CN120323932B - OCT imaging artifact elimination method and common-path OCT device - Google Patents

Abstract

The application discloses an OCT imaging artifact eliminating method and a common-path OCT device, and relates to the technical field of optical imaging, wherein the method comprises the steps of circularly executing sampling operation until a handle of the common-path OCT device stops emitting an interference light source in the process that the handle emits the interference light source to a target tissue through a catheter; the tail end of the catheter is provided with a plurality of multi-layer dielectric films at equal intervals along the circumference of the catheter; the method comprises the steps of obtaining a plurality of A-scan data sets when a handle stops emitting an interference light source, generating a multi-frame image based on the plurality of A-scan data sets, wherein the sampling operation comprises the steps of obtaining a group of coding signals, triggering a high-speed acquisition ADC module of a common-path OCT device to sample a sweep-frequency light source reflected by a target tissue based on the coding signals to obtain one A-scan data set, controlling to enter the next sampling operation when the handle does not stop emitting the interference light source, and not entering the next sampling operation when the handle stops emitting the interference light source.

Description

OCT imaging artifact elimination method and common-path OCT device

Technical Field

The present application relates to the field of optical imaging technology, and in particular to an OCT imaging artifact elimination method and a common-path OCT device.

Background Art

Optical Coherence Tomography (OCT) is a medical imaging technology based on the principle of light interference. OCT obtains depth-direction tomography capabilities based on the principle of low-coherence interference. Through scanning, it can reconstruct two-dimensional or three-dimensional images of the internal structure of biological tissues or materials. Its signal contrast is derived from the spatial variations in the optical reflection (scattering) properties within the biological tissues or materials.

Existing OCT imaging techniques assume a uniform rotation speed at the catheter tip to capture A-scan data during the sampling process. However, in practice, friction and other factors can cause the catheter tip to twist and deform, resulting in uneven rotation speed. This leads to uneven angular distribution of the collected A-scan data, which in turn causes distortion in the reconstructed two-dimensional tomographic image (B-scan), making it prone to artifacts. Therefore, there is an urgent need for an OCT imaging method that can eliminate image artifacts.

Summary of the Invention

In view of the above-mentioned defects or deficiencies in the related art, the purpose of this application is to provide an OCT imaging artifact elimination method and a common-path OCT device, which can effectively eliminate image artifacts and ensure image resolution.

To achieve the above objectives, this application provides the following solutions:

In a first aspect, the present application provides an OCT imaging artifact elimination method, comprising: while a handle of a common-path OCT device emits an interferometric light source through a catheter toward a target tissue, cyclically performing a sampling operation until the handle stops emitting the interferometric light source; the interferometric light source comprises a swept-frequency light source and an infrared light source of a preset wavelength; a plurality of multilayer dielectric films are provided at equal intervals along the circumference of the catheter at the distal end of the catheter; the plurality of multilayer dielectric films are configured to reflect the infrared light source of the preset wavelength to form reflected light;

When the handle stops emitting the interference light source, a plurality of A-scan data sets are obtained;

Generating multiple frames of images based on multiple A-scan data sets; wherein the sampling operation includes:

Acquire a set of coded signals; the coded signals are binary coded sequences formed after a plurality of reflected lights of the multilayer dielectric film pass through a wavelength division multiplexer, a preset wavelength photodetector, a low-pass filter, and a comparator of the common-path OCT device; each pulse signal of the coded signals corresponds to a unique angular position;

The high-speed acquisition ADC module of the common-path OCT device is triggered based on the coded signal to sample the swept-frequency light source reflected by the target tissue to obtain an A-scan data set;

When the handle does not stop emitting the interference light source, the control enters the next sampling operation;

When the handle stops emitting the interference light source, the next sampling operation will not be performed.

Optionally, the high-speed acquisition ADC module of the common-path OCT device is triggered based on the coded signal to sample the swept-frequency light source reflected by the target tissue to obtain an A-scan data set, including: using a digital phase-locked loop algorithm to multiply the frequency of the coded signal to the target frequency to obtain a group of equally spaced pulse signals; based on the equally spaced pulse signals, the high-speed acquisition ADC module is triggered to sample the swept-frequency light source reflected by the target tissue to obtain an A-scan data set.

Optionally, a group of the coded signals includes a Home signal; and a group of the equally spaced pulse signals and the pulse signals corresponding to the Home signal are long pulse signals.

Optionally, the high-speed acquisition ADC module is triggered based on the equally spaced pulse signal to sample the swept-frequency light source reflected by the target tissue to obtain an A-scan data set, including: synchronizing the rising edge of the equally spaced pulse signal with a clock signal; the clock signal is a periodic signal generated when the handle emits an interference light source, and is used to control the acquisition frequency of the swept-frequency light source reflected by the target tissue by the high-speed acquisition ADC module; based on the rising edge of the equally spaced pulse signal, the high-speed acquisition ADC module is triggered to sample the swept-frequency light source reflected by the target tissue to obtain an A-scan data set.

Optionally, the rising edge of the equally spaced pulse signal is used to trigger the high-speed acquisition ADC module to sample the swept-frequency light source reflected by the target tissue to obtain an A-scan data set, including: using the rising edge of the equally spaced pulse signal to trigger the high-speed acquisition ADC module to sample once; when a long pulse signal of the equally spaced pulse signal is detected, completing the sampling operation once; each time the sampling operation is completed, a group of digital signals containing amplitude information and phase information is generated; each group of the digital signals represents an A-scan data; and a group of A-scan data is an A-scan data set.

Optionally, after obtaining a plurality of A-scan data sets when the handle stops emitting the interference light source, the method further comprises: arranging the plurality of A-scan data sets in ascending order of angles to form a plurality of A-scan data sets in a polar coordinate system.

