CN108042125B

CN108042125B - High-speed endoscopic optical coherent blood flow imaging system

Info

Publication number: CN108042125B
Application number: CN201710391609.XA
Authority: CN
Inventors: 田洁
Original assignee: Tianjin Hengyu Medical Technology Co ltd
Current assignee: Tianjin Hengyu Medical Technology Co ltd
Priority date: 2017-05-27
Filing date: 2017-05-27
Publication date: 2023-04-21
Anticipated expiration: 2037-05-27
Also published as: CN108042125A

Abstract

The invention discloses a high-speed endoscopic optical coherent blood flow imaging system, which is characterized in that: the system comprises: the system comprises a red light laser, a light source, an interferometer, a reference arm, a sample arm, a balloon stabilizing system, a motion compensation algorithm, an automatic clock switching module, a data acquisition and transmission module and an optical fiber coupler; the OCT system based on endoscopic blood flow detection can observe the morphological characteristics of a focus of in-vivo tissues and diagnose the blood flow distribution condition of the lower layers of the tissues. Lesion information is diagnosed by tissue flow imaging.

Description

High-speed endoscopic optical coherent blood flow imaging system

Technical Field

The invention relates to an imaging system, in particular to a high-speed endoscopic optical coherence blood flow imaging system.

Background

OCT (optical coherence tomography) is a new imaging technique produced in the 90 th century of 20 th. The technique has high resolution, non-invasive imaging features in medical applications. OCT can be classified into time domain OCT and frequency domain OCT, where the frequency domain OCT scan speed is far greater than time domain OCT, and has replaced time domain OCT. The frequency domain OCT is different according to the imaging principle, and can be divided into SS-OCT (sweep OCT) and SD-OCT spectrum OCT. SS-OCT uses swept laser for imaging and SD-OCT uses grating-matched CCD for imaging.

Endoscopic OCT and intravascular OCT have been rapidly developed in recent years, and have obvious imaging effects in detecting tissue imaging and intravascular imaging in vivo. But endoscopic-based OCT systems are currently limited to tissue imaging.

In medicine, techniques for diagnosing certain diseases based on blood flow detection play an increasingly important role. Laser speckle blood flow imaging technology, doppler OCT blood flow detection technology, OCT-based angiography imaging. Among the emerging OCT-based angiography techniques are new vascular imaging techniques. Laser speckle imaging, with relatively low resolution, can only observe relatively large vessels. Doppler blood flow detection is affected by the detection angle, and the effect is very poor when the detection angle of the probe to the skin is nearly vertical. Angiography based on OCT has the advantages of high resolution and no influence of angle on imaging.

The company Perimed in Sweden uses laser Doppler blood flow imaging to study skin wound healing. moor corporation evaluated burn blood flow detection based on laser doppler. Laser speckle imaging and laser Doppler imaging are two-dimensional imaging, only blood flow information of imaging of a shallow layer surface can be seen, and imaging resolution is low. OCT imaging is tomographic imaging, blood flow information of different depths can be checked, and the blood flow depths of different skins can be detected according to requirements. And OCT has higher resolution, and the axial resolution reaches 10 mu m. Therefore, the OCT angiography imaging technology is used for detecting skin blood flow, and the research on skin burn and wound recovery has more ideal observation and analysis effects. However, the above study is based on in vitro blood flow imaging studies, and is also of great importance in the diagnosis of lung injury, digestive tract or esophagus injury, or tumor based on in vivo blood flow imaging studies.

When the optical signal data acquisition is carried out by the existing OCT system based on sweep frequency, the signal access method is as follows: the trigger signal is connected to the trigger end of the DAQ board card, the clock sampling signal is connected to the clock signal end, and the data signal is connected to the data channel A end. But this method of attachment is relatively poor in tamper resistance and stability. In order to solve the problem, the invention provides an automatic switching signal input acquisition method. The method designs an automatic conversion module for free switching processing aiming at two modes of a conventional connection method and a clock sampling signal and a data signal which are respectively connected by utilizing double channels. When the external clock signal is disturbed or unstable by the conventional connection method, the acquisition mode is automatically switched to the internal two-channel acquisition mode.

Endoscopic imaging requires high-speed rotation, which necessarily results in image shake, while blood flow imaging requires a stable imaging sequence. Solving this problem requires overcoming jitter generation, or compensating for motion errors. The invention provides a method for arranging a balloon at the front end of a catheter and combining motion compensation to perform anti-shake treatment.

The invention provides an endoscopic blood flow imaging system, which is designed for signal access and control modes to automatically switch signal connection modes to ensure stable transmission and simultaneously consider calculation speed. For blood flow imaging, an anti-shake balloon treatment system is presented.

Disclosure of Invention

The invention aims to provide a high-speed endoscopic optical coherent blood flow imaging system which comprises a coherent light source, an interference module, a data acquisition module, a sample arm, a reference arm, an optical rotation terminal, a balloon stabilizing system, blood flow imaging processing and a digital imaging system.

