A portable forward-looking magnetically controlled ultrasound endoscope system and device

Abstract

This invention discloses a portable forward-looking magnetically controlled ultrasonic endoscope system and its device, belonging to the field of medical imaging equipment technology. The invention achieves oscillation and real-time imaging of a single ultrasonic array element through the cooperation of an integrated flexible rotating platform, a magnetic core coil, and a permanent magnet. Signal and grounding pads are set at the bottom of the ultrasonic array element and connected to two pre-embedded enameled copper wires in the flexible rotating platform. The enameled copper wires are fixed by grooves on the outer shell, ensuring a stable connection with the coaxial cable, effectively solving the problems of easy cable breakage and mechanical interference from rotational motion in traditional probes. Furthermore, considering the sound field intensity distribution of the probe itself, this invention introduces a weighting factor in the delayed superposition beamforming image reconstruction process, significantly reducing artifacts present in traditional delayed superposition methods. The system of this invention has a compact structure, low cost, and enables any computer host to perform ultrasonic imaging. The device has a small footprint and is suitable for various surgical scenarios.

Description

Technical Field

[0001] This invention relates to the field of medical imaging equipment technology, specifically to a portable forward-looking magnetically controlled ultrasound endoscope system and its device. Background Technology

[0002] Endoscopic ultrasound (EUS) is a medical imaging device that combines a miniature ultrasound probe with an endoscope. By placing it inside human cavities, it enables real-time imaging of submucosal structures and surrounding tissues in organs such as the digestive and respiratory tracts. Traditional EUS typically uses a mechanically driven single-element scanning method, and its scanning mode is mostly constant-speed rotational scanning.

[0003] However, for certain surgical scenarios, such as spinal endoscopic surgery, it is necessary to obtain image information of the lesion directly in front of the probe, which traditional side-viewing rotating probes cannot meet. Limited by the outer diameter of the endoscope probe (typically less than 10mm), traditional mechanical hinges or gear structures struggle to achieve reliable reciprocating motion within such a confined space, and are prone to mechanical wear and fatigue fracture. While a forward-looking scanning scheme based on piezoelectric drive and cantilever beam structure is feasible, its driving force is relatively small, limiting the scanning range; simultaneously, high-voltage drive places higher demands on the hardware system, increasing system complexity.

[0004] In recent years, with advancements in probe manufacturing technology, various array-type endoscopic ultrasound probes have emerged, enabling ultrasound imaging through electronic scanning. However, array probes require a higher number of channels in the back-end instruments, leading to increased system costs and making the overall equipment larger and heavier, thus limiting their application in portable and low-cost scenarios. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention proposes a portable forward-looking magnetically controlled ultrasound endoscope system and its device.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] According to a first aspect of this specification, a forward-looking magnetically controlled ultrasound endoscope device is provided, comprising a device housing and a probe and a power unit disposed within the device housing; the probe is located at the front end inside the device housing and includes a single ultrasound array element and a flexible rotating platform.

[0008] The flexible rotating platform includes a hollow supporting cylinder, with the ultrasonic array element embedded inside the supporting cylinder and its top end flush with the top end of the supporting cylinder; the supporting cylinder is connected to the inner wall of the device shell only through two flexible connectors; the flexible connectors can rotate around their own central axis, and the two flexible connectors are symmetrically arranged at the same height along the radial direction of the supporting cylinder, with their central axes collinear;

[0009] The top surface of the ultrasonic array element is concave, and the bottom surface is provided with signal pads and ground pads. The signal pads and ground pads are electrically connected to an external coaxial cable through signal lines.

[0010] The power unit includes two permanent magnets and a magnetic core coil. The two permanent magnets are vertically fixed inside the supporting cylinder, and are symmetrically arranged about the central axis of the supporting cylinder with opposite polarities. The magnetic core coil is installed directly below the permanent magnets and coaxially assembled with the ultrasonic array element. The magnetic core coil is used to connect to an external AC power supply and generate an alternating magnetic field. The permanent magnets are used to drive the flexible rotating platform and the ultrasonic array element on it to continuously oscillate about the central axis of the flexible connector under the action of the alternating magnetic field. The frequency of the sinusoidal AC power supply is the same as the mechanical resonant frequency of the flexible rotating platform.

[0011] Preferably, the permanent magnet is axially magnetized, and two permanent magnet grooves for fixing the permanent magnet are provided at the bottom of the inner side of the supporting cylinder. The axes of the two permanent magnets are parallel to and coplanar with the axis of the supporting cylinder, and the plane is perpendicular to the central axis of the flexible connector.