Optionally, generating multiple frames of images based on multiple A-scan data sets includes: performing windowing processing and inverse Fourier transform on each A-scan data set in the polar coordinate system, and performing coordinate conversion on the A-scan data set after windowing processing and inverse Fourier transform to obtain an A-scan data set in the Cartesian coordinate system; removing background noise from the A-scan data set in the Cartesian coordinate system, and performing logarithmic compression, dynamic range adjustment, and phase mapping on the A-scan data set in the Cartesian coordinate system from which the background noise has been removed to obtain a grayscale image in the Cartesian coordinate system; and performing image compression and visualization adjustment on the grayscale image in the Cartesian coordinate system based on the JPEG standard algorithm to obtain multiple frames of images.

In a second aspect, the present application provides a common-path OCT device, comprising a handle, a catheter, a circulator, a wavelength division multiplexer, a swept-frequency light source balanced detector, a high-speed acquisition ADC module, a preset wavelength photodetector, a low-pass filter, a comparator, and a processor;

The handle receives an interference light source from the circulator and transmits the interference light source to the target tissue through the catheter; the interference light source includes a swept frequency light source and a preset wavelength infrared light source; the distal end of the catheter is provided with a plurality of multilayer dielectric films at equal intervals along the circumference of the catheter; the plurality of multilayer dielectric films are used to reflect the preset wavelength infrared light source to form reflected light;

The wavelength division multiplexer receives the return light source from the circulator and decomposes the return light source into a swept-frequency light source reflected by the target tissue and a plurality of reflected lights of the multilayer dielectric film, and sends the swept-frequency light source reflected by the target tissue to a swept-frequency light source balanced detector, and sends the plurality of reflected lights of the multilayer dielectric film to a preset wavelength photodetector; the swept-frequency light source balanced detector captures and sends the swept-frequency light source reflected by the target tissue to a high-speed acquisition ADC module;

The processor is configured to execute any one of the above-mentioned OCT imaging artifact elimination methods; specifically, the processor is configured to:

During the process of the handle emitting the interference light source toward the target tissue through the catheter, the sampling operation is cyclically performed until the handle stops emitting the interference light source;

When the handle stops emitting the interference light source, a plurality of A-scan data sets are obtained;

Generating multiple frames of images based on multiple A-scan data sets; wherein the sampling operation includes:

Acquire a set of coded signals; the coded signals are binary coded sequences formed after a plurality of reflected lights of the multilayer dielectric film are processed by the preset wavelength photodetector, the low-pass filter, and the comparator; each pulse signal of the coded signals corresponds to a unique angular position;

The high-speed acquisition ADC module is triggered based on the coded signal to sample the swept-frequency light source reflected by the target tissue to obtain an A-scan data set;

When the handle does not stop emitting the interference light source, the control enters the next sampling operation;

When the handle stops emitting the interference light source, the next sampling operation will not be performed.

Optionally, the catheter includes a connector and a tube body;

The connector includes a connecting housing, an optical connector disposed at one end of the connecting housing for connecting to a handle, an optical fiber disposed in the connecting housing and connected to the optical connector, a sliding button disposed on the connecting housing for driving the optical fiber to move axially along the tube body, and a Luer connector disposed at the other end of the connecting housing; the optical fiber passes through the Luer connector and extends to the end of the tube body;

The tube body includes a support tube connected to the Luer connector, a drive shaft arranged in the support tube and sleeved on the optical fiber, and a functional component arranged in the support tube and dynamically connected to the drive shaft, and the optical fiber extends into the functional component; a rotating assembly for driving the drive shaft to rotate along the circumference of the tube body is provided on the connecting shell near one end of the tube body; the rotating assembly includes a rotating button; and a plurality of the multilayer dielectric films are provided on the outer side wall of the support tube near one end of the functional component.

Optionally, the functional component includes a support member connected to the support tube, and a sampling member arranged on the support member and dynamically connected to the drive shaft; a light-transmitting area is provided on the support member, and an imaging acquisition window corresponding to the light-transmitting area is provided on the sampling member; an optical component for refracting and/or reflecting the light source is provided in the sampling member corresponding to the imaging acquisition window, and the optical fiber extends from the support tube to the optical component in the sampling member.

Optionally, a cutting head is provided on the sampling member at one end away from the support tube for rotating and cutting human plaques or opening occluded diseased tissue under the action of the driving shaft.

Optionally, the connector is further connected to a flushing device, and the cutting head is in fluid communication with the flushing device via the Luer connector for flushing and clearing blood from the imaging area.

In a third aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the above-mentioned methods for eliminating OCT imaging artifacts.

In a fourth aspect, the present application provides a computer program product, comprising a computer program, which, when executed by a processor, implements the steps of any of the above-mentioned OCT imaging artifact elimination methods.

According to the specific embodiments provided in this application, this application discloses the following technical effects:

The present application provides an OCT imaging artifact elimination method and a common-path OCT device. On the one hand, a plurality of multilayer dielectric films are arranged at equal intervals along the circumference of the catheter on the outer side wall of the distal end of the catheter. When the distal end of the catheter rotates, a binary code sequence generated based on the reflected light of the plurality of multilayer dielectric films, that is, each pulse signal of the coding signal corresponds to a unique angular position. Because the plurality of multilayer dielectric films are arranged at equal intervals, the pulse signals of the coding signal are distributed at equal angular intervals, and thus the A-scan data set sampled based on the coding signal is distributed at equal angular intervals on the circumference. When an image is generated using the A-scan data set distributed at equal angular intervals, image distortion such as stretching or compression will not occur, and image artifacts can be effectively eliminated to ensure image resolution. On the other hand, the high-speed acquisition ADC module is triggered by the coding signal to sample the swept-frequency light source reflected by the target tissue, thereby converting the trigger of the high-speed acquisition ADC module from a clock signal to an angle signal, thereby resolving the imaging defects caused by uneven catheter rotation speed in the prior art, further eliminating image artifacts, and ensuring image resolution.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

FIG1 is a schematic diagram of a flow chart of a method for eliminating OCT imaging artifacts according to an embodiment of the present application;

FIG2 is a schematic diagram showing the distribution of several multilayer dielectric films at the end of a catheter according to an embodiment of the present application;

FIG3 is a cross-sectional view along line C-C of FIG2 ;

FIG4 is a schematic structural diagram of a common-path OCT device provided in one embodiment of the present application;

FIG5 is a schematic diagram of the internal structure of a catheter provided in one embodiment of the present application;

FIG6 is an enlarged view of portion A in FIG5 ;

FIG7 is a schematic diagram of the connection structure of the sampling member in FIG6;

FIG8 is a schematic diagram of the connection structure of the support member in FIG6;

FIG9 is a schematic structural diagram along line B-B of FIG6 .