1. FIG. 1 is a schematic diagram of an embodiment of the present invention

2. FIG. 2 is another schematic diagram of an embodiment of the present invention

3. FIG. 3 is a schematic diagram of a first embodiment of the invention

4. FIG. 4 is a schematic circuit diagram of a second embodiment of the present invention

5. FIG. 5 is a schematic circuit diagram of a third embodiment of the present invention

6. FIG. 6 is a schematic circuit diagram of a fourth embodiment of the present invention

7. FIG. 7 is a schematic circuit diagram of a fourth embodiment of the present invention

8. FIG. 8 is a schematic circuit diagram of a fourth embodiment of the present invention

9. FIG. 9 is a schematic circuit diagram of a fifth embodiment of the present invention

10. FIG. 10 is a schematic circuit diagram of a fifth embodiment of the present invention

11. FIG. 11 is a schematic circuit diagram of a fifth embodiment of the present invention

12. FIG. 12 is a schematic diagram of a data acquisition 1

13. FIG. 13 is a schematic diagram of data acquisition 2

14. FIG. 14 is a schematic diagram of a data processing 1

15. FIG. 15 is a schematic diagram of the data processing 2

16. FIG. 16 is a schematic diagram of data transmission according to the present invention

17. FIG. 17 is another schematic diagram of the data transmission of the present invention

18. FIG. 18 is a block diagram of a sample arm according to the present invention

19. FIG. 19 is a block diagram of a blood flow imaging algorithm according to the present invention

20. FIG. 20 is a diagram showing the structure of the single balloon stabilization construct of the present invention

21. FIG. 21 is a diagram of a dual balloon stabilization construct of the present invention

22. FIG. 22 is a block diagram of an imaging system according to the present invention

23. FIG. 23 is a diagram of a motion control system according to the present invention

24. FIG. 24 is a block diagram of three-dimensional imaging and roaming in accordance with the present invention

The invention is further described in connection with the following detailed description, in order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the invention easy to understand.

Detailed description of the preferred embodiments

Referring to fig. 1, this section is an embodiment of an ultra-high-speed endoscopic optical coherent blood flow imaging system, which includes an SLD light source 2, collimated red light 1, an optical fiber coupler 3, a reference arm 4, a sample arm 5, a circulator 6, an interferometer 7, and data transmission 11.

The broadband light source generates an optical signal, the optical signal is divided into two paths of signals through the optical splitter, the two paths of signals returned from the sample arm 4 and the reference arm 5 are transmitted to the data acquisition module 8 for acquisition through the interference action of the interferometer 7, the data processing is carried out through the OCT angiography algorithm 9, the B-scan image of the blood flow image characteristic can be obtained, then the blood flow data is generated through the source algorithm, and finally the interaction with an operator is carried out through the imaging system 10. Where the data acquisition module requires a special control card to provide the sampling clock.

Detailed description of the preferred embodiments

Referring to fig. 2, another embodiment of the ultra-high-speed endoscopic optical coherent blood flow imaging system includes a red light 1, a high-speed sweep-frequency light source 12, an optical fiber coupler 3, a reference arm 4, a sample arm 5, an interferometer 7, a data acquisition module 2 (13), an oct angiography algorithm 9, and an imaging system 10.

The specific embodiment is controlled as follows:

the high-speed sweep frequency light source 12 provides an optical signal, a linear frequency clock signal and a trigger signal, the optical signal is divided into two paths of signals by a coupler and respectively enters the reference arm 4 and the sample arm 5, the returned signals enter the interferometer 7 to interfere, the signals enter the data acquisition module 2 (13), the data acquisition module 2 receives the interference signals and the trigger clock signal, the processed signals are applied to the OCT angiography algorithm 9, a blood flow distribution image can be obtained, and finally the interaction with an operator is carried out through an imaging system.

Embodiment one (automatic clock switching Module)

An automatic clock switching module as shown in fig. 3. The module consists of a data acquisition module 15, a signal channel chA 16, a signal channel chB, a K-clk input 18, an A-Trig 19, a clock switching module 20, a detector 21, a sweep frequency light source 22 and a signal source 23.

The K-clock is used as a reference clock for data acquisition, the system can adaptively select an acquisition mode in two modes, and the signal strength determines whether to adopt the mode 1 or the mode 2 by judging the clock performance parameter Jitter and the frequency range. Data acquisition was performed in mode 1 versus mode 2. When data acquisition is unstable in the mode 1, the system can adaptively detect and switch to the mode 2, so that the data acquisition can be ensured to be stable and reliable. The problem of clock jitter is solved.

Second embodiment (in the form of an external clock as the clock signal for OCT signal acquisition)

As shown in fig. 4, the figure is a schematic diagram of a clock signal for acquiring OCT signals in the form of an external clock, and the module is composed of a data acquisition module 15, a signal channel chA 16, a signal channel chB 17, a k-clk input 18, an a-Trig 19, a clock switching module 20, a detector 21, a swept light source 22, and a signal source 23.

In the first embodiment, the clock switching is described, and the clock switching module switches to the mode working state when the external clock is used as the OCT signal acquisition clock. The specific implementation mode of the embodiment is controlled as follows: two paths of Trigger signals are generated by the sweep frequency light source, one path is an A-Trigger signal, the other path is a k-Trigger signal, the A-Ttrigger signal is connected to the Trigger input end of the data acquisition module, and the k-Ttrigger signal enters the external clock input interface. While the detector data signal is coupled into the signal path ChA. And acquiring the accessed signal channel A through an external clock.

Embodiment III (acquisition of K-clock signal in parallel with OCT signal with constant frequency clock)

As shown in fig. 5, the figure is a schematic diagram of a clock signal for acquiring OCT signals in the form of an external clock, and the module is composed of a data acquisition module 15, a signal channel chA 16, a signal channel chB 17, a k-clk input 18, an a-Trig 19, a clock switching module 20, a detector 21, a swept light source 22, and a signal source 23.