[0012] Preferably, the flexible connector includes a connecting section and a fixed end. One end of the connecting section is connected to the outer wall of the supporting cylinder, and the other end is connected to the fixed end. The fixed end is embedded in the inner wall of the device housing to fix the flexible rotating platform.

[0013] Preferably, the signal line is routed internally through one of the flexible connectors and electrically connected to an external coaxial cable; an axial groove is provided on the outer wall of the device housing for the signal line routing.

[0014] Secondly, the present invention also provides a portable forward-looking magnetically controlled ultrasound endoscope system based on the aforementioned endoscope device, including a main control module, an imaging processing module, and the aforementioned endoscope device. The main control module is connected to the endoscope device and is used to control the signal transmission and reception and mechanical rotation of the endoscope device. The main control module includes a signal module and a power module. The power module is used to generate a sinusoidal drive current signal to drive the probe to rotate. The signal module is used to transmit ultrasound signals and receive ultrasound echo signals, and is also used to generate a synchronization signal to achieve time synchronization between the ultrasound echo and the sinusoidal drive current.

[0015] The signal module has an ultrasonic transceiver path, and the signal module generates a frequency of [frequency value missing]. The synchronous trigger pulse is sent to the power module, and a frequency of [frequency value] is generated simultaneously. Synchronous trigger pulses are sent to the ultrasonic transceiver path of the signal module. The synchronous trigger pulse relative to The start time delay of the synchronous trigger pulse ,Every A frame of image is formed by continuously acquired ultrasonic echo signals; the signal module performs gain adjustment, bandpass filtering and analog-to-digital conversion on the received echo signals in sequence, and then transmits them to the host through the PCIe interface.

[0016] The power module communicates with the host via a USB interface and is initialized to external trigger mode. When the signal module sends a synchronization signal, the power module responds to the signal by generating a sinusoidal drive current of the corresponding frequency.

[0017] The imaging processing module is located on the host side and is used to receive the ultrasonic echo signal transmitted by the main control module and perform beamforming to reconstruct the image.

[0018] Preferably, the signal module acquires the first to the second signals according to the acquisition scan line distribution. The ultrasound echo signals are arranged in ascending order at the host end to form the first frame of the image; the second... +1 to 2 The ultrasonic echo signals are arranged in reverse order at the host end to form the second frame of the image, and so on, to ensure that the display direction of two consecutive frames is consistent; for scanning resonant frequencies of... The probe has an image refresh rate of 2. .

[0019] Preferably, the imaging processing module includes a scanning unit, a preprocessing unit, and a reconstruction and post-processing unit, wherein:

[0020] The scanning unit is used to divide the reconstructed imaging area into a uniform scanning line grid according to the distribution of the reconstructed scanning lines, and to calculate the transmission and reception delay matrix of the ultrasonic echo signal corresponding to each pixel.

[0021] The preprocessing unit calculates the weighting factor matrix for each ultrasonic echo signal based on the sound field intensity distribution assumption. It then sums all weighting factors contributing to the same pixel to obtain a pixel omission marker matrix. This matrix is ​​used to mark pixels that were not used for reconstruction because the sum of their weighting factors is zero.

[0022] The reconstruction and post-processing unit is used to reconstruct the ultrasound image in polar coordinates based on the acquired ultrasound echo signal using the transmission and reception delay matrix and the weighting factor matrix. The polar coordinate image is then subjected to amplitude envelope, signal normalization, normalized convolution interpolation, logarithmic compression, and dynamic range adjustment in sequence. Finally, the processed polar coordinate image is mapped to the Cartesian coordinate system to obtain the B-scan image.

[0023] Preferably, when the target reconstruction imaging area is divided into a uniform scanning line grid, the distribution of the reconstruction scanning lines is different from that of the acquisition scanning lines. The angular interval between two adjacent reconstruction scanning lines should meet the following requirement: under this angular interval, the arc length at the focal depth does not exceed half of the probe focal spot width. Here, the probe focal spot width is defined as the sound field -6dB pulse width.

[0024] When calculating the transmission and reception delay matrices, the focus of the probe is regarded as an equivalent point sound source, and the transmission and reception delay matrices of the ultrasonic echo signal corresponding to each pixel are calculated based on the position of the equivalent point sound source.

