Signal enhancement system and method based on passive high-frequency opto-acoustic / ultrasonic microscopic imaging

Abstract

The invention discloses a signal enhancement system and method based on passive high-frequency opto-acoustic / ultrasonic microscopic imaging. The system comprises a laser excitation module, an ultrasonic excitation detection module and a signal processing control module. According to the invention, the required target laser is excited through the laser excitation module, so that a good light source condition is provided for microscopic imaging; the method comprises the following steps: under ultrasonic microscopic imaging, exciting high-frequency ultrasonic waves through an opto-acoustic transducer, and gathering and enhancing the ultrasonic waves in an acoustic wave transmission space of the opto-acoustic transducer and a sample to be detected by utilizing an energy gathering device; under photoacoustic microscopic imaging, ultrasonic waves are excited on a detected sample by means of laser, and the laser and sound waves are reflected, focused and enhanced by an energy concentrator, so that the sensitivity and the signal-to-noise ratio of microscopic imaging are improved, and the detection efficiency of microscopic imaging is improved; and the signal processing control module controls the three-dimensional mobile platform to scan the tested sample through the controller to realize the integrity of ultrasonic signal acquisition of the tested sample, so that an ultrasonic image of the tested sample is generated.

Description

Technical Field

[0001] The present invention relates to the technical field of photoacoustic / ultrasonic imaging, and particularly to a signal enhancement system and method based on passive high-frequency photoacoustic / ultrasonic microscopy imaging. Background Art

[0002] High-frequency ultrasonic imaging can achieve fine tissue visualization and has become a core technology for superficial tissue diagnosis, dynamic monitoring, and minimally invasive intervention, with irreplaceable value in the fields of medicine, industry, and scientific research. High-frequency ultrasonic imaging is usually achieved using an electronic transducer. Photoacoustic imaging, as an advanced imaging technology, combines the unique advantages of optical and ultrasonic imaging and shows broad application prospects in the fields of biomedical research and clinical diagnosis. The basic principle of photoacoustic imaging is to use a laser pulse to irradiate biological tissue, causing light absorbers (such as hemoglobin or pigments) in the tissue to absorb light energy and rapidly generate a thermoelastic effect. This thermoelastic effect will excite ultrasonic signals, which will be received by an ultrasonic transducer, converted into electrical signals, and used to reconstruct two-dimensional or three-dimensional images of the tissue.

[0003] Photoacoustic microscopy combines photoacoustic imaging and microscopy techniques, with advantages such as high resolution, high contrast, and non-invasiveness, achieving fine imaging of the deep structures of biological tissues. In photoacoustic microscopy, the frequency and intensity of ultrasonic signals are key factors affecting the imaging quality. High-frequency ultrasonic signals can significantly improve the resolution of the image, enabling the imaging system to resolve smaller tissue structures. However, high-frequency signals attenuate rapidly during propagation and are difficult to detect, which places high requirements on the performance of the ultrasonic transducer. At the same time, the intensity of the ultrasonic signal directly affects the signal-to-noise ratio and contrast of the imaging. If the signal is too weak, details in the image may be lost. Therefore, how to improve the detection sensitivity while maintaining high-frequency ultrasonic signals and enhance the focusing and amplification effects of ultrasonic signals has become an important direction for promoting the progress of photoacoustic / ultrasonic microscopy technology. Summary of the Invention

[0004] The present invention provides a signal enhancement system and method based on passive high-frequency photoacoustic / ultrasonic microscopy imaging to solve the technical problem that existing photoacoustic / ultrasonic microscopy imaging systems are difficult to effectively improve the detection sensitivity and focusing enhancement effect of ultrasonic signals, thereby affecting the sensitivity and signal-to-noise ratio of imaging.

[0005] The present invention provides a signal enhancement system based on passive high-frequency photoacoustic / ultrasonic microscopy imaging, and the system includes: a laser excitation module, an ultrasonic excitation and detection module, and a signal processing and control module;

[0006] The laser excitation module is used to excite a target laser and direct the target laser towards the ultrasonic excitation and detection module;

[0007] The ultrasonic excitation detection module is placed in the water tank;

[0008] When the ultrasonic excitation detection module is applied to ultrasonic microscopy, the ultrasonic excitation detection module is composed of a sample to be measured, a photoacoustic transducer, an ultrasonic probe, and a focusing transducer; the photoacoustic transducer is used to receive the target laser and excite and generate a first ultrasonic wave; the first ultrasonic wave is focused and enhanced by the focusing transducer and reflected on the sample to be measured, and the sample to be measured reflects the focused and enhanced first ultrasonic wave to obtain a reflected wave, and the reflected wave is focused and enhanced by the focusing transducer and reflected on the ultrasonic probe; wherein, the reflected wave carries acoustic information of the surface and internal structure of the sample to be measured;

