Method and system for automatically positioning OCT delay line position based on fundus B_scan image

Abstract

The present invention discloses a method and system for automatically positioning the position of an OCT delay line based on a fundus B_scan image, wherein the method includes: while collecting the B_scan image in real time, adjusting the position of the delay line along the axial direction; calculating the gradient parameters of each frame of the B_scan image according to a preset image processing model, obtaining the maximum gradient position data of the B_scan image; fitting the maximum gradient position data, and calculating the positioning data of the optimal position of the delay line with the fitting result. The present invention utilizes the characteristics of the B_scan image itself in conjunction with the high-precision real-time response of a stepper motor to quickly and accurately locate the position of the OCT delay line. During the adjustment process, feedback and compensation can be implemented according to the eye movement generated in the axial direction, so that the OCT image is always in the optimal interference state. The technical purpose of achieving high-contrast tomographic imaging and meeting the imaging needs of people with different axial lengths is achieved.

Description

Technical Field

[0001] The present invention relates to the field of intelligent exoskeletons, and in particular to a method and system for automatically locating an OCT delay line based on a fundus B_scan image. Background Art

[0002] Fundus examination is an important part of detecting eye and systemic diseases. In fundus examination, optical coherence tomography (OCT) imaging is a commonly used method. The core of OCT imaging is the Mach-Zehnder interferometer. A group of coherent light sources are divided into two paths by a fiber coupler. One path is the reference light that is collimated by a lens and returned from a plane reflector, and the other path is the sampling light beam that is focused by a lens to the sample under test. When the optical path between the two is within the coherence length of the light source, interference occurs, and the detector output signal reflects the scattering intensity of the medium. According to the position of the reflector and the corresponding interference signal intensity, the measurement of different depths (Z direction) of the sample is obtained, and then combined with the scanning of the sampling light beam in the xy plane, the obtained results are processed by a computer to obtain the three-dimensional structural information of the sample.

[0003] During the imaging process, the reflected light in the two optical paths converges in the coupler, and interference signals can only occur when the optical path difference between the reference arm and the sample arm is within a coherent length. Because the system sample arm is a confocal microscope system, the return beam has the strongest signal at the intersection of the detection beam. For broadband light sources, the detector can only detect changes in the contrast of interference fringes when the optical path difference between the two arms is within a very short coherent length. The place with the largest contrast corresponds to the equal optical path point. As the optical path increases, the contrast decreases rapidly.

[0004] However, when the OCT system is within the normal working distance range, the generation of retinal B-scan images cannot meet the interference conditions due to the different axial lengths of different patients, resulting in the optical path of the sample arm and the reference arm being unable to meet the interference conditions. The current OCT system cannot meet the imaging needs of people with different axial lengths. Summary of the invention

[0005] The object of the present invention is to provide a method and system for automatically locating the position of an OCT delay line based on a fundus B_scan image, so as to achieve high-contrast tomographic imaging and meet the imaging requirements of people with different axial lengths.

[0006] A method for automatically locating an OCT delay line position based on a fundus B_scan image, comprising:

[0007] While acquiring B_Scan images in real time, adjust the delay line position along the axial direction;

[0008] According to the preset image processing model, the gradient parameters of each frame of B_Scan image are calculated to obtain the maximum gradient position data of the B_Scan image;

[0009] The maximum gradient position data are fitted, and the positioning data of the optimal position of the delay line is calculated based on the fitting result.

[0010] Optionally, while acquiring the B_Scan image in real time, adjusting the position of the delay line along the axial direction is specifically implemented as follows:

[0011] The B_Scan image generated by eye movement in the axial direction is collected in real time through the OCT imaging optical path, and the reference arm reflector is moved from near to far relative to the sample arm to adjust the position of the delay line.

[0012] Optionally, the gradient parameters of each frame of B_Scan image include:

[0013] The gradient of the B_Scan image and the position of the row with the maximum gradient;

[0014] The reference arm reflector is moved relative to the sample arm from near to far to adjust the delay line position, which is specifically realized by obtaining the maximum coherence length when the optical path difference is close to 0, thereby obtaining the maximum gradient of the B_Scan image.

