Ultrahigh-resolution ultrasonic imaging system based on ultrasonic vortex and application thereof

Abstract

According to the ultrahigh-resolution ultrasonic imaging system based on the ultrasonic vortex and the application of the ultrahigh-resolution ultrasonic imaging system, an imaging object is detected by emitting vortex sound fields of different orders, the imaging object, an ultrasonic collecting device and an ultrasonic vortex emitting module are included, and the ultrasonic vortex emitting module comprises an amplitude phase encoding array and an ultrasonic beam modulation structure; vortex distribution is generated through the amplitude phase coding array, the size of a vortex sound field is regulated and controlled through the ultrasonic beam modulation structure, the ultrasonic collection device collects vortex information after passing through an imaging object, and initial vortex distribution which cannot directly reflect the information of the imaging object is obtained. The invention also provides an ultrahigh-resolution ultrasonic imaging method of the ultrasonic vortex, and the method comprises the steps: extracting object information from the initial vortex distribution without object imaging information, and obtaining the initial distribution of an object to be imaged; and further optimizing the initial distribution of the to-be-imaged object through a high-resolution ultrasonic imaging reconstruction algorithm to obtain a super-resolution image of the to-be-imaged object. And the imaging resolution is obviously improved.

Description

Technical Field

[0001] The present invention belongs to the field of biomedical ultrasonic imaging, and particularly relates to an ultra-high resolution ultrasonic imaging system based on ultrasonic vortex and its application. Background Art

[0002] Due to advantages such as safety, non-destructiveness, and non-radiation, ultrasonic imaging is widely used in fields such as medical imaging, industrial non-destructive testing, and underwater acoustic communication. Similar to all wave-based imaging technologies, the resolution of ultrasonic imaging is limited to half of the wavelength due to the existence of the diffraction limit. Therefore, breaking through the diffraction limit and achieving super-resolution acoustic imaging has important value.

[0003] To improve the imaging resolution, traditional super-resolution ultrasonic imaging methods mainly rely on high-frequency ultrasonic probes, synthetic aperture imaging, coded emission technology, and super-resolution technology based on microbubble contrast agents. These methods improve the resolution by increasing the acoustic wave frequency, increasing the signal bandwidth, or using the non-linear effect of microbubbles. However, traditional methods have obvious deficiencies: although high-frequency ultrasound has high resolution, its penetration ability is poor, making it difficult to be used for deep tissue imaging; synthetic aperture and coded emission technologies have high requirements for hardware and algorithms, with complex calculations and poor real-time performance; microbubble-based methods rely on contrast agents, which are costly and may cause biocompatibility problems. At the same time, traditional methods have limited ability to suppress noise and artifacts, and it is difficult to achieve stable super-resolution imaging in complex tissues. Metamaterial imaging represented by resonant superlenses and negative refractive index superlenses has problems such as short imaging distance, low signal-to-noise ratio, and complex systems due to issues such as thermo-viscous losses and large volume, restricting its further application.

[0004] Ultrasonic vortex has a helical phase distribution and contains rich high spatial frequency components. These high-frequency components can capture more subtle structural information, and the image resolution and contrast can be significantly improved by introducing ultrasonic vortex technology. Summary of the Invention

[0005] To solve the above problems, the purpose of the present invention is to provide an ultra-high resolution ultrasonic imaging system based on ultrasonic vortex, which can significantly improve the image resolution and contrast.

[0006] Another object of the present invention is to provide a method for ultra-high resolution ultrasonic imaging based on ultrasonic vortex.

[0007] Another object of the present invention is to provide the application of the ultra-high resolution ultrasonic imaging system based on ultrasonic vortex.

[0008] The object of the present invention is to provide the application of the ultra-high resolution ultrasonic imaging system based on ultrasonic vortex.

[0009] To achieve the above object, the present invention provides an ultra-high resolution ultrasonic imaging system based on ultrasonic vortices. By emitting vortex sound fields of different orders to detect the imaging object, it not only includes the imaging object and the ultrasonic acquisition device, but also includes an ultrasonic vortex emission module. The ultrasonic vortex emission module includes an amplitude-phase encodable array and an ultrasonic beam modulation structure. The amplitude-phase encodable array can generate a vortex distribution, and the ultrasonic beam modulation structure can regulate the size of the vortex sound field. The ultrasonic acquisition device can collect the vortex information after passing through the imaging object to obtain an initial vortex distribution that cannot directly reflect the information of the imaging object.

