Measuring system of ultrasonic catheter

Abstract

The utility model provides a measuring system for an ultrasonic catheter. The measuring system comprises a calculation control processing part, an adjusting platform, a camera, a microscope, a scale, an objective table, a tool and a sheath, the scale is arranged on the objective table and serves as a reference object of the head end of the catheter; the tool is used for keeping the catheter head end; the tool comprises a clamp, the clamp clamps a sheath, the sheath sleeves the ultrasonic catheter, and the head end of the catheter extends out of the sheath; the camera and the microscope are both installed on the adjusting platform and arranged above the objective table. The adjusting platform adjusts the position of the microscope, so that the catheter head end and the scale are located in the view range of the microscope; the camera shoots the head end of the catheter and the scaleplate in the field of view of the microscope to obtain an original image; and the calculation control processing part processes the original image to obtain a vibration signal of the head end of the catheter, so that vibration information of the head end of the catheter is obtained, and the accuracy and reliability of measured data are ensured.

Description

Technical Field

[0001] This utility model relates to the field of medical device testing technology, and in particular to a measurement system for an ultrasonic catheter. Background Technology

[0002] Coronary atherosclerosis and the resulting coronary atherosclerotic heart disease are major causes of high morbidity and mortality rates among cardiovascular patients worldwide. Due to its high prevalence, mortality, disability, and heavy disease burden, it has become a serious threat to human health. Traditional treatments for coronary atherosclerosis include percutaneous transluminal angioplasty, rotational atherectomy, and laser angioplasty, which aim to cut, grind, vaporize, and aspirate the atherosclerotic material to reopen the blood vessel. The latest treatment method uses an ultrasound catheter, which, with guidewire assistance, enters the heart cavity to reach the lesion. The transducer outputs vibrations to selectively ablate the embolism, thereby achieving the goal of recanalization. This method can easily penetrate "hard" plaques without damaging the blood vessel. In practice, for ultrasound catheters, the amplitude of the catheter tip is a key parameter, directly related to its ability to penetrate calcified blood vessels. In particular, the greater the axial amplitude of the catheter tip, the stronger its ability to penetrate calcified blood vessels. However, in existing technologies, the amplitude at the tip of the ultrasonic catheter is not measured before use, and the parameters are not optimized based on the specific measurement results, thus failing to achieve optimal vibration performance of the ultrasonic catheter. Summary of the Invention

[0003] In view of this, the purpose of this utility model is to provide a measurement system for ultrasonic catheters, which aims to measure the amplitude of the tip of the ultrasonic catheter in order to provide data reference for subsequent research and development, thereby improving the vibration performance of the ultrasonic catheter.

[0004] To achieve the above objectives, this utility model provides a measurement system for an ultrasonic catheter, the ultrasonic catheter including a catheter tip, and the measurement system including: a calculation and control processing unit, an adjustment platform, a camera, a microscope, a scale, a stage, tooling, and a sheath;

[0005] The scale is set on the platform; the scale serves as a reference for the catheter tip; the tooling is used to hold the catheter tip; the tooling includes a clamp for holding the sheath, the sheath for being fitted over the outside of the ultrasonic catheter, and the catheter tip extending beyond the outside of the sheath;

[0006] Both the camera and the microscope are mounted on the adjustment platform and positioned above the stage; the adjustment platform is used to adjust the position of the microscope so that the tip of the guide tube and the scale are within the field of view of the microscope.

[0007] The computational control processing unit is communicatively connected to the camera; the camera is used to capture images of the catheter tip and the scale within the microscope's field of view to obtain raw images; the computational control processing unit is used to process the raw images to obtain vibration signals of the catheter tip, and thus obtain vibration information of the catheter tip.

[0008] Optionally, the computational control processing unit is communicatively connected to the adjustment platform, which is used to move under the control of the computational control processing unit to adjust the position of the microscope.

[0009] Optionally, the computational control processing section includes a motion control module, which is used to send control signals to the adjustment platform so that the adjustment platform moves according to the received control signals.

[0010] Optionally, the computational control processing section includes an image processing module, which processes the original image to obtain the vibration signal. The image processing module is also used to sequentially perform bandpass filtering, wavelet transform, short-time Fourier transform, averaging, and gain correction on the vibration signal to obtain the vibration information.

[0011] Optionally, the image processing module is provided with a bandpass filter, the bandpass filter having a center frequency and a predetermined bandwidth, the center frequency being 20kHz and the bandwidth being -2kHz to 2kHz.

[0012] Optionally, the scale is provided with a baseline, which divides the scale in half in the width direction, and sets a number of scale lines at equal intervals in the direction perpendicular to the baseline. The range of the scale lines corresponds to the amplitude measurement range of the catheter tip.

[0013] Optionally, the measurement system further includes a light source to provide illumination for the camera; the light source is communicatively connected to the computing control processing unit to adjust the illumination state under the control of the computing control processing unit.

[0014] Optionally, the computational control processing section includes a light source control module, which is used to send control signals to the light source so that the light source adjusts its illumination state based on the received control signals.

[0015] Optionally, the measurement system further includes an exciter, which is electrically connected to a transducer on the ultrasonic catheter via a wire to output an electrical signal to the transducer. After receiving the electrical signal, the transducer is excited and outputs vibration, thereby driving the ultrasonic catheter to vibrate.

[0016] Optionally, the measurement system also satisfies at least one of the following conditions:

[0017] The camera is a CCD camera capable of achieving sub-pixel level imaging;

[0018] The microscope in question is a stereomicroscope;

[0019] The adjustment platform is a multi-degree-of-freedom motion platform;

[0020] The tooling's point of action on the ultrasonic catheter is at a certain distance from the distal end of the catheter tip;

[0021] The computational control and processing section includes an image processing module, a data output module, a display module, and a storage module.