[0025] Preferably, the weighting factor matrix is ​​obtained by multiplying the probe's sound field mask weight, amplitude apodization window weight, longitudinal sound intensity window weight, and time gain compensation weight. The calculation method for each weight is as follows:

[0026] (1) The sound field mask weight of the probe has a double cone structure, which is used to limit the effective spatial range of the sound beam propagation. The judgment rule is: taking the equivalent sound source as the vertex, if the angle between the vector pointing from the vertex to the target pixel and the vector pointing from the vertex to the origin of the coordinate is less than the sound beam diffusion angle, or greater than the supplementary angle of the sound beam diffusion angle, it is considered as an effective spatial range and the weight is set to 1; otherwise, it is considered as an invalid spatial range and the weight is set to 0.

[0027] (2) Apply an amplitude apodization window to the sound field mask weights to reduce side lobe artifacts. The application of the amplitude apodization window is determined based on the vertical distance from the target pixel to the axis where the probe focal point is located: the closer the distance, the higher the weight value; the farther the distance, the lower the weight value. The overall trend is a smooth change with high weights in the middle and low weights at both ends.

[0028] (3) Apply longitudinal sound intensity window weight to the sound field mask weight. This weight is calculated based on the sound field intensity distribution along the central axis of the probe.

[0029] (4) Apply time gain compensation weight to the sound field mask weight to compensate for the signal attenuation caused by the increase of sound field intensity with propagation distance and longitudinal sound intensity window.

[0030] Preferably, the convolution difference kernel of the normalized convolution interpolation is constructed based on the wavelength of the ultrasonic echo signal and the arc length at the focal point, and interpolation is performed to fill the pixels with a value of 0 in the pixel gap marker matrix.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] 1. This invention provides a portable forward-looking magnetically controlled ultrasound endoscope system and its device: a single-channel probe achieves scanning through electromagnetic field drive, forming a large-field-of-view forward-looking endoscope probe; by using a polydimethylsiloxane (PDMS) rotating platform with embedded signal lines, the contradiction between the requirement for thinner probe cables due to the small magnetic field driving force and the easy breakage of the cables due to free vibration when the cable connection is suspended is effectively solved; this structure ensures the stability of electrical connection while avoiding mechanical interference from the cable to the rotational motion, and eliminates the need for electronic slip rings, simplifying the mechanical design; in addition, the single-element hardware architecture significantly reduces the cost of back-end hardware and compresses the size of hardware modules, and with the detachable signal and power modules, further simplifies the system complexity and improves the portability and modularity of the device.

[0033] 2. This invention provides an imaging processing module based on pixel beamforming. By considering the sound field intensity distribution of the probe itself, the echo signal intensity is reconstructed, and the image is reconstructed using a time-delay superposition beamforming method. This significantly reduces the artifacts present in traditional time-delay superposition methods, resulting in a reconstructed image with clearer details and more distinct tissue boundaries. Attached Figure Description

[0034] Figure 1 This is a half-section schematic diagram of a magnetically controlled ultrasound endoscope device.

[0035] Figure 2 This is a top view of a magnetically controlled ultrasound endoscope device.

[0036] Figure 3 This is a schematic diagram of a portable magnetically controlled ultrasound endoscope system.

[0037] Figure 4 This is a schematic diagram of the system's synchronous trigger pulse.

[0038] Figure 5 This is the imaging result of the forward-looking magnetically controlled endoscopic ultrasound system.

[0039] In the figure: 1. Ultrasonic array element; 2. Flexible rotating platform; 3. Permanent magnet groove; 4. Enamelled copper wire; 5. Permanent magnet; 6. Magnetic core coil; 7. Cylindrical hole; 8. First groove; 9. Second groove. Detailed Implementation

[0040] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0041] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0042] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. To address the problems of existing probes having low driving force, easily broken cable connections, bulky equipment, high cost, and unclear imaging boundaries, this invention provides a portable forward-looking magnetically controlled ultrasound endoscope device, system, and image reconstruction method.

[0043] like Figure 1 and Figure 2 As shown, the present invention provides a forward-looking magnetically controlled ultrasound endoscope device, which includes a device housing and a probe and a power unit inside the device housing.

[0044] The outer casing of the device is composed of a sleeve cover, a sleeve, and a base, which are coaxially assembled in sequence. The sleeve cover is a conventional design, with its lower end nested inside the upper end of the sleeve. This invention does not limit the specific structural form of the sleeve cover; those skilled in the art can choose an appropriate connection method according to the actual application scenario. In this embodiment, the sleeve is a uniform diameter circular tube, and the base is a stepped hollow cylinder with a smaller diameter at the upper end and a larger diameter at the lower end. The outer diameter of the upper end of the base is equal to the inner diameter of the sleeve, and the upper end of the base is nested inside the lower end of the sleeve.