Description of the drawings: 10. Connector; 11. Connecting housing; 12. Optical connector; 13. Optical fiber; 14. Sliding button; 15. Luer connector; 16. Flushing device; 17. Rotating assembly;

20. Tube body; 21. Support tube; 22. Drive shaft; 23. Support member; 24. Light-transmitting area; 25. Sampling member; 26. Imaging acquisition window; 27. Optical assembly; 28. Cutting head.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

In an exemplary embodiment, as shown in FIG1 , a method for eliminating OCT imaging artifacts is provided. The method is executed by a processor of a common-path OCT device. In the embodiment of the present application, the method for eliminating OCT imaging artifacts includes the following steps S10 to S30.

Step S10 , while the handle of the common-path OCT device emits an interference light source toward the target tissue through the catheter, a sampling operation is cyclically performed until the handle stops emitting the interference light source.

In an exemplary embodiment, the interference light source includes a swept-frequency light source and a preset wavelength infrared light source; in an embodiment of the present application, the swept-frequency light source can be 1310±50nm near-infrared light; the preset wavelength infrared light source can be a 650nm red laser.

As shown in FIG2 and FIG3, a plurality of multilayer dielectric films are arranged at equal intervals along the circumference of the catheter at the end of the catheter; the plurality of multilayer dielectric films are used to reflect the infrared light source of the preset wavelength to form reflected light.

As can be understood, light is provided inside the catheter to transmit the optical signal required for OCT imaging. The outside of the catheter is coated with a number of multilayer dielectric films at equal intervals along the circumference of the catheter. For example, the multilayer dielectric films may include _SiO2 films and _{Ta2O5 films} . As shown in Table 1 below, the structure distribution of each multilayer dielectric film is as follows:

Table 1

It should be noted that the catheter end of the embodiment of the present application is the end away from the handle, and several multilayer dielectric films are coated at equal intervals on the outer wall of the catheter end. For example, each multilayer dielectric film shown in Table 1 includes 11 layers of films. By alternately stacking high-refractive-index _{Ta2O5 films} and low-refractive-index _SiO2 films in the 11 layers of films and precisely designing the optical thickness of each layer of the film, the multilayer dielectric film is formed so that not only can weak reflection of 650 nm red laser and high transmission of 1260 nm to 1360 nm near-infrared light be simultaneously achieved, but also can cause structural interference between the film layers of the incident light with a wavelength of 650 nm to prevent the generation of artifacts.

Specifically, compared to the prior art, the thickness and number of layers of the multilayer dielectric film in the embodiments of this application are non-periodic. This arrangement allows the multilayer dielectric film to achieve a reflectivity of less than 10% and a transmittance of greater than or equal to 90% for near-infrared light from the 1260nm to 1360nm range commonly used in common-path OCT devices, particularly near-infrared light near 1310nm, ensuring that the interference light source and return light source of the common-path OCT device are not affected. Furthermore, by employing a "precise thickness control + alternating refractive index" interference filtering design within the multilayer dielectric film, the film achieves both the desired weak reflection in the target visible light band and high transmittance in the target near-infrared band. For example, it achieves high reflectivity (≥80%) for 650nm red laser light and high transmittance (≥90%) for 1310nm near-infrared light.

Furthermore, in this embodiment of the present application, the preset wavelength infrared light source uses a 650nm red laser, which creates a broadband transmission zone in the near-infrared band and does not affect the echo of OCT imaging. Furthermore, the use of a 650nm red laser allows the physician to determine the integrity of the optical path and the proper connection between the handle and catheter by observing the red indicator light during use.

Step S20: When the handle stops emitting the interference light source, multiple A-scan data sets are obtained.

It should be noted that the A-scan data set is composed of multiple A-scan data. The A-scan data (depth scan line) is one-dimensional depth data along the optical axis (longitudinal direction), reflecting the light reflection intensity distribution of the target tissue at different depths in a single detection direction. It can be understood as "a fault signal from the surface of the target tissue to the deep layer."

Step S30: generating multiple frames of images based on multiple A-scan data sets.

It should be noted that one A-scan data set in the embodiment of the present application corresponds to one frame of image.

In a specific embodiment, the sampling operation in the above step S10 includes the following steps S101 to S103, specifically:

Step S101: obtain a set of coded signals.

In an exemplary embodiment, the coded signal is a binary coded sequence formed by the reflected light of several multilayer dielectric films passing through the wavelength division multiplexer, preset wavelength photodetector, low-pass filter and comparator of the common-path OCT device; each pulse signal of the coded signal corresponds to a unique angular position.

It should be noted that in the embodiments of the present application, the multilayer dielectric film on the outer wall of the catheter generates a reflection signal. The photodetector captures the reflection signal, which, after analog amplification and filtering, is fed into a comparator for signal discrimination, generating a binary signal stream, i.e., a binary code sequence containing, for example, 1/0, which is used to calibrate the rotation angle of the catheter tip. For example, a 1 in the binary code sequence corresponds to an interference light source irradiating the multilayer dielectric film; a 0 in the binary code sequence corresponds to an interference light source irradiating the spaced regions between the multilayer dielectric films. Each pulse signal of the coded signal corresponds to a unique angular position, and the real-time position of the catheter tip can be determined based on the real-time changes in each pulse signal of the coded signal.

