CN117969677B - Acoustic field detection method, system, device and medium based on coded phase imaging - Google Patents

Abstract

The invention discloses a sound field detection method, a system, equipment and a medium based on code phase imaging, wherein the system comprises the following components: the parallel light field transmitting module is used for generating a pulse parallel light field to illuminate a sound field medium, the pulse parallel light field carries out wave front modulation through the sound field medium, imaging is carried out through the imaging module, modulation is carried out through the coded plate, and light field intensity distribution is obtained through the light field detector; the system further comprises: the ultrasonic transducer module is used for generating a to-be-detected high-frequency sound field; the control and calculation module is used for controlling the synchronization of the parallel light field emission module and the light field detector, and storing the light field intensity distribution acquired by the light field detector to calculate the complex amplitude distribution of the high-frequency sound field to be detected. The invention can indirectly detect the parameter information of the sound field by utilizing the complex amplitude change of the light field after passing through the sound field medium, and the method has the advantages of simultaneously detecting the intensity and the phase of the light field, and has the characteristics of high stability, high spatial resolution and high phase resolution.

Description

Acoustic field detection method, system, device and medium based on coded phase imaging

Technical Field

The present invention belongs to the field of light field phase imaging and sound field detection, and in particular relates to a sound field detection method, system, equipment and medium based on coded phase imaging.

Background technique

Traditional sound field detection methods generally use an ultrasonic probe to scan point by point. This method is based on the propagation characteristics of ultrasonic waves in the material being detected. It uses an ultrasonic probe to scan point by point on the surface or inside of the material. By analyzing the reflection, transmission or scattering information of the ultrasonic wave, the internal structure and defects of the material are detected. However, this method requires a long scanning time and interferes with the distribution of the sound field to be measured.

At present, the distribution parameters of the acoustic field can also be determined by recording the intensity distribution of the transmitted light field stripes. This method is a technology that combines optics and acoustics. This method usually involves the principle of acoustic-optical interaction, in which the sound wave modulates the light field, causing the transmitted light field to produce a specific stripe intensity distribution. Specifically, when the sound wave propagates through the medium, it causes a change in the density of the medium, which in turn changes the refractive index of the medium. When the light field passes through this medium modulated by the sound wave, the propagation path and phase of the light will be affected, resulting in a change in the intensity distribution of the transmitted light field. However, this method detects the intensity distribution of the light field diffracted after passing through the acoustic field medium, and cannot obtain the density distribution of the acoustic field medium. It is affected by the intensity of the light source and the diffraction of the medium, and has a large error.

Summary of the invention

In view of the limitations of the above-mentioned sound field detection technology, the present invention proposes a sound field detection method, system, device and medium based on coded phase imaging.

According to a first aspect of an embodiment of the present invention, a sound field detection system based on coded phase imaging is provided, the system comprising:

A parallel light field emission module, which is used to generate a pulse parallel light field to illuminate the acoustic field medium. The pulse parallel light field is wavefront modulated by the acoustic field medium, imaged by the imaging module, modulated by the encoding plate, and the light field intensity distribution is obtained by the light field detector;

The system further comprises:

Ultrasonic transducer module, used to generate high-frequency sound field to be measured;

The control and calculation module is used to control the synchronization of the parallel light field emission module and the light field detector, and store the light field intensity distribution obtained by the light field detector to calculate the complex amplitude distribution of the high-frequency sound field to be measured.

According to a second aspect of an embodiment of the present invention, a sound field detection method based on coded phase imaging is provided, which is implemented based on the above-mentioned sound field detection system based on coded phase imaging. The method includes:

Acquire the high-frequency sound field to be measured generated by the ultrasonic transducer module;

Obtaining the light field intensity distribution recorded by the light field detector;

The plane where the light field detector is located is set as the first plane, and the plane where the encoding plate is located is set as the second plane; the initial light field complex amplitude distribution at the front surface of the encoding plate is set; the initial light field complex amplitude distribution is iteratively propagated between the first plane, the second plane, and the constraint surface; the error is calculated based on the light field intensity distribution, and the iteration is completed when the error is less than a threshold value to obtain the wavefront distribution at the front surface of the encoding plate;

The wavefront distribution at the front surface of the coding plate is transmitted back to the plane where the ultrasonic transducer module is located, so as to calculate the wavefront amplitude and phase distribution of the wavefront distribution at the front surface of the coding plate at the ultrasonic transducer module to obtain the complex amplitude distribution of the sound field.

