OCT (Optical Coherence Tomography) imaging artifact elimination method and common-path OCT equipment

Abstract

The invention discloses an OCT imaging artifact eliminating method and common-path OCT equipment, and relates to the technical field of optical imaging, the method comprises the following steps: in the process that a handle of the common-path OCT equipment transmits an interference light source to target tissue through a catheter, circularly executing sampling operation until the handle stops transmitting the interference light source; a plurality of multilayer dielectric films are arranged at the tail end of the catheter at equal intervals in the circumferential direction of the catheter; when the handle stops emitting the interference light source, a plurality of A-scan data sets are obtained; generating a plurality of frames of images based on the plurality of A-scan data sets; wherein the sampling operation comprises the following steps: acquiring a group of coded signals; triggering a high-speed acquisition ADC (Analog to Digital Converter) module of common-path OCT (Optical Coherence Tomography) equipment on the basis of the coded signal to sample a sweep-frequency light source reflected by a target tissue 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 carried out, the image artifacts can be effectively eliminated, and the resolution of the image is ensured.

Description

Technical Field

[0001] This application relates to the field of optical imaging technology, and particularly to an OCT imaging artifact elimination method and a common-path OCT device. Background Art

[0002] OCT (Optical Coherence Tomography) is a medical imaging technology based on the principle of light interference. OCT obtains tomographic capabilities in the depth direction based on the principle of low-coherence interference. By scanning, two-dimensional or three-dimensional images of the internal structure of biological tissues or materials can be reconstructed, and the signal contrast thereof stems from the spatial variation of the optical reflection (scattering) characteristics inside the biological tissues or materials.

[0003] In the prior art during the sampling process of OCT imaging, it is assumed that the rotation speed of the catheter end of the OCT device is uniform to achieve the acquisition of A-scan data. However, during the actual sampling process, the catheter will undergo torsional deformation due to factors such as friction, resulting in non-uniform rotation speed of the catheter end, leading to non-uniform angular distribution of the acquired A-scan data, and further causing distortion of the reconstructed two-dimensional tomographic image (B-scan) and prone to artifacts. Therefore, there is an urgent need to provide an OCT imaging method capable of eliminating image artifacts. Summary of the Invention

[0004] In view of the above 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 the resolution of the image.

[0005] To achieve the above purpose, this application provides the following solutions: In the first aspect, this application provides an OCT imaging artifact elimination method, including: during the process of the handle of the common-path OCT device emitting an interference light source to the target tissue through the catheter, repeatedly performing a sampling operation until the handle stops emitting the interference light source; the interference light source includes a swept-source and a preset wavelength infrared light source; a plurality of multi-layer dielectric films are arranged at equal intervals along the circumferential direction of the catheter end; the plurality of multi-layer dielectric films are used to reflect 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 multiple frames of images based on the plurality of A-scan data sets; wherein, the sampling operation includes: Obtaining a set of encoded signals; the encoded signals are binary encoded sequences formed by the reflected light of the plurality of multi-layer dielectric films passing through the wavelength division multiplexer, the preset wavelength photodetector, the low-pass filter, and the comparator of the common-path OCT device; each pulse signal of the encoded signals corresponds to a unique angular position; Trigger the high-speed acquisition ADC module of the common-path OCT device to sample the swept-frequency light source reflected by the target tissue based on the encoded signal, and obtain an A-scan data set; When the handle does not stop emitting the interference light source, control to enter the next sampling operation; When the handle stops emitting the interference light source, do not enter the next sampling operation.

[0006] Optionally, the triggering the high-speed acquisition ADC module of the common-path OCT device to sample the swept-frequency light source reflected by the target tissue based on the encoded signal, and obtaining an A-scan data set includes: multiplying the frequency of the encoded signal to the target frequency by using a digital phase-locked loop algorithm to obtain a set of equally spaced pulse signals; triggering the high-speed acquisition ADC module to sample the swept-frequency light source reflected by the target tissue based on the equally spaced pulse signals, and obtaining an A-scan data set.

[0007] Optionally, a set of the encoded signals includes a Home signal; the pulse signal corresponding to the Home signal in a set of the equally spaced pulse signals is a long pulse signal.

[0008] Optionally, the triggering the high-speed acquisition ADC module to sample the swept-frequency light source reflected by the target tissue based on the equally spaced pulse signals, and obtaining an A-scan data set includes: synchronizing the rising edge of the equally spaced pulse signals with a clock signal; the clock signal is a periodic signal generated when the handle emits the 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; triggering the high-speed acquisition ADC module to sample the swept-frequency light source reflected by the target tissue based on the rising edge of the equally spaced pulse signals, and obtaining an A-scan data set.

[0009] Optionally, the triggering the high-speed acquisition ADC module to sample the swept-frequency light source reflected by the target tissue based on the rising edge of the equally spaced pulse signals, and obtaining an A-scan data set includes: triggering the high-speed acquisition ADC module to sample once by using the rising edge of the equally spaced pulse signals; when detecting the long pulse signal of the equally spaced pulse signals, completing one sampling operation; generating a set of digital signals including amplitude information and phase information for each completed sampling operation; each set of the digital signals represents an A-scan data; a set of A-scan data is an A-scan data set.