In step S102 , a high-speed acquisition ADC module of the common-path OCT device is triggered based on the coded signal to sample the swept-frequency light source reflected by the target tissue to obtain an A-scan data set.

Optionally, the processor of the common-channel OCT device uses a digital phase-locked loop algorithm to multiply the frequency of the encoded signal to the target frequency to obtain a set of equally spaced pulse signals; then, based on the equally spaced pulse signals, the high-speed acquisition ADC module is triggered to sample the swept-frequency light source reflected by the target tissue to obtain an A-scan data set.

It should be noted that a set of coded signals includes a Home signal (zero position signal). As shown in Figure 2, the pulse corresponding to the wider multilayer dielectric film is used as the Home signal. When the processor triggers the high-speed acquisition ADC module to perform sampling based on the equally spaced pulse signals, if the processor detects the Home signal, it indicates that a sampling operation has ended and the next sampling operation can be started or ended. The pulse signal corresponding to the set of equally spaced pulse signals and the Home signal is a long pulse signal.

Multiplying the coded signal can improve OCT imaging resolution. The higher the target frequency of the multiplication, the higher the OCT imaging resolution. For example, the processor in this embodiment multiplies the coded signal from 512 to 2048, using a set of 2048 pulses as the trigger signal for A-scan data acquisition. Setting the Home signal allows for angular alignment over multiple catheter rotations, avoiding cumulative errors.

Further optionally, the processor of the common-path OCT device synchronizes the rising edge of the equally spaced pulse signal with the clock signal; based on the rising edge of the equally spaced pulse signal, the high-speed acquisition ADC module is triggered to sample the swept-frequency light source reflected by the target tissue to obtain an A-scan data set.

It should be noted that the clock signal (k-clock) in this embodiment of the application is a periodic signal generated when the handle emits an interferometric light source. It is used to control the acquisition frequency of the swept-frequency light source reflected by the target tissue by the high-speed acquisition ADC module. Specifically, the clock signal determines the sampling rhythm of the high-speed acquisition ADC module, ensuring that each A-scan data is acquired on time and avoiding phase noise introduced by timing deviations. The encoded information determines the angular position of the high-speed acquisition ADC module's sampling, ensuring that the A-scan data is distributed at equal angular intervals.

By synchronizing the rising edge of the equally spaced pulse signal with the clock signal, each time A-scan data acquisition is triggered, the angle of the A-scan data is marked, so that the collected A-scan data is arranged at equal angles rather than at equal time intervals. This ensures that the geometric position of the image reconstructed based on the A-scan data is consistent with the actual anatomical structure and eliminates artifacts caused by uneven rotation speed of the catheter end. In other words, by triggering the high-speed acquisition ADC module with the coded signal to sample the swept light source reflected by the target tissue, the triggering of the high-speed acquisition ADC module is converted from a clock signal to an angle signal. This solves the imaging defects caused by uneven catheter rotation speed in existing technologies, eliminates image artifacts, and ensures image resolution.

Further optionally, the processor of the common-channel OCT device uses the rising edge of the equally spaced pulse signal to trigger the high-speed acquisition ADC module to sample once; when a long pulse signal of the equally spaced pulse signal is detected, a sampling operation is completed.

It should be noted that each sampling operation generates a set of digital signals containing amplitude and phase information; each set of digital signals represents one A-scan data set. For example, if an equally spaced pulse signal contains 2048 rising edges, each sampling operation generates 1024 digital signals. These 1024 digital signals correspond to one A-scan data set, and 2048 A-scan data sets constitute one A-scan data set. One A-scan data set corresponds to one image frame. That is, during the A-scan data acquisition process, each time the clock signal (k-clock) arrives, the high-speed ADC module triggers data acquisition. Each sampling operation generates a digital signal containing amplitude and phase information, and one A-scan data set consists of 1024 of these digital signals. The clock signal frequency is typically determined by the scanning frequency and clock period of the common-channel OCT device. After each clock signal trigger, the high-speed ADC module acquires the corresponding optical signal data, which is used to generate the A-scan data set. Based on design and acquisition requirements, in this embodiment of the present application, A-scan data typically includes 2048 sampling points (e.g., 2048 pulses), with each pulse corresponding to one acquisition of A-scan data. Each acquired A-scan data point is generated incrementally by the high-speed ADC module using a continuously triggered clock signal until 2048 sampling points are completed.

Step S103, when the handle does not stop emitting the interference light source, the control enters the next sampling operation;

Step S104: When the handle stops emitting the interference light source, the next sampling operation is not performed.

By using a cyclic sampling operation, multiple A-scan data sets can be used to reconstruct multiple frames of images. The number of sampling cycles depends on how many A-scan data sets need to be collected.

In a specific embodiment, after step S20, the method further includes: arranging the multiple A-scan data sets in ascending order of angles to form multiple A-scan data sets in a polar coordinate system.

Optionally, the above step S30 includes the following steps S301 to S303, specifically:

Step S301: performing windowing processing and inverse Fourier transform on each A-scan dataset in the polar coordinate system, and performing coordinate transformation on the A-scan dataset after windowing processing and inverse Fourier transform to obtain an A-scan dataset in the Cartesian coordinate system;

Step S302: removing background noise from the A-scan dataset in the Cartesian coordinate system, and performing logarithmic compression, dynamic range adjustment, and phase mapping on the A-scan dataset in the Cartesian coordinate system after removing the background noise, to obtain a grayscale image in the Cartesian coordinate system;

Step S303 : performing image compression and visualization adjustment on the grayscale image in the Cartesian coordinate system based on the JPEG standard algorithm to obtain multiple frames of images.