[0045] The probe consists of a single ultrasonic array element 1 and a flexible rotating platform 2.

[0046] The flexible rotating platform 2 is disposed on the inner side of the upper part of the sleeve and is integrally formed from flexible polydimethylsiloxane (PDMS) material. It includes a hollow supporting cylinder and two flexible connectors. The ultrasonic array element 1 is embedded in the supporting cylinder, with the top of the ultrasonic array element 1 flush with the top of the supporting cylinder. The two flexible connectors are symmetrically arranged on both sides of the outer wall of the supporting cylinder along its radial direction, and the two flexible connectors are at the same height. The flexible connectors can twist around their own central axis, and their central axes are collinear and pass through the center of the supporting cylinder. Each flexible connector includes a connecting section and a fixed end. One end of the connecting section is connected to the outer wall of the supporting cylinder, and the other end is connected to the fixed end. The fixed end is embedded in the inner wall of the sleeve to fix the flexible rotating platform 2. The fixed end is a sheet-like structure, and its shape can be arc-shaped, square, etc. The present invention does not limit the shape of the fixed end. In this embodiment, it is arc-shaped to minimize the outer diameter of the endoscope device.

[0047] The ultrasonic array element 1 is a cylinder with a concave top surface to achieve sound beam focusing. That is, the probe provided by this invention is a focusing probe. The ultrasonic array element 1 is used to transmit ultrasonic signals and receive ultrasonic echo signals, and transmits the received ultrasonic echo signals to the outside for imaging. The bottom surface of the ultrasonic array element 1 is provided with signal pads and ground pads. Two enameled copper wires 4 are pre-embedded inside one of the connection sections as signal lines. The signal pad and ground pad are respectively soldered to one end of an enameled copper wire 4. The other end of the enameled copper wire 4 extends to the end of the endoscope device (base end) and is electrically connected to a coaxial cable at the end of the endoscope device. Each solder joint of the enameled copper wire 4 is coated with a waterproof insulating material to achieve electrical isolation and protection.

[0048] The power unit consists of a magnetic core coil 6 and two permanent magnets 5. Two circular permanent magnet grooves 3 are provided at the bottom of the supporting cylinder for embedding the permanent magnets 5; the centers of the two permanent magnet grooves 3 lie on a diameter of the bottom surface of the supporting cylinder. The two permanent magnets 5 are axially magnetized and vertically fixed inside the supporting cylinder, symmetrically arranged about the central axis of the supporting cylinder; the axes of the two permanent magnets are parallel and coplanar with the axis of the supporting cylinder, and the plane containing the axes of the two permanent magnets is perpendicular to the central axis of the flexible connector. The magnetic core coil 6 is located directly below the permanent magnets and coaxially assembled with the ultrasonic array element 1. The magnetic core of the magnetic core coil 6 uses a magnetically conductive material with a diameter equivalent to that of the ultrasonic array element 1 to enhance the magnetic field strength. The coil winding of the magnetic core coil 6 is made of insulated wire, and the end of the insulated wire is electrically connected to the coaxial cable at the end of the endoscope device. When a driving current (sinusoidal alternating current) is applied to the magnetic core coil 6, a continuously changing magnetic field is generated, which interacts with the permanent magnets 5. The two permanent magnets 5 have opposite polarities, thus experiencing opposite electromagnetic forces in the magnetic field. When the magnetic core coil 6 receives sufficient current and generates an alternating electromagnetic field, it can work with the permanent magnets 5 to drive the ultrasonic array element 1 to deflect in the desired direction (the direction of the central axis of the two flexible connectors) to achieve real-time imaging. The frequency of the driving current needs to be adjusted to be the same as the mechanical resonant frequency of the flexible rotating platform 2 (i.e., the mechanical resonant frequency of the endoscope scanning device). This is crucial for achieving efficient, low-power, and large-amplitude mechanical scanning, and is especially important for space-constrained ultrasound equipment such as portable endoscopes.

