Shock wave energy measurement system and method based on Raman Nesss diffraction

Abstract

The invention discloses a shock wave energy measurement system and method based on Raman Nesss diffraction. In the system, a laser is used for generating near-infrared laser; the neutral density optical filter is used for attenuating the light intensity of the near-infrared laser; a probe of the shock wave therapeutic apparatus is placed in the water tank, and the generated shock wave enables incident laser to generate Raman Nesses diffraction to form a plurality of diffraction laser light paths; the convex lens is used for collecting the multiple diffraction laser light paths; the linear array image sensor is used for detecting the intensity of the laser passing through the convex lens and converting the intensity into an analog voltage value; the image acquisition card is used for sampling the analog voltage value into a digital voltage signal, obtaining a diffraction laser digital image and then sending the diffraction laser digital image to the upper computer; and the upper computer is used for receiving and analyzing the diffraction laser digital image and calculating to obtain the energy density of the shock wave. The accuracy and reliability of shock wave measurement are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of shock wave measurement, and more specifically, to a shock wave energy measurement system and method based on Raman-Nath diffraction. Background Art

[0002] As a new non-surgical rehabilitation physiotherapy method for diseases such as pain, extracorporeal shock wave therapy (ESWT) utilizes the energy conversion and transmission principle of shock waves. After entering the human body, it promotes osteogenesis, changes local blood circulation, has a direct stimulating effect on cartilage damage, and can accelerate cartilage repair. Compared with conservative treatment and surgical treatment, extracorporeal shock wave therapy has the advantages of non-invasiveness, small tissue damage, safety and effectiveness, low cost, short treatment time, and easy acceptance by patients. At present, shock wave therapy has been widely used in the clinical treatment field of musculoskeletal system diseases (such as sports medicine, pain medicine, and rehabilitation medicine, etc.), showing broad clinical application prospects.

[0003] Compared with traditional sound waves, shock waves have many similarities in many aspects, and the detection of their energy can draw on the detection methods of sound power in acoustics. In the field of acoustics, sound power is generally used to represent sound energy. The sound energy passing through a unit area orthogonal to the propagation direction per unit time of sound wave propagation is called sound power. Commonly used sound power measurement methods mainly include hydrophone method, pulse echo method, double-exposure holography method, optical detection method, etc.

[0004] The hydrophone method uses piezoelectric and other thin film materials placed around the ultrasonic shock wave to be measured, and reflects the energy of the shock wave through parameters such as the induced pressure value. According to the principle, it can be divided into piezoelectric type, electromagnetic type, capacitive type, fiber optic type, etc., and they can also form arrays respectively to measure the sound field. In 2010, Jeffrey designed an array composed of 20 thin film hydrophone units to measure the shock wave sound field characteristics of a medical extracorporeal treatment machine, and the normalized average voltage between each array and the array is very uniform.

[0005] The principle of the pulse echo method is to utilize the basic common sense of distance = speed * time. The most typical application scenario of this method is the non-destructive detection of material thickness. The ultrasonic probe is placed close to the test plate, and the time difference between the two received echoes is calculated to determine information such as thickness. Of course, this scheme also involves some other information of the sound signal. The advantage of this type of scheme is that the experimental platform and operation are relatively simple, but the sound signal to be measured must be a sound signal with the same frequency emitted by a standard probe.

[0006] The measurement system constructed by double-exposure holography mainly includes an ultrasonic transducer, a pulsed laser, a holographic recording dry plate, a reflector, etc. The sound pressure of the sound signal excited by the ultrasonic transducer will cause changes in the water surface height, and the optical path difference formed by the coherent light beam will be recorded on the dry plate. As the holographic recording dry plate moves, the sound pressure distribution of the transducer at different positions can also be measured.

[0007] In addition, there is also the Mach-Zehnder interferometry method, which uses optical non-contact measurement of acoustic wave energy. The main principle is to use ultrasonic waves to change the refractive index of one arm of the interferometer passing through the medium to judge the intensity of the acoustic wave.

