PS-SDOCT contrast improving method and system fusing multiple depolarization parameters

Abstract

The invention discloses a PS-SDOCT contrast improving method and system fusing multiple depolarization parameters, and the method comprises the steps: inputting four polarization states into a PS-SDOCT system, obtaining horizontal and vertical component graphs according to a CCD, reconstructing a Stokes component, and carrying out the calculation to obtain an image of 16 elements of a Mueller matrix of a to-be-detected sample; calculating a plurality of polarization and depolarization parameter images by using a Mueller matrix model established by combining a propagation path of light in a medium and a method for analyzing a relationship between component matrixes in classical decomposition and polarization decomposition of the Mueller matrix; and formulating a specific polarization parameter identification group of the sample according to the sensitivity of the polarization and depolarization parameters to the microstructure of the sample. According to the method, the problem of low polarization detection accuracy caused by a single polarization parameter analysis method is solved, and the image contrast can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polarization optical coherence tomography, and in particular to a PS-SDOCT contrast enhancement method and system integrating multiple depolarization parameters. Background Art

[0002] Polarization Sensitive Optical Coherence Tomography (PS-OCT) technology combines optical coherence tomography (OCT) technology with polarization measurement methods, and uses the low coherence characteristics of the light source to obtain two-dimensional or three-dimensional depth-resolved polarization images of sample intensity and polarization characteristic parameters. Because it has the potential to obtain more comprehensive information on the structure of biological tissues, it is widely used in the diagnosis of eye disease tissues, skin tissues with burns and scars, tendon and myelinated nerve fiber tissue lesions, atherosclerosis, etc. and the monitoring of disease progression. Polarization OCT is non-contact and can obtain deep-resolved images of tissues with polarization parameters as contrast, which gives it unique advantages and great application potential in the biomedical field.

[0003] For example, a Chinese patent document with publication number CN117129425A discloses a polarization-sensitive optical coherence tomography system, including a light source, a first beam splitter coupler, a sample arm, a reference arm, and a detection unit; the first beam splitter coupler is used to divide the light beam from the light source into a first beam splitter and a second beam splitter; the sample arm is provided with a polarization delay unit, which is used to convert the first beam splitter into a polarized light beam containing two orthogonal polarization states, and project the polarized light beam to the object to be measured, and there is a preset delay between the two orthogonal polarization states; the reference arm is used to receive the second beam splitter and reflect part or all of it to the first beam splitter coupler; the detection unit is used to detect the interference light formed in the first beam splitter coupler. The system can obtain the polarization characteristics of the object to be measured by further calculating and processing the interference light, thereby completing the optical imaging of the object to be measured, and can be widely used in medical fields such as ophthalmic examination, probe-based cardiovascular, and endoscopy.

[0004] At present, many research results have shown that the changes in dichroism, birefringence and depolarization characteristics are closely related to the changes in the microstructure and morphology of biological tissues. However, most studies focus on analyzing and obtaining non-depolarization characteristic parameters and images such as birefringence. Theoretically defined parameters describing the depolarization characteristics of media are numerous and their physical meanings and generation mechanisms are unclear, which makes the process of detecting, analyzing, describing and interpreting the depolarization characteristics of thin-layer media complicated. The parameter type for evaluating depolarization characteristics is single, which weakens the advantage of polarization parameters in providing multidimensional information and limits the application of these parameters in the biomedical field. At the same time, the mechanism of polarization and depolarization characteristic parameters or images for identifying tissue microstructures is not clear enough. There have been many reports on the polarization parameter values ​​or images of various structures of biological tissues, but there has been no systematic analysis of the relationship between the information reflected by the polarization parameter values ​​or images and the state and changes of the microstructure of biological tissues, as well as the reasons why different polarization images can reveal the same microstructure, which reduces the effectiveness of polarization information and limits its use as a complementary means of medical image information. Summary of the invention

[0005] In view of the shortcomings of the existing polarization parameter analysis methods, which are single and have unclear identification mechanisms, the present invention provides a PS-SDOCT contrast enhancement method and system that integrates multiple depolarization parameters. This multi-parameter method is based on the polarization mechanism to reveal the physical facts hidden in the image information of biological tissues, so as to obtain more and better contrast images for the same tissue, thereby improving the efficiency and accuracy in the clinical diagnosis and treatment of diseases.