According to a third aspect of an embodiment of the present invention, an electronic device is provided, comprising a memory and a processor, wherein the memory is coupled to the processor; wherein the memory is used to store program data, and the processor is used to execute the program data to implement the above-mentioned sound field detection method based on coded phase imaging.

According to a fourth aspect of an embodiment of the present invention, a computer-readable storage medium is provided, on which a computer program is stored. When the program is executed by a processor, the above-mentioned sound field detection method based on coded phase imaging is implemented.

Compared with the prior art, the technical effects of the present invention are:

The present invention provides a sound field detection system and method based on coded phase imaging, which places an ultrasonic transducer in a pulsed parallel light field, reconstructs the complex amplitude distribution of the light field based on coherent modulation imaging, and combines ultrashort pulses to detect instantaneous changes in the light field, thereby achieving continuous real-time detection. At the same time, the present invention indirectly obtains the density distribution of the sound field medium by reconstructing the light field phase distribution at the sound field position. According to the density distribution of the sound field medium, the distribution parameters of the high-frequency sound field to be measured generated by the ultrasonic transducer can be determined, thereby achieving non-destructive sound field detection, and realizing the detection of sound field distribution parameters without disrupting the original sound field. In addition, the system of the present invention has a simple optical path, stable performance, and low cost.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

FIG1 is a schematic diagram of an acoustic field detection system based on coded phase imaging provided by an embodiment of the present invention;

FIG2 is a schematic diagram of an ultrasonic transducer module and a two-dimensional translation module provided in an embodiment of the present invention;

3 is a schematic diagram of an acoustic field detection system based on coded phase imaging under a spatial pulse laser provided by an embodiment of the present invention;

FIG4 is a schematic diagram of an acoustic field detection system based on coded phase imaging under a fiber pulse laser provided by an embodiment of the present invention;

FIG5 is a schematic flow chart of a method for detecting an acoustic field based on coded phase imaging according to an embodiment of the present invention;

6 is a schematic diagram of a process for obtaining the wavefront distribution at the front surface of the coding plate according to an embodiment of the present invention;

FIG7 is an amplitude and phase distribution of an acoustic field medium reconstructed under a fiber pulse laser provided by an embodiment of the present invention;

FIG. 8 is a schematic diagram of an electronic device provided by an embodiment of the present invention.

In the figure, 1-parallel light field emission module, 2-acoustic field medium module, 3-ultrasonic transducer module, 4-imaging module, 5-encoding board, 6-light field detector, 7-control and calculation module, 8-two-dimensional translation module, 9-spatial pulse laser, 10-spatial light filter, 11-collimating lens, 12-achromatic imaging lens, 13-fiber pulse laser, 14-fiber jumper.

Detailed ways

Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and/or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

It should be understood that although the terms first, second, third, etc. may be used in the present invention to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

As shown in FIG1 , the present invention provides an acoustic field detection system based on coded phase imaging, the system comprising: a parallel light field emission module 1, the parallel light field emission module 1 is used to generate a pulse parallel light field to illuminate an acoustic field medium, the pulse parallel light field is wavefront modulated by an acoustic field medium 2, imaged by an imaging module 4, modulated by a coding plate 5, and the light field intensity distribution is obtained by a light field detector 6;

The system further comprises:

Ultrasonic transducer module 3, used to generate a high-frequency sound field to be measured;

The control and calculation module 7 is used to control the synchronization of the parallel light field transmitting module 1 and the light field detector 6, and store the light field intensity distribution obtained by the light field detector 6 to calculate the complex amplitude distribution of the high-frequency sound field to be measured.