[0010] Optionally, after the handle stops emitting the interference light source and multiple A-scan data sets are obtained, the method further includes: arranging the multiple A-scan data sets in ascending order of angle to form multiple A-scan data sets in the polar coordinate system.

[0011] 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 transformation 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 after removing background noise to obtain a grayscale image in the Cartesian coordinate system; 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.

[0012] In a second aspect, the present application provides a common-path OCT device, which includes a handle, a catheter, a circulator, a wavelength division multiplexer, a swept-source balanced detector, a high-speed acquisition ADC module, a preset wavelength photodetector, a low-pass filter, a comparator, and a processor; Among them, the handle receives the interference light source from the circulator and emits the interference light source to the target tissue through the catheter; the interference light source includes a swept-source and a preset wavelength infrared light source; a plurality of multi-layer dielectric films are arranged at equal intervals along the circumferential direction of the catheter end; the plurality of multi-layer dielectric films are used to reflect the preset wavelength infrared light source to form reflected light; The wavelength division multiplexer receives the returned light source from the circulator, decomposes the returned light source into the swept-source reflected by the target tissue and the reflected light of the plurality of multi-layer dielectric films, and sends the swept-source reflected by the target tissue to the swept-source balanced detector, and sends the reflected light of the plurality of multi-layer dielectric films to the preset wavelength photodetector; the swept-source balanced detector captures and sends the swept-source reflected by the target tissue to the high-speed acquisition ADC module; The processor is used to execute the OCT imaging artifact elimination method described in any one of the above; specifically, the processor is used to: During the process that the handle emits the interference light source to the target tissue through the catheter, the sampling operation is cyclically executed until the handle stops emitting the interference light source; When the handle stops emitting the interference light source, multiple A-scan data sets are obtained; Generating multiple frames of images based on multiple A-scan data sets; wherein, the sampling operation includes: Obtain a set of encoded signals; the encoded signals are binary encoded sequences formed after the reflected light of several of the multi-layer dielectric films is processed by the preset wavelength photodetector, low-pass filter, and comparator; each pulse signal of the encoded signals corresponds to a unique angular position; Based on the encoded signals, trigger the high-speed acquisition ADC module to sample the swept light source reflected by the target tissue, and obtain an A-scan data set; When the handle has not stopped emitting the interference light source, control to enter the next sampling operation; When the handle stops emitting the interference light source, do not enter the next sampling operation.

[0013] Optionally, the catheter includes a connector and a tube body; The connector includes a connection housing, an optical connector disposed at one end of the connection housing for connecting to the handle, an optical fiber disposed in the connection housing and connected to the optical connector, a sliding button disposed on the connection housing for driving the optical fiber to move axially along the tube body, and a Luer connector disposed at the other end of the connection 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 disposed in the support tube and sleeved on the optical fiber, and a functional component disposed in the support tube and power-connected to the drive shaft, and the optical fiber extends into the functional component; a rotation assembly for driving the drive shaft to rotate circumferentially along the tube body is disposed on the connection housing near one end of the tube body; the rotation assembly includes a rotation button; several of the multi-layer dielectric films are disposed on the outer side wall of the support tube near one end of the functional component.

[0014] Optionally, the functional component includes a support member connected to the support tube and a sampling member disposed on the support member and power-connected to the drive shaft; a light-transmitting area is formed on the support member, and an imaging acquisition window corresponding to the light-transmitting area is formed on the sampling member; an optical component for refracting and / or reflecting the light source is disposed 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.

[0015] Optionally, a cutting head for cutting human plaques or opening occluded lesion tissues under the action of the drive shaft is disposed at one end of the sampling member away from the support tube.

[0016] Optionally, the connector is further connected with a flushing device, and the cutting head is in fluid communication with the flushing device through the Luer connector for flushing and removing the blood in the imaging area.

[0017] In a third aspect, the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the OCT imaging artifact elimination method described in any one of the above are implemented.

[0018] In a fourth aspect, the present application provides a computer program product, including a computer program. When the computer program is executed by a processor, the steps of the OCT imaging artifact elimination method described in any one of the above are implemented.

[0019] According to the specific embodiments provided by the present application, the following technical effects are disclosed in the present application: 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 circumferential direction of the catheter on the outer side wall of the end of the catheter. When the end of the catheter rotates, a binary coding 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, and 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, so that the A-scan data sets sampled based on the coding signal are distributed at equal angular intervals on the circumference; when generating an image using the A-scan data sets distributed at equal angular intervals, there will be no image distortion phenomena such as stretching or compression, which can effectively eliminate the artifacts of the image and ensure the image resolution; on the other hand, the high-speed acquisition ADC module is triggered by the coding signal to sample the swept light source reflected by the target tissue, realizing the change of the trigger of the high-speed acquisition ADC module from a clock signal to an angular signal, solving the imaging defects caused by uneven catheter rotation speed in the prior art, and further eliminating the artifacts of the image and ensuring the image resolution. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 It is a schematic flowchart of an OCT imaging artifact elimination method provided by an embodiment of the present application; Figure 2 It is a schematic distribution diagram of a plurality of multilayer dielectric films located at the end of the catheter provided by an embodiment of the present application; Figure 3 It is Figure 2 A cross-sectional view along the C-C line; Figure 4 It is a schematic structural diagram of a common-path OCT device provided by an embodiment of the present application; Figure 5 Schematic diagram of the internal structure of a catheter provided by an embodiment of the present application; Figure 6 For Figure 5 Enlarged view of part A in Figure 7 For Figure 6 Schematic diagram of the connection structure of the sampling part in Figure 8 For Figure 6 Schematic diagram of the connection structure of the support part in Figure 9 For Figure 6 Schematic diagram of the structure along the B-B line.