[0006] A PS-SDOCT contrast enhancement method integrating multiple depolarization parameters comprises the following steps:

[0007] (1) Four polarization states are input into the PS-SDOCT system to construct the Stokes component calculation to obtain the image of the 16 elements of the Mueller matrix of the sample to be tested;

[0008] (2) Establishing a multi-polarization parameter set obtained by combining the component matrix relationship of different decomposition methods with the light propagation path method in the medium;

[0009] (3) According to the multi-polarization parameter group expression obtained in step (2), the corresponding Mueller matrix element image in step (1) is selected, the multi-polarization and depolarization parameter images are calculated and the image processing is completed;

[0010] (4) Selecting a key structural area for observation, drawing a polarization characteristic parameter curve in the depth direction of the specific area based on the corresponding polarization image in step (3), and performing multi-polarization and depolarization parameter image analysis;

[0011] (5) Determine the polarization parameter image with high sensitivity and formulate a specific identification polarization parameter group to achieve large-scale monitoring of the tissue and efficient identification and analysis of small-scale microscopic tissues.

[0012] The invention solves the problem of low polarization detection accuracy caused by a single polarization parameter analysis method. The method has a wide range of applications and strong scalability. It can be used to monitor tissue structure status over a large range with multiple parameters, and can also be used to sense local tissue structure changes over a small range with fewer parameters. It can be extended to analyze different tissue structures and pathological samples, and establish a highly targeted polarization parameter image database.

[0013] The specific process of step (1) is as follows:

[0014] (1-1) According to the Mueller matrix form, four different input polarization states are calculated and determined;

[0015] (1-2) adjusting the corresponding incident polarization state through the polarization control component;

[0016] (1-3) The horizontal and vertical components of the interference light formed by different incident polarized light passing through the sample and the light in the reference arm are obtained through two CCDs;

[0017] (1-4) Construct the Stokes vector diagram of the four incident lights corresponding to the outgoing lights;

[0018] (1-5) The 16 element images of the Mueller matrix are obtained based on the Stokes component calculation.

[0019] The specific process of step (2) is as follows:

[0020] (2-1) Based on the component matrix relationship of different decomposition methods, a set of polarization parameter expressions are obtained as follows: dichroic parameters:

[0021]

[0022] Among them, M 1y (y=2,3,4) represents the yth element of the first row of the experimentally measured Mueller matrix; three parameters are required to fully describe dichroism: the dichroism value D and the direction angle α describing the dichroism optical axis Jd and ellipticity ε Jd :

[0023]

[0024] Depolarization parameter expression:

[0025]

[0026] Among them, the depolarization component parameter e J1and e J2 Represent the parameters of linear depolarization characteristics, e J3 Parameters representing circular depolarization characteristics:

[0027] e J1 =M 22 , e J2 =|M 33 |,e J3 =|M 44 (M 33 ,M 44 >|M 34 |,|M 43 |)

[0028] e J1 =M 22 , e J2 =|M 34 |,e J3 =|M 43 (M 33 ,M 44 <|M 34 |,|M 43 |)

[0029] Combined with the condition of weak dichroism of tissue, the phase delay R under different conditions is analyzed. J The expression of is:

[0030]

[0031] When M 33 ,M 44 >|M 34 |,|M 43 |When:

[0032]

[0033] When M 33 ,M 44 <|M 34 |,|M 43 |When:

[0034]

[0035] (2-2) Based on the propagation path of light in the medium, the Mueller matrix model is established, and the expression of the polarization characteristic parameters is obtained as follows:

[0036]

[0037]

[0038] Among them, d' depis the parameter of depolarization characteristic, t' is the parameter of birefringence characteristic, tan(2x') is the parameter of optical axis azimuth, d diat is the parameter of dichroism;

[0039] (2-3) The expressions of polarization characteristic parameters obtained by the above two methods are integrated to form a polarization parameter theoretical model, which is used to calculate various polarization parameter contrast images.

