy.

[0096] Furthermore, in complex waters like the ocean, the speed of sound varies with time and spatial position. Single-layer laser array laser sensor devices cannot avoid the influence of sound speed on measurement results, resulting in poor anti-interference capabilities. Once the sound speed changes significantly, the measurement results will show significant deviations. Multi-layer laser array laser sensor devices, on the other hand, introduce a new dimension, a multidimensional acousto-optic sensing model. Because their measurement results are unaffected by sound speed, changes in the external environment do not significantly affect the measurement results of this model. This means that multi-layer laser array laser sensor devices have strong anti-interference capabilities.

[0097] After determining the echo wave vector information of the echo signal using the method provided in any of the aforementioned embodiments, normal information at a first position on the underwater target object can be determined based on the first acoustic wave wave vector information of the first acoustic wave signal and the echo wave vector information. It will be appreciated that, because the normal information at the first position on the underwater target object can describe the curvature change of the underwater target object (particularly a circular arc-shaped target) at a local position, in one embodiment, an acoustic image of the underwater target object can be formed based on the normal information at multiple positions on the underwater target object.

[0098] Specifically, in order to facilitate understanding of the above content, a short period of time The parameters of the internal emission (i.e., the acoustic wave vector information) are The plane wave is recorded as a group, where the time interval between two adjacent groups of sound waves is set to ,and Assuming a stationary state during this short period: For example, a 75kHz acoustic signal has a period of approximately 13.33. Therefore, within 0.2ms, a maximum of approximately 15 plane waves with different wave vectors can be emitted. Substituting this into a submersible's normal speed of 38 knots (approximately 19.55m / s), the underwater target will only displace approximately 4mm. The minimum angular deflection within a set of emitted acoustic waves is 0.02°, and after 100m, the point of impact will shift by approximately 35mm. Since the hypothetical target's speed is less than this, it can be assumed that the target object is stationary during this short period.

[0099] Remember a moment Start emitting the first set of sound waves, The wave vector inside is:

[0100] ;

[0101] in, for to The last plane wave vector emitted during the time period is .

[0102] At this point, we can discuss the following situations based on whether the object is planar, that is, whether the normal vectors of the tangent planes at each point on the surface of the target object are consistent, and the object's motion state:

[0103] (1) When the target object is flat and stationary:

[0104] The emitted wave vector is The echo wave vector obtained by interacting with the target is , because the target object is stationary and flat, the normal vectors of the tangent plane at each point on the surface are equal, and the target object is stationary, so the result of the normal vector calculation in an ideal case is .

[0105] (2) When the target object is non-flat (e.g., arc-shaped) and stationary:

[0106] The emitted wave vector is The echo wave vector obtained by interacting with the target is The result of normal vector calculation is:

[0107] ;

[0108] Among them, because the target is not flat, the normal vectors of the tangent plane at each point on the surface are not equal. The elements of each row vector of will not be equal even in ideal conditions. And because the target object is stationary, It has nothing to do with time, so the elements of its column vector should be equal under ideal calculation conditions. Can be simplified to:

[0109] ;

[0110] (3) When the target object is flat and moves in a straight line:

[0111] Under this condition, the calculation results will be the same as those in condition (1), but the distance between the transmitter and the target will change due to target movement, and the flight time of the sound wave will also increase or decrease. At the same time, after the receiving end and the transmitting end are synchronized, the distance to the target can be calculated based on the flight time. Combined with the angle of arrival information obtained by the laser underwater acoustic sensor array, the preliminary positioning of the target can be completed.