Furthermore, the system further comprises: as shown in FIG. 2 , a two-dimensional translation module 8 for moving the ultrasonic transducer module 3 in the x-direction and the y-direction.

Furthermore, the parallel light field emission module 1 uses a space laser to generate a parallel light field system or a fiber laser to generate a parallel light field system; the pulse width of the pulse parallel light field generated by the parallel light field emission module 1 is less than 10ns, and the repetition frequency is less than 1kHz.

Furthermore, the imaging module 4 adopts a reduced beam imaging system for low-frequency and large-caliber sound field detection; or, the imaging module 4 adopts an imaging amplification system for high-frequency and small-caliber sound field detection.

Example 1

As shown in FIG3 , this example provides an acoustic field detection system based on coded phase imaging, wherein the parallel light field emission module 1 uses a spatial laser 10; specifically, the system comprises: a spatial pulse laser 9, a spatial light filter 10, a collimating lens 11, an acoustic field medium 2, an achromatic imaging lens 12, a coding plate 5, and an optical field detector 6, which are arranged in sequence;

The spatial pulse laser 9 is used to generate a spatial pulse light field for illuminating a transient acoustic field medium. In this example, the light source wavelength of the spatial pulse laser 9 is 1064 nm, the pulse width is 10 ns, and the repetition frequency is 10 Hz.

A spatial optical filter 10 is used to filter out stray light and generate a spherical pulse light field Q;

The collimating lens 11 is used to collimate the spherical pulse light field Q into a parallel light field for illuminating the acoustic field medium.

The acoustic field medium module 2 is used to propagate the acoustic field and generate wavefront modulation on the parallel light field;

Ultrasonic transducer module 3, used to generate a high-frequency sound field to be measured;

The imaging module 4 uses an achromatic imaging lens 12 for imaging the sound field medium. In this example, the achromatic imaging lens 12 has a focal length of 100 mm, an aperture of 50.8 mm, and an imaging magnification of 3.

In this example, the unit pixel size of the encoding plate 5 is 9 μm×9 μm, and for a wavelength of 1064 nm, the phase change is a 0-π distribution; the unit pixel size of the light field detector 6 is 9 μm×9 μm, and the dynamic range is 16 bits.

Example 2

As shown in FIG4 , this example provides an acoustic field detection system based on coded phase imaging, wherein the parallel light field emission module 1 uses a fiber pulse laser 13; specifically, the system includes: a fiber pulse laser 13, a fiber jumper 14, a collimating lens 11, an acoustic field medium 2, an achromatic imaging lens 12, a coding plate 5, and a light field detector 6 arranged in sequence.

The fiber pulse laser 13 is used to generate a fiber pulse light field for illuminating a transiently changing acoustic field medium. In this example, the fiber pulse laser 13 has a light source wavelength of 532 nm, a pulse width of 10 ps, and a repetition frequency of 1 kHz.

The optical fiber jumper 14 is used to generate a transmission light field and finally generate a spherical light field W;

A collimating lens 11, used to collimate the spherical pulse light field W into a parallel light field for illuminating the acoustic field medium;

The acoustic field medium module 2 is used to propagate the acoustic field and generate wavefront modulation on the parallel light field;

Ultrasonic transducer module 3, used to generate a high-frequency sound field to be measured;

The imaging module 4 uses an achromatic imaging lens 12 for imaging the sound field medium. In this example, the achromatic imaging lens 12 has a focal length of 150 mm, an aperture of 50.8 mm, and a reduction ratio of 3.

The coding plate 5 is used to modulate the wavefront of the light field. Its complex amplitude transmittance needs to be known during algorithm iteration. In this embodiment, the unit pixel size is 18 μm×18 μm. For a wavelength of 532 nm, the phase change is a 0-π distribution.

The light field detector 6 is used to record the intensity distribution of the light field and the intensity matrix. In this embodiment, the unit pixel size used is 9 μm×9 μm and the dynamic range is 16 bits.

As shown in FIG5 , an embodiment of the present invention further provides a sound field detection method based on coded phase imaging, which is implemented based on the above-mentioned sound field detection system based on coded phase imaging. The method includes:

Step S1, the ultrasonic transducer module 3 generates a high-frequency sound field to be measured.