[0040] The specific process of step (3) is as follows:

[0041] The obtained Mueller matrix element image is calculated using the multi-polarization parameter group expression, and multiple depth-resolved images of the sample with polarization parameters and depolarization parameters as comparison are calculated for each pixel;

[0042] The multiple polarization and depolarization parameter images obtained by calculation are segmented, key information is extracted, and filtered to be converted into color images that are easy to observe. The chromaticity bars and scales corresponding to the color images are marked to facilitate the observation and analysis of the sample structure. At the same time, the grayscale image of the sample to be tested is retained for structural comparison.

[0043] In step (4), the specific process of drawing the polarization characteristic parameter curve in the depth direction of the specific area is:

[0044] Multiple A-scan images in the selected area of ​​multiple polarization and depolarization parameter images are averaged, the specific range is marked with a box, the resolution is clear, the horizontal and vertical scales are accurately calculated, and the curves of various polarization characteristic parameters in the depth direction of the specific area are obtained.

[0045] In step (4), the specific process of performing multi-polarization and depolarization parameter image analysis is as follows:

[0046] Focus on analyzing the parts and characteristic graphs in the polarization image that can reflect the local structure or lesion to be analyzed, integrate the corresponding depth curve graphs to compare the results, select the parameter image that best reflects the structural characteristics of the specific part, and complete the classification of the sensitivity of the polarization and depolarization parameters to the microstructure of the sample; combine the sample structural characteristics and the relationship with the polarization characteristics to further analyze the reasons why the polarization parameters are sensitive or insensitive to specific microstructures in the sample.

[0047] The specific process of step (5) is as follows:

[0048] The polarization and depolarization parameter images that are sensitive to the sample structure are selected as the specific parameter group of the structure of the area to be tested of the sample, so as to realize the large-scale monitoring of the tissue;

[0049] Analyze the depth curve of the polarization image of a specific area, and further determine the specific parameter group of the special local structure of the sample, so as to achieve efficient recognition and analysis of the microstructure of a small range of tissues;

[0050] After determining the two specific polarization parameter groups, the final image processing is performed on the last selected parameter image, and the design of the specific multi-parameter group display interface is completed.

[0051] A PS-SDOCT contrast enhancement system integrating multiple depolarization parameters comprises a memory and one or more processors, wherein the memory stores executable codes, and when the one or more processors execute the executable codes, the PS-SDOCT contrast enhancement method is implemented.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The present invention solves the problem of low information content and low contrast of single polarization parameter images of PS-SDOCT, and effectively avoids the problem of missed detection and misdetection of local and microstructure information caused by insufficient contrast. It improves the weak pertinence of the existing parameter evaluation system and strongly promotes the formulation and evaluation of identification parameters of tissue structure status specificity, sensitivity and accuracy. In addition, in the face of specific identification parameter groups specified for complex tissue structures, the efficiency of distinguishing the state, composition and changes of the tissue is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a flow chart of a PS-SDOCT contrast enhancement method integrating multiple depolarization parameters according to an embodiment of the present invention;

[0055] Figure 2 It is a tissue Mueller 16 matrix element image acquired based on the PS-SDOCT system in an embodiment of the present invention;

[0056] Figure 3 The biological tissue sample image with multiple polarization parameters as contrast is obtained according to an embodiment of the present invention. DETAILED DESCRIPTION

[0057] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0058] The PS-SDOCT contrast enhancement method integrating multiple depolarization parameters is an important method to realize rapid, accurate real-time monitoring and comprehensive analysis of biological tissue structure. The enhancement method proposed in the present invention includes establishing a multi-polarization and depolarization parameter theoretical method, as well as multi-polarization and depolarization parameter image acquisition, processing and analysis, and finally completing the formulation of a highly targeted biological tissue-specific identification polarization parameter group.