[0009] When the ultrasonic excitation detection module is applied to photoacoustic microscopy, the ultrasonic excitation detection module is composed of a sample to be measured, an ultrasonic probe, and a focusing transducer; the focusing transducer is used to receive the target laser, focus and enhance the target laser, and reflect it on the sample to be measured, and the focused and enhanced target laser excites a second ultrasonic wave on the sample to be measured, and the second ultrasonic wave is focused and enhanced by the focusing transducer and reflected on the ultrasonic probe; wherein, the second ultrasonic wave carries acoustic information of the surface and internal structure of the sample to be measured;

[0010] The signal processing and control module is composed of a platform controller, a three-dimensional moving platform, and an acquisition component;

[0011] The water tank is placed on the three-dimensional moving platform; the platform controller is electrically connected to the three-dimensional moving platform and is used to drive the three-dimensional moving platform to move the sample to be measured;

[0012] The acquisition component is electrically connected to the ultrasonic probe and is used to receive and scan the focused and enhanced reflected wave or the second ultrasonic wave to generate an ultrasonic image of the sample to be measured.

[0013] Optionally, the laser excitation module is composed of a pulsed laser, a diaphragm, a focusing lens, an incident optical fiber coupler, an optical fiber, and an output optical fiber coupler;

[0014] The pulsed laser is used to emit an initial laser according to preset parameters and shoot the initial laser at the diaphragm;

[0015] The diaphragm, the focusing lens, and the incident optical fiber coupler are located on the same axis, so that the initial laser sequentially passes through the diaphragm and the focusing lens and is incident on the incident optical fiber coupler;

[0016] One end of the optical fiber is connected to the incident optical fiber coupler, and the other end thereof is connected to the output optical fiber coupler.

[0017] Optionally, the diaphragm is used to control the light flux, filter out the excess stray light of the initial laser, and obtain filtered laser light;

[0018] The focusing lens is used to receive the filtered laser light and converge the laser beam of the filtered laser light into the incident optical fiber coupler to obtain target laser light.

[0019] Optionally, the ultrasonic probe is arranged in a hollow bowl-shaped structure.

[0020] Optionally, the energy concentrator is composed of two paraboloids;

[0021] When the ultrasonic excitation detection module is applied to ultrasonic microscopy, the photoacoustic transducer is placed in the middle of the ultrasonic probe; the first ultrasonic wave generated by the excitation of the photoacoustic transducer is reflected twice by the two paraboloids and focused on the sample to be measured, and the sample to be measured reflects the first ultrasonic wave to obtain a reflected wave, and the reflected wave is received by the ultrasonic probe after being reflected twice by the two paraboloids;

[0022] When the ultrasonic excitation detection module is applied to photoacoustic microscopy, the target laser light emitted by the laser excitation module is reflected twice by the two paraboloids and focused on the sample to be measured, and the focused and enhanced target laser light excites a second ultrasonic wave on the sample to be measured, and the second ultrasonic wave is received by the ultrasonic probe after being reflected twice by the two paraboloids.

[0023] Optionally, the photoacoustic transducer is formed by sequentially laminating an acoustic confinement layer, a light absorption layer, and an acoustic matching layer.

[0024] Optionally, the acquisition component includes an amplifier, a filter, and an acquisition card;

[0025] The amplifier is electrically connected to the ultrasonic probe and is used to receive the focused and enhanced reflected wave and perform amplification processing on the focused and enhanced reflected wave to obtain an amplified voltage signal;

[0026] The filter is electrically connected to the amplifier and is used to receive the amplified voltage signal output by the amplifier and perform filtering processing on the amplified voltage signal to obtain a filtered voltage signal;

[0027] The acquisition card is electrically connected to the platform controller and the filter respectively, and is used to send a preset scanning range signal to the platform controller to drive the three-dimensional moving platform, receive the filtered voltage signal, and scan and generate the ultrasonic imaging of the sample to be measured according to the filtered voltage signal.

[0028] Optionally, the paraboloid is specifically made of a high acoustic impedance material.

[0029] Optionally, the acoustic confinement layer is made of a glass sheet with low optical absorption rate, the light absorption layer is made of a high optical absorption material, and the acoustic matching layer is made of PDMS material.

[0030] The present invention also provides a signal enhancement method based on passive high-frequency photoacoustic / ultrasonic microscopy imaging. The method includes:

[0031] Emitting initial laser by a pulsed laser according to preset parameters. The initial laser sequentially passes through a diaphragm, a focusing lens, an incident optical fiber coupler, an optical fiber, and an outgoing optical fiber coupler to form a target laser.

[0032] When the ultrasonic excitation detection module is applied to ultrasonic microscopy imaging, a photoacoustic transducer is placed in the middle of the ultrasonic probe. The photoacoustic transducer receives and generates a first ultrasonic wave according to the excitation of the target laser. The first ultrasonic wave is focused and enhanced by a concentrator and acts on the sample to be measured. The focused and enhanced first ultrasonic wave is reflected by the sample to be measured to obtain a reflected wave carrying the acoustic information of the surface and internal structure of the sample to be measured.