Specifically, the two-dimensional translation module 8 is used to translate the ultrasonic transducer module 3 into the visible range of the light field, and the ultrasonic transducer module 3 is started to emit a high-frequency sound field to be measured.

Step S2, obtaining the light field intensity distribution recorded by the light field detector 6.

Specifically, the control and calculation module 7 is used to control the time synchronization of the spatial pulse laser 9 and the light field detector 6, and store the light field intensity distribution matrix recorded by the light field detector 6. .

Step S3, setting the plane where the light field detector 6 is located as the first plane, and the plane where the encoding plate 5 is located as the second plane; setting the initial light field complex amplitude distribution at the front surface of the encoding plate 5; iteratively propagating the initial light field complex amplitude distribution between the first plane, the second plane, and the constraint surface; calculating the error based on the light field intensity distribution, completing the iteration when the error is less than a threshold, and obtaining the wavefront distribution at the front surface of the encoding plate 5.

Specifically, as shown in FIG6 , step S3 specifically includes the following sub-steps:

Step S301, setting the initial light field complex amplitude distribution at the front surface of the coding plate 5 to , where A and are the amplitude and phase distributions of random guesses, n is the corresponding time sequence number, is the recording time of the corresponding light field detector 6.

Step S302: taking the initial light field complex amplitude distribution at the front surface of the coding plate 5 as the first iteration value .

Step S303, after the complex amplitude distribution of the light field is modulated by the encoding plate 5, a first wavefront is obtained, which is expressed as follows:

;

Where k is the number of iterations, k=1,2,3…, is the transmittance complex amplitude distribution of the coding plate 5;

Step S304, when the first wavefront propagates to the first plane in the free space, the light field intensity distribution is used for constraint to obtain the second wavefront, which is expressed as follows:

;

;

Where _L1 represents the distance between the second plane and the first plane, represents the free space propagation distance L of the light field; It means taking the phase angle of the wavefront;

Step S305, the second wavefront is transmitted back to the second plane, and updated using the transmittance complex amplitude distribution to obtain the third wavefront at the front surface of the encoding plate 5, which is expressed as follows:

;

;

Step S306, transmitting the third wavefront to a constraint surface, which is a spectrum surface or a focal surface of the third wavefront; constructing an aperture constraint function, and using the aperture constraint function to constrain time and wavelength to obtain a fourth wavefront, which is expressed as follows:

;

Where _L2 represents the distance between the second plane and the constraint surface, is the aperture function constraint;

Step S307, transmitting the fourth wavefront to the second plane to obtain the fifth wavefront, which is expressed as follows:

;

Step S308, iterate according to the above process, and calculate the error based on the second wavefront and the pulse diffraction spot intensity matrix. When the error is less than the threshold, the iteration is completed, and the fifth wavefront obtained by the iteration is used as the wavefront distribution at the front surface of the encoding plate 5.

Specifically, the error expression is as follows:

;

In the formula, represents the light field intensity distribution recorded by the light field detector 6; Indicates before the second wave.

Step S4, transmit the wavefront distribution at the front surface of the coding plate 5 back to the plane where the ultrasonic transducer module 3 is located, so as to calculate the wavefront amplitude and phase distribution of the wavefront distribution at the front surface of the coding plate 5 at the ultrasonic transducer module 3, and obtain the complex amplitude distribution of the sound field.

Specifically, the wavefront distribution at the front surface of the coding plate 5 is obtained, which is recorded as ;

The wavefront distribution at the front surface of the coding plate 5 is transmitted back to the plane where the ultrasonic transducer module 3 is located, and the wavefront distribution at the plane where the ultrasonic transducer module 3 is located is obtained, and the expression is as follows:

;

In the formula, is the distance between the plane where the encoding plate 5 is located and the second plane and the plane where the ultrasonic transducer module 3 is located;

Calculate the wavefront amplitude of the wavefront at the front surface of the encoder plate 5 distributed at the ultrasonic transducer module 3 and phase distribution ; That is, the density of the sound field medium 2 is used to obtain the complex amplitude distribution of the sound field.