In the first embodiment, the clock switching is described, and the clock switching module switches to collect the K-clock signal and the OCT signal in parallel with a constant frequency clock, that is, the mode working state. The specific implementation mode of the embodiment is controlled as follows: two paths of Trigger signals are generated by the sweep frequency light source, one path is an A-Trigger signal, the other path is a k-Trigger signal, the A-Ttrigger signal is connected to the Trigger input end of the data acquisition module, and the k-Ttrigger signal enters the interface B of the signal channel. While the detector data signal is coupled into the signal path ChA. And acquiring the accessed signal channels A and k-trigger through an internal clock.

Embodiment five (switching between mode 1 and mode 2 is accomplished by hardware)

As shown in fig. 6, 7 and 8, the present embodiment is described using hardware to complete the switching between mode 1 and mode 2. The module consists of a data acquisition module 26, a signal channel chA 16, a signal channel chB, a K-clk input 18, an A-Trig 19, a clock switching module 20, a detector 21, a sweep frequency light source 22, a signal source 23, an S_in jitter judgment access 25 and a jitter judgment 24.

And (3) jitter judgment: and the k-trigger signal sent by the sweep frequency light source enters the jitter judging module to judge, and the judging result is fed back, so that the mode is switched.

The specific control mode of the embodiment is as follows: the method comprises the steps that a sweep frequency light source sends out two paths of Trigger signals, one path is a Trigger end of an A-Trigger signal accessed to a data acquisition module, the other path is a k-Trigger signal accessed to a clock switching module, and the clock switching module is divided into three paths of external clock input ends respectively accessed to the data acquisition module, a signal channel ChB end and a jitter judging module. The jitter judging module judges the accessed k-trigger clock, the judging signal is fed back to the data acquisition module, and the data acquisition module selects whether to acquire the k-trigger by adopting an internal clock through ChB or acquire the k-trigger by utilizing an external clock channel according to the feedback signal.

Example six (mode switching done with algorithm)

As shown in fig. 9, 10 and 11, this embodiment describes the algorithm for switching between the mode 1 and the mode 2. The module consists of a data acquisition module 26, a signal channel chA 16, a signal channel chB, a K-clk input 18, an A-Trig 19, a clock switching module 20, a detector 21, a sweep frequency light source 22, a signal source 23 and an S_out output 27.

The specific control mode of the embodiment is as follows: the sweep frequency light source sends out two paths of Trigger signals, one path is the Trigger end of the A-Trigger signal access data acquisition module, the other path is the k-Trigger signal access clock switching module, and the clock switching module is respectively connected with the external clock input end and the signal channel ChB end of the data acquisition module in two paths. The method comprises the steps of collecting k-trigger module signals by using an S_cout channel and an algorithm, evaluating clock performance parameters Jitter, frequency range and signal strength of a current signal clock, judging whether signals are fed back to a data collecting module, and selecting whether the k-trigger is collected by using an internal clock through a ChB or the k-trigger is collected by using an external clock channel by the data collecting module according to feedback signals.

Example seven (data acquisition 1)

Such as the data acquisition module shown in fig. 12. The module is composed of a high-speed sweep frequency light source 2, a linear clock k-trigger30, an A-trigger 31, an interference light signal 32, a photoelectric detector 33, an automatic switching module, an acquisition card 34, a memory 35 and a data processing module 1 (37).

When data signal acquisition is performed, three signal channels, a trigger signal, a clock signal and a data signal are generally required. Typically, the trigger signal is connected to the trigger input of the acquisition board, the clock signal is connected to the clock input of the acquisition board, and the data signal is connected to data channel A or B (if dual channel). Because an external clock is used, the stability of the connection mode is not particularly good, and errors can occur in a strong interference environment. Another connection mode is as follows: the trigger signal is connected with the trigger input end of the acquisition board card, the clock signal is connected with the data channel A of the acquisition board card, and the data signal is connected with the data channel B. The mode uses the internal clock to collect the clock signal of the A channel, which is more stable than the former mode, but after the clock signal of the input channel A is collected, the clock signal collected by the A channel is needed to carry out resampling processing on the B collection, so that the operation amount is increased. The embodiment provides a system for automatically switching two connection modes, and the module can switch in real time according to the environment and hardware. The normal operation defaults to work in the connection mode A, the switching module is provided with an automatic detection circuit to detect the detected trigger signal, and if the trigger signal is abnormal or jumps, the switching module can automatically switch to the connection working mode B.

The linear clocks k-trigger and A-trigger are provided by a high-speed sweep frequency light source. The linear clock k-trigger refers to the fact that when the clock signal corresponds to the collected signal, the collected signals are all integer wave numbers.

Photo detector: the interference optical signals need to be converted into electric signals through a photoelectric conversion module so as to acquire signal data through an acquisition card.

And an automatic switching module: the detector circuit, the signal shunt connection module and the command feedback module are arranged. The detection circuit detects an input trigger signal, the signal is connected in a shunt way, and the trigger signal is divided into two paths of signals, one path of the signals is connected to the trigger input end of the board card, and the other path of the signals is connected to the signal input end. And the command feedback is used for the detection circuit to send a mode switching command to the detection jump signal.

And (3) an acquisition card: the data acquisition card can provide single-channel or multi-channel data acquisition by adopting the high-speed data acquisition card, and adopts the acquisition card supporting the high-speed external clock mode.