[0033] When the ultrasonic excitation detection module is applied to photoacoustic microscopy imaging, the concentrator receives the target laser and focuses and enhances the target laser and reflects it on the sample to be measured. The focused and enhanced target laser excites a second ultrasonic wave carrying the acoustic information of the surface and internal structure of the sample to be measured on the sample to be measured. The second ultrasonic wave is reflected and focused and enhanced by the concentrator and shot towards the ultrasonic probe.

[0034] Amplify and filter the focused and enhanced reflected wave or the second ultrasonic wave in sequence through an amplifier and a filter to obtain a filtered voltage signal.

[0035] Control the three-dimensional moving platform by a platform controller to drive the sample to be measured to move until the acquisition card receives the filtered voltage signals corresponding to all preset imaging points in the sample to be measured. The acquisition card scans and generates the ultrasonic imaging of the sample to be measured according to all the filtered voltage signals.

[0036] It can be seen from the above technical solutions that the present invention has the following advantages:

[0037] The present invention provides a signal enhancement system and method based on passive high-frequency photoacoustic / ultrasonic microscopy imaging. The system includes: a laser excitation module, an ultrasonic excitation detection module, and a signal processing and control module. The laser excitation module is used to excite a target laser and shoot the target laser towards the ultrasonic excitation detection module. The ultrasonic excitation detection module is placed in a water tank.

[0038] When the ultrasonic excitation detection module is applied to ultrasonic microscopy, the ultrasonic excitation detection module consists of a sample to be measured, a photoacoustic transducer, an ultrasonic probe, and a focusing energy concentrator; the photoacoustic transducer is used to receive the target laser and excite the generation of the first ultrasonic wave; the first ultrasonic wave is focused and enhanced by the focusing energy concentrator and reflected onto the sample to be measured, and the sample to be measured reflects the focused and enhanced first ultrasonic wave to obtain a reflected wave, and the reflected wave is focused and enhanced by the focusing energy concentrator and reflected onto the ultrasonic probe; when the ultrasonic excitation detection module is applied to photoacoustic microscopy, the ultrasonic excitation detection module consists of a sample to be measured, an ultrasonic probe, and a focusing energy concentrator; the focusing energy concentrator is used to receive the target laser, focus and enhance the target laser, and reflect it onto the sample to be measured, and the focused and enhanced target laser excites the second ultrasonic wave on the sample to be measured, and the second ultrasonic wave is focused and enhanced by the focusing energy concentrator and reflected onto the ultrasonic probe;

[0039] The signal processing and control module consists of a platform controller, a three-dimensional moving platform, and an acquisition component; the water tank is placed on the three-dimensional moving platform; the platform controller is electrically connected to the three-dimensional moving platform and is used to drive the three-dimensional moving platform to move the sample to be measured; the acquisition component is electrically connected to the ultrasonic probe and is used to receive and scan based on the focused and enhanced reflected wave or the second ultrasonic wave to generate the ultrasonic imaging of the sample to be measured.

[0040] In the present invention, the required target laser is excited by the laser excitation module to provide good light source conditions for microscopy; during ultrasonic microscopy, high-frequency ultrasonic waves are excited by the photoacoustic transducer to improve the resolution of microscopy. In the acoustic wave transmission space between the photoacoustic transducer and the sample to be measured, the focusing energy concentrator is used to aggregate and enhance the acoustic waves, improving the sensitivity and signal-to-noise ratio of imaging; during photoacoustic imaging, the focusing energy concentrator is used to aggregate and enhance the laser and acoustic waves, and at the same time, the sample to be measured is excited by the laser to obtain ultrasonic waves, improving the sensitivity and signal-to-noise ratio of imaging; the three-dimensional moving platform is controlled by the controller to scan the sample to be measured to achieve the integrity of the acquisition of the ultrasonic signal of the sample to be measured, improving the operation efficiency of microscopy. Finally, the acquisition component generates the ultrasonic imaging of the sample to be measured, thus solving the technical problem that the existing photoacoustic / ultrasonic microscopy system is difficult to effectively improve the detection sensitivity of ultrasonic signals and the focusing and enhancement effect, thereby affecting the sensitivity and signal-to-noise ratio of imaging. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0042] Figure 1Schematic diagram of an embodiment of a signal enhancement system based on passive high-frequency ultrasonic microscopy provided by this application;

[0043] Figure 2 Schematic diagram of an embodiment of a signal enhancement system based on passive high-frequency photoacoustic microscopy provided by this application;

[0044] Figure 3 Schematic structural diagram of an embodiment of an ultrasonic probe provided by this application;

[0045] Figure 4 Schematic structural diagram of an embodiment of a concentrator provided by this application;