[0022] Description of the drawings: 10. Connector; 11. Connection housing; 12. Optical connector; 13. Optical fiber; 14. Slide button; 15. Luer connector; 16. Flushing device; 17. Rotating assembly; 20. Tube body; 21. Support tube; 22. Drive shaft; 23. Support part; 24. Translucent area; 25. Sampling part; 26. Imaging acquisition window; 27. Optical component; 28. Cutting head. Detailed implementation manners

[0023] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0024] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0025] In an exemplary embodiment, as Figure 1 shown, an OCT imaging artifact elimination method is provided. This method is executed by the processor of a common-path OCT device. In the embodiments of the present application, the OCT imaging artifact elimination method includes the following steps S10 to step S30. Among them: Step S10, during the process of the handle of the common-path OCT device emitting an interference light source to the target tissue through the catheter, the sampling operation is repeatedly executed until the handle stops emitting the interference light source.

[0026] In the exemplary embodiment, the interference light source includes a swept-source and a preset wavelength infrared light source; in the embodiments of the present application, the swept-source can be a near-infrared light of 1310 ± 50 nm; the preset wavelength infrared light source can be a red laser of 650 nm.

[0027] AsFigure 2 and Figure 3 As shown in Figure 3 , a plurality of multi-layer dielectric films are arranged at equal intervals along the circumferential direction of the catheter end; the plurality of multi-layer dielectric films are used to reflect a preset wavelength infrared light source to form reflected light.

[0028] It can be understood that light is arranged inside the catheter for transmitting the optical signal required for OCT imaging, and a plurality of multi-layer dielectric films are coated at equal intervals along the circumferential direction of the outside of the catheter. For example, the multi-layer dielectric film may include a SiO2 film and a Ta2O5 film; as shown in Table 1 below, the structural distribution of each multi-layer dielectric film is as follows: Table 1

[0029] It should be noted that the catheter end in the embodiment of the present application is the end far from the handle, and a plurality of multi-layer dielectric films are coated at equal intervals on the outer side wall of the catheter end. For example, each multi-layer dielectric film shown in Table 1 includes 11 layers of films. By alternately stacking Ta2O5 films with a high refractive index and SiO2 films with a low refractive index in the 11 layers of films and precisely designing the optical thickness of each layer of film, the formed multi-layer dielectric film can not only simultaneously achieve weak reflection of 650 nm red laser and high transmission of near-infrared light from 1260 nm to 1360 nm, but also make the incident light with a wavelength of 650 nm undergo constructive interference between the film layers to prevent artifacts from occurring.

[0030] That is, compared with the prior art, the thickness and number of layers of the multi-layer dielectric film in the embodiment of the present application are non-periodically designed. By setting it like this, the multi-layer dielectric film can make the reflectivity of the near-infrared light from 1260 nm to 1360 nm commonly used in the common-path OCT device, especially the near-infrared light near 1310 nm, less than 10%, and the transmittance greater than or equal to 90%, ensuring that the interference light source and the return light source of the common-path OCT device are not affected. And, through the interference filter design of "precise thickness control + alternating refractive index" for the multi-layer dielectric film, the multi-layer dielectric film can not only generate the required weak reflection in the target visible light band, but also achieve high transmission in the target near-infrared band. For example, it has high reflection (≥80%) for 650 nm red laser and high transmission (≥90%) for 1310 nm near-infrared light.

[0031] And, in the embodiment of the present application, the preset wavelength infrared light source uses a 650 nm red laser to form a broadband transmission region in the near-infrared band, which does not affect the echo of OCT imaging. And by using a 650 nm red laser, during use, doctors can judge whether the optical path is complete and whether the connection between the handle and the catheter is normal by observing the red indicator light.

[0032] Step S20, when the handle stops emitting the interference light source, a plurality of A-scan data sets are obtained.

[0033] It should be noted that the A - scan data set consists of multiple A - scan data. The A - scan data (depth scan line) is one - dimensional depth data along the optical axis direction (longitudinal), which reflects the light reflection intensity distribution of the target tissue at different depths in a single detection direction, and can be understood as "a tomographic signal from the surface to the deep layer of the target tissue".

[0034] Step S30: Generate multiple frames of images based on multiple A - scan data sets.

[0035] It should be noted that one A - scan data set in the embodiment of the present application corresponds to one frame of image.

[0036] 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 encoded signals.

[0037] In the exemplary embodiment, the encoded signal is a binary - coded sequence formed by the reflected light of several multi - layer dielectric films passing through the wavelength - division multiplexer, a preset - wavelength photodetector, a low - pass filter, and a comparator of a common - path OCT device; each pulse signal of the encoded signal corresponds to a unique angular position.