[0059] like Figure 1As shown, a PS-SDOCT contrast enhancement method integrating multiple depolarization parameters comprises the following steps:

[0060] Step 1: Obtain the images of 16 elements of the Mueller matrix.

[0061] After calculation, the 0 degree, 45 degree, 90 degree and right-hand circular polarization states are determined as the polarization states of the incident light. The horizontal and vertical components of the interference light formed by the four polarized lights passing through the sample and the light of the reference arm are detected to construct the Stokes components of the outgoing light. The Stokes vector of the outgoing light corresponding to each determined incident polarization state can be expressed as:

[0062]

[0063] Among them, H (z) and V (z) represent the horizontal and vertical components of the interference signal, respectively, S i (i=1,2,3,4) represents the i-th element in the vector, and * represents the complex conjugate. The expression of the Mueller matrix element is obtained based on the output Stokes component:

[0064]

[0065] Among them, M mn (m,n=1,2,3,4) represents the element in the mth row and nth column of the Mueller matrix, S r (i) (r = 0°, 45°, 90°, Y; i = 1, 2, 3, 4) represents the i-th element of the outgoing Stokes vector corresponding to the incident light being in the r polarization state. Y represents that the polarization state of the incident light is the right-hand circular polarization state.

[0066] Step 2: Establish theoretical methods for multi-polarization and depolarization parameters.

[0067] A set of polarization parameter expressions based on the component matrix relationship of different decomposition methods are as follows: dichroic parameters:

[0068]

[0069] Among them, M 1y (y=2,3,4) represents the yth element of the first row of the experimentally measured Mueller matrix. A complete description of dichroism usually requires three parameters: the dichroism value D, and the direction angle α describing the dichroism optical axis Jd and ellipticity ε Jd :

[0070]

[0071] By introducing the auxiliary matrix, the classical decomposition expression is transformed to obtain the depolarization parameter expression:

[0072]

[0073] Among them, the depolarization component parameter e J1 and e J2 Represent the parameters of linear depolarization characteristics, e J3 Parameters representing circular depolarization characteristics:

[0074] e J1 =M 22 , e J2 =|M 33 |,e J3 =|M 44 (M 33 ,M 44 >|M 34 |,|M 43 |)

[0075] e J1 =M 22 , e J2 =|M 34 |,e J3 =|M 43 (M 33 ,M 44 <|M 34 |,|M 43 |)

[0076] Combined with the condition of weak dichroism of tissue, the phase delay R under different conditions can be obtained by analysis. J The expression of is:

[0077]

[0078] Similarly, three parameters are also needed to fully describe the birefringence characteristics: the phase delay parameter R, the parameter describing the birefringence characteristics of the optical axis direction angle, and the ellipticity parameter: α r and ε r . Then analyze and characterize the phase delay matrix containing α Jr and ε Jr The element expression of is:

[0079] When M 33 ,M 44 >|M 34 |,|M 43 |When:

[0080]

[0081] When M 33 ,M 44 <|M34 |,|M 43 |When:

[0082]

[0083] According to the above multi-polarization parameter model, a contrast image characterizing the dichroism, depolarization characteristics and birefringence characteristics of the tissue is calculated.

[0084] The Mueller matrix model was established based on the propagation path of light in the medium, and the expression of typical polarization characteristic parameters was obtained. Among them, the mathematical model was established based on the premise that the interface at a specific depth is described by the depolarization matrix, and the influence of the microstructure on the light in the corresponding thickness is described by the birefringence characteristics and dichroism matrix in the propagation direction of the polarized light beam. After selecting matrix elements with relatively simple expressions and omitting some high-order terms of trigonometric functions, the specific expression is finally obtained:

[0085]

[0086] Among them, d' dep is the parameter of depolarization characteristic, t' is the parameter of birefringence characteristic, tan(2x') is the parameter of optical axis azimuth, d diat is the parameter of dichroism.