Memory: the data acquisition card transmits the acquired data to a memory, wherein the memory refers to an on-board memory or a processor memory. The on-board memory refers to the acceleration processing of the on-board memory.

Data processing module 1: subsequent processing of the memory-incoming data is described in more detail in the embodiments below.

The specific implementation mode is as follows: the high-speed sweep frequency light source 11 outputs linear clock k-trigger and A-trigger signals, the interference optical signals are converted into electric signals through the photoelectric detector, and the linear clock k-trigger, the A-trigger and the data signals are jointly connected into the acquisition card. Wherein the clock signal is simultaneously connected to the trigger input and the signal input. The detection circuit provides a feedback instruction and switches the acquisition mode. The acquisition card acquires signal data and transmits the signal data into the memory. The data processing module 1 reads data from the memory to perform data processing.

Example eight (data acquisition Module 2)

Such as the data acquisition module 2 shown in fig. 13. The part comprises an interference optical signal 32, a high-speed CCD38, a control card 39, an acquisition card 34, a memory 35 and a data processing module 2.

The high-speed CCD adopts a frequency-adjustable camera, and the CCD frequency can reach 150KHZ.

And (3) a control card: the control card adopts an output signal card, and can generate a control signal to provide a-trigger control for the camera. And meanwhile, the acquisition card trigger pulse signal is provided, and the acquisition card trigger signal and the camera trigger signal are provided for synchronization.

The data processing module 2: and resampling the acquired signal in a software scaling mode, and then carrying out data processing of the next module. By software scaling, it is meant that the interference envelope is first used to perform a calibration, and the calibrated data is then used to resample the acquired signal.

The specific implementation mode is as follows: the interference light signals enter the high-speed CCD, the CCD generates trigger to enter the control card, the control card generates synchronous trigger signals through the input trigger signals, one path enters the high-speed CCD, and the other path enters the acquisition card. And the data acquired by the high-speed CCD is transmitted to the acquisition card. The data acquired by the acquisition card is transmitted to the memory, and the memory transmission is from the on-board memory to the processor memory or directly transmitted to the processor memory. And the data processing module 2 acquires data from the memory and performs subsequent processing.

Example nine (data processing 1)

Referring to fig. 14, this section describes an embodiment of data transmission, including: memory data 35, data demodulation, acceleration card processing 46, image reconstruction 44, thresholding and color conversion 45. The accelerator card processing includes windowing 41, fft conversion 42, and power spectrum calculation 43.

In this embodiment, two data processing modes a and B are performed on imaging data, and the B mode is added to the data demodulation step.

And (3) data demodulation: in the data transmission section, two modes of automatic switching are mentioned. When switching to the B mode, the data channel a and the data channel B acquire the clock signal and the data signal, respectively, so that the acquired data needs to be re-demodulated by adopting the mode. The demodulation method uses a clock signal to resample the data signal.

Windowing: in fourier transform, a signal of a radio length is cut, so that spectrum leakage is caused to bring shot noise to an image. By adopting a signal windowing mode, the image of the signal side lobe can be restrained, so that the energy is relatively concentrated on the main lobe, and the spectrum information can be restored more truly. The windowing mode can adopt a hanning window or a hamming window.

FFT conversion: and carrying out Fourier transform on the windowed data, and carrying out operation on the Fourier transform by adopting a function based on a graph acceleration library. The Fourier transform of the spectrum is equal to the autocorrelation of the light amplitude, and is a factor reflecting the depth information of the optical coherence tomography, and only the collected photoelectric conversion signals are subjected to Fourier transform to obtain the amplitude information and the phase information. The amplitude information may be displayed directly as a B-frame image and the phase information may be used to determine angiography.

Power spectrum calculation: and transforming the data in a form of taking 10 times of data to obtain power spectrum data.

Image reconstruction: and performing image transformation on the obtained power spectrum data. The continuous envelope data is divided to generate a data matrix block of a single frame image, and then the polar coordinate image is converted into a rectangular coordinate image by solving the coordinate transformation. As an endoscopic scan image, the scanned data should be in accordance with the shape of a cross section of a blood vessel or an intestinal tract or the like. The system of the invention is an endoscopic scan, so its cross section is a circular figure. The diameter image of the circle represents the scan depth information. The circular graph tangential represents the rotational scan direction.

When the coordinate transformation is carried out, the pixel distribution is uneven due to the fact that the rectangular pixel matrix is converted into a circular graph, the pixel distribution is sparse when the pixels are distinguished near the edge, and the imaging quality is improved in an interpolation mode. The interpolation mode can adopt bicubic interpolation or circular tangential interpolation.

Threshold and color conversion: and setting a threshold value, namely setting reasonable gray threshold value parameters according to the image display effect, and adjusting the contrast and brightness change of the image. And the color conversion provides several pseudo-color schemes, and the gray domain space of the image is converted into the color domain space, so that the visual effect is improved.

The method of the present embodiment may be controlled as follows: the memory data are transmitted to an acceleration processing card for processing, windowing processing and FFT conversion are carried out in the acceleration processing card, and then the power spectrum is obtained. And after the power spectrum data is obtained, the power spectrum data is transmitted to an upper computer for image reconstruction, and then the image threshold and the color conversion are adjusted.

Example ten (data processing 2)

Referring to fig. 15, the present embodiment is another implementation of data transmission. The method comprises the following steps: interference envelope data 46, calibration algorithms 47, memory data 35, linear wavenumber data 48, accelerator card processing 49, image reconstruction 50, threshold and color conversion 51.