[0038] It should be noted that in the embodiment of the present application, the multi - layer dielectric film on the outer wall of the catheter will form a reflected signal. The photodetector captures the reflected signal, which is sent to the comparator for signal discrimination after analog amplification and filtering, generating a binary signal stream, that is, generating a binary - coded sequence containing, for example, 1 / 0, which is used to calibrate the rotation angle of the catheter end. Among them, for example, 1 in the binary - coded sequence corresponds to the interference light source irradiating on the multi - layer dielectric film; 0 in the binary - coded sequence corresponds to the interference light source irradiating on the interval region between the multi - layer dielectric films. Each pulse signal of the encoded signal corresponds to a unique angular position, and the real - time position of the catheter end can be determined according to the real - time change of each pulse signal of the encoded signal.

[0039] Step S102: Based on the encoded signal, trigger the high - speed acquisition ADC module of the common - path OCT device to sample the swept - source light reflected by the target tissue, and obtain an A - scan data set.

[0040] Optionally, the processor of the common - path OCT device uses the 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, trigger the high - speed acquisition ADC module to sample the swept - source light reflected by the target tissue, and obtain an A - scan data set.

[0041] It should be noted that a set of encoded signals includes a Home signal (zero - position signal); asFigure 2 The pulse corresponding to the wider multi-layer dielectric film is used as the Home signal. When the processor triggers the high-speed acquisition ADC module to sample based on the equally-spaced pulse signal, if the processor detects the Home signal, it indicates the end of one sampling operation, and the next sampling operation can be started or the sampling operation can be ended. Among them, the pulse signal corresponding to a group of equally-spaced pulse signals and the Home signal is a long pulse signal.

[0042] The resolution of OCT imaging can be improved by doubling the encoded signal. The higher the target frequency of frequency doubling, the higher the resolution of OCT imaging. For example, the processor in the embodiment of the present application doubles the encoded signal from 512 to 2048, and uses a group of 2048 pulse signals as the acquisition trigger signal for A-scan data. By setting the Home signal, the angular alignment of the multi-turn rotation of the catheter can be achieved, and cumulative errors can be avoided.

[0043] 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 light source reflected by the target tissue, and an A-scan data set is obtained.

[0044] It should be noted that the clock signal (k-clock) in the embodiment of the present application 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 light source reflected by the target tissue. That is, the clock signal determines the time rhythm of the sampling of the high-speed acquisition ADC module, ensures that each A-scan data is obtained on time, and avoids introducing phase noise due to timing deviation; the encoded information determines the angular position of the sampling of the high-speed acquisition ADC module, ensuring that the A-scan data is distributed at equal angular intervals.

[0045] By synchronizing the rising edge of the equally-spaced pulse signal with the clock signal, it is possible to mark the angle of the A-scan data every time an A-scan data acquisition is triggered, so that the acquired A-scan data is arranged at equal angular intervals instead of equal time intervals, ensuring that the geometric position of the image reconstructed based on the A-scan data is consistent with the real anatomical structure, and eliminating the artifacts caused by uneven rotation speed of the catheter end. In other words, by triggering the high-speed acquisition ADC module to sample the swept light source reflected by the target tissue through the encoded signal, the trigger of the high-speed acquisition ADC module is changed from a clock signal to an angular signal, solving the imaging defect caused by uneven catheter rotation speed in the prior art, being able to eliminate the artifacts in the image, and ensuring the image resolution.

[0046] Further optionally, the processor of the common-path OCT device uses the rising edge of the equally-spaced pulse signal to trigger the high-speed acquisition ADC module to sample once; when the long pulse signal of the equally-spaced pulse signal is detected, one sampling operation is completed.

[0047] It should be noted that each sampling operation generates a set of digital signals containing amplitude information and phase information; each set of digital signals represents an A-scan data. For example, an equally spaced pulse signal contains 2048 rising edges. Completing one sampling operation generates 1024 digital signals, and 1024 digital signals correspond to one A-scan data. 2048 A-scan data form an A-scan data set, and one A-scan data set corresponds to one frame of image. That is, during the A-scan data acquisition process, every time the clock signal (k-clock) arrives, it triggers the high-speed ADC module to perform a data acquisition. The high-speed ADC module generates a digital signal containing amplitude information and phase information each time it samples. One A-scan data is composed of 1024 such digital signals. The frequency of the clock signal is usually determined by the scanning frequency and the clock period of the common-path OCT device. After each clock signal trigger, the high-speed ADC module will collect the corresponding optical signal data, and these data are used to generate A-scan data. According to the design and acquisition requirements, in the embodiments of the present application, A-scan data usually contains 2048 sampling points (for example, for 2048 pulses), and each pulse corresponds to one acquisition of A-scan data. Each acquired A-scan data is gradually generated by the high-speed ADC module through continuously triggered clock signals until 2048 sampling points are completed.

[0048] Step S103, when the handle does not stop emitting the interference light source, control to enter the next sampling operation; Step S104, when the handle stops emitting the interference light source, do not enter the next sampling operation.

[0049] By performing cyclic sampling operations, multiple sets of A-scan data sets can be acquired, and then multiple frames of images can be reconstructed. Among them, the number of cycles of the sampling operation depends on how many sets of A-scan data sets need to be acquired.

[0050] In a specific embodiment, after the above step S20, the method further includes: arranging multiple A-scan data sets in ascending order of angle to form multiple A-scan data sets in the polar coordinate system.