[0087] The expressions obtained by the above two methods are reasonably integrated to form a polarization parameter theoretical model, which is used to calculate various polarization parameter contrast images.

[0088] Step 3: Acquisition and processing of multi-polarization and depolarization parameter images.

[0089] The Mueller matrix element image obtained in step 1 is calculated according to the polarization and depolarization parameter expressions obtained in step 2, and multiple depth-resolved images of the sample with polarization parameters and depolarization parameters as comparisons are obtained for each pixel.

[0090] The calculated multiple polarization and depolarization parameter images are segmented, key information is extracted, and filtered to convert them into color images that are easy to observe. The chromaticity bars and scales corresponding to the color images are marked to facilitate the observation and analysis of the sample structure. At the same time, the grayscale image of the sample to be tested is retained as a structural comparison. The details and deficiencies that can be distinguished by a single intensity image are compared, and more details that can be distinguished after adding multiple contrast images are analyzed.

[0091] Step 4: Multi-polarization and depolarization parameter image analysis.

[0092] Multiple A-scan images in selected areas (such as areas that need to be observed and analyzed or abnormal areas such as lesions) in multiple polarization and depolarization parameter images are averaged, and the specific range is marked with a box to clarify the resolution, accurately calculate the horizontal and vertical scales, and obtain the curves of various polarization characteristic parameters in the depth direction of the specific area.

[0093] Focus on analyzing the parts and characteristic graphs in the polarization image that can reflect similar structural features, integrate the corresponding depth curve graphs together to compare the results, select the parameter image that best reflects the structural characteristics of the specific part, and complete the classification of the sensitivity of the polarization and depolarization parameters to the microstructure of the sample.

[0094] Combined with the structural characteristics of the sample and its connection with polarization properties, for example, the existence of birefringence is related to the anisotropy of important components of biological tissues: fiber orientation, collagen and other structures; the obvious inhomogeneity of biological tissues will cause the tissue structure to have a depolarization effect on polarized light. Further analysis is conducted on the reasons why polarization parameters are sensitive or insensitive to specific microstructures in the sample.

[0095] Step 5: Formulate tissue-specific identification polarization parameter group.

[0096] The polarization and depolarization parameter images that are sensitive to the sample structure are selected as the specific parameter group of the sample area structure to be tested, so as to achieve large-scale monitoring of the tissue. The depth curve of the polarization image of a specific area is analyzed, and the specific parameter group of the special local structure of the sample is further determined, so as to achieve efficient identification and analysis of the microscopic structure of a small area of ​​the tissue.

[0097] After determining the two specific polarization parameter groups, the final image processing is performed on the last selected parameter image, and the design of the specific multi-parameter group display interface is completed.

[0098] Step 6: Extended application and optimization of theoretical methods.

[0099] The invented method performs multiple experiments on the same state of the same tissue site to verify and optimize the specified specific identification parameter set; performs different experiments on different states of the same tissue site, such as normal and pathological stages, to accurately determine the polarization and depolarization parameter sets for identifying different stages. In addition, it can be used to analyze different tissue structures and establish different polarization parameter image databases.

[0100] In order to verify the effect of the present invention, the following experiment was conducted using normal telogen skin tissue of mice as a sample.

[0101] S01, obtain 16 element images of the Mueller matrix. The incident light polarization states are 0 degrees, 45 degrees, 90 degrees and right-hand circular polarization states. The sample is normal skin tissue of mice in vitro. The first element image of the Mueller matrix is ​​the intensity map of the sample, and the next 15 images are obtained by normalizing the original first element image of the Mueller matrix. The image width is about 2mm, and the effective imaging depth is about 1mm. See Figure 2 , where M mn (m,n=1,2,3,4) is the image of the element in the mth row and nth column of the Mueller matrix.

[0102] S02, calculating multi-polarization and depolarization parameter images. According to the established multi-polarization parameter model, the Mueller matrix element diagram required by each expression is selected to complete the calculation.