As can be understood from the above embodiments, for example, each time the processor triggers the high-speed acquisition ADC module based on an equally spaced pulse signal, the module samples the swept-frequency light reflected by the target tissue at 2048 points, generating a set of digital signals containing amplitude and phase information, i.e., an A-scan data set. Each A-scan data point is associated with an angle label (e.g., 0 degrees, 0.176 degrees, 0.352 degrees, etc.) for subsequent polar-to-Cartesian conversion ( x = rcosθ, y = rsinθ ) during image reconstruction.

It should be noted that, in the embodiment of the present application, each A-scan data is arranged in ascending order of angle to form an A-scan data set in polar coordinates, namely:

;

Among them, an A-scan dataset corresponds to an angle range of 0 degrees to 359.824 degrees.

Furthermore, in an embodiment of the present application, a programmable complex window function is applied to the acquired coded signal for windowing and group delay dispersion compensation. The window function can be a Hamming window, Hanning window, Blackman window, Kaiser window, etc. The window function length is the actual number of sampling points, and is then expanded to 2048 points by zero padding, achieving integrated windowing and zero padding processing. When the windowed coded signal is subjected to an inverse fast Fourier transform (IFFT), the coded signal is converted from a frequency domain signal to a time domain signal, retaining only the first 1024 positive frequency components. The JPEG standard algorithm is applied for image compression, including discrete cosine transform (DCT), quantization, and entropy coding. The processed 8-bit image data is transmitted to the display interface of the common-channel OCT device, where the user can perform brightness, contrast, gamma correction, or pseudo-color mapping as needed.

In implementing the above-mentioned steps S10 to S30, on the one hand, a plurality of multilayer dielectric films are arranged at equal intervals along the circumference of the catheter on the outer side wall of the distal end of the catheter. When the distal end of the catheter rotates, a binary code sequence generated based on the reflected light of the plurality of multilayer dielectric films, that is, each pulse signal of the code signal corresponds to a unique angular position. Moreover, because the plurality of multilayer dielectric films are arranged at equal intervals, the pulse signals of the code signal are distributed at equal angular intervals, and thus the A-scan data set sampled based on the code signal is distributed at equal angular intervals on the circumference. When an image is generated using the A-scan data set distributed at equal angular intervals, image distortion such as stretching or compression will not occur, and image artifacts can be effectively eliminated to ensure image resolution. On the other hand, the high-speed acquisition ADC module is triggered by the code signal to sample the swept-frequency light source reflected by the target tissue, thereby converting the trigger of the high-speed acquisition ADC module from a clock signal to an angle signal, thereby resolving the imaging defects caused by uneven catheter rotation speed in the prior art, further eliminating image artifacts, and ensuring image resolution.

Based on the same inventive concept, embodiments of the present application also provide a common-path OCT device for implementing the aforementioned OCT imaging artifact elimination method. The implementation solution provided by this common-path OCT device is similar to the implementation solution described in the aforementioned method. Therefore, the specific limitations in one or more common-path OCT device embodiments provided below can be found in the above-mentioned limitations of the OCT imaging artifact elimination method and will not be repeated here.

In an exemplary embodiment, as shown in Figure 4, a common-path OCT device is provided. This common-path OCT device utilizes a shared optical path design, meaning that the light source and detection light path share the same optical path. This design offers greater stability and anti-interference capabilities than traditional non-common-path OCT (e.g., a Michelson interferometer structure), particularly in the presence of environmental vibration or temperature fluctuations.

The common-path OCT device includes: a handle, a catheter, a circulator, a wavelength division multiplexer, a swept-frequency light source balanced detector, a high-speed acquisition ADC module, a preset wavelength photodetector, a low-pass filter, a comparator, and a processor. The handle receives an interference light source from the circulator and transmits the interference light source to the target tissue through the catheter. The interference light source includes a swept-frequency light source and a preset wavelength infrared light source. The catheter end is provided with a plurality of multilayer dielectric films arranged at equal intervals along the catheter circumference. The plurality of multilayer dielectric films are used to reflect the preset wavelength infrared light source to form reflected light. The wavelength division multiplexer receives the return light from the circulator and decomposes the return light source into the swept-frequency light source reflected by the target tissue and the reflected light of the plurality of multilayer dielectric films, and transmits the swept-frequency light source reflected by the target tissue to the swept-frequency light source balanced detector and transmits the reflected light of the plurality of multilayer dielectric films to the preset wavelength photodetector. The preset wavelength photodetector captures and transmits the reflected light of the plurality of multilayer dielectric films to the low-pass filter. The low-pass filter performs low-pass filtering on the reflected light of the plurality of multilayer dielectric films and transmits the reflected light of the plurality of multilayer dielectric films after the low-pass filtering to the comparator. The comparator processes the reflected light of the plurality of multilayer dielectric films to generate a coded signal.

The processor is configured to execute the OCT imaging artifact elimination method of the above embodiment; specifically, the processor is configured to: while the handle emits an interferometric light source through the catheter toward the target tissue, cyclically perform a sampling operation until the handle stops emitting the interferometric light source; when the handle stops emitting the interferometric light source, obtain multiple A-scan data sets; and generate multiple image frames based on the multiple A-scan data sets;

The sampling operation includes: obtaining a set of coded signals; the coded signals are binary coded sequences formed after the reflected light of several multilayer dielectric films is processed by a preset wavelength photodetector, a low-pass filter, and a comparator; each pulse signal of the coded signal corresponds to a unique angular position; based on the coded signal, the high-speed acquisition ADC module is triggered to sample the swept light source reflected by the target tissue to obtain an A-scan data set; when the handle has not stopped emitting the interference light source, the control enters the next sampling operation; when the handle stops emitting the interference light source, the next sampling operation is not entered.