[0049] In this embodiment, a first groove 8 is formed on the outer wall of the sleeve directly below the first hinge, running axially. The first groove 8 is used to fix the enameled copper wire 4. After passing through the first groove 8, the enameled copper wire 4 is electrically connected to the coaxial cable laid outside the end of the endoscope device and fixed in a second groove 9 formed on the outer wall of the base. The first groove 8 and the second groove 9 are aligned. A cylindrical hole 7 is formed in the center of the base. A coaxial cable is laid in the cylindrical hole 7. The insulated wire end of the magnetic core coil 6 is electrically connected to the coaxial cable and passes through the cylindrical hole 7 to exit the base. The design of the flexible rotating platform 2 and the sleeve groove ensures the stability of the electrical connection while avoiding mechanical interference of the cable to the rotational movement.

[0050] Secondly, the present invention provides a portable forward-looking magnetically controlled ultrasound endoscope system based on the aforementioned endoscope device. In addition to the aforementioned endoscope device, it also includes a main control module and an imaging processing module. The main control module is used to control the signal transmission and reception and mechanical rotation of the endoscope device. Figure 3 As shown. The main control module works in conjunction with the aforementioned endoscope device and establishes communication with the host terminal. The main control module includes a signal module and a power module. The power module is used to generate a sinusoidal current signal to drive the rotation of the endoscope device; the signal module has an ultrasound transceiver path, which is used to transmit ultrasound signals and receive ultrasound echo signals through the endoscope device, and also to generate a synchronization signal and send it to the power module to achieve timing synchronization between the ultrasound echo signal and the sinusoidal drive current. Specifically, the signal module generates a frequency of... The synchronous trigger pulse is sent to the power module, and a frequency of [frequency value] is generated simultaneously. The synchronous trigger pulse is sent to the ultrasonic transceiver path of the signal module to ensure the timing synchronization of the ultrasonic echo signal and the sinusoidal drive current, and to achieve spatial continuity of intra-frame data. Compared to Start time delay The endoscopic device is operated according to frequency. Transmitting ultrasonic signals and receiving corresponding ultrasonic echo signals, each Continuously acquired ultrasonic echo signals constitute one frame of image. The signal module sequentially performs gain adjustment, bandpass filtering, and analog-to-digital conversion on the received ultrasonic echo signals before transmitting them to the host computer via the PCIe interface. The power module communicates with the host computer via a USB interface and is initialized to external trigger mode; when the signal module sends a synchronization signal, the power module responds by generating a sinusoidal drive current of the corresponding frequency; the host computer controls the system's start / stop and parameter adjustments through a user interface.

[0051] The first to the signal module acquired Ultrasonic echo signal Arranged sequentially on the host side, they form the first frame of the image, such as... Figure 4 B-scan1, For time variables, The angular distribution of the ultrasonic echo signal (i.e., the distribution of the acquisition scan lines); the first +1 to 2 The echo signals are arranged in reverse order at the host end to form the second frame of the image, such as... Figure 4 B-scan2; and so on, to ensure that the display direction of two consecutive frames is consistent; for a resonant frequency of The endoscopic device has an image refresh rate of up to 2... .

[0052] The main control module can be equipped with a detachable ultrasonic signal transmitting and receiving motherboard and a signal generating motherboard for generating the driving magnetic field. The signal module is integrated on the ultrasonic signal transmitting and receiving motherboard, and the power module is integrated on the signal generating motherboard for generating the driving magnetic field.

[0053] This system integrates the synchronization signal transmission function into the signal module, eliminating the need for a traditional synchronization module. The high integration of each module significantly reduces the system size and improves system portability. Furthermore, this invention can achieve scanning using only a single ultrasonic array element, effectively reducing system costs.

[0054] The imaging processing module receives the ultrasonic echo signal transmitted from the main control module and performs beamforming to reconstruct the image. The imaging processing module includes a reconstruction scanning unit, a preprocessing unit, and a reconstruction and post-processing unit, wherein:

[0055] The scanning unit is used to divide the target reconstruction imaging area into a uniform scanning line grid. , For the depth distribution of pixels, For the angular distribution of pixels (i.e., the reconstruction of the scan line distribution), calculate the angular distribution of each pixel. The corresponding ultrasonic echo signal transmission and reception delay matrix ;

[0056] The preprocessing unit is used to calculate the weighting factor matrix of each ultrasonic echo signal based on the assumption of sound field intensity distribution. The pixel gap marker matrix is ​​calculated by summing all the weight factors contributing to the same pixel. Pixel gap marker matrix The pixel gap marker matrix is ​​used to mark pixels that did not participate in the reconstruction because the sum of the weight factors is 0. The formula for calculating the pixel gap marker matrix is ​​as follows:

[0057]

[0058] The post-processing unit is used to process the acquired echo signals. Combined with delay matrix and weighting factors Reconstruction The reconstruction formula is:

[0059]

[0060] right After performing amplitude envelope, signal normalization, normalized convolution interpolation, logarithmic compression, and dynamic range adjustment, the polar coordinates are... Mapping to the Cartesian coordinate system yields a B-scan image based on pixel beamforming.