[0046] Figure 5 Schematic composition diagram of an embodiment of a photoacoustic transducer provided by this application;

[0047] Figure 6 Schematic diagram of the simulation design of a concentrator and the simulation diagram of the propagation characteristics of sound waves in the concentrator provided by this application;

[0048] Figure 7 Flow chart of the steps of a signal enhancement method based on passive high-frequency photoacoustic / ultrasonic microscopy provided by this application

[0049] Among them, the reference numerals are: laser excitation module 1, pulsed laser 11, aperture 12, focusing lens 13, incident light fiber coupler 14, optical fiber 15, outgoing light fiber coupler 16, ultrasonic excitation and detection module 2, photoacoustic transducer 21, ultrasonic probe 22, concentrator 23, sample to be measured 24, water tank 25, signal processing and control module 3, three-dimensional moving platform 31, platform controller 32, amplifier 33, filter 34, and acquisition card 35. Detailed implementation manners

[0050] The embodiments of the present invention provide a signal enhancement system and method based on passive high-frequency photoacoustic / ultrasonic microscopy, which are used to solve the technical problem that the existing photoacoustic / ultrasonic microscopy system is difficult to effectively improve the detection sensitivity of ultrasonic signals and the focusing enhancement effect, thereby affecting the sensitivity and signal-to-noise ratio of imaging.

[0051] In order to make the purpose, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0052] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0053] Unless otherwise clearly specified and defined, the terms "mounted", "connected", "coupled" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0054] Please refer to Figure 1 and Figure 2 , this application provides an embodiment of a signal enhancement system based on passive high-frequency photoacoustic / ultrasonic microscopy. The system includes: a laser excitation module 1, an ultrasonic excitation and detection module 2, and a signal processing and control module 3;

[0055] The laser excitation module 1 is used to excite the target laser and direct the target laser towards the ultrasonic excitation and detection module 2;

[0056] The ultrasonic excitation and detection module 2 is placed in the water tank 25;

[0057] When the ultrasonic excitation and detection module 2 is applied to ultrasonic microscopy, the ultrasonic excitation and detection module 2 is composed of a measured sample 24, a photoacoustic transducer 21, an ultrasonic probe 22, and a focusing transducer 23; the photoacoustic transducer 21 is used to receive the target laser and excite and generate the first ultrasonic wave; the first ultrasonic wave is focused and enhanced by the focusing transducer 23 and reflected onto the measured sample 24, and the measured sample 24 reflects the focused and enhanced first ultrasonic wave to obtain a reflected wave, and the reflected wave is focused and enhanced by the focusing transducer 23 and reflected onto the ultrasonic probe 22; wherein, the reflected wave carries the acoustic information of the surface and internal structure of the measured sample 24;

[0058] When the ultrasonic excitation detection module 2 is applied to photoacoustic microscopy imaging, the ultrasonic excitation detection module 2 is composed of a sample to be measured 24, an ultrasonic probe 22, and a concentrator 23; the concentrator 23 is used to receive the target laser, focus and enhance the target laser, and reflect it onto the sample to be measured 24. The focused and enhanced target laser excites the second ultrasonic wave on the sample to be measured 24, and the second ultrasonic wave is focused and enhanced by the concentrator 23 and then reflected onto the ultrasonic probe 22; wherein, the second ultrasonic wave carries the acoustic information of the surface and internal structure of the sample to be measured 24.

[0059] The signal processing and control module 3 is composed of a platform controller 32, a three-dimensional moving platform 31, and an acquisition component.

[0060] The water tank 25 is placed on the three-dimensional moving platform 31; the platform controller 32 is electrically connected to the three-dimensional moving platform 31 and is used to drive the three-dimensional moving platform 31 to move the sample to be measured 24.

[0061] The acquisition component is electrically connected to the ultrasonic probe 22 and is used to receive and generate the ultrasonic imaging of the sample to be measured 24 according to the focused and enhanced reflected wave or the second ultrasonic wave.

[0062] In this embodiment, please refer to Figure 1 , for the ultrasonic microscopy imaging system, the target laser required is excited by the laser excitation module 1 to provide good light source conditions for subsequent microscopy imaging; the photoacoustic transducer 21 uses the photoacoustic effect to generate high-frequency ultrasonic waves, and the concentrator 23 focuses and enhances the received and reflected sound waves to improve the imaging sensitivity and signal-to-noise ratio. Finally, the ultrasonic probe 22 arranged at the focal point receives the focused and enhanced reflected wave and transmits the focused and enhanced reflected wave to the acquisition component; in the signal processing and control module 3, the platform controller 32 drives the three-dimensional moving platform 31 to scan the sample to be measured 24 to achieve the detection integrity of the sample to be measured 24, and the acquisition component generates the ultrasonic imaging of the sample to be measured according to the focused and enhanced reflected wave.