Interference envelope data: the signals returned by the sample arm and the reference arm are subjected to interference by an interferometer to form envelope data.

Calibration algorithm: the clock sampling signal is a signal at equal time intervals, and the swept source is an envelope signal with a continuously varying frequency wavelength. Direct acquisition may result in the acquired signal not being an integer wavelength. This requires a conversion of the clock signal into a clock signal that can be acquired at an integer wavelength. The directly acquired signal is then resampled with the transformed signal. The method of converting the equal time interval clock into the equal wave number interval clock can be a Hilbert transform method or a wave number method.

Linear wavenumber data: and resampling the directly acquired data signal by using the converted linear clock to obtain data.

Acceleration card processing: and (3) performing acceleration calculation and processing on the obtained data, wherein the acceleration calculation adopts a parallel acceleration processing method at the equipment end, and a cuda-based processing method can be adopted.

The present embodiment can be controlled as follows: and calibrating the interference envelope data by using a calibration algorithm to obtain a linear wave number clock signal. And directly collecting signal data, entering a memory, resampling by a linear wave number clock to obtain linear wave number data, entering an accelerator card to process the linear wave number data to obtain processed data to be imaged, reconstructing an image, and then performing threshold value and color conversion.

Example eleven (data Transmission 1)

Referring to fig. 16, the present embodiment is a method for implementing a data transmission mode. Comprising the following steps: the photoelectric detection data 52, the collection card board carries the memory 53, the co-processing card 54, the PC memory 55, the man-machine interaction 56. The specific description is as follows:

photoelectric detection data: the interference envelope is converted into electric signal data after being subjected to a photoelectric conversion module.

Collecting a card board on-load memory: the data collected by the collection card is transmitted into the on-board memory at the first time, and the on-board memory is used as a data buffer area.

Co-processing card: the co-processing card is used as a bottom layer for accelerating calculation, data of the card board on-board memory are collected, and the data are transmitted into the co-processing card for carrying out large data volume algorithm operation.

PC memory: and the memory of the application layer industrial personal computer.

Man-machine interaction: the upper computer software control system is used for data display and user interaction.

The present embodiment can be controlled as follows: the photoelectric detector data is acquired and input into the card board on-board memory, and the data in the card on-board memory enters the co-processing card to carry out large data volume algorithm acceleration operation. The calculated data enter the PC memory and then are transmitted into the man-machine interaction software control system.

Embodiment twelve (data transfer 2)

Referring to fig. 17, another embodiment of the present invention is a data transmission method. Comprising the following steps: the photoelectric detection data 52, the collection card board carries the memory 53, PC memory 55, accelerate card memory 57, man-machine interaction 58. Wherein the modules are configured in detail as follows:

photodetector data: as in the fifth embodiment.

Collecting a card board on-load memory: as in the fifth embodiment.

PC memory: as in the fifth embodiment.

Acceleration card memory: the accelerator card adopts a graphic accelerator operation card, and the memory referred to herein refers to the memory of the device side provided with the graphic accelerator card.

Man-machine interaction: as in the fifth embodiment.

The specific implementation manner of this embodiment is as follows:

photoelectric detection data are collected by the collection card and enter an onboard memory, the onboard memory data enter a PC memory, a data exchange process is carried out between the PC memory and an accelerator card memory, namely, the data at the PC memory end are transmitted into the accelerator card memory for processing, and the data are transmitted into the PC memory end by the accelerator card memory after processing. And finally, the data of the PC memory end enter human-computer interaction.

Example thirteen (sample arm)

Referring to fig. 18, this section is one embodiment of a sample arm. The method comprises the following steps: an optical rotation motor 59, an endoscopic optical catheter 60, a single balloon stabilization system 61.

An optical rotation motor: and the mechanical movement part can realize high-speed rotation and pull-back, and the load guide pipe realizes complete action.

Endoscopic optical catheter: can enter into the human body to make diagnosis.

Single balloon stabilization system: the probe is designed at the balloon front end using a single balloon design mode. The catheter and the inner wall can be kept relatively stable, and a relatively stable image is obtained when data acquisition is carried out, so that calculation of a blood flow algorithm is realized.

Dual balloon stabilization system: the probe is designed between the two balloons using two balloon design modes. The catheter and the inner wall can be kept relatively stable, and a relatively stable image is obtained when data acquisition is carried out, so that calculation of a blood flow algorithm is realized.

The embodiments are as follows:

at the catheter head end prism, a single balloon stabilization system or a double balloon stabilization system is integrated. And (3) rotating the motor optically, and rotating and pulling the load guide tube back to collect data. The optical rotary motor integrates an optical slip ring, a stepper motor and a brushless motor. While integrating a stopper at a specific position. When data is collected and stored, the optical rotary motor rotates at high speed and pulls back to cooperate with the image system to collect and store the data. Because the catheter rotates at a high speed in the body, the balloon system has a supporting force relative to the tissue in the body, so that the relative stability of the catheter relative to the tissue can be ensured, and further, the acquired image frame can also be kept relatively stable.

Fourteen embodiments (motion Compensation)

This section is a motion compensation algorithm for high-speed scanning endoscopic optical coherence blood flow imaging systems. In an eleventh embodiment, a balloon design is made for a catheter probe, whereby the tissue and probe motion can be kept relatively stationary. However, in practice, the rotation of the catheter may cause axial movement of the tissue relative to the catheter. The motion compensation algorithm of the part comprises the following steps: image preprocessing, image pixel statistics, deviation calculation and motion compensation.