[0015] Optionally, fitting the maximum gradient position data and calculating the positioning data of the optimal position of the delay line based on the fitting result is specifically implemented as follows:

[0016] Perform polynomial fitting on the maximum gradient position data of each frame of B_Scan collected during the adjustment process to obtain the maximum gradient position data of the B_Scan image;

[0017] Calculate the motor compensation amount and the motor movement direction according to the maximum gradient position data;

[0018] Predict the optimal position by calculating the motor compensation and the motor movement direction;

[0019] The predicted optimal position information is used as the positioning data of the optimal position of the delay line.

[0020] Optionally, a B_Scan image generated by eye movement in the axial direction is collected in real time through an OCT imaging optical path, and a reference arm reflector is moved from near to far relative to the sample arm to adjust the position of the delay line, including:

[0021] Acquisition step, acquiring the B_Scan image at the moment of eye movement as the reference B_Scan image;

[0022] Calculation steps: calculate the gradient of the B_Scan image after eye movement and find the maximum row number of the gradient;

[0023] The judging step is to judge the change value of the maximum number of rows where the gradient is located relative to the maximum number of rows where the gradient is located in the reference B_Scan image, so as to adjust the position of the delay line to be within the range allowed by the threshold.

[0024] Optionally, the present invention further comprises: a change value calculation step, comprising: calculating whether the gradient change value falls within a preset threshold range by comparing the maximum number of rows where the gradient is located with the maximum row where the gradient of the reference B_Scan image is located;

[0025] The collecting step, the calculating step and the judging step are repeated until it is judged that the change value falls within the preset threshold range.

[0026] Optionally, the present invention further comprises:

[0027] The motor is moved to the optimal position of the delay line according to the motor compensation amount and the motor movement direction.

[0028] A system for automatically positioning an OCT delay line based on a fundus B_scan image realizes the function of the method for automatically positioning an OCT delay line based on a fundus B_scan image.

[0029] A fundus imaging device, comprising: a control host, the control host comprising:

[0030] at least one processor; and

[0031] a memory communicatively connected to the at least one processor; wherein,

[0032] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the above method.

[0033] A readable medium stores a computer program, which, when executed by a processor, can implement the above-mentioned method for automatically locating the position of an OCT delay line based on a fundus B_scan image.

[0034] Through the method of automatically positioning the position of the OCT delay line based on the fundus B_scan image of the present invention, the gradient parameters of each frame of the B_Scan image are collected in real time, and the maximum gradient position data of the B_Scan image is obtained; the positioning data of the optimal position of the delay line is calculated according to the fitting result. The position of the OCT delay line can be quickly and accurately positioned by utilizing the characteristics of the B_Scan image itself and the high-precision real-time response of the stepper motor. During the adjustment process, feedback and compensation can be implemented according to the eye movement generated in the axial direction, so that the OCT image is always in the optimal interference state. The technical purpose of achieving high-contrast tomographic imaging and meeting the imaging needs of people with different axial lengths is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flow chart of a method for automatically locating the position of an OCT delay line based on a fundus B_scan image according to an embodiment of the present invention;

[0036] Figure 2a A schematic flow chart of a method for automatically locating the position of an OCT delay line based on a fundus B_scan image according to another embodiment of the present invention;

[0037] Figure 2b A curve diagram showing the correspondence between the maximum line position of the image gradient and the delay line position for automatically locating the OCT delay line position based on the fundus B_scan image according to another embodiment of the present invention;

[0038] Figure 3 A flow chart of a method for automatically locating the position of an OCT delay line based on a fundus B_scan image according to another embodiment of the present invention

[0039] Figure 4 A schematic flow chart of a method for automatically locating the position of an OCT delay line based on a fundus B_scan image according to another embodiment of the present invention;

[0040] Figure 5 A schematic diagram of the structure of a system for automatically locating the position of an OCT delay line based on a fundus B_scan image according to another embodiment of the present invention;

[0041] Figure 6 A schematic diagram of a readable medium structure according to an embodiment of the present invention;

[0042] Figure 7 Schematic diagram of the structure of an exoskeleton robot according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The specific implementation of the present invention relates to a method and system for automatically positioning the position of an OCT delay line based on a fundus B_scan image, so as to achieve high-contrast tomographic imaging and meet the imaging requirements of people with different axial lengths.