[0022] Compared with the prior art, the ultrasonic catheter measurement system provided by this utility model has at least the following beneficial effects:

[0023] The aforementioned ultrasonic catheter measurement system includes: a computational control processing unit, an adjustment platform, a camera, a microscope, a scale, a stage, a fixture, and a sheath; the scale is mounted on the stage; the scale serves as a reference for the catheter tip; the fixture holds the catheter tip; the fixture includes a clamp for holding the sheath, which is fitted over the ultrasonic catheter, with the catheter tip extending beyond the sheath; the camera and the microscope are both mounted on the adjustment platform and positioned above the stage; the adjustment platform adjusts the position of the microscope so that the catheter tip and the scale are within the microscope's field of view; the computational control processing unit is communicatively connected to the camera; the camera captures images of the catheter tip and the scale within the microscope's field of view to obtain raw images; the computational control processing unit processes the raw images to obtain vibration signals from the catheter tip, thereby obtaining vibration information from the catheter tip. This allows for the measurement of the amplitude of the ultrasonic catheter tip, ensuring the accuracy and reliability of the measurement data. Attached Figure Description

[0024] Those skilled in the art will understand that the accompanying drawings are provided to better understand this application and do not constitute any limitation on the scope of this application.

[0025] Figure 1 This is a schematic diagram of the structure of the ultrasonic catheter measurement system provided according to an embodiment of this application.

[0026] Figure 2 This is a top view of the catheter tip and the scale below it according to an embodiment of this application; wherein the catheter tip is indicated by a dashed line.

[0027] Figure 3 This is a flowchart of the amplitude measurement process provided according to an embodiment of this application.

[0028] Figure 4 This is a time-domain diagram of the original signal provided according to the embodiments of this application, with the horizontal axis representing time (in seconds) and the vertical axis representing amplitude (in meters).

[0029] Figure 5 This is a frequency domain diagram of the original signal provided according to the embodiments of this application, with the horizontal axis representing frequency (in Hz) and the vertical axis representing amplitude (in m).

[0030] Figure 6 This is a flowchart of amplitude calculation based on an embodiment of this application.

[0031] Figure 7 This is a time-domain graph of a bandpass filtered signal provided according to an embodiment of this application. The horizontal axis represents time (in seconds), and the vertical axis represents amplitude (in meters).

[0032] Figure 8 This is a time-domain diagram of a wavelet-transformed signal according to an embodiment of this application, where the horizontal axis represents time (in seconds) and the vertical axis represents amplitude (in meters).

[0033] Figure 9 This is a frequency domain diagram of a wavelet-transformed signal provided according to an embodiment of this application. The horizontal axis represents frequency (in Hz), and the vertical axis represents amplitude (in m).

[0034] Figure 10 This is a two-dimensional display graph of time-frequency amplitude after short-time Fourier transform provided according to the embodiments of this application. The horizontal axis is time (in seconds) and the vertical axis is frequency (in Hz).

[0035] Figure 11 The three-dimensional time-frequency-amplitude display diagram provided according to the embodiments of this application is shown below, with the X-axis representing time (in seconds), the Y-axis representing frequency (in Hz), and the Z-axis representing amplitude (in meters).

[0036] Figure 12 This is a module composition diagram of the computing control processing section provided according to the embodiments of this application.

[0037] Figure 13This is a flowchart illustrating the entire process of image acquisition, image processing, and signal processing analysis provided in the embodiments of this application.

[0038] Figure 14 This is a schematic diagram showing that the clamp provided in the embodiment of this application holds the sheath and the sheath is sleeved on the outside of the ultrasonic catheter, while the catheter tip extends out of the sheath.

[0039] in, Figures 1-14 In the middle: 1-Computational control and processing section; 101-Motion control module; 102-Light source control module; 103-Image processing module; 104-Data output module; 105-Display module; 106-Storage module; 2-Adjustment platform; 3-Camera; 4-Microscope; 5-Scale; 51-Graduation line; 52-Baseline; 6-Stage; 7-Tooling; 71-Clamp; 8-Light source; 9-Exciter; 10-Wire; 11-Sheath; 20-Ultrasonic catheter; 21-Catheter tip. Detailed Implementation

[0040] To make the content of this application clearer and easier to understand, the following description, in conjunction with the accompanying drawings, further illustrates this application. Of course, this application is not limited to the specific embodiments provided below, and common substitutions well-known to those skilled in the art are also covered within the scope of protection of this application.

[0041] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “the,” and “the” used in this application are also intended to include the plural forms unless the context clearly indicates otherwise. It should be understood that “a” or “one,” and similar words do not indicate a quantity limitation, but rather indicate the presence of at least one; “a plurality” indicates two or more. The terms “comprising” or “including,” and similar words mean that the element or object preceding “comprising” or “including” encompasses the element or object listed following “comprising” or “including” and its equivalents, and do not exclude other elements or objects. Secondly, this application uses schematic diagrams for detailed illustration, but these diagrams are only for illustrative purposes and should not be construed as limiting the application. Furthermore, the terms “one end” and “the other end,” and “proximal end” and “head end,” generally refer to two corresponding parts, which include not only the endpoints. In this document, “head end” generally refers to the end furthest from the catheter operator, and “proximal end” refers to the end closest to the catheter operator. It should also be noted that, as used in this application, the terms "X-axis" and "Y-axis" are used to represent two mutually perpendicular directions on a horizontal plane, and "Z-axis" is used to represent the vertical direction.