[0051] Optionally, the above step S30 includes the following steps S301 to S303. Specifically: Step S301, perform windowing processing and inverse Fourier transform on each A-scan data set in the polar coordinate system, and perform coordinate transformation 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; Step S302: Remove the background noise of 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 after removing the background noise to obtain a grayscale image in the Cartesian coordinate system; Step S303: Perform 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.

[0052] As can be understood in combination with the above embodiments, for example, after the processor triggers the high-speed acquisition ADC module each time based on an equally spaced pulse signal, the high-speed acquisition ADC module samples the swept light source reflected by the target tissue 2048 times to generate a set of digital signals containing amplitude and phase information, that is, an A-scan data. The angle tags corresponding to each A-scan data (such as 0 degrees, 0.176 degrees, 0.352 degrees, etc.) are used for polar coordinate-Cartesian coordinate conversion during subsequent image reconstruction ( x = rcosθ, y = rsin θ ).

[0053] It should be noted that in the embodiments of the present application, each A-scan data is arranged in ascending order of angle to form an A-scan data set in the polar coordinate system, that is: ; Among them, an A-scan data set corresponds to an angle range of 0 degrees to 359.824 degrees.

[0054] In addition, in the embodiments of the present application, a programmable complex window function is applied to the acquired encoded signal for windowing processing and compensation of group delay dispersion. The window function can be a Hamming window, a Hanning window, a Blackman window, a Kaiser window, etc. The length of the window function is the actual number of sampling points, and then it is extended to 2048 points by zero padding to realize the integration of windowing and zero padding. When performing the inverse fast Fourier transform (IFFT) on the windowed encoded signal, the encoded signal is converted from a frequency-domain signal to a time-domain signal, and only the first 1024 positive frequency components are retained. Applying the JPEG standard algorithm for image compression includes discrete cosine transform (DCT), quantization, and entropy coding. The processed 8-bit image data is transmitted to the display interface of the common-path OCT device, and the user can perform brightness, contrast, gamma correction, or pseudo-color mapping as needed.

[0055] Implementing the above steps S10 to S30, on the one hand, several multi-layer dielectric films are arranged on the outer side wall of the end of the catheter at equal intervals along the circumferential direction of the catheter. When the end of the catheter rotates, for the binary coding sequence generated based on the reflected light of the several multi-layer dielectric films, that is, each pulse signal of the coding signal corresponds to a unique angular position. And because the several multi-layer dielectric films are arranged at equal intervals, the pulse signals of the coding signal are distributed at equal angular intervals. Furthermore, the A-scan data sets sampled based on the coding signal are distributed at equal angular intervals on the circumference. When generating an image using the A-scan data sets distributed at equal angular intervals, there will be no image distortion phenomena such as stretching or compression, and it can effectively eliminate image artifacts and ensure image resolution. On the other hand, the high-speed acquisition ADC module is triggered by the coding signal to sample the swept light source reflected by the target tissue, realizing the change of the trigger of the high-speed acquisition ADC module from a clock signal to an angular signal, solving the imaging defects caused by uneven catheter rotation speed in the prior art, and further eliminating image artifacts and ensuring image resolution.

[0056] Based on the same inventive concept, the embodiment of the present application also provides a common-path OCT device for implementing the above-mentioned OCT imaging artifact elimination method. The solution provided by this common-path OCT device for solving problems is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the common-path OCT device provided below can refer to the limitations on the OCT imaging artifact elimination method in the above text, and will not be repeated here.

[0057] In an exemplary embodiment, as Figure 4 shown, a common-path OCT device is provided. This common-path OCT device adopts a shared optical path design, that is, the light source and the detection optical path share the same optical path. This design has higher stability and anti-interference ability compared with traditional non-common-path OCT (such as the Michelson interferometer structure), and performs better especially when there are environmental vibrations or temperature fluctuations.

[0058] The common-path OCT device includes: a handle, a catheter, a circulator, a wavelength division multiplexer, a swept-source optical balance detector, a high-speed acquisition ADC module, a preset-wavelength photodetector, a low-pass filter, a comparator, and a processor; wherein, the handle receives the interference light source from the circulator and emits the interference light source to the target tissue through the catheter; the interference light source includes a swept-source light and a preset-wavelength infrared light source; a plurality of multi-layer dielectric films are arranged at equal intervals along the circumferential direction of the catheter end; the plurality of multi-layer dielectric films are used to reflect the preset-wavelength infrared light source to form reflected light; the wavelength division multiplexer receives the returned light source from the circulator, decomposes the returned light source into the swept-source light reflected by the target tissue and the reflected light of the plurality of multi-layer dielectric films, and sends the swept-source light reflected by the target tissue to the swept-source optical balance detector, and sends the reflected light of the plurality of multi-layer dielectric films to the preset-wavelength photodetector; the preset-wavelength photodetector captures and sends the reflected light of the plurality of multi-layer dielectric films to the low-pass filter; the low-pass filter performs low-pass filtering on the reflected light of the plurality of multi-layer dielectric films and sends the reflected light of the plurality of multi-layer dielectric films after low-pass filtering to the comparator; the comparator processes the reflected light of the plurality of multi-layer dielectric films to generate a coded signal.