[0008] After analysis, there are certain deficiencies in the existing shock wave energy measurement methods. For example, contact measurement methods such as hydrophones require the sensor to be in direct contact with the shock wave acting medium. The sensor itself will affect the shock wave sound field, and generally the bandwidth and pressure resistance of the sensor are relatively low, with low accuracy and being prone to failure after long-term use. The pulse echo method and double-exposure holography method are only applicable to the measurement of single-frequency acoustic signal energy and are not applicable to complex broadband acoustic signals such as shock waves. The optical path system of the Mach-Zehnder interferometry method is relatively complex, requiring the use of more precision beam splitters and reflectors to build the optical path. The cost of the measurement system is relatively high, and it is also difficult to control the accuracy. Summary of the Invention

[0009] The object of the present invention is to overcome the defects of the above-mentioned existing technologies and provide a shock wave energy measurement system and method based on Raman-Nath diffraction.

[0010] According to the first aspect of the present invention, a shock wave energy measurement system based on Raman-Nath diffraction is provided. The system includes a laser, a neutral density filter, a shock wave therapy probe, a water tank, a convex lens, a linear array image sensor, an image acquisition card, and a host computer. Among them, the laser is used to generate near-infrared laser; the neutral density filter is used to attenuate the light intensity of the near-infrared laser; the shock wave therapy probe is placed in the water tank, and the generated shock wave causes Raman-Nath diffraction of the incident laser to form a multi-path diffracted laser optical path; the convex lens is used to converge the multi-path diffracted laser optical path; the linear array image sensor is used to detect the laser intensity passing through the convex lens and convert it into an analog voltage value; the image acquisition card is used to sample the analog voltage value into a digital voltage signal, obtain a diffracted laser digital image, and then send it to the host computer; the host computer is used to receive and analyze the diffracted laser digital image and calculate the energy density of the shock wave.

[0011] According to the second aspect of the present invention, a shock wave energy measurement method based on Raman-Nath diffraction is provided. The method includes the following steps:

[0012] Control the laser to generate near-infrared laser;

[0013] A neutral density filter is provided to attenuate the intensity of the near-infrared laser;

[0014] Place the shock wave therapy instrument probe in the water tank, and control the generated shock wave to cause Raman-Nath diffraction of the incident laser, forming a multi-path diffracted laser optical path;

[0015] Use a convex lens to converge the multi-path diffracted laser optical path;

[0016] Use a linear array image sensor to detect the laser intensity passing through the convex lens and convert it into an analog voltage value;

[0017] Sample the analog voltage value into a digital voltage signal to obtain a digital image of the diffracted laser;

[0018] Analyze the digital image of the diffracted laser and calculate the energy density of the shock wave.

[0019] Compared with the prior art, the advantages of the present invention are that, compared with contact measurement methods such as the hydrophone method, the present invention uses near-infrared laser Raman-Nath diffraction to non-contact measure the energy of the shock wave, reducing the influence of the measurement system on the shock wave sound field and improving the measurement accuracy and reliability. Compared with traditional optical non-contact measurement methods such as the Mach-Zehnder interferometer method, the optical path system proposed by the present invention has a simple structure, low cost, is convenient to build and use, and is easy to promote and apply.

[0020] Through the following detailed description of the exemplary embodiments of the present invention with reference to the accompanying drawings, other features and advantages of the present invention will become clear. Description of the Drawings

[0021] The drawings incorporated in the specification and constituting a part of the specification illustrate embodiments of the present invention and, together with the description, are used to explain the principles of the present invention.

[0022] Figure 1 is a schematic diagram of a shock wave energy measurement system based on Raman-Nath diffraction according to an embodiment of the present invention;

[0023] Figure 2 is a flowchart of a method for measuring shock wave energy based on Raman-Nath diffraction according to an embodiment of the present invention. Detailed Embodiments

[0024] Now, various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that: unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps described in these embodiments do not limit the scope of the present invention.

[0025] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way a limitation on the present invention, its application, or its use.

[0026] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be considered as part of the specification.

[0027] In all examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values.

[0028] It should be noted that like reference numerals and letters denote like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof in subsequent figures is not required.

[0029] See Figure 1 As shown, the provided shock wave energy measurement system based on Raman-Nath diffraction mainly includes a laser, a neutral density filter, a shock wave therapy probe, a water tank, a convex lens, a linear array image sensor, an image acquisition card, and a host computer, etc.