[0042] The core idea of ​​this application is to provide a measurement system for ultrasonic catheters that can accurately measure the amplitude at the tip of the ultrasonic catheter, so as to optimize the ultrasonic catheter based on the specific measurement results and achieve the best vibration performance of the ultrasonic catheter.

[0043] The ultrasound catheter involved in this application is mainly a vascular recanalization ultrasound catheter, preferably a coronary recanalization ultrasound catheter. The coronary recanalization ultrasound catheter is a medical device used to place a guidewire within the lumen of a chronic total occlusion coronary artery via atherosclerosis surgery. The following description refers to the accompanying drawings.

[0044] Reference Figure 1 and Figure 2 As shown, this application embodiment relates to an ultrasonic catheter 20, which includes a catheter tip 21. A transducer can be installed at the proximal end of the ultrasonic catheter 20, and the transducer can drive the ultrasonic catheter 20 to vibrate after outputting vibration.

[0045] It should be noted that the ultrasonic catheter 20 itself is very small, therefore, the requirements for the measurement system are relatively high. In order to accurately measure the amplitude of the tip of the ultrasonic catheter 20, it is necessary to acquire the original image of the catheter tip 21 vibrating through microscopic imaging. Then, the acquired original image is processed to obtain the vibration signal of the catheter tip 21. The vibration signal is then further processed by bandpass filtering, wavelet transform, short-time Fourier transform, averaging, and gain correction. Finally, the frequency-time-amplitude correspondence of the catheter tip 21 vibration can be obtained, thereby achieving high-precision measurement of the catheter tip amplitude and ensuring the accuracy and reliability of the measurement data.

[0046] Therefore, this application provides a measurement system, which includes at least: a calculation and control processing unit 1, an adjustment platform 2, a camera 3, a microscope 4, a scale 5, a stage 6, and a tooling 7. The measurement method used by this measurement system is as follows:

[0047] Using scale 5 as a reference for the catheter tip 21, the ultrasonic catheter 20 is driven to vibrate. During this process, camera 3 captures images of the catheter tip 21 and scale 5 within the field of view of microscope 4 to obtain raw images. Then, the computational control processing unit 1 processes these raw images to obtain the vibration signal of the catheter tip 21. The vibration signal is then subjected to bandpass filtering, wavelet transform, short-time Fourier transform, averaging, and gain correction to obtain the frequency, time, and amplitude correspondence, thus acquiring the vibration information of the catheter tip 21. This measurement method achieves high measurement accuracy, precisely extracting useful information from the raw images and ensuring the measurement accuracy of the catheter tip 21.

[0048] More specifically, both camera 3 and microscope 4 are mounted on adjustment platform 2, with camera 3 positioned above microscope 4. The relative positions of camera 3 and microscope 4 are fixed. Camera 3 is always pointed at microscope 4, allowing for real-time online imaging of the catheter tip 21 and scale 5 within the field of view of microscope 4. In other words, camera 3 performs microscopic imaging through microscope 4. Camera 3 can be a CCD camera, capable of sub-pixel level imaging, accurately capturing images of the catheter tip 21 vibrating. Microscope 4 can be a stereomicroscope, also known as a stereo microscope, which is a binocular microscope that allows observation of objects from different angles, creating a stereoscopic effect for both eyes.

[0049] The computational control processing unit 1 is communicatively connected to the camera 3. Preferably, the computational control processing unit 1 is also communicatively connected to the adjustment platform 2. The computational control processing unit 1 can process and analyze the raw images acquired by the camera 3. The adjustment platform 2 is used to adjust the position of the microscope 4, ensuring that the guide tube tip 21 and the scale 5 are completely within the field of view of the microscope 4, and that the guide tube tip 21 is exactly above the scale 5. Preferably, the adjustment platform 2 is used to move under the control of the computational control processing unit 1 to adjust the position of the microscope 4. The communication method between the computational control processing unit 1, the camera 3, and the adjustment platform 2 is not limited; it can be wireless or wired communication, but wired communication is preferred.

[0050] The adjustment platform 2 is a multi-degree-of-freedom motion platform, capable of movement along the X and Y axes, and rotation around the Z axis. Optionally, the adjustment platform 2 can also perform lifting motion along the Z axis to adjust the height of the camera 3 and the microscope 4. Optionally, the adjustment platform 2 can achieve six degrees of freedom motion, specifically movement along the X, Y, and Z axes, and rotation around the X, Y, and Z axes. The adjustment platform 2 is mainly driven by motors to ensure its adjustment accuracy. For example, in this embodiment, the adjustment platform 2 includes an X-axis linear motor, a Y-axis linear motor, and a Z-axis rotary motor; the X-axis linear motor can drive the adjustment platform 2 to translate along the X-axis; the Y-axis linear motor can drive the adjustment platform 2 to translate along the Y-axis; and the Z-axis rotary motor can drive the adjustment platform 2 to rotate around the Z-axis. In summary, the adjustment platform 2 has at least a fine-tuning function and further, a coarse-tuning function.

[0051] The scale 5 serves as a reference point for the catheter tip 21, and can be used to determine the vibration amplitude and location of the catheter tip 21. For example... Figure 2 As shown in this embodiment, the scale 5 has a built-in scale line 51. During measurement, it is only necessary to ensure that the range of the scale line 51 can cover the amplitude measurement range of the catheter tip 21. This structure is simple and easy to use.

[0052] In some embodiments, the scale 5 may be a rectangular glass slide, such as a rectangular glass slide with a length of 5cm, a width of 1.5cm, and a thickness of 0.5mm, which is similar in shape to a glass slide.