[0063] It can be understood that the photoacoustic transducer 21 adopted in this embodiment is based on a passive design. The passive photoacoustic transducer 21 does not require additional power supply, can simplify the structure of the system, and provide enhanced system stability. At the same time, using high-frequency ultrasonic waves for microscopy imaging can improve the imaging resolution; the present invention also takes into account that high-frequency ultrasonic waves are prone to attenuation during propagation and introduces the concentrator 23 to focus and enhance the sound waves.

[0064] Please refer to Figure 2, for a photoacoustic microscopy imaging system, the target laser is excited by the laser excitation module 1 to provide good light source conditions for subsequent microscopy imaging; the target laser emitted by the laser excitation module 1 will be focused on the focus of the energy concentrator 23 and reflected on the energy concentrator 23; the target laser is focused and enhanced by the energy concentrator 23, and then acts on the sample to be measured 24 while exciting ultrasound on the sample surface and being reflected by the energy concentrator. Finally, the ultrasonic probe 22 arranged at the focus receives the focused and enhanced ultrasonic wave and transmits the focused and enhanced ultrasonic signal to the acquisition component, improving the sensitivity and signal-to-noise ratio of imaging; in the signal processing and control module 3, the three-dimensional moving platform 31 is driven by the platform controller 32 to scan the sample to be measured 24 to achieve the detection integrity of the sample to be measured 24, and the acquisition component generates the ultrasonic imaging of the sample to be measured according to the focused and enhanced ultrasonic wave.

[0065] In a specific embodiment, the laser excitation module 1 is composed of a pulsed laser 11, a diaphragm 12, a focusing lens 13, an incident optical fiber coupler 14, an optical fiber 15, and an outgoing optical fiber coupler 16;

[0066] The pulsed laser 11 is used to emit the initial laser according to preset parameters and shoot the initial laser towards the diaphragm 12; the diaphragm 12, the focusing lens 13, and the incident optical fiber coupler 14 are located on the same axis, so that the initial laser passes through the diaphragm 12 and the focusing lens 13 in sequence and is incident on the incident optical fiber coupler 14; one end of the optical fiber 15 is connected to the incident optical fiber coupler 14, and the other end is connected to the outgoing optical fiber coupler 16.

[0067] It should be noted that the preset parameters can be emission parameters such as the pulse width and laser power of the pulsed laser 11; one end of the optical fiber 15 is connected to the incident optical fiber coupler 14, and the other end is connected to the outgoing optical fiber coupler 16, which can transmit the target laser to the photoacoustic transducer 21 at any position to excite ultrasound, or transmit the target laser to the energy concentrator 23 at any position.

[0068] In a specific embodiment, the diaphragm 12 is used to control the light flux and filter out the excess stray light of the initial laser to obtain filtered laser; the focusing lens 13 is used to receive the filtered laser and converge the laser beam of the filtered laser into the incident optical fiber coupler 14 to obtain the target laser.

[0069] In a specific embodiment, please refer to Figure 3 , the ultrasonic probe 22 is set as a hollow bowl-shaped structure. The high-efficiency reception and convergence of the reflected wave focused by the energy concentrator 23 are realized through the inner wall structure around the ultrasonic probe 22.

[0070] In a specific embodiment, please refer to Figure 4 , the energy concentrator 23 is composed of two paraboloids;

[0071] When the ultrasonic excitation detection module 2 is applied to ultrasonic microscopy, the photoacoustic transducer 21 is placed in the middle of the ultrasonic probe 22; the first ultrasonic wave generated by exciting the photoacoustic transducer 21 is reflected twice by two paraboloids and focused on the sample under test 24. The sample under test 24 reflects the first ultrasonic wave to obtain a reflected wave, and the reflected wave is received by the ultrasonic probe 22 after being reflected twice by two paraboloids. Among them, the ultrasonic probe 22 and the photoacoustic transducer 21 are co-integrated in the focal region of the energy concentrator 23. In addition, the ultrasonic wave generated by exciting the photoacoustic transducer 21 is also a diffused spherical wave.

[0072] When the ultrasonic excitation detection module 2 is applied to photoacoustic microscopy, the target laser emitted by the laser excitation module 1 is reflected twice by two paraboloids and focused on the sample under test 24. The focused and enhanced target laser excites a second ultrasonic wave on the sample under test 24, and the second ultrasonic wave is received by the ultrasonic probe 22 after being reflected twice by two paraboloids.

[0073] It can be understood that the energy concentrator 23 is composed of two paraboloids with specific designs. These two paraboloids can collimate and refocus the diffused sound waves, and can also act as mirrors for the laser, that is to say, the paraboloid can reflect both ultrasonic waves and lasers. In ultrasonic microscopy, the diffused spherical wave excited by the photoacoustic transducer 21 can form a focused and energy-enhanced ultrasonic wave through two reflections by two paraboloids; the reflected wave reflected by the sample under test 24 also passes through two reflections by two paraboloids to form a focused and energy-enhanced reflected wave. In photoacoustic microscopy, the target laser emitted by the laser excitation module 1 can form a focused and energy-enhanced laser through two reflections by two paraboloids; the focused and energy-enhanced laser excites an ultrasonic wave on the sample under test 24, and the excited ultrasonic wave also passes through two reflections by two paraboloids to form a focused and energy-enhanced ultrasonic wave.