[0010] On the basis of the above solution, the ultrasonic vortex emission module can generate several vortex distributions of different orders, and the distribution of the highest-order vortex energy generated is within the imaging region. After passing through the imaging object, ultrasonic vortices of different orders can be collected by the ultrasonic acquisition device. By emitting vortex sound fields of different orders to detect the imaging object, the spiral phase distribution and rich high-frequency spatial components of the vortex sound field can be utilized to transmit fine structural information.

[0011] On the basis of the above solution, the ultrasonic acquisition device collects the vortex information of different orders respectively. The number of acquisitions is consistent with the total number of vortex orders. The acquisition area is a rectangular area containing the imaging object. The acquisition step is determined by the wavelength of the vortex emitted at a specific frequency. The emission frequency can be a common frequency in medical ultrasound, such as 1 MHz. The acquisition step can be one-tenth of a wavelength. The smaller the step, the higher the imaging accuracy.

[0012] On the basis of the above solution, The amplitude-phase controllable encoding array includes a high-precision amplitude-phase regulation emission device and an ultrasonic transducer array composed of several independently controlled transducer units. The high-precision amplitude-phase regulation emission device generates an amplitude and phase distribution with multi-channel independent control and separately controls each transducer unit to generate an amplitude and phase distribution that satisfies the vortex sound field.

[0013] Preferably, the vortex sound field emitted by the amplitude-phase controllable encoding array has a spiral wavefront. m The phase of the m th-order acoustic orbital angular momentum has M periodic changes along the circumferential direction. The total sound field formula generated by a total of transducer units is described as: where r is the radius, t is the time variable, l is the topological order, A l is lThe amplitude of the acoustic orbital angular momentum of the order is the phase of the acoustic orbital angular momentum of the l-th order.

[0014] Preferably, the transducer units in the ultrasonic transducer array are arranged in a concentric circular array, a spiral array or a uniform square array.

[0015] On the basis of the above solution, the ultrasonic beam modulation structure is a pipe-shaped structure with a gradually decreasing radius, so that the vortex sound field passing through the ultrasonic beam modulation structure is reduced to the size required for imaging an imaging object. The ultrasonic beam modulation structure can modulate the vortex sound beams generated by each transducer unit to reduce them to any size, which can be customized according to the size of the object to be imaged, so as to image objects of any size.

[0016] The present invention also provides an application of the ultra-high resolution ultrasonic imaging system based on ultrasonic vortex.

[0017] The present invention also provides an ultra-high resolution ultrasonic imaging method according to the above ultra-high resolution ultrasonic imaging system based on ultrasonic vortex. Information of the imaging object is extracted from the initial vortex distribution collected by the ultrasonic acquisition device through an ultrasonic vortex information processing method to obtain an initial distribution consistent with the distribution of the imaging object, and then the initial distribution of the imaging object is further optimized through a high-resolution ultrasonic imaging reconstruction algorithm to obtain an ultra-high resolution imaging object image of the imaging object.

[0018] Preferably, the ultrasonic vortex information processing method is to use the backpropagation algorithm (abbreviated as BP algorithm) to extract the information of the imaging object from the vortex ultrasonic distribution that cannot directly reflect the object information, and obtain an initial distribution consistent with the distribution of the imaging object, and this initial distribution is of low resolution.

[0019] Preferably, the high-resolution ultrasonic imaging reconstruction algorithm is to use the subspace-based optimization algorithm (abbreviated as SOM algorithm) to further optimize the initial distribution obtained by the BP algorithm, and iteratively reduce the cost function by modifying the initial distribution to obtain high-resolution imaging object information.

[0020] Advantages of the present invention: 1. By emitting vortex sound fields of different orders to detect an imaging object, the present invention can utilize the spiral phase distribution and rich high-frequency spatial components of the vortex sound field to transmit fine structural information, thereby realizing super-resolution ultrasonic imaging.

[0021] 2. In the present invention, the generation of the vortex sound field and the transformation of the order are generated by an ultrasonic vortex emission module with amplitude-phase encoding, which has high stability and high precision. The size of the vortex sound field is modulated by a pipe-shaped ultrasonic beam modulation structure with a gradually decreasing radius, which has a simple structure, convenient operation and low cost, facilitating the wide application of the present invention.

