A polarization control method, device and equipment of OCT image and readable storage medium

Abstract

The application discloses a polarization control method, device and equipment of an OCT image and a readable storage medium, and relates to the technical field of optical imaging and optoelectronic technology. The method comprises the following steps: obtaining candidate OCT images of a target region based on different candidate polarization states of incident light; calculating the image quality of each candidate OCT image by using an image evaluation algorithm; selecting a candidate OCT image corresponding to the highest image quality as a target OCT image, and selecting the candidate polarization state of the incident light corresponding to the target OCT image as an optimal polarization state. The method can determine the optimal polarization state, and thus the image quality of the acquired OCT image is increased.

Description

Technical Field

[0001] This invention relates to the fields of optical imaging and optoelectronics, and more specifically to a polarization control method, apparatus, device, and readable storage medium for OCT images. Background Technology

[0002] Optical coherence tomography (OCT) is a high-resolution medical imaging technology that plays an irreplaceable role in the medical field, especially in ophthalmology. This technology enables the acquisition of high-quality images without surgery or contact with tissue, is non-invasive to patients, and has a fast scanning speed that can acquire cross-sectional images of tissues in real time.

[0003] However, this technology is affected by polarization. The contrast and resolution of the image are greatly reduced after being affected by polarization. In order to reduce the impact of polarization, some polarization optimization schemes have been proposed by those skilled in the art, such as polarization-sensitive optical coherence tomography (PS-OCT). However, this technology is too complex and has very limited adjustment and optimization of polarization. Therefore, in order to further improve the image quality of medical imaging, there is an urgent need for a polarization control method for OCT images that can overcome the above defects. Summary of the Invention

[0004] The purpose of this invention is to provide a polarization control method, apparatus, device, and readable storage medium for OCT images. Image quality calculations are performed on candidate OCT images corresponding to all different polarization states, and the candidate polarization state corresponding to the highest image quality is selected as the optimal polarization state. This allows the optimal polarization state to be selected from all polarization states. Subsequent OCT image acquisition can be directly based on this optimal polarization state, thus minimizing the impact of polarization on the acquired OCT image and significantly improving its contrast and resolution.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a polarization control method for OCT images, the method comprising:

[0007] Acquire candidate OCT images of the target region based on incident light with different candidate polarization states;

[0008] Image quality of each candidate OCT image is calculated using an image evaluation algorithm;

[0009] The candidate OCT image with the highest image quality is selected as the target OCT image, and the candidate polarization state of the incident light corresponding to the target OCT image is taken as the optimal polarization state.

[0010] In some embodiments, the image quality of each candidate OCT image is calculated using an image evaluation algorithm, including:

[0011] Fundus region identification is performed on candidate OCT images to obtain fundus images from the candidate OCT images;

[0012] The pixel values ​​in the fundus images are evaluated to determine the image quality of each candidate OCT image.

[0013] In some embodiments, fundus region identification is performed on candidate OCT images to obtain fundus images from the candidate OCT images, including:

[0014] Binarize the candidate OCT image to separate the target region and background region in the candidate OCT image;

[0015] Morphological opening and closing operations and boundary refinement are performed on the target region to obtain fundus images from candidate OCT images.

[0016] In some embodiments, performing morphological opening and closing operations on the target region includes:

[0017] Perform an opening operation on the target region to remove noise from the target region;

[0018] Then perform a closing operation on the target region to connect the broken parts in the target region.

[0019] In some embodiments, the boundary refinement process for the target region includes:

[0020] The gradient magnitude of the target region is calculated using edge detection operators;

[0021] Based on gradient magnitude, a multi-stage edge detection algorithm is used to refine the boundaries of the target region.

[0022] In some embodiments, acquiring candidate OCT images of the target region based on incident light with different polarization states includes:

[0023] By controlling the polarizer and waveplate, the polarization angle of the incident light illuminating the target area can be adjusted;

[0024] The reflected light corresponding to the incident light is separated by a polarization beam splitter to obtain reflected light with different candidate polarization states;

[0025] Candidate OCT images of the target region are obtained based on reflected light with different candidate polarization states.