[0030] The laser is used to generate near-infrared laser. For example, it generates near-infrared laser with a central wavelength of 915 nm, and a semiconductor laser can be used. Compared with common visible light lasers such as red or green light, near-infrared laser has better penetration in water and is less affected by absorption and scattering, so the accuracy of shock wave energy measurement is higher. The laser should be selected in the intensity stable mode to ensure the stability of the output laser intensity, which is crucial for subsequent measurements.

[0031] The neutral density filter is used to attenuate the light intensity of the near-infrared laser so that the attenuated light intensity is just close to the upper limit of the input range of the subsequent linear array photodetector (i.e., the linear array image sensor) to improve the measurement accuracy.

[0032] The shock wave therapy probe to be measured is placed in the water tank, with the probe axis perpendicular to the water surface and the lower surface just tangent to the water surface, for simulating the shock wave passing through human tissues to reach the target treatment site. The acoustic field parameters such as the medium density and the medium sound transmission speed of water are very close to those of muscle and soft tissue, and currently, during the treatment of bone and muscle diseases, stones, cardiovascular and cerebrovascular diseases, etc. using extracorporeal shock waves, the shock waves usually reach the lesion through muscle or soft tissue. Therefore, water can better simulate the actual situation of extracorporeal shock waves.

[0033] The convex lens is used to converge the laser light path to facilitate subsequent imaging with a photodetector. The focal length is selected to be 50 mm, for example, and it should be ensured that the convex lens has a high transmittance in the near-infrared band.

[0034] The linear array image sensor is used to detect the intensity of the diffracted laser. A general near-infrared monochromatic CMOS image sensor can be selected. By choosing an appropriate length and adjusting the window position and size according to the intensity distribution of the incident laser, the linear array image sensor can just detect the diffracted laser of the positive first order or negative first order. To ensure the adaptability of the linear array image sensor to the ambient temperature and operating heat generation, and avoid errors in the shock wave energy measurement caused by temperature fluctuations, the linear array image sensor can be equipped with a two-way thermoelectric cooler (TEC) for rapid cooling or heating. After the incident laser passes through the image sensor, it is converted into an analog voltage value and output to the subsequent image acquisition card.

[0035] The image acquisition card samples the analog voltage value into a digital voltage signal and sends it to the host computer for further analysis and processing. The image acquisition card can be equipped with an external synchronous trigger input function to synchronize the data acquisition with the moment when the shock wave therapeutic apparatus emits shock waves, thereby improving the anti-interference ability and measurement accuracy of the system.

[0036] The host computer is used to receive and analyze the digital image of the diffracted laser output by the image acquisition card, and give the energy density characterizing the shock wave therapeutic apparatus through calculation. For example, the host computer includes modules such as acquisition card parameter setting, image acquisition, image preprocessing, data storage, real-time energy calculation and display. The acquisition card parameter setting module is used to set parameters such as the sampling channel, sampling frequency, and sampling time of the above-mentioned image acquisition card. The image acquisition module is used to receive the digital image data output by the image acquisition card in real time. The image preprocessing module is used to filter out the low-frequency and DC noise of the image data. The data storage module is used to save and playback the image data. The real-time energy calculation and display module calculates the energy density parameters of the shock wave according to the image data.

[0037] Based on Figure 1 the system, the basic physical law of the shock wave energy measurement method based on Raman-Nath diffraction is the acousto-optic effect. The acousto-optic effect refers to the phenomenon that light will be diffracted when it encounters sound waves during the process of propagating in a straight line. When ultrasonic waves propagate in media such as human tissues and water, they will exert a stress on the medium, causing the medium density to change in a certain pattern. When light passes perpendicularly through the propagation direction of the shock wave, the transparent medium with density change essentially forms an ultrasonic grating, and light will undergo a diffraction phenomenon. The diffracted light is divided into 0th-order diffracted light, ±1st-order diffracted light, ±2nd-order diffracted light, etc. The diffracted light contains a large amount of information about the shock wave. By analyzing the diffracted light, information such as the phase and sound pressure of the shock wave source can be inverted. The greatest advantage of using the acousto-optic diffraction method lies in its non-contact nature, which can achieve non-destructive detection of the sound field.