[0074] Therefore, the energy concentrator 23 in this embodiment can form a focused ultrasonic wave by reflecting the spherical wave in the propagation process through the paraboloid. The focusing by the paraboloid can enhance the intensity of the signal received by the ultrasonic probe 22, thereby significantly improving the signal-to-noise ratio and the detection sensitivity.

[0075] In a specific embodiment, the photoacoustic transducer 21 is sequentially attached with a sound confinement layer, a light absorption layer, and a sound matching layer.

[0076] In a specific embodiment, the acquisition component includes an amplifier 33, a filter 34, and an acquisition card 35;

[0077] The amplifier 33 is electrically connected to the ultrasonic probe 22 and is used to receive and amplify the focused and enhanced reflected wave or the second ultrasonic wave to obtain an amplified voltage signal;

[0078] The filter 34 is electrically connected to the amplifier 33, and is used to receive the amplified voltage signal output by the amplifier 33 and perform filtering processing on the amplified voltage signal to obtain a filtered voltage signal; the filter 34 is responsible for suppressing interference in non-target frequency bands and improving the signal-to-noise ratio;

[0079] The acquisition card 35 is electrically connected to the platform controller 32 and the filter 34 respectively, and is used to send a preset scanning range signal to the platform controller 32 to drive the three-dimensional moving platform 31, receive the filtered voltage signal, and generate an ultrasonic image of the measured sample 24 according to the filtered voltage signal by scanning.

[0080] In this specific embodiment, the acquisition card 35 controls the three-dimensional moving platform 31 to move during sample scanning detection through the platform controller 32, and then drives the water tank 25 to make the measured sample 24 move, so as to realize point-by-point scanning of the measured sample 24; at the same time, the acquisition card 35 also receives the filtered voltage signals of each position in the measured sample 24 that are sequentially processed by the amplifier 33 and the filter 34, and finally generates an ultrasonic image of the measured sample 24 according to all the filtered voltage signals.

[0081] In a specific embodiment, the paraboloid is specifically made of a high acoustic impedance material, and the focal length of the concentrator 23 can be adjusted by setting the focus of the paraboloid.

[0082] In a specific embodiment, as Figure 5 shown, the acoustic confinement layer uses a glass sheet (Glass) with low optical absorption rate to reflect sound waves forward; the light absorption layer is made of a high optical absorption material, (CSPs + PDMS), which can absorb laser energy and generate heat, thereby producing a thermoelastic or ablation effect to excite an ultrasonic spherical wave; the acoustic matching layer is made of PDMS material, which has a protective effect on the light absorption layer and can couple the ultrasonic propagation between the photoacoustic transducer 21 and other substances.

[0083] In addition, since the photoacoustic transducer 21 is placed in the water tank 25, the ultrasonic waves excited by the photoacoustic transducer 21 can propagate downward through the water (Water) in the water tank 25 as a propagation medium.

[0084] Please refer to Figure 6 , the present invention also shows a simulation analysis of the propagation characteristics of sound waves in the concentrator. As can be seen in Figure 5 , the ultrasonic waves spread outward from the focus, are converted into a collimated beam after being reflected by the primary paraboloid of the concentrator, and then undergo a secondary reflection at the second paraboloid, finally realizing the efficient convergence of sound wave energy to form a new focusing focus.

[0085] Please refer to Figure 7 , this application also provides a signal enhancement method based on passive high-frequency photoacoustic / ultrasonic microscopy imaging. The method includes:

[0086] Step 101: A pulsed laser emits an initial laser according to preset parameters. The initial laser sequentially passes through a diaphragm, a focusing lens, an incident optical fiber coupler, an optical fiber, and an output optical fiber coupler to form a target laser.

[0087] In this step, the pulsed laser can be controlled to start by an acquisition card, and then the pulsed laser emits an initial laser according to preset parameters; setting the diaphragm, the focusing lens, the incident optical fiber coupler, the optical fiber, and the output optical fiber coupler can ensure that the laser beam can be transmitted to the target position, i.e., the photoacoustic transducer, with high efficiency and high precision, thereby providing good light source conditions for subsequent photoacoustic imaging.

[0088] Step 102: When the ultrasonic excitation detection module is applied to ultrasonic microscopy imaging, place the photoacoustic transducer in the middle of the ultrasonic probe. The photoacoustic transducer receives and generates a first ultrasonic wave according to the excitation of the target laser; the first ultrasonic wave is focused and enhanced by a concentrator and acts on the sample to be measured; the reflected wave carrying the acoustic information of the surface and internal structure of the sample to be measured is obtained by the sample reflecting the focused and enhanced first ultrasonic wave; the reflected wave is focused and enhanced by the concentrator and directed towards the ultrasonic probe.