As shown in Figure 7, (a) in Figure 7 is the amplitude of the light field at the sound field position and (b) in Figure 7 is the phase distribution, where the sound field distribution information cannot be distinguished from the amplitude, but the phase fringe distribution at this position is the same as the distribution of the sound field. By calculating the fringe interval, it can be obtained that the sound field is 1.96MHz.

In summary, the present invention provides a sound field detection system and method based on coded phase imaging, which places an ultrasonic transducer in a pulsed parallel light field, reconstructs the complex amplitude distribution of the light field based on single coherent modulation imaging, and combines ultrashort pulses to detect instantaneous changes in the light field, while achieving continuous real-time detection. At the same time, the present invention indirectly obtains the density distribution of the sound field medium by reconstructing the light field phase distribution at the sound field position. According to the density distribution of the sound field medium, the distribution parameters of the high-frequency sound field to be measured generated by the ultrasonic transducer can be determined, thereby achieving non-destructive sound field detection and detecting the sound field distribution parameters without disrupting the original sound field. In addition, the system of the present invention has a simple optical path, stable performance, and low cost.

The present specification also provides a computer-readable storage medium, which stores a computer program, and the computer program can be used to execute the above-mentioned data synchronization method.

This specification also provides a schematic structural diagram of an electronic device as shown in FIG8. As shown in FIG8, at the hardware level, the electronic device includes a processor, an internal bus, a network interface, a memory, and a non-volatile memory, and may also include hardware required for other services. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it to implement the above-mentioned data synchronization method.

Of course, in addition to software implementation, this specification does not exclude other implementation methods, such as logic devices or a combination of software and hardware, etc., that is to say, the executor of the following processing flow is not limited to each logic unit, but can also be hardware or logic devices.

In the 1990s, it was very clear whether the improvement of a technology was hardware improvement (for example, improvement of the circuit structure of diodes, transistors, switches, etc.) or software improvement (improvement of the method flow). However, with the development of technology, many improvements of the method flow today can be regarded as direct improvements of the hardware circuit structure. Designers almost always obtain the corresponding hardware circuit structure by programming the improved method flow into the hardware circuit. Therefore, it cannot be said that the improvement of a method flow cannot be implemented with hardware entity modules. For example, a programmable logic device (PLD) (such as a field programmable gate array (FPGA)) is such an integrated circuit whose logical function is determined by the user's programming of the device. Designers can "integrate" a digital system on a PLD by programming themselves, without having to ask chip manufacturers to design and make dedicated integrated circuit chips. Moreover, nowadays, instead of manually making integrated circuit chips, this kind of programming is mostly implemented by "logic compiler" software, which is similar to the software compiler used when developing and writing programs, and the original code before compilation must also be written in a specific programming language, which is called hardware description language (HDL). There is not only one kind of HDL, but many kinds, such as ABEL (Advanced Boolean Expression Language), AHDL (Altera Hardware Description Language), Confluence, CUPL (Cornell University Programming Language), HDCal, JHDL (Java Hardware Description Language), Lava, Lola, MyHDL, PALASM, RHDL (Ruby Hardware Description Language), etc. The most commonly used ones are VHDL (Very-High-Speed Integrated Circuit Hardware Description Language) and Verilog. Those skilled in the art should also know that it is only necessary to program the method flow slightly in the above-mentioned hardware description languages and program it into the integrated circuit, and then it is easy to obtain the hardware circuit that implements the logic method flow.

The controller may be implemented in any suitable manner, for example, the controller may take the form of a microprocessor or processor and a computer-readable medium storing a computer-readable program code (e.g., software or firmware) executable by the (micro)processor, a logic gate, a switch, an application-specific integrated circuit (ASIC), a programmable logic controller, and an embedded microcontroller. Examples of controllers include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicone Labs C8051F320. The memory controller may also be implemented as part of the control logic of the memory. It is also known to those skilled in the art that, in addition to implementing the controller in a purely computer-readable program code manner, the controller may be implemented in the form of a logic gate, a switch, an application-specific integrated circuit, a programmable logic controller, and an embedded microcontroller by logically programming the method steps. Therefore, such a controller may be considered as a hardware component, and the devices for implementing various functions included therein may also be considered as structures within the hardware component. Or even, the devices for implementing various functions may be considered as both software modules for implementing the method and structures within the hardware component.