The specific implementation mode of the embodiment is controlled as follows: and carrying out pixel statistics on the collected image preprocessing signals by an operation center, then carrying out deviation calculation according to the pixel distribution characteristics among frames, adopting an inter-frame variance to obtain a deviation calculation method, and carrying out inter-frame moving iteration to obtain a minimum variance. And finally subtracting the motion error between each frame by using a motion compensation method. Therefore, the situation that the image is blurred due to dislocation caused by movement can be well reduced through a motion compensation method.

Example fifteen (blood flow imaging algorithm)

Referring to fig. 19, this section is one embodiment of a blood flow imaging algorithm. The method comprises the following steps: memory data 35, calibration algorithm resampling 62, power spectrum calculation 43, generation of continuous images 63, blood flow imaging algorithm parameter settings 64, blood flow algorithm processing 65, end processing algorithm 66, blood flow images 67, sampled data 68, power raw data 69, image data 70. The specific description is as follows:

resampling by a calibration algorithm: resampling of data acquired based on a nonlinear wavenumber clock is already mentioned in embodiment four.

Generating successive images: before the blood flow algorithm data is obtained, it is necessary to complete continuous image data. These data should be more than or equal to 5 frames of image data at each location.

Blood flow imaging algorithm parameter settings: the threshold ranges of the tissue structure image, the blood flow image and the normalized blood flow image need to be set separately. For data images acquired by resampling, calibration parameters need to be set.

Processing a blood flow radiography algorithm: the OCT microangiography algorithm is a new type of vessel imaging algorithm. The method does not need contrast agent, has the characteristics of high imaging resolution, no invasiveness and the like, and has wide prospect in medical application. Basic principle of contrast algorithm: because the skin or other tissue site is stationary and the blood flow is moving. So that blood flow information can be obtained by subtracting the difference between adjacent frames. The algorithm is specifically described as follows: 5-8 frames of image data are acquired at the same location, each frame of image data comprising an amplitude component a and a phase component ω. The OCT angiography algorithm may calculate blood flow information by using only the method Δa based on the difference in the amplitude component, or by calculating blood flow information Δa+Δω based on the difference between the amplitude and the phase. The method for calculating the blood flow distribution information by using only the amplitude difference has relatively low requirement on acquisition and relatively simple processing time complexity, and does not require phase stability. The method for obtaining the blood flow distribution information based on the amplitude and phase difference can achieve better effects in imaging details and vascular connectivity. The specific application method can be used according to the needs.

Enface processing: and splicing all the calculated blood flow characteristic information B-frame data into cuboid data, and then obtaining distributed blood flow distribution information by using a strongest projection algorithm.

Blood flow image: a blood flow distribution image obtained by the enface algorithm.

Image data: image data referred to herein means scan data in which a large number of images are obtained in a scan range and 5 or more pieces of image data are present at each position.

Algorithm channel: the memory data is connected with the calibration algorithm resampling, the calibration algorithm resampling is connected with the power spectrum calculation, the power spectrum calculation is connected with the generation of continuous frames, the generation of continuous images is connected with the blood flow imaging algorithm parameter setting, the blood flow imaging algorithm parameter setting is connected with the blood flow imaging algorithm processing, the blood flow imaging algorithm processing is connected with the end face processing, and the end face processing is connected with the blood flow image. And the data channel is parallel to the data channel, the memory data is connected with the sampled data, the sampled data is connected with the power original data, the power original data is connected with the image data, and the image data is connected with the blood flow image.

The specific implementation mode is as follows: and resampling the memory data through a calibration algorithm to obtain sampled data, and calculating the power spectrum of the sampled data to obtain power original data. The power raw data is subjected to generation of a continuous frame calculation algorithm to obtain continuous image data. Then, the acquired blood flow imaging algorithm is used for calculating blood flow characteristics of the continuous image data, and then the enface algorithm is further used for solving blood flow distribution characteristics.

Example sixteen (balloon catheter stabilization System)

Referring to fig. 20 and 21, the present invention provides a balloon OCT imaging catheter, the balloon being configured as a single balloon system or as a dual balloon system. The reference numerals in the drawings are included to illustrate: interface end 71, inlet port 72, inlet tube 73, imaging inner tube 74, balloon outer tube 75, expansion port 76, hub tube 77, probe 78. The central tube is respectively connected with the interface end, the injection tube, the balloon outer tube, the imaging inner tube and the expansion opening. The interface end is connected with the OCT equipment. The end of the injection tube is provided with an injection inlet for injecting cleaning liquid and contrast agent. The front end of the balloon outer tube is provided with a balloon which is made of a material with good light transmittance. The inside of the balloon outer tube is an imaging inner tube, an imaging probe is arranged in the front end of the imaging inner tube, and the probe is always positioned in the balloon in the scanning process. The expansion port is connected with an external device and is used for injecting normal saline or air to realize the expansion of the saccule.

Advantages are: the expanding saccule can keep the positions of the OCT probe and the detection part relatively stable, avoid image blurring caused by tiny movement of human tissues during detection, greatly improve imaging quality, obtain clear images accurately reflecting focus conditions, and facilitate diagnosis of doctors on diseases.