[0026] Secondly, the present invention also provides a polarization control device for OCT images, the device comprising:

[0027] The image acquisition module is used to acquire candidate OCT images of the target area based on incident light with different candidate polarization states;

[0028] The quality calculation module is used to calculate the image quality of each candidate OCT image using an image evaluation algorithm.

[0029] The polarization control module is used to select the candidate OCT image with the highest image quality as the target OCT image, and to take the candidate polarization state of the incident light corresponding to the target OCT image as the optimal polarization state.

[0030] Thirdly, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the polarization control method for OCT images provided in the first aspect.

[0031] Fourthly, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the polarization control method for OCT images provided in the first aspect.

[0032] Fifthly, the present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the polarization control method for OCT images provided in the first aspect.

[0033] The beneficial effects of this invention are as follows:

[0034] The polarization control method for OCT images in this invention first acquires candidate OCT images of the target region based on incident light with different candidate polarization states; then, it uses an image evaluation algorithm to calculate the image quality of each candidate OCT image; finally, it selects the candidate OCT image with the highest image quality as the target OCT image, and takes the candidate polarization state of the incident light corresponding to the target OCT image as the optimal polarization state. Image quality calculations are performed on all candidate OCT images corresponding to different polarization states, and the candidate polarization state with the highest image quality is taken as the optimal polarization state. This allows the selection of the optimal polarization state from all polarization states. Subsequent OCT image acquisition can be directly based on this optimal polarization state, thus minimizing the impact of polarization on the acquired OCT image and significantly improving its contrast and resolution.

[0035] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0036] Figure 1 This is a flowchart illustrating a polarization control method for OCT images according to an embodiment of the present invention;

[0037] Figure 2 This is a flowchart illustrating another method for polarization control of OCT images according to an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the structure of an OCT image polarization control device according to an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of another OCT image polarization control device according to an embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram of the structure of another OCT image polarization control device according to an embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of an electronic device structure provided in an embodiment of this application. Detailed Implementation

[0042] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] It should be noted that references to "an embodiment," "embodiment," "example embodiment," etc., in this specification refer to the described embodiment including specific features, structures, or characteristics; however, not every embodiment must include these specific features, structures, or characteristics. Furthermore, such expressions do not refer to the same embodiment. Moreover, when describing specific features, structures, or characteristics in conjunction with embodiments, whether or not explicitly described, it is indicated that incorporating such features, structures, or characteristics into other embodiments is within the knowledge of those skilled in the art.

[0044] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0045] In some embodiments, such as Figure 1 As shown, a polarization control method for OCT images is provided, the specific method including:

[0046] S101, acquire candidate OCT images of the target area based on incident light with different candidate polarization states.

[0047] The target area can be the eye region where OCT image acquisition is required.

[0048] Specifically, during OCT image acquisition, the polarization angle of the incident light can be controlled to change from 0 degrees to 180 degrees. While changing the polarization angle, candidate OCT images corresponding to each polarization angle are recorded.

[0049] Optionally, the polarization angle of the incident light illuminating the target area can be adjusted by controlling the polarizer and waveplate; the reflected light corresponding to the incident light can be separated by a polarization beam splitter to obtain reflected light with different candidate polarization states; and a candidate OCT image of the target area can be obtained based on the reflected light with different candidate polarization states.

[0050] Specifically, by controlling the polarizer and waveplate, the angle of the incident light can be gradually adjusted from 0 degrees to 180 degrees. After the incident light shines on the target area, the reflected light can be separated into light with different polarization states by the polarization beam splitter, that is, reflected light with different candidate polarization states. Each candidate polarization state of the reflected light corresponds to an OCT image, so candidate OCT images of incident light with different candidate polarization states can be obtained.

[0051] S102, use an image evaluation algorithm to calculate the image quality of each candidate OCT image.

[0052] Specifically, image evaluation algorithms can be integrated into an image evaluation model. After obtaining different candidate OCT images, each candidate OCT image is input into the image evaluation model, and the image evaluation model can output the image quality of each candidate OCT image.

[0053] Optionally, the method for calculating the image quality of each candidate OCT image using an image evaluation algorithm can also be: performing fundus region recognition on the candidate OCT image to obtain the fundus image in the candidate OCT image; evaluating the pixel values ​​in the fundus image to determine the image quality of each candidate OCT image.