[0038] According to the differences in ultrasonic frequency and acousto-optic interaction length, acousto-optic diffraction can be divided into Raman-Nath diffraction and Bragg diffraction. When light propagates perpendicular to the direction of ultrasonic wave propagation, the diffraction phenomenon is Raman-Nath diffraction, and at this time, multiple-order diffracted light is formed. The diffracted light of each order is symmetrically distributed, the intensities of any two symmetrically distributed diffracted lights are the same, the intensity of the zero-order diffracted light is the highest, and the sum of the intensities of all diffracted lights is the same as the light intensity of the light source. In the case of Raman-Nath diffraction, the change in medium density is directly related to the magnitude of the sound pressure. To obtain the relationship between pressure and refractive index, considering the interference of the ultrasonic sound field on the refractive index as Δn, the relationship between the refractive index and the change in sound pressure can be expressed by the following formula:

[0039] n(y,t) = n 0 ±Δn·p(y,t) (1)

[0040] where n(y,t) is the refractive index at the position y in the medium at time t, p(y,t) is the distribution function of the ultrasonic sound pressure, and n 0 is the refractive index without ultrasonic disturbance.

[0041] Ultrasonic waves can cause periodic changes in the refractive index of the medium, forming an ultrasonic grating. The distribution of the diffracted light of Raman-Nath diffraction conforms to the symmetry law. Except for the zero-order diffracted light, the intensities of the positive and negative diffracted lights of each order are equal. The complex amplitude distribution of the diffracted light intensity on the focal plane of the lens is expressed as:

[0042]

[0043] where J m is the Bessel function of the first kind of order m, is the phase shift amount of light caused by ultrasound, ω is the laser angular frequency, and ω s is the ultrasonic angular frequency. It can be seen from the above formula that the ultrasonic grating formed by the change of the medium refractive index will cause simultaneous changes in the light phase and intensity. Among them, the result of phase modulation is to cause a frequency shift of mω s for the m-th order diffracted light; while the result of amplitude modulation is to cause the same modulation of the diffracted light amplitude as and can be calculated by the following formula:

[0044]

[0045] where k l is the laser wave number, P op is the piezoelectric constant of the medium. For a fixed laser and ultrasonic wave conduction medium, k l and P op are both known constants, L is the acousto-optic interaction length, and the y-axis is the laser propagation direction. If the laser completely penetrates the medium without being scattered and absorbed, the following Raman-Nath diffraction relationship exists:

[0046]

[0047]

[0048] Among them, I m is the intensity of a certain order of diffracted light, I is the total laser intensity without any perturbation, and v is the Raman-Nath parameter, which can be calculated from the ratio of the diffracted light intensities. Since the intensities of the diffracted lights of ±2nd order and above are extremely small and can be neglected, only I 1 , that is, the intensity of the first-order diffracted light, needs to be measured to obtain the pressure distribution p(y, t) within the spatial range of the acousto-optic interaction length.

[0049] Specifically, as shown in combination with Figure 1 and Figure 2 , the shock wave energy measurement method based on Raman-Nath diffraction includes the following steps:

[0050] Step S1: Set up a shock wave energy measurement system based on Raman-Nath diffraction and prepare for measurement.

[0051] For example, set up the measurement system as shown in Figure 1 . Turn on the laser, linear array image sensor, data acquisition card, shock wave therapeutic apparatus, and upper computer. Preheat the laser and linear array image sensor until they work stably, and turn on the air conditioner to ensure a constant ambient temperature.

[0052] Step S2: Adjust the height of the shock wave probe so that it is tangent to the laser optical path, and calculate the distance from the probe to the laser based on this.

[0053] The height of the shock wave probe being tangent to the laser optical path means that the distance from the probe to the laser is zero.

[0054] Step S3: Turn off the shock wave therapeutic apparatus, and measure the total light intensity of the laser without shock wave perturbation through the linear array image sensor.

[0055] Step S4: Adjust the distance from the probe to the laser to a predetermined distance, and inject pure water into the water tank so that the water surface just reaches the lower surface of the probe.

[0056] For example, adjust the distance from the probe to the laser to 5 mm.

[0057] Step S5: Turn on the shock wave therapeutic apparatus to make it emit shock waves periodically, and analyze the corresponding image data by the upper computer.