As can be understood from Figure 4, when using a common-path OCT device, a wavelength division multiplexer (WDM) combines 650nm red laser light with near-infrared light and transmits it to a circulator. The circulator provides unidirectional transmission of the light source: light from the WDM can only be transmitted to the handle, while light returning from the handle can only be transmitted to the returning light source. The returning light source includes a swept-frequency light source reflected from the human body and red laser light reflected from the multilayer dielectric film. The returning light source is separated from the swept-frequency light source by a WDM. The swept-frequency light source then enters a swept-frequency light source balanced detector for OCT imaging. The red laser light enters a pre-set wavelength photodetector, where it undergoes signal processing through a low-pass filter and comparator to generate a binary code sequence of 0101. The processor then acquires the position signal. Because a single image frame requires 2048 A-scan data points, the processor uses a frequency multiplier (or a digital phase-locked loop algorithm) to frequency-multiply the light reflected from the multilayer dielectric film to generate a coded signal with 2048 resolution. Each rising edge of the frequency-multiplied coded signal triggers the acquisition of an A-scan data point.

Optionally, the above-mentioned processor is also used to use a digital phase-locked loop algorithm to multiply the frequency of the encoded signal to the target frequency to obtain a set of equally spaced pulse signals; based on the equally spaced pulse signals, the high-speed acquisition ADC module is triggered to sample the swept frequency light source reflected by the target tissue to obtain an A-scan data set.

Optionally, the above-mentioned set of coded signals includes a Home signal; and a set of equally spaced pulse signals and a pulse signal corresponding to the Home signal are long pulse signals.

Optionally, the above-mentioned processor is also used to synchronize the rising edge of the equally spaced pulse signal with the clock signal; the clock signal is a periodic signal generated when the handle emits an interference light source, and is used to control the acquisition frequency of the high-speed acquisition ADC module for the swept-frequency light source reflected by the target tissue; based on the rising edge of the equally spaced pulse signal, the high-speed acquisition ADC module is triggered to sample the swept-frequency light source reflected by the target tissue to obtain an A-scan data set.

Optionally, the above-mentioned processor is also used to use the rising edge of the equally spaced pulse signal to trigger the high-speed acquisition ADC module to sample once; when a long pulse signal of the equally spaced pulse signal is detected, a sampling operation is completed; each time a sampling operation is completed, a group of digital signals containing amplitude information and phase information is generated; each group of digital signals represents an A-scan data; a group of A-scan data is an A-scan data set.

Optionally, the processor is further configured to arrange the multiple A-scan data sets in ascending order of angles to form multiple A-scan data sets in a polar coordinate system.

Optionally, the above-mentioned processor is also used to perform windowing processing and inverse Fourier transform on each A-scan data set in the polar coordinate system, and perform coordinate conversion on the A-scan data set after windowing processing and inverse Fourier transform to obtain an A-scan data set in the Cartesian coordinate system; remove background noise from the A-scan data set in the Cartesian coordinate system, and perform logarithmic compression, dynamic range adjustment and phase mapping on the A-scan data set in the Cartesian coordinate system from which the background noise has been removed to obtain a grayscale image in the Cartesian coordinate system; perform image compression and visualization adjustment on the grayscale image in the Cartesian coordinate system based on the JPEG standard algorithm to obtain multiple frame images.

As an optional embodiment, as shown in FIG5 , the catheter includes a connector 10 and a tube body 20 .

As shown in Figures 5 and 6, the connector 10 includes a connecting housing 11, an optical connector 12 disposed at one end of the connecting housing 11 for connecting to a handle, an optical fiber 13 disposed within the connecting housing 11 and connected to the optical connector 12, a sliding button 14 disposed on the connecting housing 11 for driving the optical fiber 13 to move axially along a tubular body 20, and a Luer connector 15 disposed at the other end of the connecting housing 11. The optical fiber 13 extends through the Luer connector 15 to the distal end of the tubular body 20. The tubular body 20 includes a support tube 21 connected to the Luer connector 15, a drive shaft 22 disposed within the support tube 21 and sleeved around the optical fiber 13, and a functional component disposed within the support tube 21 and dynamically connected to the drive shaft 22. The optical fiber 13 extends into the functional component. A rotation assembly 17, including a rotation button, is disposed on the connecting housing 11 near one end of the tubular body 20 for driving the drive shaft 22 to rotate circumferentially along the tubular body.

Furthermore, as shown in Figure 6 , the functional components include a support member 23 connected to the support tube 21, and a sampling member 25 disposed on the support member 23 and dynamically connected to the drive shaft 22. As shown in Figure 7 , a light-transmitting area 24 is defined on the support member 23, and as shown in Figure 8 , an imaging acquisition window 26 corresponding to the light-transmitting area 24 is defined on the sampling member 25. An optical assembly 27 for refracting and/or reflecting a light source is disposed within the sampling member 25 corresponding to the imaging acquisition window 26. The optical fiber 13 extends from the support tube 21 to the optical assembly 27 within the sampling member 25.

As can be understood from the above embodiments, during the acquisition of A-Scan data, the tube body 20 of the catheter is located in the human body, the wavelength division multiplexer combines the 650nm red laser and the near-infrared light to form an interference light source, and sends the interference light source to the circulator. The circulator is used for unidirectional transmission of the light source, that is, it receives the interference light source emitted by the wavelength division multiplexer and transmits the interference light source to the handle. The handle transmits the interference light source to the optical fiber 13 through the optical connector 12 of the catheter; the optical fiber 13 transmits the interference light source, and the interference light source is reflected and/or refracted by the optical component 27 and transmitted through the imaging acquisition window 26 before being irradiated on the target tissue; the optical fiber 13 collects the interference light source reflected by the target tissue and sends the reflected interference light source as a return light source to the circulator. The wavelength division multiplexer receives the return light source from the circulator and decomposes the return light source into a swept frequency light source reflected by the target tissue and a certain The apparatus includes a plurality of multilayer dielectric film sections, a plurality of multilayer dielectric film sections, and a plurality of multilayer dielectric film sections. The plurality of multilayer dielectric film sections are reflected by the plurality of multilayer dielectric film sections, and a swept-frequency light source reflected by the target tissue is sent to a swept-frequency light source balance detector. The plurality of multilayer dielectric film sections are reflected by the plurality of multilayer dielectric film sections to a preset wavelength photodetector. The preset wavelength photodetector captures and sends the plurality of multilayer dielectric film sections reflected by the plurality of multilayer dielectric film sections to a low-pass filter. The low-pass filter performs low-pass filtering on the plurality of multilayer dielectric film sections reflected by the plurality of multilayer dielectric film sections, and sends the plurality of multilayer dielectric film sections reflected by the plurality of multilayer dielectric film sections to a comparator. The comparator processes the plurality of multilayer dielectric film sections reflected by the plurality of multilayer dielectric film sections to generate a coded signal. The processor obtains a set of coded signals and triggers a high-speed acquisition ADC module based on the coded signals to sample the swept-frequency light source reflected by the target tissue, thereby obtaining an A-scan data set. When the handle does not stop emitting the interference light source, the control enters the next sampling operation. When the handle stops emitting the interference light source, the control does not enter the next sampling operation. When the handle stops emitting the interference light source, multiple A-scan data sets are obtained. Multiple frames of images are generated based on the multiple A-scan data sets.