[0061] The scanning unit specifically includes the following:

[0062] (1) Divide the target reconstruction imaging area into a uniform scan line grid. Reconstruct the distribution of scanning lines and the distribution of scanning lines They can be different, where the angular interval between two adjacent reconstructed scan lines is different. The following conditions must be met:

[0063]

[0064] in The focal spot width of the probe. This refers to the probe's focusing depth. This is the probe scanning radius. This formula indicates that, at this angular interval, the arc length at the focal depth does not exceed half the width of the probe focal spot. Here, the probe focal spot width is defined as the sound field -6dB pulse width:

[0065]

[0066] in The wavelength of the ultrasonic signal. The diameter is the probe diameter; if If it is too small, it will result in a pixel gap marker matrix. If the range is too large, artifacts will be introduced during the normalization convolution interpolation process; if If the size is too large, the number of reconstructed pixels will decrease, and the clarity of image details will decline;

[0067] (2) Calculate the transmission and reception delay matrix of the ultrasonic echo signal corresponding to each pixel. During the calculation, the focus of the probe is regarded as an equivalent point sound source. Based on the position of this equivalent point sound source, the transmission delay and reception delay corresponding to each pixel are calculated. The specific delay formula is as follows:

[0068]

[0069] in This indicates that the vertex is the origin, and the path points from the origin to the target pixel. The vector, Indicates the first During the second scan, the vector pointing from the origin to the equivalent point sound source is taken as the vertex.

[0070] The preprocessing unit specifically includes the following:

[0071] (1) Sound field mask weight of the probe It has a double-conical structure, with a virtual sound source at its center, used to define the effective spatial range of sound beam propagation. The specific calculation formula is as follows:

[0072]

[0073] in , which represents the angle between the vector pointing from the equivalent point sound source to the target pixel and the vector pointing from the equivalent point sound source to the origin, with the equivalent point sound source as the vertex; , representing the beam spread angle;

[0074] (2) Reconstruction weights Apply amplitude apodization window weights To reduce sidelobe artifacts during beamforming, this invention does not limit the amplitude apodization window function; in this embodiment, a Hamming window is used. The application of this window is determined based on the vertical distance from the target pixel to the axis of the probe focal point: the closer the distance, the higher the weight value; the farther the distance, the lower the weight value, exhibiting a smooth variation with a high weight in the middle and low weight at both ends. The specific calculation formula is as follows:

[0075]

[0076] in , which represents the vertical distance from the target pixel to the axis where the probe focal point is located;

[0077] (3) Reconstruction weights Apply longitudinal sound intensity window weights This window is calculated based on the sound field intensity distribution along the central axis of the focusing probe. The specific calculation formula is as follows:

[0078]

[0079] in , is the normalized vertical distance; , is the sag of the probe's concave surface; , is the ratio of probe radius to focusing depth; for the sound field intensity oscillation part, the longitudinal sound intensity window weight is simplified to .

[0080] By using the weighting of this window, artifacts caused by fewer signals participating in reconstruction at the probe's focal point and more signals participating in reconstruction outside the focal point can be effectively compensated.

[0081] (4) You can choose to adjust the reconstruction weights. Apply time gain compensation weight This is to compensate for the signal attenuation caused by the increase of sound field intensity with propagation distance and the longitudinal sound intensity window; the determination of the time gain compensation weight is a conventional technique well known to those skilled in the art, and the present invention does not specifically limit it.

[0082] (5) Multiply all weights to obtain the weighting factor. The specific calculation formula is as follows:

[0083]

[0084] In the post-processing unit's operations, this embodiment only describes normalized convolution interpolation. Amplitude envelope, signal normalization, logarithmic compression, and dynamic range adjustment are all conventional techniques well-known to those skilled in the art. During normalized convolution interpolation, an anisotropic kernel is constructed based on the ultrasonic echo signal wavelength and the arc length at the focal point, and a pixel gap marking matrix is ​​used. Pixels with a value of 0 are filled by interpolation. This invention does not limit the kernel function; in this embodiment, it is... Kernel function.