[0044] In the related technology, when the OCT system is within the normal working distance range, the optical path of the sample arm and the reference arm cannot meet the interference conditions due to the different axial lengths of different patients. The existing processing methods are: relying on manual position adjustment, the error is large, and it is more dependent on personal experience and technical maturity; in clinical use, the speed is slow and the efficiency is low, and it is difficult to adjust for patients with poor cooperation; it is impossible to adjust the demonstration position and focus at the same time, which increases the debugging time; the operator needs to judge the debugging direction and adjustment amount according to the test process, which has high requirements for the operator and increases the training cost; the operator sees the image during the test, which is difficult to correctly and quickly locate, and the debugging time is extended.

[0045] The present invention uses the B_Scan image to quickly locate the position of the reference arm reflector to find the delay line balance point of the changed reference reflector, thereby achieving high-contrast tomographic imaging and meeting the imaging needs of people with different axial lengths.

[0046] Figure 1 A method for automatically locating the position of an OCT delay line based on a fundus B_scan image is shown, comprising:

[0047] S11: while acquiring the B_Scan image in real time, adjusting the position of the delay line along the axial direction;

[0048] While acquiring the B_Scan image in real time, the delay line position is adjusted along the axial direction as follows:

[0049] The B_Scan image generated by eye movement in the axial direction is collected in real time through the OCT imaging optical path, and the reference arm reflector is moved from near to far relative to the sample arm to adjust the position of the delay line.

[0050] During the adjustment process, feedback and compensation for the motor can be completed according to the axial eye movement, so that the OCT image is always in the optimal interference state.

[0051] S12: Calculate the gradient parameters of each frame of the B_Scan image according to the preset image processing model, and obtain the maximum gradient position data of the B_Scan image;

[0052] According to the regulation rule of the reference arm from near to far, the maximum coherence length is obtained only when the optical path difference is close to 0, at which time the gradient of the image is the largest.

[0053] Optionally, the gradient parameters of each frame of B_Scan image include:

[0054] The gradient of the B_Scan image and the position of the row with the maximum gradient;

[0055] The reference arm reflector is moved relative to the sample arm from near to far to adjust the delay line position, which is specifically realized by obtaining the maximum coherence length when the optical path difference is close to 0, thereby obtaining the maximum gradient of the B_Scan image.

[0056] Since interference signals can only occur when the optical path difference between the reference arm and the sample arm is within a coherence length, if one wants to obtain the maximum gradient of the B_Scan image, one needs to find the maximum coherence length during the movement.

[0057] The method of the present invention is applicable to most patients within the axial length range (standard axial length 22-24), and the axial length range covers patients with ultra-short axial length and patients with high myopia and ultra-long axial length, and realizes automatic delay line position.

[0058] S13: Fitting the maximum gradient position data, and using the fitting result to calculate the positioning data of the optimal position of the delay line.

[0059] In the present invention, the position information is fed back to the motor drive module, the size and direction of the motor compensation are calculated according to the result obtained after fitting, and the motor is moved to the optimal position, thereby completing the positioning of the optimal position of the delay line.

[0060] Optionally, fitting the maximum gradient position data and calculating the positioning data of the optimal position of the delay line based on the fitting result is specifically implemented as follows:

[0061] refer to Figure 2a :

[0062] S21: performing polynomial fitting on the maximum gradient position data of each frame of B_Scan collected during the adjustment process to obtain the maximum gradient position data of the B_Scan image;

[0063] refer to Figure 2b , which is a curve diagram of the corresponding relationship between the row position of the maximum image gradient and the position of the delay line. The horizontal axis represents the interference position of the delay line, and the vertical axis represents the position of the row vector field where the maximum image gradient is located.

[0064] Optionally, the figure illustrates the correspondence between the moving position of the delay line and the row vector field where the maximum gradient of the image is located. The sampling points are fitted with a polynomial to obtain a fitting curve series 1, and the polynomial extreme point is obtained. According to the position of the image row vector field, the optimal position of the delay line motor compensation can be calculated.

[0065] S22: Calculating the motor compensation amount and the motor movement direction according to the maximum gradient position data;

[0066] S23: predicting the optimal position by calculating the motor compensation amount and the motor movement direction;

[0067] S24: Use the predicted optimal position information as the positioning data of the optimal position of the delay line.

[0068] Optionally, the present invention further comprises:

[0069] The motor is moved to the optimal position of the delay line according to the motor compensation amount and the motor movement direction.