The systems, devices, modules or units described in the above embodiments may be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, the computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

For the convenience of description, the above device is described in various units according to their functions. Of course, when implementing this specification, the functions of each unit can be implemented in the same or multiple software and/or hardware.

Those skilled in the art will appreciate that the embodiments of this specification may be provided as methods, systems, or computer program products. Therefore, this specification may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, this specification may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

This specification is described with reference to the flowcharts and/or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of this specification. It should be understood that each process and/or box in the flowchart and/or block diagram, as well as the combination of the processes and/or boxes in the flowchart and/or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

In a typical configuration, a computing device includes one or more processors (CPU), input/output interfaces, network interfaces, and memory.

The memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and/or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

Those skilled in the art will appreciate that the embodiments of this specification may be provided as methods, systems or computer program products. Therefore, this specification may take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware. Furthermore, this specification may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

This specification may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. This specification may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

The above description is only an embodiment of the present specification and is not intended to limit the present specification. For those skilled in the art, the present specification may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present specification shall be included in the scope of the claims of the present specification.

Claims (9)

1. A method of sound field detection based on code phase imaging, characterized in that it is implemented by a sound field detection system based on code phase imaging, said system comprising:

The parallel light field transmitting module (1) is used for generating a pulse parallel light field to illuminate a sound field medium, the pulse parallel light field carries out wave front modulation through the sound field medium (2), imaging is carried out through the imaging module (4), modulation is carried out through the encoding plate (5), and light field intensity distribution is obtained through the light field detector (6);

The system further comprises:

An ultrasonic transducer module (3) for generating a sound field of high frequency to be detected;

the control and calculation module (7) is used for controlling the synchronization of the parallel light field emission module (1) and the light field detector (6), and storing the light field intensity distribution acquired by the light field detector (6) so as to calculate the complex amplitude distribution of the high-frequency sound field to be detected;

the method comprises the following steps:

The ultrasonic transducer module (3) generates a sound field of high frequency to be detected;

acquiring light field intensity distribution recorded by a light field detector (6);

Setting the plane of the light field detector (6) as a first plane, and setting the plane of the coding plate (5) as a second plane; setting an initial light field complex amplitude distribution at the front surface of the code plate (5); the initial optical field complex amplitude distribution is iteratively propagated among the first plane, the second plane and the constraint plane; calculating errors based on the light field intensity distribution, and finishing iteration when the errors are smaller than a threshold value to obtain wavefront distribution at the front surface of the coding plate (5);

and transmitting the wave front distribution at the front surface of the coding plate (5) back to the plane where the ultrasonic transducer module (3) is located, so as to calculate wave front amplitude and phase distribution of the wave front at the front surface of the coding plate (5) at the ultrasonic transducer module (3) and obtain complex amplitude distribution of the sound field.

2. A sound field detection method based on code phase imaging according to claim 1, characterized in that the process of acquiring the wavefront distribution at the front surface of the code plate (5) comprises:

setting the initial light field complex amplitude distribution at the front surface of the code plate (5) as Wherein A andThe amplitude and phase distribution of random guess are respectively, n is the corresponding time sequence number, and t _n is the recording time of the corresponding light field detector (6);

Taking the initial light field complex amplitude distribution at the front surface of the code plate (5) as a1 st iteration value E ¹(x,y,t_n)＝E⁰(x,y,t_n);

after the light field complex amplitude distribution is modulated by the encoding plate (5), a first wavefront is obtained, and the expression is as follows:

ψ^k(x,y,t_n)＝E^k(x,y,t_n)·T(x,y)；

wherein k is the iteration number, k=1, 2,3 …, and T (x, y) is the transmittance complex amplitude distribution of the coding plate (5);

when the first wavefront propagates to the first plane in the free space, the first wavefront is constrained by using the light field intensity distribution to obtain a second wavefront, and the expression is as follows:

Wherein L ₁ denotes a distance between the second plane and the first plane, Representing the light field free space propagation L distance; angle (G (x, y, t _n)) represents the phase angle taken for the wavefront;

And (3) transmitting the second wavefront back to the second plane, and updating by using the transmittance complex amplitude distribution to obtain a third wavefront at the front surface of the coding plate (5), wherein the expression is as follows:

E'(x,y,t_n)＝E(x,y,t_n)+T^*(x,y)/max(T^*(x,y)·T(x,y))·[ψ'(x,y,t_n)-ψ(x,y,t_n)];

transmitting the third wavefront to a constraint surface, wherein the constraint surface is a spectrum surface or a focus surface of the third wavefront; constructing an aperture constraint function, and constraining time and wavelength by using the aperture constraint function to obtain a fourth wavefront, wherein the expression is as follows:

wherein L ₂ represents the distance between the second plane and the constraint surface, and H (x, y) is the aperture function constraint;

transmitting the fourth wavefront to the second plane to obtain a fifth wavefront, where the expression is as follows:

And iterating according to the process, calculating an error based on the second wavefront and the pulse diffraction light spot intensity matrix, finishing iteration when the error is smaller than a threshold value, and taking a fifth wavefront obtained by iteration as wavefront distribution at the front surface of the coding plate (5).

3. The method of claim 2, wherein calculating the error based on the light field intensity distribution comprises:

The expression of the error is as follows:

Wherein I (x, y, t _n) represents the light field intensity distribution recorded by the light field detector (6); g (x, y, t _n) represents the second wavefront.

4. A sound field detection method based on coded phase imaging according to claim 1, characterized in that the step of transmitting back the wave front distribution at the front surface of the code plate (5) to the plane in which the ultrasound transducer module (3) is located, thereby calculating the wave front amplitude and phase distribution of the wave front distribution at the front surface of the code plate (5) at the ultrasound transducer module (3), resulting in a complex amplitude distribution of the sound field comprises:

Acquiring a wavefront distribution at the front surface of the code plate (5), denoted as E (x, y, t _n);

the wave front distribution at the front surface of the coding plate (5) is transmitted back to the plane where the ultrasonic transducer module (3) is located, and the wave front distribution at the plane where the ultrasonic transducer module (3) is located is obtained, and the expression is as follows:

Wherein L ₃ is the distance between the second plane and the plane of the ultrasonic transducer module (3);

Calculating a wavefront amplitude abs (U (x, y, t _n)) and a phase distribution angle (U (x, y, t _n)) that distribute a wavefront at the front surface of the encoding plate (5) at the ultrasound transducer module (3); based on the density of the sound field medium (2), a complex amplitude distribution of the sound field is obtained.

5. The encoding phase imaging based sound field detection method of claim 1, wherein the system further comprises: a two-dimensional translation module (8) for moving the ultrasound transducer module (3) in x-direction and y-direction.

6. The sound field detection method based on code phase imaging according to claim 1, wherein the parallel light field emission module (1) selects a space laser to generate a parallel light field system or a fiber laser to generate a parallel light field system; the pulse width of the pulse parallel light field generated by the parallel light field transmitting module (1) is smaller than 10ns, and the repetition frequency is smaller than 1kHz.

7. The sound field detection method based on code phase imaging according to claim 1, wherein the imaging module (4) adopts a beam-shrinking imaging system for low-frequency large-caliber sound field detection; or the imaging module (4) adopts an imaging amplification system for detecting the high-frequency small-caliber sound field.

8. An electronic device comprising a memory and a processor, wherein the memory is coupled to the processor; wherein the memory is configured to store program data and the processor is configured to execute the program data to implement the encoding phase imaging based sound field detection method of any one of claims 1 to 7.

9. A computer-readable storage medium, on which a computer program is stored, characterized in that the program, when being executed by a processor, implements the encoding phase imaging based sound field detection method according to any one of claims 1 to 7.