[0053] In some embodiments, the scale 5 is provided with a reference line 52, which divides the scale 5 in the width direction. A plurality of graduation lines 51 are equally spaced in a direction perpendicular to the reference line 52 (the graduation lines 51 are highlighted at a magnified viewpoint A). The range of the graduation lines 51 corresponds to the amplitude measurement range of the catheter tip 21. For example, a set of 20 equally spaced graduation lines 51 with a spacing of 5 μm are marked in a direction perpendicular to the reference line 52, thereby allowing the measurement of vibration distances within 100 μm.

[0054] The measurement system also includes a stage 6, which is positioned below the camera 3 and the microscope 4. The stage 6 is used to hold the scale 5 and the tooling 7, allowing for convenient and stable fixation of the guide tube tip 21 and the scale 5 within the field of view of the microscope 4, facilitating image capture by the camera 3. The stage 6 can be a dedicated stage or a conventional stage.

[0055] The measurement system also includes a fixture 7, which can be mounted on the stage 6 or placed in other locations. The fixture 7 is used to hold the catheter tip 21, maintaining its stability. The point of action of the fixture 7 on the ultrasonic catheter 20 is at a certain distance from the distal end of the catheter tip 21, such as 10cm, 20cm, or 30cm. This distance should not be too small to interfere with imaging. It should be noted that the fixture 7, when holding the catheter tip 21, does not significantly affect the catheter's vibration or the amplitude measurement. Furthermore, the fixture 7 can use various structures to hold the catheter tip 21; this application does not limit its use.

[0056] To make the measurement process more consistent with the in vivo environment, such as Figure 14 As shown, preferably, the measurement system further includes a sheath 11, and the tooling 7 includes a clamp 71. In use, the clamp 71 holds the sheath 11, which is simultaneously fitted over the ultrasound catheter 20, with the catheter tip 21 extending beyond the sheath 11. This configuration simulates the ultrasound catheter 20's insertion into a blood vessel through the sheath 11 and its movement within the vessel. The clamp 71 only needs to hold the sheath 11, and the sheath 11 does not affect the vibration of the ultrasound catheter 20, ensuring the accuracy of amplitude measurement. The sheath 11 can be any commonly used guide sheath, such as a guide sheath adapted to a 6F ultrasound catheter.

[0057] Furthermore, during the vibration of the ultrasonic catheter 20, the measurement system provided in this application can process the original image acquired by the camera 3 in real time online through the calculation and control processing unit 1 to obtain the vibration signal of the catheter tip 21. The calculation and control processing unit 1 then further processes the vibration signal sequentially through bandpass filtering, wavelet transform, short-time Fourier transform, averaging, and gain correction to obtain the correspondence between frequency, time, and amplitude. Based on this correspondence, the vibration information of the catheter tip 21 can be obtained. This configuration, while ensuring image quality, can effectively remove noise and interference signals, extract useful signal components, and thus accurately measure the amplitude of the catheter tip 21. Based on the specific measurement results, the design parameters of the ultrasonic catheter 20 can be optimized, thereby improving the vibration performance of the ultrasonic catheter 20.

[0058] It should also be noted that the image processing method used in the computational control processing section 1 of this application will be further described later, and this part is also easily implemented by those skilled in the art based on their common knowledge.

[0059] In some embodiments, the measurement system also includes a built-in light source 8, which provides illumination for the camera 3 to capture clear and accurate images. Optionally, the light source 8 is communicatively connected to the computing control processing unit 1, allowing the light source 8 to adjust its illumination state, such as illumination time, intensity, angle, and whether the illumination is turned off or stopped, under the control of the computing control processing unit 1. This makes the entire measurement process more automated and convenient. The light source 8 can be positioned below or above the stage 6; the specific installation location of the light source 8 is not required.

[0060] In some embodiments, the measurement system further provides an exciter 9 (or driver), which is electrically connected to a transducer on the ultrasonic catheter 20 via a wire 10 to output an electrical signal (such as a voltage of a certain frequency) to the transducer. Upon receiving the electrical signal, the transducer is excited and outputs vibration, thereby driving the ultrasonic catheter 20 to vibrate. Specifically, after the tip of the catheter head 21 is adjusted to a suitable range, the exciter 9 is activated, and the exciter 9 provides a frequency and voltage adapted to the ultrasonic catheter 20 to drive the ultrasonic catheter 20 to vibrate.

[0061] It should be further explained that the computing control processing unit 1 can be a computer, console, central control console, or other device or equipment with control, image processing, and computational analysis functions. The computing control processing unit 1 can consist of one device or multiple devices; when multiple devices are used, they can operate independently. In other words, this application does not impose any particular restrictions on the implementation form of the computing control processing unit 1, as long as it can achieve the corresponding functions and technical effects.

[0062] Preferably, the computing control and processing unit 1 adopts an integrated device that takes into account multiple functions such as control, image processing, and image analysis. These functions can be implemented by software function modules, hardware devices, or a combination of software and hardware.

[0063] In addition, it should be clarified that the measurement system of this application can measure the principal amplitude in the axial direction of the ultrasound catheter 20. The principal amplitude refers to the peak displacement in the direction of maximum amplitude at the catheter tip 21. This parameter is related to the ability to penetrate vascular calcification. Within a certain range, the larger the principal amplitude, the stronger the ability to penetrate vascular calcification.

[0064] Reference Figure 3 Furthermore, the workflow of the measurement system of this application preferably includes position calibration, image acquisition, image processing, signal processing analysis, and data output performed sequentially.