[0070] That is to say, the motor is moved according to the size and direction of the motor compensation, and the positioning data of the optimal position of the delay line is used to finally complete the imaging through the OCT imaging system, so as to achieve the technical purpose of realizing high-contrast tomographic imaging and meeting the imaging needs of people with different axial lengths.

[0071] As a preferred implementation, the B_Scan image generated by eye movement in the axial direction is collected in real time through the OCT imaging optical path, and the reference arm reflector is moved from near to far relative to the sample arm to adjust the position of the delay line, including:

[0072] S31: an acquisition step, acquiring a B_Scan image at the moment of eye movement as a reference B_Scan image;

[0073] S32: a calculation step, calculating the gradient of the B_Scan image after eye movement, and obtaining the maximum number of rows where the gradient is located;

[0074] S33: a judgment step, judging the maximum number of rows where the gradient is located and the gradient change value of the reference B_Scan image, so as to adjust the delay line position to be within the range allowed by the threshold;

[0075] According to the size of eye movement generated in the direction of the eye axis, the current B_Scan image is collected as the reference image, the gradient field of the B_Scan image after the eye movement is calculated, and then the maximum number of rows where the gradient is located is obtained and compared with the gradient field of the reference B_Scan image. According to the changes in the gradient fields of the two B_Scan images, the size δd and direction of the motor compensation are recalculated, and it is determined whether the current gradient field change value is within the range allowed by the threshold.

[0076] refer to Figure 4 ,exist Figure 3 On the basis of, the change value calculation step is also included, including:

[0077] S41: calculating whether the gradient change value falls within a preset threshold range by comparing the maximum number of rows where the gradient is located with the maximum row where the gradient of the reference B_Scan image is located;

[0078] S42: Repeat steps S31-33 until the change value is determined to fall within the threshold range.

[0079] refer to Figure 5, shows a device for locating the position of an OCT delay line using a B_Scan image, comprising: an OCT imaging optical path 51, an image analysis and recognition module 52, a delay line module 53 and a motor drive module 54.

[0080] The OCT imaging optical path 51 in the device is used to perform OCT imaging;

[0081] The image analysis and recognition module 52 and the delay line module 53 are used to execute S11-S13;

[0082] The motor driving module 54 is used to receive and execute the data of the motor compensation amount and the motor movement direction.

[0083] Optionally, the device of this embodiment can be implemented in an embedded manner according to actual conditions. Figure 1-4 steps.

[0084] refer to Figure 6 , shows a readable medium, including: a computer program stored thereon, which, when executed by a processor, can implement the above-mentioned method of automatically locating the position of the OCT delay line based on the fundus B_scan image.

[0085] refer to Figure 7 , shows a fundus image device, including: a control host, the control host including:

[0086] at least one processor; and

[0087] a memory communicatively connected to the at least one processor; wherein,

[0088] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to implement the method.

[0089] The computing device 70 is in the form of a general computing device. The components of the computing device 70 may include, but are not limited to: at least one processor 71, at least one memory 72, and a bus 73 connecting different system components (including the memory 72 and the processor 71).

[0090] Bus 73 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, a processor or local bus using any of a variety of bus architectures.

[0091] The memory 72 may include a readable medium in the form of a volatile memory, such as a random access memory (RAM) 721 and / or a cache memory 722 , and may further include a read-only memory (ROM) 723 .

[0092] The memory 72 may also include a program / utility 725 having a set (at least one) of program modules 724, such program modules 724 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0093] The computing device 70 may also communicate with one or more external devices 74 (e.g., keyboards, pointing devices, etc.), one or more devices that enable a user to interact with the computing device 70, and / or any device that enables the computing device 70 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 75. In addition, the computing device 70 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 76. As shown, the network adapter 76 communicates with other modules for the computing device 70 via a bus 73. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the computing device 70, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0094] In some possible implementations, various aspects of a fall risk assessment and prevention method provided by the present application may also be implemented in the form of a program product, which includes a program code. When the program product is run on a computer device, the program code is used to enable the computer device to execute the steps of the encryption method for information to be verified and / or the verification method for information to be verified according to various exemplary embodiments of the present application described above in this specification. For example, the computer device may execute the following steps: Figure 1 Steps S11-S14 shown in FIG.