[0059] The processor is used to execute the OCT imaging artifact elimination method of the above embodiment; specifically, the processor is used to: during the process of the handle emitting the interference light source to the target tissue through the catheter, repeatedly execute the sampling operation until the handle stops emitting the interference light source; when the handle stops emitting the interference light source, obtain a plurality of A-scan data sets; generate multiple frames of images based on the plurality of A-scan data sets; Wherein, the sampling operation includes: obtaining a set of coded signals; the coded signal is a binary coded sequence formed by the reflected light of the plurality of multi-layer dielectric films after being processed by the preset-wavelength photodetector, the low-pass filter, and the comparator; each pulse signal of the coded signal corresponds to a unique angular position; triggering the high-speed acquisition ADC module to sample the swept-source light reflected by the target tissue based on the coded signal to obtain an A-scan data set; when the handle does not stop emitting the interference light source, control to enter the next sampling operation; when the handle stops emitting the interference light source, do not enter the next sampling operation.

[0060] Combined with Figure 4It is understandable that when using a common-path OCT device, a wavelength division multiplexer is used to combine a 650-nm red laser and near-infrared light and send them to a circulator. The circulator is used for the unidirectional transmission of the light source, that is, the light from the wavelength division multiplexer can only be transmitted to the handle, and the light returned from the handle can only be transmitted back to the light source. The returned light source includes the swept-frequency light source reflected from the human body and the red laser reflected from the multilayer dielectric film. The returned light source separates the red laser and the swept-frequency light source through a wavelength demultiplexer. The swept-frequency light source enters the swept-frequency light source balanced detector for OCT imaging. The red laser enters a preset wavelength photodetector, and signal processing is performed through a low-pass filter and a comparator to form a binary coding sequence of 0101. Then, the processor collects the position signal. Since one frame of image requires 2048 A-Scan data, in the processor, the reflected light of the multilayer dielectric film is frequency-multiplied through a frequency multiplier (or a digital phase-locked loop algorithm) to form a coding signal with a resolution of 2048. Each rising edge of the frequency-multiplied coding signal triggers the acquisition of an A-Scan data.

[0061] Optionally, the above-mentioned processor is further configured to use a digital phase-locked loop algorithm to multiply the frequency of the coding signal to a target frequency to obtain a set of equally spaced pulse signals; based on the equally spaced pulse signals, 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.

[0062] Optionally, the above-mentioned set of coding signals includes a Home signal; the pulse signal corresponding to the Home signal in the set of equally spaced pulse signals is a long pulse signal.

[0063] Optionally, the above-mentioned processor is further configured to synchronize the rising edge of the equally spaced pulse signals 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 signals, 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.

[0064] Optionally, the above-mentioned processor is further configured to use the rising edge of the equally spaced pulse signals to trigger the high-speed acquisition ADC module to sample once; when detecting the long pulse signal of the equally spaced pulse signals, complete a sampling operation; each time a sampling operation is completed, generate a set of digital signals including amplitude information and phase information; each set of digital signals represents an A-scan data; a set of A-scan data is an A-scan data set.

[0065] Optionally, the above-mentioned processor is further configured to arrange multiple A-scan data sets in ascending order of angle to form multiple A-scan data sets in a polar coordinate system.

[0066] Optionally, the above-mentioned processor is further configured to perform windowing processing and inverse Fourier transform on each A-scan data set in the polar coordinate system, and perform coordinate transformation 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 the background noise of 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 after removing the background noise 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 frames of images.

[0067] As an alternative embodiment, as Figure 5 shown, the above catheter includes a connector head 10 and a tube body 20.

[0068] As Figure 5 and Figure 6 shown, the connector head 10 includes a connection housing 11, an optical connector 12 provided at one end of the connection housing 11 for connecting to a handle, an optical fiber 13 provided inside the connection housing 11 and connected to the optical connector 12, a sliding button 14 provided on the connection housing 11 for driving the optical fiber 13 to move axially along the tube body 20, and a Luer connector 15 provided at the other end of the connection housing 11. The optical fiber 13 passes through the Luer connector 15 and extends to the end of the tube body 20; the tube body 20 includes a support tube 21 connected to the Luer connector 15, a drive shaft 22 provided inside the support tube 21 and sleeved on the optical fiber 13, and a functional component provided inside the support tube 21 and power-connected to the drive shaft 22; the optical fiber 13 extends into the functional component. A rotation assembly 17 for driving the drive shaft 22 to rotate circumferentially along the tube body is provided at one end of the connection housing 11 close to the tube body 20, and the rotation assembly includes a rotation button.

[0069] Further, as Figure 6 shown, the functional component includes a support member 23 connected to the support tube 21, and a sampling member 25 provided on the support member 23 and power-connected to the drive shaft 22. As Figure 7 shown, a light-transmitting area 24 is provided on the support member 23. As Figure 8 shown, an imaging acquisition window 26 corresponding to the light-transmitting area 24 is provided on the sampling member 25; an optical component assembly 27 for refracting and / or reflecting a light source is provided in the sampling member 25 corresponding to the imaging acquisition window 26, and the optical fiber 13 extends from inside the support tube 21 to the optical component assembly 27 inside the sampling member 25.