[0085] To verify the superiority of the system provided by this invention, rabbit intestines were used as the scanning target. B-scan images obtained through traditional beamforming were compared with B-scan images based on pixel beamforming. The comparison results are as follows: Figure 5 As shown. Compared with traditional beamforming methods, the image reconstruction method based on pixel beamforming provided by this invention can not only effectively suppress salt-and-pepper noise in the image and reduce artifacts caused by the superposition of out-of-focus non-uniform signals, but also present a clearer low-density tissue boundary and tissue edge inside the rabbit intestine.

[0086] In summary, this invention provides signal pads and grounding pads at the bottom of the ultrasonic array element 1, which are respectively connected to two enameled copper wires 4 pre-embedded in the flexible rotating platform 2. Simultaneously, the enameled copper wires 4 are fixed by the first groove 8 and the second groove 9 on the outer shell, ensuring a stable connection with the coaxial cable. This structure effectively solves the problems of easy cable breakage and mechanical interference from rotational motion in traditional probes. Furthermore, considering the sound field intensity distribution of the probe itself, a weighting factor is introduced during the time-delay superposition beamforming image reconstruction process, significantly reducing artifacts present in traditional time-delay superposition methods.

[0087] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A portable forward-looking magnetically controlled ultrasound endoscope system based on a forward-looking magnetically controlled ultrasound endoscope, characterized in that, It includes a main control module, an imaging processing module, and the endoscope device; The endoscopic device includes a housing and a probe and a power unit disposed within the housing; the probe is located at the front end inside the housing and includes a single ultrasound array element and a flexible rotating platform. The flexible rotating platform includes a hollow supporting cylinder, with the ultrasonic array element embedded inside the supporting cylinder and its top end flush with the top end of the supporting cylinder; the supporting cylinder is connected to the inner wall of the device shell only through two flexible connectors; the flexible connectors can rotate around their own central axis, and the two flexible connectors are symmetrically arranged at the same height along the radial direction of the supporting cylinder, with their central axes collinear; The top surface of the ultrasonic array element is concave, and the bottom surface is provided with signal pads and ground pads. The signal pads and ground pads are electrically connected to an external coaxial cable through signal lines. The power unit includes two permanent magnets and a magnetic core coil. The two permanent magnets are vertically fixed inside the supporting cylinder, and are symmetrically arranged about the central axis of the supporting cylinder with opposite polarities. The magnetic core coil is installed directly below the permanent magnets and coaxially assembled with the ultrasonic array element. The magnetic core coil is used to connect to an external AC power supply and generate an alternating magnetic field. The permanent magnets are used to drive the flexible rotating platform and the ultrasonic array element on it to continuously oscillate about the central axis of the flexible connector under the action of the alternating magnetic field. The frequency of the sinusoidal AC power supply is the same as the mechanical resonant frequency of the flexible rotating platform. The main control module is connected to the endoscope device and is used to control the signal transmission and reception and mechanical rotation of the endoscope device. The main control module includes a signal module and a power module. The power module is used to generate a sinusoidal drive current signal to drive the probe to rotate. The signal module is used to transmit ultrasound signals and receive ultrasound echo signals, and is also used to generate a synchronization signal to achieve time synchronization between the ultrasound echo and the sinusoidal drive current. The signal module has an ultrasonic transceiver path, and the signal module generates a frequency of [frequency value missing]. The synchronous trigger pulse is sent to the power module, and a frequency of [frequency value] is generated simultaneously. Synchronous trigger pulses are sent to the ultrasonic transceiver path of the signal module. The synchronous trigger pulse relative to The start time delay of the synchronous trigger pulse ,Every A frame of image is formed by continuously acquired ultrasonic echo signals; the signal module performs gain adjustment, bandpass filtering and analog-to-digital conversion on the received echo signals in sequence, and then transmits them to the host through the PCIe interface. The power module communicates with the host via a USB interface and is initialized to external trigger mode. When the signal module sends a synchronization signal, the power module responds to the signal by generating a sinusoidal drive current of the corresponding frequency. An imaging processing module is located on the host side and is used to receive ultrasonic echo signals transmitted by the main control module and perform beamforming to reconstruct the image. The imaging processing module includes a scanning unit, a preprocessing unit, and a reconstruction and post-processing unit. The preprocessing unit is used to calculate the weight factor matrix of each ultrasonic echo signal based on the assumption of sound field intensity distribution, and sum all the weight factors contributing to the same pixel to obtain a pixel void marker matrix. The pixel void marker matrix is ​​used to mark pixels that were not used for reconstruction because the sum of the weight factors is zero. The weighting factor matrix is ​​obtained by multiplying the probe's sound field mask weight, amplitude apodization window weight, longitudinal sound intensity window weight, and time gain compensation weight. The calculation method for each weight is as follows: (1) The sound field mask weight of the probe has a double cone structure, which is used to limit the effective spatial range of the sound beam propagation. The judgment rule is: taking the equivalent sound source as the vertex, if the angle between the vector pointing from the vertex to the target pixel and the vector pointing from the vertex to the origin of the coordinate is less than the sound beam diffusion angle, or greater than the supplementary angle of the sound beam diffusion angle, it is considered as an effective spatial range and the weight is set to 1; otherwise, it is considered as an invalid spatial range and the weight is set to 0. (2) Apply an amplitude apodization window to the sound field mask weights to reduce side lobe artifacts. The application of the amplitude apodization window is determined based on the vertical distance from the target pixel to the axis where the probe focal point is located: the closer the distance, the higher the weight value; the farther the distance, the lower the weight value. The overall trend is a smooth change with high weights in the middle and low weights at both ends. (3) Apply longitudinal sound intensity window weight to the sound field mask weight. This weight is calculated based on the sound field intensity distribution along the central axis of the probe. (4) Apply time gain compensation weight to the sound field mask weight to compensate for the signal attenuation caused by the increase of sound field intensity with propagation distance and longitudinal sound intensity window.