[0054] Specifically, since candidate OCT images contain not only eye images but also background images, it is necessary to separate the eye images from the background images, that is, to identify the fundus images in the candidate OCT images. Subsequently, only the image quality assessment needs to be performed based on the fundus images, which reduces the workload of image assessment. The pixel values ​​in the fundus images are directly evaluated. When the pixel value quality of the fundus image is high, the image quality of its corresponding candidate OCT image is determined to be high. When the pixel value quality of the fundus image is low, the image quality of its corresponding candidate OCT image is determined to be low.

[0055] Optionally, another method to obtain the fundus image in the candidate OCT image is to: perform binarization processing on the candidate OCT image to separate the target region and background region in the candidate OCT image; perform morphological opening and closing operations and boundary thinning processing on the target region to obtain the fundus image in the candidate OCT image.

[0056] Specifically, after determining the target region, an opening operation can be performed on the target region to remove noise; then a closing operation can be performed on the target region to connect the broken parts; the gradient magnitude of the target region can be calculated using an edge detection operator; and based on the gradient magnitude, a multi-stage edge detection algorithm can be used to refine the boundary of the target region.

[0057] For example, the candidate OCT image can be a grayscale image. First, the grayscale image is binarized into a binary image, and then the binary image is converted into a black and white image, so as to separate the target region and the background region from the candidate OCT image. Specifically, the Otsu thresholding method can be used to automatically select the optimal threshold, and then separate the target region and the background region, as shown in the following formula (1):

[0058]

[0059] Where I(x,y) is the pixel value (0~255) of the original image at coordinates (x,y), T is the global threshold (which can be set manually or calculated automatically by an algorithm), and Ibinary(x,y) is the pixel value (0 or 255) after binarization.

[0060] Next, an opening operation is performed on the target region, which involves first eroding and then dilating the binarized target region to remove noise. Then, a closing operation is performed on the target region, which involves first dilating and then eroding the binarized target region to connect any breaks in the target region. Finally, the Sobel edge detection operator is used to calculate the gradients of the target region in the horizontal and vertical directions. These gradients are then combined to obtain the gradient magnitude of the target region. The specific calculation method is as follows:

[0061] Sobel convolution kernel, horizontal direction (detecting vertical edges) refer to formula (2):

[0062]

[0063] Vertical direction (detecting horizontal edges) reference formula (3):

[0064]

[0065] Regarding gradient calculation, for each pixel (x, y) in the image, the formula for calculating its gradient G is as shown in formula (4):

[0066]

[0067] Where I(x,y) is the pixel value of the image at point (x,y).

[0068] The gradient magnitude (edge ​​intensity) is calculated using formula (5) or (6):

[0069]

[0070] G≈|G x |+|G y | (6)

[0071] The gradient direction (edge ​​direction) is calculated using the following formula (7):

[0072]

[0073] Then edge detection is performed. By setting a threshold T, if G≥T, the point is considered to be an edge point.

[0074] Finally, based on the gradient magnitude, a multi-stage edge detection algorithm (Canny edge detection algorithm) is used to refine the boundary of the target region. Specifically, Gaussian filtering is first used to make the target region smoother, and then non-maximum suppression is used to remove non-edge pixels, making the edge of the target region clearer. Finally, a high threshold and a low threshold are set for dual threshold detection to obtain the true boundary of the target region, thus completing the boundary refinement of the target region.

[0075] Finally, the signal intensity of the target region after boundary refinement can be calculated, that is, the average intensity value of the signal pixels in the target region, as shown in the following formula (8):

[0076]

[0077] Where SS corresponds to the average intensity of the signal pixel, and N s The total number of pixels in the entire image is given by I(x,y), where I(x,y) represents the signal strength of each pixel, w is the width of the image, and h is the height of the image.

[0078] S103, select the candidate OCT image with the highest image quality as the target OCT image, and take the candidate polarization state of the incident light corresponding to the target OCT image as the optimal polarization state.

[0079] Specifically, higher signal strength indicates higher pixel intensity in the candidate OCT image, meaning a clearer image with higher contrast and resolution. Therefore, the signal strength of each candidate OCT image is compared, and the candidate OCT image with the highest signal strength is designated as the candidate OCT image with the highest image quality. This candidate OCT image is then used as the target OCT image, and the candidate polarization state of the incident light corresponding to the target OCT image is the optimal polarization state. When acquiring OCT images of other patients subsequently, these images can be directly acquired under the optimal polarization state, thereby improving the contrast and clarity of the OCT images, i.e., the image quality.