Furthermore, as shown in FIG6 and FIG7 , a cutting head 28 for rotary cutting of human body plaques or opening of occluded diseased tissues under the action of the driving shaft 22 is provided on the end of the sampling member 25 away from the support tube 21 .

Furthermore, as shown in FIG5 and FIG6, the connector 10 is also connected to a flushing device 16, and the cutting head 28 is in fluid communication with the flushing device 16 via the Luer connector 15 for flushing and clearing blood from the imaging area.

Furthermore, as shown in FIG9 , a plurality of multilayer dielectric films are provided on the outer side wall of the support tube 21 close to one end of the functional component.

It should be noted that the tube body 20, support tube 21, and sampling member 25 in the present embodiment are all transparent and flexible structures. The outer layer of the catheter body 20 is a segmented polyetheramide layer, the middle layer is a low-density polyethylene layer, and the inner layer is a high-density polyethylene layer to prevent damage to the inner wall of the blood vessel.

In this embodiment, on the one hand, a plurality of multilayer dielectric films are arranged at equal intervals along the circumference of the catheter on the outer side wall of the distal end of the catheter. When the distal end of the catheter rotates, a binary code sequence generated based on the reflected light of the plurality of multilayer dielectric films, that is, each pulse signal of the coding signal corresponds to a unique angular position. Since the plurality of multilayer dielectric films are arranged at equal intervals, the pulse signals of the coding signal are distributed at equal angular intervals, and thus the A-scan data set sampled based on the coding signal is distributed at equal angular intervals on the circumference. When an image is generated using the A-scan data set distributed at equal angular intervals, image distortion phenomena such as stretching or compression will not occur, and image artifacts can be effectively eliminated to ensure image resolution. On the other hand, the high-speed acquisition ADC module is triggered by the coding signal to sample the swept-frequency light source reflected by the target tissue, thereby converting the trigger of the high-speed acquisition ADC module from a clock signal to an angle signal, thereby resolving the imaging defects caused by uneven catheter rotation speed in the prior art, further eliminating image artifacts and ensuring image resolution.

It should be noted that those skilled in the art will understand that the structure shown in FIG4 is merely a block diagram of a portion of the structure related to the solution of the present application, and does not constitute a limitation on the common-path OCT device involved in the solution of the present application. The specific common-path OCT device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

In an exemplary embodiment, a computer device is further provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

In an exemplary embodiment, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may include, but are not limited to, general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic units, data processing logic units based on quantum computing, and the like.

The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims (12)

1. An OCT imaging artifact eliminating method is characterized in that, the OCT imaging artifact eliminating method comprises the following steps:

in the process that a handle of the common-path OCT equipment emits an interference light source to a target tissue through a catheter, sampling operation is circularly performed until the handle stops emitting the interference light source, wherein the interference light source comprises a sweep frequency light source and a preset wavelength infrared light source, and a plurality of multi-layer dielectric films are arranged at the tail end of the catheter at equal intervals along the circumferential direction of the catheter and are used for reflecting the preset wavelength infrared light source to form reflected light;

when the handle stops emitting the interference light source, a plurality of A-scan data sets are obtained;

Generating a multi-frame image based on a plurality of A-scan data sets, wherein the sampling operation comprises:

The method comprises the steps of obtaining a group of coded signals, wherein the coded signals are binary coded sequences formed by a plurality of reflected light of the multilayer dielectric films after passing through a wavelength division multiplexing device, a preset wavelength photoelectric detector, a low-pass filter and a comparator of the common-path OCT equipment, and each pulse signal of the coded signals corresponds to a unique angle position;

Triggering a high-speed acquisition ADC module of the common-path OCT equipment to sample a sweep-frequency light source reflected by a target tissue based on the coding signal to obtain an A-scan data set;

When the handle does not stop emitting the interference light source, controlling to enter the next sampling operation;

When the handle stops emitting the interference light source, the next sampling operation is not performed.

2. The OCT imaging artifact removal method of claim 1, wherein the triggering the high-speed acquisition ADC module of the common-path OCT device based on the encoded signal samples a swept source reflected by a target tissue to obtain an a-scan dataset, comprising:

multiplying the frequency of the coded signal to a target frequency by using a digital phase lock loop algorithm to obtain a group of equidistant pulse signals;

and triggering the high-speed acquisition ADC module to sample the sweep frequency light source reflected by the target tissue based on the equidistant pulse signals to obtain an A-scan data set.

3. The OCT imaging artifact removal method of claim 2, wherein the set of encoded signals comprises a Home signal and the set of equally spaced pulse signals corresponds to the Home signal as long pulse signals.