[0095] In summary:

[0096] Through the method of automatically positioning the position of the OCT delay line based on the fundus B_scan image of the present invention, the gradient parameters of each frame of the B_Scan image are collected in real time, and the maximum gradient position data of the B_Scan image is obtained; the positioning data of the optimal position of the delay line is calculated according to the fitting result. The position of the OCT delay line can be quickly and accurately positioned by utilizing the characteristics of the B_Scan image itself and the high-precision real-time response of the stepper motor. During the adjustment process, feedback and compensation can be implemented according to the eye movement generated in the axial direction, so that the OCT image is always in the optimal interference state. The technical purpose of achieving high-contrast tomographic imaging and meeting the imaging needs of people with different axial lengths is achieved.

[0097] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures and processing steps disclosed herein, but should be extended to equivalent substitutions of these features understood by ordinary technicians in the relevant field. It should also be understood that the terms used herein are only used for the purpose of describing specific embodiments and are not meant to be limiting.

[0098] The "one embodiment" or "embodiment" mentioned in the specification means that the specific features, structures or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "embodiment" appearing in various places throughout the specification do not necessarily refer to the same embodiment.

[0099] Although the embodiments disclosed in the present invention are as above, the contents are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A method for automatically locating the position of an OCT delay line based on a fundus B_scan image, characterized in that: include: While acquiring B_Scan images in real time, adjust the delay line position along the axial direction; According to the preset image processing model, the gradient parameters of each frame of B_Scan image are calculated to obtain the maximum gradient position data of the B_Scan image; Fitting the maximum gradient position data, and calculating the positioning data of the optimal position of the delay line based on the fitting result; While acquiring B_Scan images in real time, adjust the delay line position along the axial direction, including: The B_Scan image generated by eye movement in the axial direction is collected in real time through the OCT imaging optical path, and the reference arm reflector is moved from near to far relative to the sample arm to adjust the position of the delay line; The gradient parameters of each B_Scan image include: The gradient of the B_Scan image and the position of the row with the maximum gradient; The reference arm reflector is moved relative to the sample arm from near to far to adjust the delay line position, including: obtaining a maximum coherence length when the optical path difference is close to 0, thereby obtaining a maximum gradient of the B_Scan image; Fitting the maximum gradient position data and calculating the positioning data of the optimal position of the delay line with the fitting result, including: Perform polynomial fitting on the maximum gradient position data of each frame of B_Scan collected during the adjustment process to obtain the maximum gradient position data of the B_Scan image; Calculate the motor compensation amount and the motor movement direction according to the maximum gradient position data; Predict the optimal position by calculating the motor compensation and the motor movement direction; The predicted optimal position information is used as the positioning data of the optimal position of the delay line.

2. The method according to claim 1, characterized in that The B_Scan image generated by eye movement in the axial direction is collected in real time through the OCT imaging optical path, and the reference arm reflector is moved from near to far relative to the sample arm to adjust the position of the delay line, including: Acquisition step, acquiring the B_Scan image at the moment of eye movement as the reference B_Scan image; Calculation steps: calculate the gradient of the B_Scan image after eye movement and find the maximum row number of the gradient; The judging step is to judge the change value of the maximum number of rows where the gradient is located relative to the maximum number of rows where the gradient is located in the reference B_Scan image, so as to adjust the position of the delay line to be within the range allowed by the threshold.

3. The method according to claim 2, characterized in that Also includes: a change value calculation step, calculating whether the gradient change value falls within a preset threshold range by comparing the maximum row number of the gradient with the maximum row of the reference B_Scan image gradient; The collecting step, the calculating step and the judging step are repeated until it is judged that the change value falls within the preset threshold range.

4. The method according to claim 1 or 3, characterized in that: Also includes: The motor is moved to the optimal position of the delay line according to the motor compensation amount and the motor movement direction.

5. A system for automatically locating the position of an OCT delay line based on fundus B_scan images, characterized in that: Used to implement the function of the method described in any one of claims 1 to 4.

6. A fundus imaging device, characterized in that: include: A control host, the control host comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 4.

7. A readable medium, characterized in that include: A computer program is stored thereon, characterized in that when the computer program is executed by a processor, it can implement the method according to any one of claims 1 to 4.

Images