Example seventeen (imaging system)

Referring to fig. 21, an embodiment of an imaging system is described in this section. Including data input 80, image preview, 81 image acquisition 82, B-frame image display 83, blood flow image display 84, feature recognition 85, three-dimensional imaging and roaming 86, repeated acquisition 87.

And (3) feature recognition: identifying focus information in the image by using an intelligent identification algorithm, and classifying focus types, such as: calcification, fibrosis, etc.

Three-dimensional imaging and roaming: and carrying out three-dimensional reconstruction on the acquired endoscopic data, and based on the scanned pipeline characteristics, utilizing virtual endoscopic roaming to look over the internal structure of the lumen.

The step connection mode of the embodiment is as follows: the method comprises the steps of starting to be connected with data input, connecting the data input with image preview, connecting the image preview with image acquisition, connecting the image acquisition with B-frame image display, connecting the B-frame image display with blood flow image display, feature recognition, three-dimensional imaging and roaming, connecting the blood flow image display, feature recognition, three-dimensional imaging and roaming with repeated acquisition, and connecting the repeated acquisition with the data input.

The specific implementation mode of the embodiment is controlled as follows:

and inputting data into a system memory, previewing an image, and observing an imaging effect. And starting the acquisition function by clicking the image system to save the image. And playing back and displaying the stored image. Next, blood flow image display, feature recognition, and three-dimensional imaging and roaming are performed on a b-frame basis. If the acquisition card needs to be repeated, the whole flow can be repeatedly circulated, otherwise, the acquisition process is ended.

Example eighteen (motion control System)

Referring to fig. 22, this section is one embodiment of a motion control system. The method comprises the following steps: a PC89, an instruction set 90, a motion control card 91, an optical motion control 92, an optical rotation motor control 93, a lock control 94, a polarization control 95.

Optical path movement control: and controlling a motor for adjusting the optical path distance.

Optical rotation motor control: and controlling the movement of the rotating motor and the pull-back motor of the rotating motor. And controlling the rotation speed, the pull-back distance and the start-stop time.

And (3) lock head control: when the catheter is inserted into the connector of the rotary motor, the induction detector is embedded in the lock head to inform the lock head to automatically lock so as to prevent the rotary motor from falling out of the catheter when the rotary motor rotates at a high speed, and when the equipment acquisition is finished or a catheter dismounting instruction is sent, the lock head is automatically opened so as to facilitate the dismounting of the catheter.

Polarization control: the rotation of the optical fiber affects the optical polarization, and the motor controlling the rotation of the optical fiber is controlled to perform polarization control.

The embodiment is specifically controlled as follows: the command is sent from PC to form command set, which is transmitted to motion control card to send command to optical path motion control, optical rotation motor control, lock head control and polarization control. And the control modules are sent to the upper computer through limit feedback to form a closed-loop command control system. The lock head automatic locking function that this implementation set up can prevent the rotatory time possible automatic whereabouts of pipe, plays better effect to the promotion of optical system rotational stability.

Example nineteen (three-dimensional imaging and roaming Structure)

Referring to fig. 23, this section is an embodiment of a three-dimensional imaging and roaming structure for an imaging system, which includes: the FFT power spectrum data information 96, frame data 97 after coordinate transformation, the extracted catheter central position 98, the VTK data import 99, the isosurface extraction 100, the inner cavity surface rendering 104, n pieces of data central point sets (n >1 natural numbers) 101, the space axis 105, the attribute setting 102, the interaction setting 103, the IGSTK 106 and the endoscopic roaming 107. The specific description is as follows:

extracting the central position of the catheter: the view of virtual roaming starts with the position of the catheter axis as the view point. And extracting the center point of the catheter, namely the center position of the circle in each frame of view.

VTK data import: and importing the coordinate-transformed pie chart data into an algorithm module constructed by the VTK for preprocessing.

Iso-surface extraction: the endoscopic roaming is realized by taking the inner cavity as a channel, and the extraction of the equivalent surface of the inner cavity of the pipeline is a precondition for three-dimensional slow-moving. In the VTK data importing section, a three-dimensional reconstruction is performed on a continuous image sequence. The part performs an isosurface extraction on the three-dimensional reconstruction body cavity. And storing the extracted isosurface information into a memory.

Rendering an inner cavity surface: and (3) performing surface rendering on the extracted equivalent surface information by using the VTK to obtain a complete inner cavity surface channel.

N sets of data center points: for several hundred consecutive data, all the coordinates of the central point are extracted.

Spatial axis: all images have an axis consisting of a set of center points. The axis is obtained through center point fitting, and the fitting method adopts cubic spline interpolation to ensure the smoothness of the axis.

Endoscopic roaming: the viewing angle of the simulated endoscope looks at the lumen inner wall configuration from inside the lumen.

Attribute setting: and setting color attribute, transparency attribute, contrast attribute, window width and window level attribute of the inner cavity to be rendered.

And (3) interaction setting: and setting the interaction mode of the mouse event, the keyboard event and the rendering body.

IGSTK: the virtual roaming function can be developed through the IGSTK library, and the operation is performed in a progressive coordinate axis coordinate mode.

The specific implementation manner of this embodiment is as follows:

and after coordinate transformation is carried out on the FFT power spectrum data information, continuous frame data are obtained. And extracting the central position of the catheter from the continuous frame data, and acquiring N (N generally 300-500) data center point sets, so that the spatial axis data can be obtained. And simultaneously, importing VTK data of the transformed frame, then calculating an isosurface for extraction, and rendering an inner cavity surface. And performing attribute setting and interaction setting on the obtained rendering body. And performing comprehensive treatment on the set inner cavity surface rendering and the space axis by using an IGSTK library to realize endoscopic roaming.