[0058] For example, observe the linear array image data output by the image acquisition card on the host computer. By adjusting (the angle of the neutral density filter and the magnification of the linear array image sensor), make the peak value of the image signal about 80% of the full scale. Observe the light intensity of the positive first-order diffracted light in the image signal. By measuring the shock wave data multiple times, obtain the average value of the first-order diffracted light intensity.

[0059] Step S6: According to the ratio of the average value of the first-order diffracted light intensity to the total light intensity value, use the first-order Bessel function to perform inverse iteration to calculate the Raman-Nath parameter, and then calculate the sound pressure at this point.

[0060] Specifically, after obtaining the Raman-Nath parameter v, the sound pressure p(y, t) at this point can be obtained using the above formula (5).

[0061] Step S7: By moving the light source, perform multiple measurements to obtain the distribution function of the shock wave sound pressure at different depths, and calculate the energy density of the shock wave.

[0062] For example, by moving the light source, repeat the above steps S1 - S6 to obtain the distribution function p(y, t) of the shock wave sound pressure at different depths. After obtaining the distribution function, the energy density of the shock wave can be obtained using the following formula:

[0063]

[0064] Among them, ρ is the medium density, c is the medium sound speed. When using water as the medium, the medium density and sound speed are 1×10³ kg / m³ and 1500 m / s respectively.

[0065] In summary, the present invention designs and constructs a shock wave energy measurement system based on Raman-Nath diffraction. According to the ratio of the average value of the first-order diffracted light intensity to the total light intensity value, uses the first-order Bessel function to perform inverse iteration to calculate the Raman-Nath parameter, and then obtains the distribution function of the shock wave sound pressure from the Raman-Nath parameter, and further obtains the energy density of the shock wave. Compared with contact measurement methods such as the hydrophone method, the present invention uses near-infrared laser Raman-Nath diffraction to non-contact measure the energy of the shock wave, reduces the influence of the measurement system on the shock wave sound field, and improves the measurement accuracy and reliability. Compared with traditional optical non-contact measurement methods such as the Mach-Zehnder interferometer method, the method proposed by the present invention has a simple optical path system structure, low cost, is convenient to build and use, and is easy to popularize and apply. Moreover, through simulation tests and experimental verification, the present invention achieves the desired effect.

[0066] The present invention can be a system, a method, and / or a computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions thereon for causing a processor to implement various aspects of the present invention.

[0067] A computer-readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. A computer-readable storage medium can be, for example, but is not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), a memory stick, a floppy disk, a mechanically encoded device such as a punch card or raised structures in grooves having instructions stored thereon, and any suitable combination of the foregoing. The computer-readable storage medium as used herein is not construed as being a transitory signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagated through a waveguide or other transmission medium (e.g., an optical pulse through an optical fiber cable), or an electrical signal transmitted through a wire.

[0068] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to respective computing / processing devices, or can be downloaded to an external computer or an external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include a copper transmission cable, an optical fiber transmission, a wireless transmission, a router, a firewall, a switch, a gateway computer, and / or an edge server. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in each computing / processing device.

[0069] The computer program instructions for performing the operations of the present invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine - related instructions, microcode, firmware instructions, state - setting data, or source code or object code written in any combination of one or more programming languages, including object - oriented programming languages such as Smalltalk, C++, Python, etc., and conventional procedural programming languages such as the "C" language or similar programming languages. The computer - readable program instructions may be executed entirely on the user's computer, partially on the user's computer, executed as a stand - alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or, alternatively, may be connected to an external computer (e.g., through the Internet using an Internet service provider). In some embodiments, by using the state information of the computer - readable program instructions to customize an electronic circuit, such as a programmable logic circuit, a field - programmable gate array (FPGA), or a programmable logic array (PLA), the electronic circuit can execute the computer - readable program instructions to implement various aspects of the present invention.

[0070] Aspects of the present invention are described herein with reference to the flowchart and / or block diagram of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart and / or block diagram, and combinations of blocks in the flowchart and / or block diagram, can be implemented by computer - readable program instructions.