[0112] (4) When the target object is flat and rotates:

[0113] The emitted wave vector is The echo wave vector obtained by interacting with the target is , the result of normal vector calculation:

[0114] ;

[0115] Since the target object is flat, the normal vectors of the tangent plane at each point on the surface are equal, so ideally the elements of each row vector are equal; however, due to the rotation of the target object, the normal vectors of the tangent plane at each point on the surface will change over time. Can be simplified to:

[0116] ;

[0117] (5) When the target object is not flat and is moving:

[0118] The emitted wave vector is The echo wave vector obtained by interacting with the target is , the result of normal vector calculation:

[0119] ;

[0120] According to the matrix The row vector in derives the normal vector of the tangent plane of the target surface at the time corresponding to the row vector, and thus the shape information of the target in the detection area at that time. Comparing the "overlap" of elements in different row vectors can not only further depict the surface shape of the target, but also be used to preliminarily determine the target's motion state:

[0121] For example, if the following situation occurs, it can be preliminarily determined that the target surfaces corresponding to the three vectors are in the same area:

[0122] ;

[0123] Then on the one hand, we can use the matrix The second and third row vectors supplement and expand the information of the first row vector to obtain more surface information of the target object, thereby expanding the imaging range. On the other hand, it also proves that the target is There are at least two motion states within a certain period of time, and the motion state of the target object can be preliminarily obtained based on factors such as time difference, echo direction and sound speed.

[0124] Furthermore, in order to achieve more accurate acoustic imaging of underwater target objects, in one embodiment, the transducer is further configured to transmit at least one second acoustic wave signal to the laser sensor device;

[0125] The laser sensing device is further configured to determine second acoustic wave vector information of the second acoustic wave signal based on second phase information of the laser beam under the influence of the second acoustic wave signal;

[0126] The laser sensing device is further configured to determine a first propagation time for the first acoustic wave signal to reach the laser sensing device after being reflected by the underwater target object, and a second propagation time for the second acoustic wave signal to reach the laser sensing device;

[0127] The processor is used to determine the positioning information at the first position based on the first propagation time, the second propagation time, the first acoustic wave vector information, the second acoustic wave vector information and the echo wave vector information, so as to obtain the tangent plane at the first position according to the positioning information and the normal information, so that the tangent planes at multiple positions of the underwater target object form an acoustic imaging of the underwater target object.

[0128] Specifically, to understand the above content, please refer to Figure 3 , Figure 3A schematic diagram of the effect of an imaging model of an underwater target object provided in an embodiment of the present application is described in detail as follows.

[0129] Here, S represents the sound source, i.e., the transducer; T represents the point of action of the sound wave on the target, i.e., the first position; and O represents the laser sensor device, i.e., the laser array. It represents the angle between the tangent line of the target at the point of action and the x-axis, and is also equal to the angle between the normal vector of the target at the point of action and the y-axis. is the angle between the direct signal wave vector at the laser array and the y-axis, that is, the second acoustic wave vector information of the second acoustic wave signal, is the angle between the echo signal wave vector at the laser array and the y-axis, that is, the echo wave vector information, It represents the angle formed by connecting the emitted sound wave vector and the echo wave vector end to end at the target point of action.

[0130] In addition, the distance between the sound source (S) and the laser array (O) can be obtained based on the time difference between the second sound wave signals; on the other hand, the laser array will also receive the echo signal reflected by the target object, and then calculate the angle And the sum of the distances between the sound source (S) and the target (T), and the distance between the target (T) and the laser array (O).

[0131] Therefore, by solving the triangle (triangle STO) formed by the sound source (S), the point of action of the sound wave and the target on the target (T), and the laser array (O), the three sides and three angles of the triangle can be obtained. :

[0132] ;

[0133] ;

[0134] ;

[0135] ;

[0136] ;

[0137] ;

[0138] ;

[0139] in, The sound velocity information can be determined by combining the multi-layer laser array provided above. represents the time it takes for the sound source to directly propagate to the laser array, It indicates the time it takes for the sound wave to be emitted by the sound source, reflected by the target object, and propagate to the laser array.