4. The OCT imaging artifact removal method of claim 3, wherein the triggering the high-speed acquisition ADC module to sample the swept source reflected by the target tissue based on the equally spaced pulse signal results in an a-scan dataset comprising:

The clock signal is a periodic signal generated when the handle emits an interference light source and is used for controlling the acquisition frequency of the sweep frequency light source reflected by the high-speed acquisition ADC module to the target tissue;

And triggering the high-speed acquisition ADC module to sample the sweep frequency light source reflected by the target tissue based on the rising edge of the equidistant pulse signal, so as to obtain an A-scan data set.

5. The OCT imaging artifact removal method of claim 4, wherein the triggering the high-speed acquisition ADC module to sample the swept source reflected by the target tissue based on the rising edge of the equally spaced pulse signal results in an a-scan dataset comprising:

triggering the high-speed acquisition ADC module to sample once by adopting the rising edge of the equidistant pulse signal;

and when the long pulse signal of the equidistant pulse signal is detected, the sampling operation is finished once, a group of digital signals containing amplitude information and phase information are generated each time the sampling operation is finished, each group of digital signals represents one A-scan data, and one group of A-scan data is one A-scan data set.

6. The OCT imaging artifact removal method of claim 1, wherein after obtaining a plurality of a-scan datasets when the handle stops emitting interference light sources, the method further comprises:

And arranging the A-scan data sets according to the increasing order of angles to form a plurality of A-scan data sets in a polar coordinate system.

7. The OCT imaging artifact removal method of claim 6, wherein the generating a multi-frame image based on a plurality of a-scan data sets comprises:

windowing and performing inverse Fourier transform on each A-scan data set in the polar coordinate system, and performing coordinate transformation on the A-scan data sets subjected to the windowing and the inverse Fourier transform to obtain an A-scan data set in the Cartesian coordinate system;

Removing background noise of the A-scan data set under the Cartesian coordinate system, and carrying out logarithmic compression, dynamic range adjustment and phase mapping on the A-scan data set under the Cartesian coordinate system with the background noise removed to obtain a gray level image under the Cartesian coordinate system;

And carrying out image compression and visual adjustment on the gray level image under the Cartesian coordinate system based on a JPEG standard algorithm to obtain a multi-frame image.

8. The common-path OCT equipment is characterized by comprising a handle, a catheter, a circulator, a wavelength division multiplexer, a sweep-frequency light source balance detector, a high-speed acquisition ADC module, a preset wavelength photoelectric detector, a low-pass filter, a comparator and a processor;

The handle receives an interference light source from the circulator and emits the interference light source to a target tissue through a catheter, wherein the interference light source comprises a sweep frequency light source and a preset wavelength infrared light source, a plurality of multilayer dielectric films are arranged at the tail end of the catheter at equal intervals along the circumference of the catheter, and the plurality of multilayer dielectric films are used for reflecting the preset wavelength infrared light source to form reflected light;

The wave-splitting multiplexer receives a return light source from the circulator and splits the return light source into a sweep light source reflected by a target tissue and a plurality of pieces of reflected light of the multilayer dielectric film, and sends the sweep light source reflected by the target tissue to the sweep light source balance detector and sends the reflected light of the plurality of pieces of multilayer dielectric film to the preset wavelength photoelectric detector;

The processor is configured to perform the OCT imaging artifact removal method of any one of the above claims 1-7, in particular the processor is configured to:

in the process that the handle emits the interference light source to the target tissue through the catheter, the sampling operation is circularly executed until the handle stops emitting the interference light source;

when the handle stops emitting the interference light source, a plurality of A-scan data sets are obtained;

Generating a multi-frame image based on a plurality of A-scan data sets, wherein the sampling operation comprises:

the method comprises the steps of obtaining a group of coded signals, wherein the coded signals are binary coded sequences formed by processing reflected light of a plurality of multi-layer dielectric films through a photoelectric detector with preset wavelength, a low-pass filter and a comparator, and each pulse signal of the coded signals corresponds to a unique angle position;

triggering the high-speed acquisition ADC module to sample a sweep-frequency light source reflected by a target tissue based on the coding signal to obtain an A-scan data set;

When the handle does not stop emitting the interference light source, controlling to enter the next sampling operation;

When the handle stops emitting the interference light source, the next sampling operation is not performed.

9. A common path OCT apparatus according to claim 8, wherein the catheter includes a connector and a tube body;

The connector comprises a connecting shell, an optical connector arranged at one end of the connecting shell and used for connecting a handle, an optical fiber arranged in the connecting shell and connected with the optical connector, a sliding button arranged on the connecting shell and used for driving the optical fiber to axially move along a tube body, and a luer connector arranged at the other end of the connecting shell, wherein the optical fiber penetrates through the luer connector and extends to the tail end of the tube body;

The tube body comprises a supporting tube connected with the luer connector, a driving shaft arranged in the supporting tube and sleeved on the optical fiber, and a functional component arranged in the supporting tube and in power connection with the driving shaft, wherein the optical fiber extends into the functional component, a rotating component used for driving the driving shaft to rotate along the circumferential direction of the tube body is arranged at one end, close to the tube body, of the connecting shell, the rotating component comprises a rotating button, and a plurality of multi-layer dielectric films are arranged on the outer side wall, close to one end of the functional component, of the supporting tube.

10. The common-path OCT apparatus according to claim 9, wherein the functional component includes a support member connected to the support tube, a sampling member disposed on the support member and dynamically connected to the drive shaft, a light-transmitting region is provided on the support member, an imaging collection window corresponding to the light-transmitting region is provided on the sampling member, an optical component for refracting and/or reflecting a light source is disposed in the sampling member corresponding to the imaging collection window, and the optical fiber extends from within the support tube to an optical component in the sampling member.

11. A common path OCT apparatus according to claim 10, wherein a cutting head for rotating a plaque of a human body under the action of the driving shaft is provided on an end of the sampling member remote from the supporting tube.

12. A common path OCT apparatus according to claim 11, wherein the connector is further connected with a flushing device, the cutting head being in fluid communication with the flushing device through the luer connector for opening the occluded diseased tissue.