[0070] As can be understood from the above embodiments, during the acquisition of A-Scan data, the catheter body 20 is located inside the human body. The wavelength division multiplexer combines the 650-nm 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 the 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 emits 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. After the interference light source is reflected and / or refracted by the optical component assembly 27 and transmitted through the imaging acquisition window 26, it irradiates 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 demultiplexer receives the return light source from the circulator and decomposes the return light source into the swept-frequency light source reflected by the target tissue, the reflected light of several multi-layer dielectric films, and sends the swept-frequency light source reflected by the target tissue to the swept-frequency light source balanced detector, and sends the reflected light of several multi-layer dielectric films to the preset wavelength photodetector; the preset wavelength photodetector captures and sends the reflected light of several multi-layer dielectric films to the low-pass filter; the low-pass filter performs low-pass filtering on the reflected light of several multi-layer dielectric films and sends the low-pass filtered reflected light of several multi-layer dielectric films to the comparator; the comparator processes the reflected light of several multi-layer dielectric films to generate a coded signal, and the processor obtains a set of coded signals, and based on the coded signals, triggers 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; when the handle does not stop emitting the interference light source, control enters the next sampling operation; when the handle stops emitting the interference light source, it 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.

[0071] Further, as Figure 6 and Figure 7 shown, a cutting head 28 for cutting human plaques or opening occluded diseased tissues under the action of the drive shaft 22 is provided at one end of the sampling member 25 far from the support tube 21.

[0072] Further, as Figure 5 and Figure 6 shown, the connector 10 is further connected with a flushing device 16. The cutting head 28 is in fluid communication with the flushing device 16 through a luer connector 15 for flushing and clearing the blood in the imaging area.

[0073] Further, as Figure 9 shown, several multi-layer dielectric films are provided on the outer wall of the support tube 21 near one end of the functional component.

[0074] It should be noted that the tube body 20, the support tube 21, and the sampling member 25 in the embodiments of the present application are all light-transmitting flexible structures. The outer layer of the tube body 20 of the catheter is a block polyether amide layer, the middle layer is a low-density polyethylene layer, and the inner layer is a high-density polyethylene layer, which can prevent damage to the inner wall of the blood vessel.

[0075] Among them, when implementing this implementation method, on the one hand, several multi-layer dielectric films are arranged at equal intervals along the circumferential direction of the catheter on the outer side wall of the catheter end. When the catheter end rotates, the binary coding sequence generated based on the reflected light of the several multi-layer dielectric films, that is, each pulse signal of the coding signal corresponds to a unique angular position, and because the several multi-layer dielectric films are arranged at equal intervals, the pulse signals of the coding signal are distributed at equal angular intervals, so that the A-scan data sets sampled based on the coding signal are distributed at equal angular intervals on the circumference; when generating an image using the A-scan data sets distributed at equal angular intervals, there will be no image distortion phenomena such as stretching or compression, and it can effectively eliminate image artifacts and ensure image resolution; on the other hand, the high-speed acquisition ADC module is triggered by the coding signal to sample the swept light source reflected by the target tissue, realizing the change of the trigger of the high-speed acquisition ADC module from a clock signal to an angular signal, solving the imaging defects caused by uneven catheter rotation speed in the prior art, and further eliminating image artifacts and ensuring image resolution.

[0076] It should be noted that those skilled in the art can understand that Figure 4 the structure shown in [the figure] is only a block diagram of some structures 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 those shown in the figure, or combine some components, or have different component arrangements.

[0077] In an exemplary embodiment, a computer device is further provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the steps in the above method embodiments are implemented.

[0078] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0079] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0080] 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 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 need to comply with relevant regulations.

[0081] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing 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 embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the various embodiments provided in this application can include at least one of non-volatile and volatile memories. 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), magnetoresistive 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 can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0082] The databases involved in the various embodiments provided in this application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the various embodiments provided in this application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0083] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as these technical feature combinations do not conflict, they should all be considered as within the scope described in this specification.

[0084] In this text, specific examples are used to illustrate the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. An OCT imaging artifact elimination method, characterized in that, The method for eliminating OCT imaging artifacts includes: During the process of the handle of the common-path OCT device emitting an interference light source to the target tissue through a catheter, the sampling operation is cyclically executed until the handle stops emitting the interference light source; the interference light source includes a swept-source and a preset-wavelength infrared light source; a plurality of multi-layer dielectric films are arranged at equal intervals along the circumferential direction of the catheter end; the plurality of multi-layer dielectric films are used to reflect the preset-wavelength infrared light source to form a 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 the plurality of A-scan data sets; wherein, the sampling operation includes: Obtaining a set of encoded signals; the encoded signals are binary encoded sequences formed by the reflected lights of the plurality of multi-layer dielectric films passing through the wavelength division multiplexer, the preset-wavelength photodetector, the low-pass filter, and the comparator of the common-path OCT device; each pulse signal of the encoded signals corresponds to a unique angular position; Triggering the high-speed acquisition ADC module of the common-path OCT device to sample the swept-source reflected by the target tissue based on the encoded signals, and obtaining 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, not entering the next sampling operation.

2. The OCT imaging artifact elimination method according to claim 1, characterized in that The triggering the high-speed acquisition ADC module of the common-path OCT device to sample the swept-source reflected by the target tissue based on the encoded signals and obtaining an A-scan data set includes: Doubling the frequency of the encoded signals to the target frequency by using the digital phase-locked loop algorithm to obtain a set of equally spaced pulse signals; Triggering the high-speed acquisition ADC module to sample the swept-source reflected by the target tissue based on the equally spaced pulse signals, and obtaining an A-scan data set.