[0080] The polarization control method for OCT images in the above embodiments first acquires candidate OCT images of the target region based on incident light with different candidate polarization states; then, it uses an image evaluation algorithm to calculate the image quality of each candidate OCT image; finally, it selects the candidate OCT image with the highest image quality as the target OCT image, and takes the candidate polarization state of the incident light corresponding to the target OCT image as the optimal polarization state. Image quality calculations are performed on all candidate OCT images corresponding to different polarization states, and the candidate polarization state with the highest image quality is taken as the optimal polarization state. This allows the selection of the optimal polarization state from all polarization states. Subsequent OCT image acquisition can be directly based on this optimal polarization state, thus minimizing the impact of polarization on the acquired OCT image and significantly improving its contrast and resolution.

[0081] To more comprehensively demonstrate this solution, this embodiment presents an optional method for polarization control of OCT images, such as... Figure 2 As shown:

[0082] S201 adjusts the polarization angle of the incident light illuminating the target area by controlling the polarizer and waveplate.

[0083] S202 uses a polarization beam splitter to separate the reflected light corresponding to the incident light, thus obtaining reflected light with different candidate polarization states.

[0084] S203, based on reflected light with different candidate polarization states, obtain candidate OCT images of the target region.

[0085] S204, perform binarization processing on the candidate OCT image to separate the target region and background region in the candidate OCT image.

[0086] S205 performs an opening operation on the target region to remove noise from the target region.

[0087] S206, then perform a closing operation on the target region to connect the broken parts in the target region.

[0088] S207 uses an edge detection operator to calculate the gradient magnitude of the target region.

[0089] S208, based on gradient magnitude, uses a multi-stage edge detection algorithm to refine the boundary of the target region, obtaining the fundus image in the candidate OCT image.

[0090] S209, evaluate the pixel values ​​in the fundus image to determine the image quality of each candidate OCT image.

[0091] S210, select the candidate OCT image with the highest image quality as the target OCT image, and take the candidate polarization state of the incident light corresponding to the target OCT image as the optimal polarization state.

[0092] The specific processes of S201-S210 described above can be found in the description of the above method embodiments. Their implementation principles and technical effects are similar, and will not be repeated here.

[0093] Based on the same inventive concept, this application also provides an OCT image polarization control device for implementing the OCT image polarization control method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations of one or more OCT image polarization control device embodiments provided below can be found in the limitations of the OCT image polarization control method described above, and will not be repeated here.

[0094] In one embodiment, such as Figure 3 As shown, a polarization control device for OCT images is provided, the device comprising:

[0095] Image acquisition module 30 is used to acquire candidate OCT images of the target area based on incident light with different candidate polarization states;

[0096] The quality calculation module 31 is used to calculate the image quality of each candidate OCT image using an image evaluation algorithm;

[0097] The polarization control module 32 is used to select the candidate OCT image with the highest image quality as the target OCT image, and to take the candidate polarization state of the incident light corresponding to the target OCT image as the optimal polarization state.

[0098] In another embodiment, such as Figure 4 As shown above, Figure 3 The quality calculation module 31 in the middle includes:

[0099] Image recognition unit 310 is used to perform fundus region recognition on candidate OCT images to obtain fundus images in candidate OCT images;

[0100] The pixel evaluation unit 311 is used to evaluate the pixel values ​​in the fundus image and determine the image quality of each candidate OCT image.

[0101] In another embodiment, the above Figure 4 The image recognition unit 310 in the image recognition unit includes:

[0102] The image separation subunit is used to perform binarization processing on the candidate OCT image to separate the target region and the background region in the candidate OCT image.

[0103] The image thinning subunit is used to perform morphological opening and closing operations and boundary thinning processing on the target region to obtain the fundus image in the candidate OCT image.

[0104] In another embodiment, the image thinning subunit described above is specifically used to: perform an opening operation on the target region to remove noise in the target region; then perform a closing operation on the target region to connect the broken parts in the target region; perform an opening operation on the target region to remove noise in the target region; then perform a closing operation on the target region to connect the broken parts in the target region.