The foregoing has shown and described the basic principles and main features of the present invention and the advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A high-speed endoscopic optical coherence blood flow imaging system, characterized in that: the system comprises: the system comprises a red light laser, a light source, an interferometer, a reference arm, a sample arm, a balloon stabilizing system, a motion compensation algorithm, an automatic clock switching module, a data acquisition and transmission module, an optical fiber coupler, an optical rotary motor and an upper computer image processing system; the optical signal is divided into two paths, one path enters the sample arm, and the other path is the reference arm; and transmitting the light returned by the reference arm and the sample arm into the interferometer; the upper computer image processing system is used for carrying out image imaging display on the acquired data, carrying out angiography algorithm processing on the acquired blood flow imaging data, carrying out 3D imaging and virtual endoscopic roaming display, and carrying out man-machine interaction and display;

the automatic clock switching module is used for switching and selecting the acquisition clock by utilizing a hardware automatic switching mode or an algorithm automatic switching mode;

when the hardware automatic switching mode is utilized, the automatic clock switching module comprises a data acquisition module, a clock switching module, a detector, a sweep frequency light source, a signal source and a jitter judging module, wherein the data acquisition module is provided with a signal channel chA, a signal channel chB, an external clock input end K-clk, a trigger end A-Trig and a jitter judging access end S_in; the sweep frequency light source sends out two paths of Trigger signals, one path is that an A-Trigger signal is connected with a Trigger end A-Trig of the data acquisition module, and the other path is that a k-Trigger signal is connected with the clock switching module; the clock switching module is divided into three paths which are respectively connected with an external clock input end K-clk, a signal channel ChB end and a jitter judging module of the data acquisition module; the jitter judging module is connected to the jitter judging access terminal S_in, judges the connected k-trigger signal and feeds the judging signal back to the data acquisition module, and the data acquisition module selects to acquire the k-trigger signal by adopting an inner clock channel or acquire the k-trigger signal by utilizing an outer clock channel according to the feedback signal;

when an algorithm automatic switching mode is utilized, the automatic clock switching module comprises a data acquisition module, a clock switching module, a detector, a sweep frequency light source and a signal source, wherein the data acquisition module is provided with a signal channel chA, a signal channel chB, an external clock input end K-clk, a trigger end A-Trig and an output end S_out; the sweep frequency light source sends out two paths of Trigger signals, one path is that an A-Trigger signal is connected with a Trigger end A-Trig of the data acquisition module, and the other path is that a k-Trigger signal is connected with the clock switching module; the clock switching module is respectively connected into an external clock input end K-clk and a signal channel ChB end of the data acquisition module in two paths; the clock switching module acquires the k-trigger signal output by the output end S_out, judges according to the clock performance parameter, the frequency range and the signal intensity of the current signal clock, feeds back the judging signal to the data acquisition module, and the data acquisition module selectively acquires the k-trigger signal by adopting an inner clock channel or acquires the k-trigger signal by utilizing an outer clock channel according to the feedback signal.

2. A high-speed endoscopic optical coherence blood flow imaging system according to claim 1, wherein: the light source for the high-speed endoscopic optical coherent blood flow imaging system is a sweep frequency light source or an SLD broadband light source.

3. A high-speed endoscopic optical coherence blood flow imaging system according to claim 2, wherein: the sweep frequency light source is a high-speed sweep frequency light source capable of providing a linear clock and a trigger, and is a narrow-band coherent light source; the SLD broadband light source is a broadband coherent light source.

4. A high-speed endoscopic optical coherence blood flow imaging system according to claim 1, wherein: the high-speed endoscopic optical coherent blood flow imaging system is characterized in that the high-speed endoscopic optical coherent blood flow imaging system is used for an image processing system of a host computer, wherein the angiography is based on an OCT (optical coherence tomography) contrast algorithm.

5. A high-speed endoscopic optical coherence blood flow imaging system according to claim 1, wherein: the reference arm has an automatic adjustable function, and a balloon stabilizing system is designed on the probe part of the sample arm.

6. A high-speed endoscopic optical coherence blood flow imaging system according to claim 1, wherein: the motion compensation algorithm calculates motion deviation by utilizing pixel difference among frames based on image information analysis, thereby achieving registration through the motion compensation algorithm to improve the accuracy of a blood flow imaging algorithm.

7. A high-speed endoscopic optical coherence blood flow imaging system according to claim 1, wherein: the data acquisition and transmission module is used for carrying out signal conversion on the interference signals and acquiring and inputting the interference signals into the memory.

8. A high-speed endoscopic optical coherence blood flow imaging system according to claim 7, wherein: the input to the memory means that the acquired data are transmitted to the acquisition processing card board load memory, the GPU acceleration card memory and the calculator processor memory.

9. A high-speed endoscopic optical coherence blood flow imaging system according to claim 1, wherein: the upper computer image processing system is used for carrying out image imaging display on the acquired data, carrying out angiography algorithm processing on the acquired blood flow imaging data, and carrying out man-machine interaction and display.

10. A high-speed endoscopic optical coherence blood flow imaging system according to claim 1, wherein: the reference arm includes an automatic optical path adjustment system and the sample arm includes an endoscopic scanning catheter with a balloon stabilization system that controls an optical rotation motor.