[0071] These computer - readable program instructions can be provided to a processor of a general - purpose computer, a special - purpose computer, or other programmable data - processing apparatus to produce a machine such that the instructions, when executed by the processor of the computer or other programmable data - processing apparatus, create a means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer - readable program instructions can also be stored in a computer - readable storage medium, which causes a computer, a programmable data - processing apparatus, and / or other devices to operate in a particular manner, so that the computer - readable medium storing the instructions includes a manufacture, which includes instructions for implementing various aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0072] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other devices to produce a computer-implemented process such that the instructions executed on the computer, other programmable data processing apparatus, or other devices implement the functions / acts specified in one or more boxes of the flowchart and / or block diagram.

[0073] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagram may represent a module, a segment of code, or a portion of an instruction, which contains one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two consecutive blocks may in fact be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block of the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based system that performs the specified functions or acts, or by a combination of dedicated hardware and computer instructions. It is well known to those skilled in the art that implementation by hardware, implementation by software, and implementation by a combination of software and hardware are equivalent.

[0074] The embodiments of the present invention have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, the practical application, or the improvement of technologies in the market, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein. The scope of the present invention is defined by the appended claims.

Claims

1. A shock wave energy measurement system based on Raman-Nath diffraction, comprising a laser, a neutral density filter, a shock wave therapy probe, a water tank, a convex lens, a linear array image sensor, an image acquisition card and a host computer. Among them, The laser is used to generate near-infrared laser; the neutral density filter is used to attenuate the light intensity of the near-infrared laser; the shock wave therapy probe is placed in the water tank, and the generated shock wave causes the incident laser to undergo Raman-Nath diffraction, forming a multi-path diffracted laser light path; the convex lens is used to converge the multi-path diffracted laser light path; the linear array image sensor is used to detect the laser intensity passing through the convex lens and convert it into an analog voltage value. The image acquisition card is used to sample the analog voltage value into a digital voltage signal, obtain a digital image of the diffracted laser, and then send it to the host computer; the host computer is used to receive and analyze the digital image of the diffracted laser and calculate the energy density of the shock wave.

2. The system according to claim 1, Characterized in that, The laser is set to generate near-infrared laser with a central wavelength of 915 nm, and the focal length of the convex lens is set to 50 mm.

3. The system according to claim 1, Characterized in that, The linear array image sensor is set to be able to detect the diffracted laser of the positive first order or the negative first order, and the linear array image sensor is equipped with a two-way thermoelectric cooler.

4. The system according to claim 1, Characterized in that, The host computer calculates the energy density ω of the shock wave according to the following formula: Among them, p(y,t) is the distribution function of the ultrasonic sound pressure, ρ is the density of the water medium, and c is the sound speed of the water medium.

5. The system according to claim 4, Characterized in that, The distribution function p(y,t) of the ultrasonic sound pressure is calculated according to the following formula: where J m is the first kind of Bessel function of order m, I m is the intensity of the diffracted light of order m, I is the total laser intensity without any perturbation, v is the Raman-Nath parameter, k l is the laser wave number, P op is the piezoelectric constant of the medium, L is the acousto-optic interaction length, and the y-axis is the laser propagation direction.

6. The system according to claim 1, Characterized in that, The image acquisition card is equipped with an external synchronous trigger controller for controlling the acquisition of data to be synchronized with the moment when the shock wave therapy instrument emits a shock wave.

7. The system according to claim 1, Characterized in that, The linear array image sensor is a near-infrared monochrome CMOS image sensor.

8. The system according to claim 1, Characterized in that, The laser is a semiconductor laser.

9. A method for measuring shock wave energy based on Raman-Nath diffraction of the system according to any one of claims 1 to 8, Comprising the following steps: Controlling the laser to generate near-infrared laser; Setting a neutral density filter to attenuate the light intensity of the near-infrared laser; Placing the shock wave therapy probe in the water tank and controlling the generated shock wave to cause the incident laser to undergo Raman-Nath diffraction to form a multi-path diffracted laser light path; Using a convex lens to converge the multi-path diffracted laser light path; Using a linear array image sensor to detect the laser intensity passing through the convex lens and convert it into an analog voltage value; Sampling the analog voltage value into a digital voltage signal to obtain a digital image of the diffracted laser; Analyzing the digital image of the diffracted laser and calculating the energy density of the shock wave.

10. A computer-readable storage medium, on which a computer program is stored, Among them, When the computer program is executed by a processor, the steps of the method according to claim 9 are implemented.

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