[0089] It can be understood that when the ultrasonic excitation detection module is applied to ultrasonic microscopy imaging, the ultrasonic probe and the photoacoustic transducer are integrated and coordinated in the focal region of the concentrator to enhance the acoustic wave signal; among them, for the acoustic wave during the propagation process, the concentrator forms a focused and enhanced ultrasonic wave through the reflection of its two paraboloids. Through the focusing of the paraboloid, the signal intensity received by the ultrasonic probe can be enhanced, thereby significantly improving the signal-to-noise ratio and the detection sensitivity.

[0090] Step 103: When the ultrasonic excitation detection module is applied to photoacoustic microscopy imaging, the concentrator receives the target laser, focuses and enhances the target laser, and reflects it on the sample to be measured; the focused and enhanced target laser excites a second ultrasonic wave carrying the acoustic information of the surface and internal structure of the sample to be measured on the sample to be measured; the second ultrasonic wave is focused and enhanced by the concentrator and directed towards the ultrasonic probe.

[0091] It can be understood that when the ultrasonic excitation detection module is applied to photoacoustic microscopy imaging, the laser emitted by the output optical fiber coupler will be focused on the focal point of the concentrator, then spread and hit the concentrator. The concentrator focuses and reflects the laser, then acts on the sample and simultaneously excites ultrasound on the sample surface. The ultrasonic wave is then reflected and focused by the concentrator and the signal is received by the ultrasonic probe.

[0092] Step 104: The focused and enhanced reflected wave or the second ultrasonic wave is sequentially amplified and filtered by an amplifier and a filter to obtain a filtered voltage signal.

[0093] Step 105: Control the three-dimensional moving platform through the platform controller to drive the sample under test until the acquisition card receives the filtered voltage signals corresponding to all the preset imaging points in the sample under test, and then the acquisition card scans and generates the ultrasonic imaging of the sample under test according to all the filtered voltage signals.

[0094] In practical applications, after the acquisition card receives the filtered voltage signal corresponding to the current preset imaging point, the acquisition card starts to control the three-dimensional moving platform to drive according to the preset scanning range through the platform controller until the acquisition card receives the filtered voltage signals corresponding to all the preset imaging points in the sample under test. Finally, the acquisition card scans and generates the ultrasonic imaging of the sample under test according to all the received filtered voltage signals, realizing the surface and internal structure characteristic scanning and detection of the sample under test.

[0095] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A signal enhancement system based on passive high-frequency photoacoustic / ultrasonic microscopy imaging, characterized in that, The system includes: a laser excitation module, an ultrasonic excitation detection module, and a signal processing and control module; The laser excitation module is configured to excite a target laser and direct the target laser towards the ultrasonic excitation detection module; The ultrasonic excitation detection module is placed in a water tank; When the ultrasonic excitation detection module is applied to ultrasonic microscopy imaging, the ultrasonic excitation detection module consists of a sample to be measured, a photoacoustic transducer, an ultrasonic probe, and a focusing energy collector; the photoacoustic transducer is configured to receive the target laser and excite and generate a first ultrasonic wave; the first ultrasonic wave is focused and enhanced by the focusing energy collector and reflected onto the sample to be measured, and the sample to be measured reflects the focused and enhanced first ultrasonic wave to obtain a reflected wave, and the reflected wave is focused and enhanced by the focusing energy collector and reflected onto the ultrasonic probe; wherein, the reflected wave carries acoustic information about the surface and internal structure of the sample to be measured; When the ultrasonic excitation detection module is applied to photoacoustic microscopy imaging, the ultrasonic excitation detection module consists of a sample to be measured, an ultrasonic probe, and a focusing energy collector; the focusing energy collector is configured to receive the target laser, focus and enhance the target laser, and reflect it onto the sample to be measured, and the focused and enhanced target laser excites a second ultrasonic wave on the sample to be measured, and the second ultrasonic wave is focused and enhanced by the focusing energy collector and reflected onto the ultrasonic probe; wherein, the second ultrasonic wave carries acoustic information about the surface and internal structure of the sample to be measured; The signal processing and control module consists of a platform controller, a three-dimensional moving platform, and a collection component; The water tank is placed on the three-dimensional moving platform; the platform controller is electrically connected to the three-dimensional moving platform and is configured to drive the three-dimensional moving platform to move the sample to be measured; The collection component is electrically connected to the ultrasonic probe and is configured to receive and scan the focused and enhanced reflected wave or the second ultrasonic wave to generate an ultrasonic image of the sample to be measured.