[0140] The following vector imaging is performed on the target:

[0141] After obtaining the three side lengths and three angles of the triangle STO, the coordinates of the target action point in the coordinate system can be obtained to complete the positioning of the target action point. At the same time, the angle between the target's normal vector at the point of action and the y-axis is , complete the imaging: According to the first set of data, at the coordinates in the two-dimensional xoy coordinate system Make an angle with x The line segment is expanded into a sub-plane passing through the line segment and perpendicular to the xoy plane in the spatial coordinate system. Each set of data is processed in the same way to obtain several sub-planes. These sub-planes are combined to obtain preliminary vector imaging results, that is, the acoustic imaging of the target object.

[0142] In addition, it should be noted that the underwater target acoustic imaging system provided by the present application is particularly suitable for acoustic imaging of curved structural objects in motion underwater, for example, for detecting underwater vehicles. This is mainly because the movement of the curved structural target itself in a moving state can also modulate the echo vector of the sound field, that is, change the characteristics of the echo signal (such as frequency, phase or direction). Therefore, when there is a priori estimate of the target's moving speed, the echo vector can be predicted and corrected based on the speed. Alternatively, the Doppler frequency movement (Doppler shift) of the echo signal can be analyzed through the Doppler effect to calculate the echo vector. That is, in one embodiment, when the underwater target object is a curved structural object in motion, the transducer is further used to transmit at least one beam of first acoustic wave signals to the underwater target object at multiple time instants, and collect the corresponding echo signals at multiple time instants.

[0143] The processor is further configured to determine the echo wave vector information corresponding to the echo signal based on the Doppler frequency offset of the echo signal corresponding to the multiple moments, or based on the echo signal corresponding to the multiple moments and the moving speed of the underwater target object.

[0144] It can be understood that the scheme provided above can be used to realize the calculation of echo wave vector information. Of course, the echo wave vector information calculated above can also be used to correct the echo wave vector information collected by the laser sensor device. For example, on the basis of the echo wave vector information determined by the laser sensor device, combined with the correction amount of the echo wave vector information determined by the Doppler frequency offset or the moving speed, more accurate echo wave vector information can be further obtained.

[0145] Of course, the above-mentioned solution relies on the movement of the underwater target. In fact, in one embodiment, it is only necessary to control the relative movement of the acoustic imaging system provided by this application and the underwater target object. In other words, the solution provided by this application can also be used to image a target object in a stationary state. For example, in one embodiment of this application, the transducer is set on a moving mechanism, and the moving mechanism is used to control the movement of the transducer so that the transducer transmits a first acoustic wave signal to the underwater target object at multiple different positions to form multiple echo signals corresponding to the multiple first acoustic wave signals.

[0146] The laser sensor device is further used to determine echo wave vector information of the multiple echo signals;

[0147] The processor is further configured to determine normal information at a first position on the underwater target object based on the displacement information of the transducer and the echo wave vector information of the multiple echo signals.

[0148] The normal information at the first position on the underwater target object is determined based on the displacement information of the transducer and the echo wave vector information of the multiple echo signals. This embodiment of the present application is not described in detail here. Specifically, different normal information can be determined based on the acoustic wave information of different incident angles emitted by transducers at different positions and the reflection angles of the corresponding echo signals, and more accurate normal information can be obtained based on the statistics of these normal information. This embodiment of the present application is not described in detail here.

[0149] Specifically, in order to clearly understand the underwater target acoustic imaging system provided in the embodiment of the present application, please refer to Figure 4 , Figure 4 This is a schematic diagram of an application scenario for an underwater target acoustic imaging system provided in an embodiment of the present application. For information about the various devices in this schematic scenario, refer to the relevant descriptions provided in the preceding embodiments. Furthermore, this embodiment does not limit other acoustic imaging-assisted devices, such as the power amplifier, signal generator, computer measurement and control system, and anechoic structure (anechoic wedge) shown in the schematic scenario.