[0065] In step S1, position calibration is performed. Specifically, before driving the ultrasonic catheter 20 to vibrate, it is necessary to determine whether to activate the adjustment platform 2 to adjust the position of the microscope 4 based on the image captured by the camera 3, ensuring that the catheter tip 21 and the scale 5 are completely within the field of view of the microscope 4. Specifically, if the image captured by the camera 3 indicates that part of the catheter tip 21 and the scale 5 are outside the field of view of the microscope 4, the calculation and control processing unit 1 sends a control signal. When the adjustment platform 2 receives the control signal, it starts the motor to move until the captured image can confirm that the catheter tip 21 and the scale 5 are completely within the field of view of the microscope 4, thus placing the catheter tip 21 in the optimal measurement position.

[0066] Reference Figure 12 In some embodiments, the computational control processing unit 1 includes a motion control module 101, which is used to send control signals to the adjustment platform 2 so that the adjustment platform 2 moves according to the received control signals.

[0067] Specifically, in this embodiment, the ultrasonic catheter 20 is first connected to the fixture 7 at a preset position, and the catheter tip 21 is placed above the scale 5 and aligned precisely with the baseline 52 of the scale 5. Simultaneously, the tip of the catheter tip 21 is aligned with a graduation line 51 on the baseline 52, and the range of the graduation line 51 covers the amplitude measurement range of the catheter tip 21. The scale 5 assists in calculating the amplitude; essentially, the catheter tip 21 vibrates above the scale 5, and the graduation line 51 on the scale 5 can detect the vibration distance of the catheter tip 21.

[0068] In some embodiments, the computational control processing unit 1 may further include a light source control module 102, which is used to send a control signal to the light source 8 so that the light source 8 adjusts the illumination state based on the received control signal.

[0069] Further, in step S2, image acquisition is performed: once the catheter tip 21 and scale 5 are completely within the field of view of the microscope 4, the exciter 9 is activated to drive the ultrasonic catheter 20 to vibrate. During the vibration, the camera 3 takes real-time online images of the catheter tip 21 and scale 5 within the field of view of the microscope 4 to obtain raw images. The raw images are then converted into digital images for processing and analysis.

[0070] In this embodiment, the conversion of the original image into a digital image can be accomplished by the camera 3 or by the computing control processing unit 1, and the specific method is not limited.

[0071] Next, in step S3, image processing is performed. At this point, to obtain a valid image signal, the computational control processing unit 1 needs to sequentially perform denoising, image segmentation extraction, and digital filtering on the original image to obtain a clear and stable image signal. Specifically, the converted digital image is first denoised to remove background noise and irrelevant information; then, image segmentation technology is used to extract the vibration signal of the catheter tip 21; subsequently, the extracted vibration signal is digitally filtered to remove high-frequency noise and low-frequency drift. It should also be noted that after image processing, the amplitude of the catheter tip 21 can be roughly detected; this amplitude is the original amplitude.

[0072] Continue to refer to Figure 12 As shown, in some embodiments, the computational control processing unit 1 includes an image processing module 103, which is used to sequentially perform denoising, image segmentation and extraction, and digital filtering on the original image to obtain the vibration signal (containing amplitude information) of the catheter tip 21.

[0073] For ease of understanding, an illustrative example will be provided using a vibration frequency of 20 kHz for the ultrasonic catheter 20. Based on this, after image processing (step S3), the following can be obtained: Figure 4 The description corresponds to the time-domain plot of the original signal. Furthermore, to illustrate the amplitude of the original signal in the frequency domain, the following is also provided: Figure 5 The frequency domain plot of the original signal described. From Figure 4 It can be seen that the vibration amplitude range of the original signal is 0 to 0.00002 m, that is, Figure 4 The amplitude range of the original signal is -0.0001m to +0.0001m.

[0074] Further, the signal processing analysis in step S4 is performed. That is, after image processing, the vibration signal needs to be further processed and analyzed to further remove noise and interference. Specifically, the vibration signal obtained from image processing is sequentially subjected to bandpass filtering, wavelet transform, short-time Fourier transform, averaging, and gain correction.

[0075] like Figure 12 As shown, in some embodiments, the image processing module 103 is further used to sequentially perform bandpass filtering, wavelet transform, short-time Fourier transform, averaging and gain correction on the vibration signal obtained by image processing.

[0076] For more details, see [link to relevant documentation]. Figure 6 As shown, firstly, the vibration signal obtained through image processing (i.e., the image signal of the part of interest) is subjected to bandpass filtering to filter out high and low frequency signals and retain the intermediate frequency signal, thereby obtaining a filtered signal centered on the target frequency and covering a certain bandwidth. The target frequency is the vibration frequency of the ultrasonic catheter 20, and the bandwidth is adjusted and set according to the vibration frequency range of the catheter.

[0077] In some embodiments, the image processing module 103 is provided with a bandpass filter, which has a center frequency and a predetermined bandwidth, thereby enabling the bandpass filter to perform bandpass filtering processing on the vibration signal. Optionally, the center frequency of the bandpass filter is 20kHz, and the bandwidth is -2kHz to +2kHz.

[0078] It should be understood that the bandpass filter can extract signals near the target frequency (e.g., 20kHz) and effectively filter out interference and noise outside the target frequency range, thereby improving measurement accuracy. When setting the bandpass filter, first determine the center frequency and bandwidth. The center frequency generally corresponds to the catheter vibration frequency, thus effectively covering the valid vibration data within the target frequency range. After setting the bandpass filter, the vibration signal processed by image processing can be filtered, retaining the signal components centered at the target frequency and within the bandwidth range, while filtering out interference and noise from other frequency components, thereby extracting the signal of interest. For example, when the center frequency is 20kHz, since the vibration frequency range of the ultrasonic catheter 20 itself is 19kHz to 21kHz, the center frequency is determined to be 20kHz based on this vibration frequency range, and the bandwidth can be -2kHz to +2kHz.