[0022] 3. On the basis of realizing high-resolution ultrasonic imaging, the present invention can significantly improve the signal-to-noise ratio, imaging quality and contrast through the BP algorithm and SOM algorithm, bringing new hope for detecting tiny lesions and greatly expanding the application scope of vortex ultrasonic imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following further details the specific embodiments of the present invention with reference to the drawings, where: Figure 1 is a schematic diagram of the ultra-high resolution ultrasonic imaging system of the present invention; Figure 2 is a diagram of the ultrasonic imaging reconstruction results of different sub-wavelength objects in the underwater free space in the first embodiment of the present invention.

[0024] Reference numerals in the drawings: 1 - ultrasonic vortex emission module; 11 - ultrasonic beam modulation structure; 2 - imaging object; 3 - ultrasonic acquisition device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following further details the present invention with reference to the drawings and specific embodiments. The advantages and features of the present invention will be clearer according to the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise ratios, only for conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention.

[0026] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0027] Embodiment 1 As Figure 1 and Figure 2As shown, this embodiment provides an ultra-high resolution ultrasonic imaging system based on ultrasonic vortices. The entire system is located in the underwater free space and includes seven imaging objects 2 with different sub-wavelengths and an ultrasonic acquisition device 3. Among them, it further includes an ultrasonic vortex emission module 1. The ultrasonic vortex emission module 1 includes an amplitude-phase encodable array and an ultrasonic beam modulation structure 11. The amplitude-phase controllable encoding array includes a high-precision amplitude-phase regulation emission device and an ultrasonic transducer array composed of several independently controlled transducer units. The transducer units in the ultrasonic transducer array are arranged in concentric circles. The high-precision amplitude-phase regulation emission device can generate an amplitude and phase distribution with multi-channel independent control and separately control each transducer unit (whether it is controlled by the high-precision amplitude-phase regulation emission device). The amplitude-phase controllable encoding array can generate several vortex distributions of different orders, and the distribution of the highest-order vortex energy generated is within the imaging area. The vortex sound field emitted by the amplitude-phase controllable encoding array has a spiral wavefront. The phase of the m-th order acoustic orbital angular momentum has m periodic changes along the circumferential direction. The total sound field formula generated by a total of M transducer units is described as: , where r is the radius, t is the time variable, l is the topological order, Al is the amplitude of the l-th order acoustic orbital angular momentum, is the phase of the l-th order acoustic orbital angular momentum. The ultrasonic beam modulation structure 11 is a pipe-shaped structure with a gradually decreasing radius, which can modulate the vortex sound beam generated by each transducer unit, so that the vortex sound beam passing through the ultrasonic beam modulation structure 11 is reduced to the size required for imaging the imaging object 2. The ultrasonic beam modulation structure 11 can regulate the size of the vortex sound field. After ultrasonic vortices of different orders pass through the imaging object 2, they can be separately collected by the ultrasonic acquisition device 3. The number of acquisitions is consistent with the total number of vortex orders. The acquisition area is a rectangular area containing the imaging object 2. The acquisition step is determined by the wavelength of the emitted vortex of a specific frequency. The emission frequency can be a commonly used frequency in medical ultrasound. In this embodiment, 1 MHz is selected; the acquisition step can be one-tenth of a wavelength. The smaller the step, the higher the imaging accuracy, and an initial vortex distribution that cannot directly reflect the information of the imaging object 2 is obtained.

[0028] This embodiment also provides a high-resolution ultrasonic imaging method according to the above-mentioned ultrasonic vortex-based ultra-high-resolution ultrasonic imaging system. Among them, information of the imaging object 2 is extracted from the initial vortex distribution collected by the ultrasonic acquisition device 3 through the BP algorithm (Back Propagation algorithm), and a low-resolution initial distribution consistent with the imaging object 2 is obtained. The SOM algorithm (Subspace-based Optimization Method) further optimizes the initial distribution obtained by the BP algorithm, and iteratively reduces the cost function by modifying the initial distribution to obtain an ultra-high-resolution imaging object image of the imaging object 2.

[0029] Preferably, the high-resolution ultrasonic imaging reconstruction algorithm further optimizes the initial distribution obtained by the BP algorithm by using the SOM algorithm (Subspace-based Optimization Method), and iteratively reduces the cost function by modifying the initial distribution to obtain high-resolution imaging object information.