[0150] An embodiment of the present application provides an acoustic imaging system for underwater targets, which transmits at least one first acoustic wave signal to the underwater target object through a transducer to reflect at a first position on the underwater target object and form an echo signal corresponding to the first acoustic wave signal, and uses a laser sensor device to generate a laser beam to accurately obtain the wave vector information of the echo signal by utilizing the acousto-optic effect, thereby detecting the normal vector at the first position on the underwater target object in combination with the wave vector information of the first acoustic wave signal, and integrating the vector information into the acoustic imaging process of the underwater target object, thereby achieving high-quality imaging of the underwater target object, and the accuracy of the wave vector information of the echo signal determined by the above method also meets the requirements of high-resolution acoustic imaging, especially in the imaging detection scenario of long-distance and small targets underwater, which can effectively meet the effect of acoustic imaging.

[0151] On the basis of the above-mentioned solution, the present application also provides an acoustic imaging method for the acoustic imaging system of the above-mentioned underwater target. For details, please refer to Figure 5 , Figure 5 A schematic flow chart of a method for acoustic imaging of an underwater target provided in an embodiment of the present application, specifically comprising steps S510 to S530:

[0152] S510 , transmitting at least one first acoustic wave signal to an underwater target object through a transducer, so as to be reflected at a first position on the underwater target object and form an echo signal corresponding to the first acoustic wave signal.

[0153] S520, emitting at least two mutually orthogonal laser beams through a laser sensor device arranged on the propagation path of the echo signal, and determining the echo wave vector information of the echo signal based on the first phase information of the laser beam under the influence of the echo signal.

[0154] S530, determining the normal information at a first position on the underwater target object based on the first acoustic wave vector information of the first acoustic wave signal and the echo wave vector information, so as to form an acoustic imaging of the underwater target object based on the normal information at multiple positions of the underwater target object.

[0155] In the embodiment of the present application, the specific implementation process of each step in the acoustic imaging method can refer to the relevant description of the acoustic imaging system for underwater targets mentioned above, and the embodiment of the present application will not be repeated here.

[0156] Specifically, in one embodiment, determining the echo wave vector information of the echo signal based on the first phase information of the laser beam under the influence of the echo signal includes:

[0157] For a target orthogonal direction, receiving laser signals of at least two laser beams in the target orthogonal direction affected by the echo signal, and performing Fourier transform on the laser signals to obtain a phase spectrum of the laser beam;

[0158] Based on the frequency of the echo signal, the phase difference between the at least two laser beams at the frequency is determined from the phase spectrum of the at least two laser beams, so as to determine the echo wave vector information of the echo signal in the orthogonal direction of the target based on the phase difference and the distance between the at least two laser beams.

[0159] Specifically, in one embodiment, the echo angle of the echo wave vector information is calculated using the following formula:

[0160] ;

[0161] in, is the echo angle in the echo wave vector information of the echo signal in the orthogonal direction of the target, represents a function, is the distance between the laser beams, is an integer fuzzy number, is the phase difference of the first phase information of the plurality of laser beams under the influence of the echo signal, is the echo signal wavelength, is the echo signal frequency, is the echo signal speed.

[0162] Specifically, in one embodiment, the method further includes: determining the echo wave vector information of the echo signal based on the phase information of the laser beam in each layer of the laser array under the influence of the echo signal, and the response time difference of the at least two layers of laser arrays under the influence of the echo signal.

[0163] Specifically, in one embodiment, the method further includes: determining the sound velocity information of the echo signal based on the phase information of the laser beam in each layer of the laser array under the influence of the echo signal, and the response time difference of the at least two layers of laser arrays under the influence of the echo signal, wherein the sound velocity information is used to assist in achieving acoustic imaging of the underwater target object.

[0164] Specifically, in one embodiment, the method further includes: determining second acoustic wave vector information of the second acoustic wave signal based on second phase information of the laser beam under the influence of the second acoustic wave signal;

[0165] determining a first propagation time for the first acoustic wave signal to reach the laser sensing device after being reflected by the underwater target object, and a second propagation time for the second acoustic wave signal to reach the laser sensing device;

[0166] The positioning information at the first position is determined based on the first propagation time, the second propagation time, the first acoustic wave vector information, the second acoustic wave vector information, and the echo wave vector information, so as to obtain the tangent plane at the first position according to the positioning information and the normal information, so that the tangent planes at multiple positions of the underwater target object form an acoustic imaging of the underwater target object.