[0079] An illustrative example is given using a vibration frequency of 20kHz. After bandpass filtering, it can be... Figure 4 The original signal processing is Figure 7 The filtered signal (time domain) is described. Comparing the original signal and the filtered signal shows that bandpass filtering removes some interference signals and noise from the original signal, thereby improving measurement accuracy.

[0080] Secondly, after bandpass filtering, wavelet transform threshold denoising is applied to filter out small-amplitude noise signals, resulting in the wavelet transform signal. See details... Figure 6 .

[0081] It should be understood that wavelet transform has significant advantages in multi-scale analysis and denoising, and can effectively extract useful signals near the target frequency (e.g., 20kHz) while suppressing noise and interference.

[0082] Specifically, the image processing module 103 can implement wavelet transform processing in the following manner: First, the bandpass filtered signal is decomposed into wavelet coefficients and approximation coefficients at different scales; then, the decomposed detail coefficients are thresholded to remove noise components; finally, the thresholded detail coefficients and the original approximation coefficients are reconstructed into a denoised image signal (i.e., a wavelet transform signal) through inverse wavelet transform. This further improves signal quality and ensures measurement accuracy.

[0083] As those skilled in the art will understand, commonly used thresholding methods include hard thresholding and soft thresholding. Choosing an appropriate thresholding method can effectively remove noise.

[0084] The illustrative explanation continues with a vibration frequency of 20kHz. After wavelet transform threshold denoising, it can be... Figure 7 Time-domain filtering signal processing is Figure 8 The wavelet transform signal described (time domain) corresponds to the obtained signal. Figure 9 The wavelet transform signal (frequency domain) described is used to further suppress noise and interference, making the measurement results more accurate.

[0085] On the other hand, after wavelet transform processing, the time-domain signal is transformed into a frequency-domain signal through short-time Fourier transform (STFT) (see...). Figure 6 In other words, based on the signal denoised by bandpass filtering and wavelet transform, the short-time Fourier transform is used to further process the image signal. The short-time Fourier transform can provide a time-frequency representation of the signal, helping to more accurately locate amplitude changes near the target frequency (e.g., 20kHz), especially in cases where the signal is non-stationary.

[0086] Specifically, the image processing module 103 implements short-time Fourier transform processing in the following way: first, the image signal after wavelet transform denoising is divided into multiple time periods, and Fourier transform is performed in each time period to obtain an image signal whose spectrum changes with time.

[0087] An illustrative example is given using a vibration frequency of 20 kHz. When the vibration frequency is 20 kHz, after short-time Fourier transform processing, the following can be obtained: Figure 10 The frequency-time amplitude two-dimensional graph shown is understandable. Figure 10The amplitude intensity is represented by color. Therefore, by observing the time-frequency distribution of the short-time Fourier transform, signal characteristics near the target frequency (such as 20kHz) can be more accurately identified and analyzed, and the frequency components of interest and their variation patterns can be found.

[0088] Continue to refer to Figure 6 After short-time Fourier transform processing, averaging is further performed to obtain a weighted average result. After averaging, gain correction is performed to obtain a gain-corrected result.

[0089] More specifically, camera 3 is used to obtain multiple sets of original images through multiple samplings; then, the multiple sets of original images are processed to obtain multiple sets of vibration signals of the catheter tip 21; further, the multiple sets of vibration signals of the catheter tip 21 are sequentially processed by bandpass filtering, wavelet transform, and short-time Fourier transform; then, the short-time Fourier transform results of the multiple sets of vibration signals are averaged, and gain correction is performed after averaging; finally, the correspondence between frequency, time, and amplitude after averaging and gain correction is obtained.

[0090] Here, this application reduces the impact of random noise by averaging multiple measurement results. In other words, by sampling multiple times and weighted averaging, the signal-to-noise ratio (SNR) of the measurement results can be improved. In practice, it is usually necessary to sample the same signal multiple times to obtain multiple sets of data. Then, these data are weighted and averaged to reduce the impact of random noise, thereby obtaining a more stable and accurate signal. This process can significantly improve the signal-to-noise ratio and enhance the reliability and accuracy of the measurement.

[0091] In this embodiment, before gain correction, the frequency response of the bandpass filter is calculated to determine the gain of the filter at different frequencies. Then, the gain correction coefficient is calculated, which is the ratio between the actual amplitude and the ideal amplitude of the filtered signal. Based on the calculated gain correction coefficient, the weighted average processing result is subjected to gain correction to adjust the amplitude of the signal so that it is closer to the true signal amplitude.

[0092] Therefore, this application further improves the measurement accuracy through gain correction to ensure that the final signal amplitude accurately reflects the true state of the signal.

[0093] In this embodiment, the image processing module 103 performs weighted averaging and gain correction processing. An illustrative example is given using a vibration frequency of 20kHz. When the vibration frequency is 20kHz, after gain correction, the following can be obtained: Figure 11The described time-frequency-amplitude three-dimensional display diagram shows the vibration intensity (amplitude) of the catheter tip 21 at different frequencies and times. Figure 11 The amplitude results described are the final results after gain correction and averaging.

[0094] Therefore, by using bandpass filtering, wavelet transform, short-time Fourier transform, averaging, and gain correction, the frequency and amplitude of the catheter tip 21 can be accurately calculated, ensuring measurement accuracy.

[0095] Return to reference Figure 3 In some embodiments, the measurement results can be further output and displayed. For example, the measurement results can be stored digitally in a computer for easy subsequent analysis and retrieval, as well as for easy viewing and recording by operators. Furthermore, based on the measurement results, a detailed verification report can be generated, including information such as amplitude values, measurement time, and equipment status, ensuring that all data is verifiable.