2. The signal enhancement system according to claim 1, wherein The laser excitation module consists of a pulsed laser, a diaphragm, a focusing lens, an incident optical fiber coupler, an optical fiber, and an exit optical fiber coupler; The pulsed laser is configured to emit an initial laser according to preset parameters and direct the initial laser towards the diaphragm; The diaphragm, the focusing lens, and the incident optical fiber coupler are located on the same axis, such that the initial laser sequentially passes through the diaphragm and the focusing lens and is incident on the incident optical fiber coupler; One end of the optical fiber is connected to the incident optical fiber coupler, and the other end thereof is connected to the exit optical fiber coupler.

3. The signal enhancement system according to claim 2, wherein The diaphragm is configured to control the light flux and filter out excess stray light of the initial laser to obtain filtered laser light; The focusing lens is configured to receive the filtered laser light and converge the laser beam of the filtered laser light into the incident optical fiber coupler to obtain a target laser.

4. The signal enhancement system according to claim 1, wherein The ultrasonic probe is configured as a hollow bowl-shaped structure.

5. The signal enhancement system according to claim 4, wherein The focusing energy collector consists of two paraboloids; When the ultrasonic excitation detection module is applied to ultrasonic microscopy, the photoacoustic transducer is placed in the middle of the ultrasonic probe; the first ultrasonic wave generated by exciting the photoacoustic transducer is focused on the sample to be measured after two reflections by the two paraboloids, and the sample to be measured reflects the first ultrasonic wave to obtain a reflected wave, and the reflected wave is received by the ultrasonic probe after two reflections by the two paraboloids; When the ultrasonic excitation detection module is applied to photoacoustic microscopy, the target laser emitted by the laser excitation module is focused on the sample to be measured after two reflections by the two paraboloids, and the focused and enhanced target laser excites a second ultrasonic wave on the sample to be measured, and the second ultrasonic wave is received by the ultrasonic probe after two reflections by the two paraboloids.

6. The signal enhancement system according to claim 1, wherein The photoacoustic transducer is formed by sequentially laminating a sound confinement layer, a light absorption layer, and a sound matching layer.

7. The signal enhancement system according to claim 1, wherein The acquisition component includes an amplifier, a filter, and an acquisition card; The amplifier is electrically connected to the ultrasonic probe and is used to receive and amplify the focused and enhanced reflected wave or the second ultrasonic wave to obtain an amplified voltage signal; The filter is electrically connected to the amplifier and is used to receive the amplified voltage signal output by the amplifier and filter the amplified voltage signal to obtain a filtered voltage signal; The acquisition card is electrically connected to the platform controller and the filter respectively, and is used to send a preset scanning range signal to the platform controller to drive the three-dimensional moving platform, receive the filtered voltage signal, and scan and generate an ultrasonic image of the sample to be measured according to the filtered voltage signal.

8. The signal enhancement system according to claim 5, characterized in that The paraboloid is specifically made of a material with a high acoustic impedance.

9. The signal enhancement system according to claim 6, wherein, The sound confinement layer is made of a glass sheet with a low optical absorption rate, the light absorption layer is made of a high optical absorption material, and the sound matching layer is made of a PDMS material.

10. A signal enhancement method based on passive high-frequency photoacoustic / ultrasonic microscopy imaging related to the signal enhancement system according to claim 1, characterized in that, The method includes: Emitting an initial laser by a pulsed laser according to preset parameters, and the initial laser sequentially passes through a diaphragm, a focusing lens, an incident optical fiber coupler, an optical fiber, and an outgoing optical fiber coupler to form a target laser; When the ultrasonic excitation detection module is applied to ultrasonic microscopy, place the photoacoustic transducer in the middle of the ultrasonic probe, receive and generate a first ultrasonic wave according to the target laser by the photoacoustic transducer; focus and enhance the first ultrasonic wave by a concentrator and act on the sample to be measured; the sample to be measured reflects the focused and enhanced first ultrasonic wave to obtain a reflected wave carrying the acoustic information of the surface and internal structure of the sample to be measured; focus and enhance the reflected wave by a concentrator and shoot it at the ultrasonic probe; When the ultrasonic excitation detection module is applied to photoacoustic microscopy, receive the target laser by a concentrator, focus and enhance the target laser and reflect it on the sample to be measured; the focused and enhanced target laser excites a second ultrasonic wave carrying the acoustic information of the surface and internal structure of the sample to be measured on the sample to be measured; reflect and focus and enhance the second ultrasonic wave by a concentrator and shoot it at the ultrasonic probe; The amplified and filtered reflection wave with enhanced focusing or the second ultrasonic wave is amplified and filtered in sequence by an amplifier and a filter to obtain a filtered voltage signal; The platform controller controls the three-dimensional moving platform to drive the measured sample to move until the acquisition card receives the filtered voltage signals corresponding to all the preset imaging points in the measured sample, and the acquisition card scans and generates the ultrasonic imaging of the measured sample based on all the filtered voltage signals.

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