[0167] Specifically, in one embodiment, the method further includes: transmitting a first acoustic wave signal to the underwater target object at a plurality of different positions to form a plurality of echo signals corresponding to the plurality of first acoustic wave signals;

[0168] determining echo wave vector information of the plurality of echo signals;

[0169] Normal information at a first position on the underwater target object is determined based on the displacement information of the transducer and the echo wave vector information of the multiple echo signals.

[0170] An embodiment of the present application provides an acoustic imaging method for underwater targets, which transmits at least one first acoustic wave signal to the underwater target object through a transducer to reflect at a first position on the underwater target object and form an echo signal corresponding to the first acoustic wave signal, and uses a laser sensor device to generate a laser beam to accurately obtain the wave vector information of the echo signal by utilizing the acousto-optic effect, thereby detecting the normal vector at the first position on the underwater target object in combination with the wave vector information of the first acoustic wave signal, and integrating the vector information into the acoustic imaging process of the underwater target object, thereby achieving high-quality imaging of the underwater target object, and the accuracy of the wave vector information of the echo signal determined by the above method also meets the requirements of high-resolution acoustic imaging, especially in the imaging detection scenario of long-distance and small targets underwater, which can effectively meet the effect of acoustic imaging.

[0171] In one embodiment, the present application further provides an electronic device that interacts with an acoustic imaging system of an underwater target to achieve imaging of the underwater target object. Taking the electronic device as an example, its internal structure diagram can be as follows: Figure 6 As shown. The electronic device 600 may include: a processor, a memory. The electronic device may also include one or more of a multimedia component, an input / output (I / O) component, and a communication component. In this embodiment, the electronic device may be a processing device in the acoustic imaging system for underwater targets provided in this embodiment.

[0172] The processor is used to control the overall operation of the electronic device to complete all or part of the steps in the above-mentioned method for acoustic imaging of underwater targets. The memory is used to store various types of data to support the operation of the auxiliary electronic device. This data may include, for example, instructions for any application or method operating on the auxiliary electronic device, as well as application-related data, such as contact information, sent and received messages, pictures, audio, video, etc. The memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk, or optical disk. The multimedia component may include a screen and an audio component. The screen may be, for example, a touch screen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signals may be further stored in a memory or transmitted via a communication component. The audio component also includes at least one speaker for outputting audio signals. The I / O component provides an interface between the processor and other interface modules, which may be a keyboard, a mouse, buttons, etc. These buttons may be virtual buttons or physical buttons. The communication component is used for wired or wireless communication between the electronic device and other devices, such as a target imaging device that integrates sound field gradient information. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G, Narrow Band Internet of Things (NBIOT), Enhanced Machine Type Communication (eMTC), or other 5G, etc., or a combination of one or more of them, is not limited here. Therefore, the corresponding communication component may include: a Wi-Fi module, a Bluetooth module, an NFC module, etc.

[0173] In an exemplary embodiment, the electronic device may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the underwater target acoustic imaging method provided in any of the above embodiments, for example:

[0174] Transmitting at least one first acoustic wave signal toward an underwater target object through a transducer, so as to reflect at a first position on the underwater target object and form an echo signal corresponding to the first acoustic wave signal;

[0175] emitting at least two mutually orthogonal laser beams through a laser sensor device disposed on a propagation path of the echo signal, and determining echo wave vector information of the echo signal based on first phase information of the laser beams under the influence of the echo signal;

[0176] Based on the first acoustic wave vector information of the first acoustic wave signal and the echo wave vector information, normal information at a first position on the underwater target object is determined to form an acoustic imaging of the underwater target object based on the normal information at multiple positions of the underwater target object.