[0103] S03, multi-polarization and depolarization parameter image processing. The obtained multi-polarization parameter images are presented together and converted into color images for easy observation. The approximate depth of the skin tissue structure can be known from the intensity image, and the polarization parameter image within the effective imaging depth is processed. The pore structure is selected as a local special structure for analysis, and 20 A scans are selected for numerical analysis of the depth direction of the polarization parameter image. The multiple polarization parameter images after image processing are as follows: Figure 3 shown.

[0104] S04, multi-polarization, depolarization parameter image analysis. 14 polarization parameter images were analyzed. Four of the images in the boxes were obtained by establishing the Mueller matrix model method through the propagation path of light in the medium, and the other images were calculated by another method. There are parameters that characterize the same characteristics in the two, which can be used as a comparison. For example, the overall strength distribution of the depolarization and dichroic images tends to be consistent, while the birefringence characteristic image in the large box shows a more obvious difference, which shows that this method is more obvious for sample tissues; the two methods also have a certain degree of complementarity. The contrast of the depolarization parameter images of the two methods is not strong enough at depth, but one of the methods also gives a depolarization component parameter map, and its depth contrast is significantly enhanced. At the same time, the hole structure on the right side of the optical axis image in the box is not clear enough, but it is clearer in the optical axis component parameter image of the other method. See. Figure 3 and the markings therein.

[0105] S05, formulation of tissue-specific identification polarization parameter groups. Based on the above analysis, for mouse skin tissue, the polarization parameter images of the two methods combined, and the parameter images obtained by the same method, can select any one of the methods if the images reflect similar information. Among the remaining multiple parameter images, the formulation of specific parameter groups is determined according to the needs (including pore structure and surrounding tissue analysis, surface tissue analysis, or transition tissue structure analysis between the surface and deep layers).

[0106] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A PS-SDOCT contrast enhancement method integrating multiple depolarization parameters, characterized in that: The following steps are involved: (1) Four polarization states are input into the PS-SDOCT system to construct the Stokes component calculation to obtain the image of the 16 elements of the Mueller matrix of the sample to be tested; (2) Establishing a multi-polarization parameter set obtained by combining the component matrix relationship of different decomposition methods with the light propagation path method in the medium; (3) According to the multi-polarization parameter group expression obtained in step (2), the corresponding Mueller matrix element image in step (1) is selected, the multi-polarization and depolarization parameter images are calculated and the image processing is completed; (4) Selecting a key structural area for observation, drawing a polarization characteristic parameter curve in the depth direction of the specific area based on the corresponding polarization image in step (3), and performing multi-polarization and depolarization parameter image analysis; (5) Determine the polarization parameter image with high sensitivity and formulate a specific identification polarization parameter group to achieve large-scale monitoring of the tissue and efficient identification and analysis of small-scale microscopic tissues.

2. The PS-SDOCT contrast enhancement method integrating multiple depolarization parameters according to claim 1, characterized in that: The specific process of step (1) is as follows: (1-1) According to the Mueller matrix form, four different input polarization states are calculated and determined; (1-2) adjusting the corresponding incident polarization state through the polarization control component; (1-3) The horizontal and vertical components of the interference light formed by different incident polarized light passing through the sample and the light in the reference arm are obtained through two CCDs; (1-4) Construct the Stokes vector diagram of the four incident lights corresponding to the outgoing lights; (1-5) The 16 element images of the Mueller matrix are obtained based on the Stokes component calculation.