[0096] Turning Figure 12 In some embodiments, the computational control processing unit 1 may further include a data output module 104, which can output measurement results for storage and analysis.

[0097] In some embodiments, the calculation control processing unit 1 may further include a display module 105, which can display the measurement results in real time.

[0098] In some embodiments, the calculation control processing unit 1 may further include a storage module 106, which can store the measurement results in digital form in a computer for easy querying and analysis.

[0099] To facilitate understanding, the advantages of the signal analysis and processing method used in this application will be further explained below.

[0100] Firstly, regarding time-frequency localization: the combined use of Short-Time Fourier Transform (STFT) and Wavelet Transform can simultaneously provide time and frequency information from the signal, thus offering significant advantages in processing non-stationary signals. Compared to Discrete Cosine Transform (traditional FFT), the combined processing of STFT and Wavelet Transform can better capture instantaneous changes in the signal, making it suitable for fine analysis of signals near the target frequency of the ultrasonic catheter 20, ensuring measurement accuracy.

[0101] Secondly, in terms of multi-scale analysis: Since wavelet transform has multi-scale analysis capabilities and can decompose signals at different scales, this application can perform analysis at multiple scales through wavelet transform, which can extract useful information from the signal more accurately and retain the key features of the signal during the denoising process, thus ensuring measurement accuracy.

[0102] Furthermore, in terms of signal denoising, wavelet transform provides an effective thresholding technique that can suppress noise at different scales, thereby improving signal quality. In contrast, while traditional FFT can also be used for denoising, its performance is not as ideal as wavelet transform when processing signals with complex noise characteristics.

[0103] Furthermore, regarding the accuracy of spectral analysis: Short-time Fourier Transform (SFT) can obtain a detailed time-frequency distribution of a signal. When measuring amplitude changes of a signal near a target frequency, SFT provides more accurate spectral analysis results, helping to more accurately locate and analyze the frequency components of the signal. Therefore, spectral analysis accuracy is higher. Additionally, wavelet transform and SFT offer greater flexibility. Different wavelet bases and window functions can be selected according to specific application requirements, adjusting the accuracy and resolution of the analysis, thus adapting to different application needs and offering greater flexibility. Moreover, in real-time signal processing: SFT and wavelet transform better meet real-time requirements, especially excelling in dynamic signal monitoring and analysis, thus demonstrating strong real-time processing capabilities.

[0104] Therefore, in general, the signal analysis and processing method adopted in this application has the characteristics of stronger time-frequency localization capability, multi-scale analysis capability, better noise reduction performance, wider applicability, higher spectrum analysis accuracy, greater flexibility, and better real-time processing capability.

[0105] The image processing method used in this application will be explained in more detail below.

[0106] Please refer to Figure 13 In a preferred embodiment, the catheter tip amplitude measurement step includes:

[0107] Step 1) Obtain the image sequence (i.e., the original image) of the catheter tip vibration. Specifically, the image or video frame sequence of the catheter tip 21 during the vibration process is acquired in real time by a CCD camera and used for subsequent image processing and signal processing analysis.

[0108] Step 2) Use a Gaussian blur filter to eliminate image noise in order to reduce the impact of noise on subsequent edge detection;

[0109] Step 3) Detect the edge of the catheter tip using an edge detection algorithm;

[0110] Step 4) Use a corner detection algorithm to perform sub-pixel level edge localization;

[0111] Step 5) Calculate the change in edge position to obtain the amplitude;

[0112] Step 6) Signal processing and analysis.

[0113] It should be noted that the above steps utilize sub-pixel level image interpolation and edge detection algorithms to accurately locate the catheter tip in the image. Here, precise edge detection facilitates sub-pixel level amplitude recognition and measurement when subsequently calculating the amplitude of the catheter tip, thereby significantly improving amplitude measurement accuracy.

[0114] Preferably, the edge detection algorithm is the Canny edge detection algorithm, and the corner detection algorithm is the Harris corner detection algorithm. In this embodiment, when processing the catheter tip vibration image by combining the Canny edge detection and Harris corner detection algorithms, phase contrast-based amplitude detection is achieved. Phase contrast imaging increases the edge contrast of the catheter tip vibration image, thereby improving the accuracy of amplitude measurement.

[0115] In some embodiments, step 2), when using a Gaussian blur filter to eliminate image noise, specifically involves preprocessing the image sequence of the captured duct tip 21. During preprocessing, a Gaussian blur filter is used to eliminate high-frequency noise in the vibration image. The Gaussian blur formula is as follows:

[0116]

[0117] Where: x represents the pixel's coordinate along the x-axis, and y represents the pixel's coordinate along the y-axis; I blur (x,y) represents the filtered image of the original image at the tip of the catheter; I(x,y) represents the set of image pixels; I(x,y)σ* represents the convolution operation; σ is the standard deviation of the image, which is the control parameter for the degree of blur. The larger σ is, the higher the degree of blur. It is suitable for images with different noise levels.

[0118] Here, step 2) effectively reduces noise interference in subsequent edge detection by smoothing the original image of the catheter tip 21. Specifically, Gaussian blurring of the image sequence reduces the noise level of the image, making subsequent edge detection more reliable.