[0105] In another embodiment, such as Figure 5 As shown above, Figure 3 The image acquisition module 30 includes:

[0106] Angle adjustment unit 300 is used to adjust the polarization angle of incident light illuminating the target area by controlling the polarizer and waveplate;

[0107] The reflection separation unit 301 is used to separate the reflected light corresponding to the incident light through a polarization beam splitter to obtain reflected light with different candidate polarization states.

[0108] The image acquisition unit 302 is used to obtain candidate OCT images of the target region based on reflected light with different candidate polarization states.

[0109] This application also provides an electronic device, in some embodiments, referring to... Figure 6 As shown, the electronic device 700 includes an input unit 710, a memory 720, a processor 730, and an output unit 740. The memory 720 stores program instructions that can be executed on the processor 730. The processor 730 can execute the polarization control method and / or technical solution based on the OCT image in the foregoing embodiments by calling the program instructions. The electronic device 700 can be a mobile terminal device such as a mobile phone or a computer.

[0110] Furthermore, embodiments of this application also provide a computer-readable storage medium for storing a computer program that performs a polarization control method for OCT images. For example, computer program instructions, when executed by a computer, can invoke or provide the methods and / or technical solutions according to this application through the operation of the computer. The program instructions that invoke the methods of this application may be stored in a fixed or removable storage medium, and / or transmitted via data streams in broadcast or other signal carrying media, and / or stored in a storage medium that operates according to the program instructions.

[0111] Obviously, those skilled in the art should understand that the modules or steps of this application described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a storage device for execution by a computing device, or fabricating them separately as individual integrated circuit modules, or fabricating multiple modules or steps as a single integrated circuit module. Thus, this application is not limited to any particular combination of hardware and software.

[0112] The technical features of the above embodiments can be arbitrarily integrated. For the sake of brevity, not all possible integrations of the technical features in the above embodiments are described. However, as long as the integration of these technical features does not contradict each other, they should be considered to be within the scope of this specification.

[0113] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A polarization control method for OCT images, characterized in that, The method includes: Acquire candidate OCT images of the target region based on incident light with different candidate polarization states; The candidate OCT image is binarized to separate the target region and background region in the candidate OCT image; Morphological opening and closing operations and boundary refinement are performed on the target region to obtain the fundus image in the candidate OCT image; The pixel values ​​in the fundus images are evaluated to determine the image quality of each candidate OCT image; The candidate OCT image with the highest image quality is selected as the target OCT image, and the candidate polarization state of the incident light corresponding to the target OCT image is taken as the optimal polarization state.

2. The polarization control method for OCT images as described in claim 1, characterized in that, Performing morphological opening and closing operations on the target region includes: An opening operation is performed on the target region to remove noise from the target region; Then, a closing operation is performed on the target region to connect the broken parts in the target region.

3. The polarization control method for OCT images as described in claim 2, characterized in that, The target region is subjected to boundary refinement processing, including: The gradient magnitude of the target region is calculated using an edge detection operator; Based on the gradient magnitude, a multi-stage edge detection algorithm is used to refine the boundary of the target region.

4. The polarization control method for OCT images as described in claim 1, characterized in that, Acquire candidate OCT images of the target region based on incident light with different polarization states, including: By controlling the polarizer and waveplate, the polarization angle of the incident light illuminating the target area can be adjusted; The incident light is separated into reflected light corresponding to the incident light by a polarization beam splitter to obtain reflected light with different candidate polarization states; Based on the reflected light of the different candidate polarization states, candidate OCT images of the target region are obtained.

5. A polarization control device for OCT images, characterized in that, The device includes: The image acquisition module is used to acquire candidate OCT images of the target area based on incident light with different candidate polarization states; A quality calculation module is used to calculate the image quality of each of the candidate OCT images using an image evaluation algorithm; The polarization control module is used to select the candidate OCT image with the highest image quality as the target OCT image, and to take the candidate polarization state of the incident light corresponding to the target OCT image as the optimal polarization state.

6. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the polarization control method for OCT images according to any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the polarization control method for OCT images according to any one of claims 1 to 4.

8. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the polarization control method for OCT images according to any one of claims 1 to 4.

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