[0030] This embodiment verifies that the present invention can achieve high-resolution ultrasonic reconstruction imaging of the imaging object.

[0031] The above has described in detail the embodiments of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, provided that these changes fall within the scope of the claims of the present invention and their equivalent technologies, they still fall within the protection scope of the present invention.

Claims

1. An ultra-high resolution ultrasonic imaging system based on ultrasonic vortex, comprising an imaging object and an ultrasonic acquisition device, characterized in that: It also includes an ultrasonic vortex emission module, which includes an amplitude-phase encodable array and an ultrasonic beam modulation structure; the amplitude-phase encodable array generates a vortex distribution, the ultrasonic beam modulation structure regulates the size of the vortex sound field, and the ultrasonic acquisition device acquires vortex information after passing through the imaging object to obtain an initial vortex distribution that cannot directly reflect the imaging object information.

2. The ultra-high resolution ultrasonic imaging system based on ultrasonic vortex according to claim 1, characterized in that: The ultrasonic vortex emission module generates a plurality of vortex distributions of different orders, and the highest order vortex energy generated is distributed within the imaging area. After passing through the imaging object, ultrasonic vortices of different orders are collected by the ultrasonic collection device.

3. The ultra-high resolution ultrasonic imaging system based on ultrasonic vortex according to claim 1 or 2, characterized in that: The ultrasonic acquisition device collects vortex information of different orders respectively. The number of acquisitions is consistent with the total number of vortex orders. The acquisition area is a rectangular area containing the imaging object. The acquisition step is determined by the wavelength of the vortex emitted at a specific frequency. The emission frequency is a commonly used medical ultrasound frequency including 1 MHz, and the acquisition step is one tenth of a wavelength.

4. The ultra-high resolution ultrasonic imaging system based on ultrasonic vortex according to claim 1, characterized in that: The amplitude and phase controllable coding array includes a high-precision amplitude and phase control transmitting device and an ultrasonic transducer array composed of a plurality of independently controlled transducer units; the high-precision amplitude and phase control transmitting device generates multi-channel independently controlled amplitude and phase distribution, and controls each transducer unit individually to generate an amplitude and phase distribution that satisfies the vortex sound field.

5. The ultra-high resolution ultrasonic imaging system based on ultrasonic vortex according to claim 4, characterized in that: The vortex sound field emitted by the amplitude-phase controllable coding array has a spiral wavefront. m The phase of the orbital angular momentum of the order sound is m cycle changes, the total number is M The total sound field generated by a transducer unit is described by: , in, r is the radius, t is the time variable, l is the topological order, A l for l The amplitude of the order acoustic orbital angular momentum, is the phase of the l-order acoustic orbital angular momentum.

6. The ultra-high resolution ultrasonic imaging system based on ultrasonic vortex according to claim 4, characterized in that: The transducer units in the ultrasonic transducer array are arranged in a concentric circular array, a spiral array or a uniform square array.

7. The ultra-high resolution ultrasonic imaging system based on ultrasonic vortex according to claim 1, characterized in that: The ultrasonic beam modulation structure is a pipe-shaped structure with a gradually decreasing radius, so that the vortex sound field passing through the ultrasonic beam modulation structure is reduced to a size required for imaging the imaging object.

8. An ultra-high resolution ultrasonic imaging method of an ultra-high resolution ultrasonic imaging system based on ultrasonic vortex according to any one of claims 1 to 7, characterized in that: The information of the imaging object is extracted from the initial vortex distribution collected by the ultrasonic acquisition device through the ultrasonic vortex information processing method, and the initial distribution with consistent distribution with the imaging object is obtained. The initial distribution of the imaging object is further optimized through the high-resolution ultrasonic imaging reconstruction algorithm to obtain an ultra-high resolution imaging object image of the imaging object.

9. The ultra-high resolution ultrasonic imaging method according to claim 8, characterized in that: The ultrasonic vortex information processing method uses the back propagation algorithm BP algorithm to extract the information of the imaging object from the vortex ultrasonic distribution that cannot directly reflect the object information, and obtains an initial distribution that is consistent with the imaging object.

10. The ultra-high resolution ultrasonic imaging method according to claim 8, characterized in that: The high-resolution ultrasound imaging reconstruction algorithm further optimizes the initial distribution using the subspace-based optimization algorithm SOM algorithm, and iteratively reduces the cost function by modifying the initial distribution to obtain high-resolution imaging object information.

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