3. The OCT imaging artifact elimination method according to claim 2, wherein A set of the encoded signals includes a Home signal; the pulse signal corresponding to the Home signal in the set of equally spaced pulse signals is a long pulse signal.

4. The OCT imaging artifact elimination method according to 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 signals and obtaining an A-scan data set includes: Synchronizing the rising edge of the equally spaced pulse signals with the clock signal; the clock signal is a periodic signal generated when the handle emits the interference light source, and is used to control the acquisition frequency of the swept-source reflected by the target tissue by the high-speed acquisition ADC module; 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 signals, and obtaining an A-scan data set.

5. The OCT imaging artifact elimination method according to 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 signals and obtaining an A-scan data set includes: Triggering the high-speed acquisition ADC module to sample once by using the rising edge of the equally spaced pulse signals; When a long pulse signal of the equally spaced pulse signal is detected, one sampling operation is completed; one set of digital signals including amplitude information and phase information is generated for each completed sampling operation; each set of the digital signals represents an A-scan data; one set of A-scan data is an A-scan data set.

6. The OCT imaging artifact elimination method according to claim 1, wherein After the handle stops emitting the interference light source and multiple A-scan data sets are obtained, the method further includes: Arranging the multiple A-scan data sets in ascending order of angle to form multiple A-scan data sets in the polar coordinate system.

7. The OCT imaging artifact elimination method according to claim 6, wherein Generating multiple frames of images based on the 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 transformation 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 the background noise of 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 after removing the background noise to obtain a grayscale image in the Cartesian coordinate system; 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.

8. A common-path OCT device, characterized in that, The common-path OCT device includes a handle, a catheter, a circulator, a wavelength division multiplexer, a swept-source balanced detector, a high-speed acquisition ADC module, a preset wavelength photodetector, a low-pass filter, a comparator, and a processor; Wherein, the handle receives the interference light source from the circulator and emits the interference light source to the target tissue through the catheter; the interference light source includes a swept-source and a preset wavelength infrared light source; a plurality of multi-layer dielectric films are arranged at equal intervals along the circumferential direction of the catheter end; the plurality of multi-layer dielectric films are used for reflecting the preset wavelength infrared light source to form a reflected light; The wavelength division multiplexer receives the returned light source from the circulator and decomposes the returned light source into the swept-source reflected by the target tissue and the reflected lights of the plurality of multi-layer dielectric films, and sends the swept-source reflected by the target tissue to the swept-source balanced detector, and sends the reflected lights of the plurality of multi-layer dielectric films to the preset wavelength photodetector; the swept-source balanced detector captures and sends the swept-source reflected by the target tissue to the high-speed acquisition ADC module; The processor is configured to execute the OCT imaging artifact elimination method according to any one of claims 1-7 above; specifically, the processor is configured to: During the process that the handle emits the interference light source to the target tissue through the catheter, repeatedly execute the sampling operation until the handle stops emitting the interference light source; When the handle stops emitting the interference light source, multiple A-scan data sets are obtained; Generating multiple frames of images based on the multiple A-scan data sets; wherein, the sampling operation includes: Obtain a set of encoded signals; the encoded signals are binary encoding sequences formed after the reflected light of several of the multi-layer dielectric films is processed by the preset wavelength photodetector, low-pass filter, and comparator; each pulse signal of the encoded signals corresponds to a unique angular position; Based on the encoded signals, trigger the high-speed acquisition ADC module 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, control to enter the next sampling operation; When the handle stops emitting the interference light source, do not enter the next sampling operation.

9. The common-path OCT device according to claim 8, wherein The catheter includes a connector and a tube body; The connector includes a connection housing, an optical connector disposed at one end of the connection housing for connecting to the handle, an optical fiber disposed in the connection housing and connected to the optical connector, a sliding button disposed on the connection housing for driving the optical fiber to move axially along the tube body, and a Luer connector disposed at the other end of the connection housing; the optical fiber extends through the Luer connector to the end of the tube body; The tube body includes a support tube connected to the Luer connector, a drive shaft disposed in the support tube and sleeved on the optical fiber, a functional component disposed in the support tube and power-connected to the drive shaft, and the optical fiber extends into the functional component; a rotation assembly for driving the drive shaft to rotate circumferentially along the tube body is disposed on the connection housing near one end of the tube body; the rotation assembly includes a rotation button; several of the multi-layer dielectric films are disposed on the outer sidewall of the support tube near one end of the functional component.

10. The common-path OCT device according to claim 9, wherein, The functional component includes a support member connected to the support tube, and a sampling member disposed on the support member and power-connected to the drive shaft; a light-transmitting area is formed on the support member, and an imaging acquisition window corresponding to the light-transmitting area is formed on the sampling member; an optical component for refracting and / or reflecting the light source is disposed 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.

11. The common-path OCT device according to claim 10, wherein, A cutting head for cutting human plaques under the action of the drive shaft is disposed at one end of the sampling member away from the support tube.

12. The common-path OCT device according to claim 11, wherein The connector is also connected with a flushing device, and the cutting head is in fluid communication with the flushing device through the Luer connector for opening occluded diseased tissues.

Images