[0177] In another exemplary embodiment, a computer-readable storage medium including program instructions is also provided. When the program instructions are executed by a processor, the steps of the target imaging method for integrating acoustic field gradient information are implemented. For example, the computer-readable storage medium may be the aforementioned memory including the program instructions. The program instructions may be executed by a processor of an electronic device to implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application.

[0178] Alternatively, when the instructions are executed by a computer, the computer may implement or execute the methods, steps, and logic diagrams disclosed in the embodiments of the present application, for example, executing the following steps:

[0179] Transmitting at least one first acoustic wave signal toward an underwater target object through a transducer, so as to reflect at a first position on the underwater target object and form an echo signal corresponding to the first acoustic wave signal;

[0180] emitting at least two mutually orthogonal laser beams through a laser sensor device disposed on a propagation path of the echo signal, and determining echo wave vector information of the echo signal based on first phase information of the laser beams under the influence of the echo signal;

[0181] Based on the first acoustic wave vector information of the first acoustic wave signal and the echo wave vector information, normal information at a first position on the underwater target object is determined to form an acoustic imaging of the underwater target object based on the normal information at multiple positions of the underwater target object.

[0182] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0183] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing related hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods.

[0184] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0185] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. An acoustic imaging system for underwater targets, characterized in that: including a transducer, a laser sensor device, and a processor; The transducer is configured to transmit at least one first acoustic wave signal toward an underwater target object, so as to reflect at a first position on the underwater target object and form an echo signal corresponding to the first acoustic wave signal; The laser sensing device is arranged on a propagation path of the echo signal, and is used to emit at least two mutually orthogonal laser beams, and determine the echo wave vector information of the echo signal based on first phase information of the laser beams under the influence of the echo signal; The processor is configured to determine normal information at a first position on the underwater target object based on the first acoustic wave wave vector information of the first acoustic wave signal and the echo wave vector information, so as to form an acoustic imaging of the underwater target object based on the normal information at multiple positions of the underwater target object; Wherein, determining the echo wave vector information of the echo signal based on the first phase information of the laser beam under the influence of the echo signal includes: For a target orthogonal direction, performing Fourier transform on laser signals of at least two laser beams affected by the echo signal in the target orthogonal direction to obtain a phase spectrum of the laser beam; determining, based on the frequency of the echo signal, a phase difference between the at least two laser beams at the frequency from the phase spectra of the at least two laser beams, and determining echo wave vector information of the echo signal in an orthogonal direction of the target based on the phase difference and a distance between the at least two laser beams; The echo vector information of the echo signal in the target orthogonal direction is calculated by the following formula: ； in, is the echo angle in the echo wave vector information of the echo signal in the orthogonal direction of the target, represents a function, d is the distance between the laser beams, n is an integer fuzzy number, is the phase difference of the first phase information of the plurality of laser beams under the influence of the echo signal, is the echo signal wavelength, is the echo signal frequency, is the echo signal speed.

2. The system according to claim 1, wherein: The echo wave vector information of the echo signal includes at least wave vector information in two orthogonal directions, and the laser beam emitted by the laser sensing device includes at least a first laser beam and a second laser beam in the two orthogonal directions, wherein the first laser beam includes at least two parallel laser beams in the first orthogonal direction, and the second laser beam includes at least two parallel laser beams in the second orthogonal direction.

3. The system according to claim 1, wherein: The laser sensor device comprises at least two layers of laser arrays, wherein each layer of the laser array is used to emit at least two mutually orthogonal laser beams; The laser sensing device is also used to determine the echo wave vector information of the echo signal based on the phase information of the laser beam in each layer of the laser array under the influence of the echo signal, and the response time difference of the at least two layers of laser arrays under the influence of the echo signal.

4. The system according to claim 3, characterized in that The laser sensing device is further used to determine the sound velocity information of the echo signal based on the phase information of the laser beam in each layer of the laser array under the influence of the echo signal, and the response time difference of the at least two layers of laser arrays under the influence of the echo signal, wherein the sound velocity information is used to assist in achieving acoustic imaging of the underwater target object.