2. The system according to claim 1, characterized in that, The permanent magnet is axially magnetized, and two permanent magnet grooves are provided at the bottom of the inner part of the supporting cylinder for fixing the permanent magnet. The axes of the two permanent magnets are parallel to and coplanar with the axis of the supporting cylinder, and the plane containing the axes of the two permanent magnets is perpendicular to the central axis of the flexible connector.

3. The system according to claim 1, characterized in that, The flexible connector includes a connecting section and a fixed end. One end of the connecting section is connected to the outer wall of the supporting cylinder, and the other end is connected to the fixed end. The fixed end is embedded in the inner wall of the device housing to fix the flexible rotating platform.

4. The system according to claim 1, characterized in that, The signal line is routed internally through one of the flexible connectors and electrically connected to an external coaxial cable; an axial groove is provided on the outer wall of the device housing for the signal line routing.

5. The system according to claim 1, characterized in that, The signal module collects data according to the distribution of the acquisition scan lines, from the first to the last. The ultrasound echo signals are arranged in ascending order at the host end to form the first frame of the image; the second... to The ultrasonic echo signals are arranged in reverse order at the host end to form the second frame of the image, and so on, to ensure that the display direction of two consecutive frames is consistent; for scanning resonant frequencies of... The probe has an image refresh rate of [missing information]. .

6. The system according to claim 1, characterized in that, The scanning unit is used to divide the reconstructed imaging area into a uniform scanning line grid according to the distribution of the reconstructed scanning lines, and to calculate the transmission and reception delay matrix of the ultrasonic echo signal corresponding to each pixel. The reconstruction and post-processing unit is used to reconstruct the ultrasound image in polar coordinates based on the acquired ultrasound echo signal using the transmission and reception delay matrix and the weighting factor matrix. The polar coordinate image is then subjected to amplitude envelope, signal normalization, normalized convolution interpolation, logarithmic compression, and dynamic range adjustment in sequence. Finally, the processed polar coordinate image is mapped to the Cartesian coordinate system to obtain the B-scan image.

7. The system according to claim 6, characterized in that, When the target reconstruction imaging area is divided into a uniform scanning line grid, the distribution of the reconstruction scanning lines is different from that of the acquisition scanning lines. The angular interval between two adjacent reconstruction scanning lines should meet the following: under this angular interval, the arc length at the focal depth does not exceed half of the probe focal spot width. Here, the probe focal spot width is defined as the sound field -6dB pulse width. When calculating the transmission and reception delay matrices, the focus of the probe is regarded as an equivalent point sound source, and the transmission and reception delay matrices of the ultrasonic echo signal corresponding to each pixel are calculated based on the position of the equivalent point sound source.

8. The system according to claim 6, characterized in that, The normalized convolution interpolation kernel is an anisotropic kernel constructed based on the wavelength of the ultrasonic echo signal and the arc length at the focal point, which is used to interpolate and fill pixels with a value of 0 in the pixel gap marker matrix.

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