3. The PS-SDOCT contrast enhancement method integrating multiple depolarization parameters according to claim 1, characterized in that: The specific process of step (2) is as follows: (2-1) Based on the component matrix relationship of different decomposition methods, a set of polarization parameter expressions are obtained as follows: dichroic parameters: Among them, M 1y (y=2,3,4) represents the yth element of the first row of the experimentally measured Mueller matrix; three parameters are required to fully describe dichroism: the dichroism value D and the direction angle α describing the dichroism optical axis Jd and ellipticity ε Jd : Depolarization parameter expression: Among them, the depolarization component parameter e J1 and e J2 Represent the parameters of linear depolarization characteristics, e J3 Parameters representing circular depolarization characteristics: e J1 =M 22 ,e J2 =|M 33 |,e J3 =|M 44 (M 33 ,M 44 >|M 34 |,|M 43 |) e J1 =M 22 ,e J2 =|M 34 |,e J3 =|M 43 (M 33 ,M 44 <|M 34 |,|M 43 |) Combined with the condition of weak dichroism of tissue, the phase delay R under different conditions is analyzed. J The expression of is: When M 33 ,M 44 >|M 34 |,|M 43 |When: When M 33 ,M 44 <|M 34 |,|M 43 |When: (2-2) Based on the propagation path of light in the medium, the Mueller matrix model is established, and the expression of the polarization characteristic parameters is obtained as follows: Among them, d' dep is the parameter of depolarization characteristic, t' is the parameter of birefringence characteristic, tan(2x') is the parameter of optical axis azimuth, d diat is the parameter of dichroism; (2-3) The expressions of polarization characteristic parameters obtained by the above two methods are integrated to form a polarization parameter theoretical model, which is used to calculate various polarization parameter contrast images.

4. The PS-SDOCT contrast enhancement method integrating multiple depolarization parameters according to claim 1, characterized in that: The specific process of step (3) is as follows: The obtained Mueller matrix element image is calculated using the multi-polarization parameter group expression, and multiple depth-resolved images of the sample with polarization parameters and depolarization parameters as comparison are calculated for each pixel; The multiple polarization and depolarization parameter images obtained by calculation are segmented, key information is extracted, and filtering is performed to convert them into color images that are easy to observe. The chromaticity bars and scales corresponding to the color images are marked to facilitate the observation and analysis of the sample structure. At the same time, the grayscale image of the sample to be tested is retained for structural comparison.

5. The PS-SDOCT contrast enhancement method integrating multiple depolarization parameters according to claim 1, characterized in that: In step (4), the specific process of drawing the polarization characteristic parameter curve in the depth direction of a specific area is as follows: Multiple A-scan images in the selected area of ​​multiple polarization and depolarization parameter images are averaged, the specific range is marked with a box, the resolution is clear, the horizontal and vertical scales are accurately calculated, and the curves of various polarization characteristic parameters in the depth direction of the specific area are obtained.

6. The PS-SDOCT contrast enhancement method integrating multiple depolarization parameters according to claim 5, characterized in that: In step (4), the specific process of performing multi-polarization and depolarization parameter image analysis is as follows: Focus on analyzing the parts and characteristic graphs in the polarization image that can reflect the local structure or lesion to be analyzed, integrate the corresponding depth curve graphs to compare the results, select the parameter image that best reflects the structural characteristics of the specific part, and complete the classification of the sensitivity of the polarization and depolarization parameters to the microstructure of the sample; combine the sample structural characteristics and the relationship with the polarization characteristics to further analyze the reasons why the polarization parameters are sensitive or insensitive to specific microstructures in the sample.

7. The PS-SDOCT contrast enhancement method integrating multiple depolarization parameters according to claim 1, characterized in that: The specific process of step (5) is as follows: The polarization and depolarization parameter images that are sensitive to the sample structure are selected as the specific parameter group of the structure of the area to be tested of the sample, so as to realize the large-scale monitoring of the tissue; Analyze the depth curve of the polarization image of a specific area, and further determine the specific parameter group of the special local structure of the sample, so as to achieve efficient recognition and analysis of the microstructure of a small range of tissues; After determining the two specific polarization parameter groups, the final image processing is performed on the last selected parameter image, and the design of the specific multi-parameter group display interface is completed.

8. A PS-SDOCT contrast enhancement system integrating multiple depolarization parameters, characterized in that: The invention comprises a memory and one or more processors, wherein the memory stores executable codes, and when the one or more processors execute the executable codes, the method for improving the PS-SDOCT contrast is implemented as described in any one of claims 1 to 7.

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