5. The system according to claim 1, wherein: The transducer is further configured to transmit at least one second acoustic wave signal to the laser sensor device; The laser sensing device is further configured to determine second acoustic wave vector information of the second acoustic wave signal based on second phase information of the laser beam under the influence of the second acoustic wave signal; The laser sensing device is further configured to determine a first propagation time for the first acoustic wave signal to reach the laser sensing device after being reflected by the underwater target object, and a second propagation time for the second acoustic wave signal to reach the laser sensing device; The processor is used to determine the positioning information at the first position based on the first propagation time, the second propagation time, the first acoustic wave vector information, the second acoustic wave vector information and the echo wave vector information, so as to obtain the tangent plane at the first position according to the positioning information and the normal information, so that the tangent planes at multiple positions of the underwater target object form an acoustic imaging of the underwater target object.

6. The system according to claim 1, wherein: When the underwater target object is a curved structure object in a moving state, the transducer is further used to transmit at least one beam of first acoustic wave signals to the underwater target object at multiple moments, and collect corresponding echo signals at multiple moments; The processor is further configured to determine the echo wave vector information corresponding to the echo signal based on the Doppler frequency offset of the echo signal corresponding to the multiple moments, or based on the echo signal corresponding to the multiple moments and the moving speed of the underwater target object.

7. The system according to claim 1, wherein: The transducer is disposed on a moving mechanism, and the moving mechanism is used to control the movement of the transducer so that the transducer transmits a first acoustic wave signal to the underwater target object at a plurality of different positions to form a plurality of echo signals corresponding to the plurality of first acoustic wave signals; The laser sensor device is further used to determine echo wave vector information of the multiple echo signals; The processor is further configured to determine normal information at a first position on the underwater target object based on the displacement information of the transducer and the echo wave vector information of the multiple echo signals.

8. The system according to claim 1, wherein: The transducer is composed of a plurality of array element sound sources, and the plurality of array element sound sources control sound emission through a phased array model to transmit at least one beam of first sound wave signals to the underwater target object, wherein the first sound wave signal is a plane wave signal.

9. A method for acoustic imaging of underwater targets, characterized in that: Applied to the acoustic imaging system for underwater targets according to any one of claims 1 to 8, the method comprises: Transmitting at least one first acoustic wave signal toward an underwater target object through a transducer, so as to reflect at a first position on the underwater target object and form an echo signal corresponding to the first acoustic wave signal; emitting at least two mutually orthogonal laser beams through a laser sensor device disposed on a propagation path of the echo signal, and determining echo wave vector information of the echo signal based on first phase information of the laser beams under the influence of the echo signal; determining normal information at a first position on the underwater target object based on the first acoustic wave wave vector information of the first acoustic wave signal and the echo wave vector information, so as to form an acoustic imaging of the underwater target object based on the normal information at multiple positions of the underwater target object; Wherein, determining the echo wave vector information of the echo signal based on the first phase information of the laser beam under the influence of the echo signal includes: For a target orthogonal direction, performing Fourier transform on laser signals of at least two laser beams affected by the echo signal in the target orthogonal direction to obtain a phase spectrum of the laser beam; determining, based on the frequency of the echo signal, a phase difference between the at least two laser beams at the frequency from the phase spectra of the at least two laser beams, and determining echo wave vector information of the echo signal in an orthogonal direction of the target based on the phase difference and a distance between the at least two laser beams; The echo vector information of the echo signal in the target orthogonal direction is calculated by the following formula: ； in, is the echo angle in the echo wave vector information of the echo signal in the orthogonal direction of the target, represents a function, d is the distance between the laser beams, n is an integer fuzzy number, is the phase difference of the first phase information of the plurality of laser beams under the influence of the echo signal, is the echo signal wavelength, is the echo signal frequency, is the echo signal speed.

Images