[0119] In some embodiments, in step 3), detecting the edge of the catheter tip using an edge detection algorithm specifically involves: using the Canny edge detection algorithm to perform edge detection on the Gaussian blurred image, identifying the edge position of the catheter tip in each image frame. The Canny edge detection steps may include:

[0120] S31. Gradient Calculation: The gradient of the image is calculated using the Sobel operator. The gradient formula is as follows:

[0121]

[0122] Where: x represents the pixel coordinate along the x-axis, y represents the pixel coordinate along the y-axis; G(x, y) is the calculated image gradient; G x (x,y) and G y (x, y) are the gradients of the image (i.e., the image at the tip of the catheter) in the x-axis and y-axis directions, respectively;

[0123] S32. Non-maximum suppression: Suppresses non-edge points along the gradient direction while preserving local maxima;

[0124] S33, Dual Threshold Hysteresis: High and low thresholds are used to classify and connect edges, ultimately obtaining a clear edge image.

[0125] For Canny edge detection, multi-stage processing (including gradient calculation, non-maximum suppression, double threshold hysteresis, etc.) is used to achieve accurate edge recognition in the image. The gradient calculation formula provides the direction and magnitude information of the fastest changing edge in the image.

[0126] In some embodiments, in step 4), a corner detection algorithm is used to perform sub-pixel-level edge localization on the catheter tip edge detected in step 3). Harris corner detection calculates the response value of corner points in the image by calculating the second moments of the image in the x and y directions. This response value is used to identify the most salient feature points in the image. The specific calculation formula is as follows:

[0127] R = det(M) - k·(trace(M)) 2

[0128] Where R is the response value of the corner point in the image; det(M) is the determinant of the matrix; trace(M) is the trace of the matrix; M is the second-order moment matrix of the pixel values ​​in the image; k is an empirical parameter that controls the sensitivity of corner point detection, usually between 0.04 and 0.06. By analyzing the extreme points of the response value R, the edge of the catheter tip can be accurately located.

[0129] In some embodiments, step 5) involves calculating the edge position change to obtain the amplitude in the catheter tip image. Specifically, this involves analyzing the edge position changes in multiple frames of images to calculate the amplitude of the catheter tip 21 during vibration. The amplitude calculation formula is as follows:

[0130]

[0131] Where A is the calculated amplitude value; P i (t1) and P i (t2) represents the positions of the i edge points at times t1 and t2, respectively, and n is the total number of edge points.

[0132] In amplitude calculation, the amplitude of the catheter tip 21 is calculated by comparing the edge positions in multiple frames of images. The amplitude calculation formula can effectively reflect the movement amplitude of the catheter tip 21 and accurately measure the amplitude of the catheter tip 21.

[0133] Therefore, it can be seen that in the process of image acquisition, processing and recognition, this application can achieve high-precision measurement of the amplitude at the tip of the catheter through the above steps 1)-6), ensuring measurement accuracy.

[0134] It should be noted that those skilled in the art can make various improvements and additions without departing from the scope of this application, and these improvements and additions should also be considered within the protection scope of this application. Any modifications, alterations, and variations made by those skilled in the art without departing from the spirit and scope of this application, based on the disclosed technical content, are equivalent embodiments of this application; furthermore, any modifications, alterations, and variations made to the above embodiments based on the essential technology of this application still fall within the scope of the technical solution of this application.

Claims

1. A measurement system for an ultrasonic catheter, the ultrasonic catheter including a catheter tip, characterized in that, The measurement system includes: a computing and control processing unit, an adjustment platform, a camera, a microscope, a scale, a stage, tooling, a light source, an exciter, and a sheath; The light source provides illumination for the camera; the scale is set on the stage; the scale serves as a reference for the catheter tip; the tooling is used to hold the catheter tip; the tooling includes a clamp for holding the sheath, the sheath for covering the outside of the ultrasonic catheter, and the catheter tip extends out of the sheath. The exciter is electrically connected to the transducer on the ultrasonic catheter via a wire to output an electrical signal to the transducer. After receiving the electrical signal, the transducer is excited and outputs vibration, thereby driving the ultrasonic catheter to vibrate. Both the camera and the microscope are mounted on the adjustment platform and positioned above the stage. The adjustment platform is a multi-degree-of-freedom motion platform, used to achieve movement along the X and Y axes, and rotation around the Z axis. The adjustment platform is used to adjust the position of the microscope so that the guide tube tip and the scale are within the field of view of the microscope. The computational control processing unit is an integrated device and is communicatively connected to the camera. The camera is used to capture images of the catheter tip and the scale within the microscope's field of view to obtain raw images. The computational control processing unit is used to process the raw images to obtain vibration signals from the catheter tip, thereby obtaining vibration information from the catheter tip.

2. The measurement system for ultrasonic catheters according to claim 1, characterized in that, The computational control processing unit is communicatively connected to the adjustment platform, which is used to move under the control of the computational control processing unit to adjust the position of the microscope.

3. The measurement system for ultrasonic catheters according to claim 1, characterized in that, The scale has a baseline that divides the scale in half in the width direction, and several graduation lines are set at equal intervals in the direction perpendicular to the baseline. The range of the graduation lines corresponds to the amplitude measurement range of the catheter tip.

4. The measurement system for ultrasonic catheters according to claim 1, characterized in that, The light source is communicatively connected to the computing control processing unit to adjust the illumination state under the control of the computing control processing unit.

5. The measurement system for ultrasonic catheters according to claim 1, characterized in that, The camera is a CCD camera capable of achieving sub-pixel level imaging.

6. The measurement system for ultrasonic catheters according to claim 1, characterized in that, The microscope in question is a stereomicroscope.

7. The measurement system for ultrasonic catheters according to claim 1, characterized in that, The tooling's point of action on the ultrasonic catheter is at a certain distance from the distal end of the catheter tip.

8. The measurement system of an ultrasonic catheter of claim 1, wherein, The computational control and processing section includes an image processing module, a data output module, a display module, and a storage module.

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