Symmetrical single LCVR polarization imaging system and imaging method

Abstract

The invention belongs to the technical field of biomedical treatment, and particularly discloses a symmetric single LCVR polarization imaging system which comprises a light source, a camera, an optical filter, a first polaroid, a first liquid crystal phase delayer, a second liquid crystal phase delayer and a second polaroid. Compared with the prior art, the number of elements formed by the whole system is small, and the system is convenient to build; the time for collecting the whole image is shorter, and the average time for measuring each time is only 150s; the system precision is higher, and the overall precision can reach 90% or above when the system is used for lung cancer detection; the error of the detected lung cancer image is smaller, so that the number of array elements with distinguishing significance in the generated Mueller matrix is larger; compared with a traditional LCVR imaging system, the number of used LCVRs is smaller, and the cost is lower.

Description

Technical Field

[0001] The present invention relates to the field of biomedical technology, and in particular to a symmetrical single LCVR polarization imaging system and an imaging method. Background Art

[0002] Lung cancer is the most common cancer in the world and the leading cause of cancer-related death. When cancer is detected early, treatment is more effective and survival rates are greatly improved. However, most patients lose the chance of radical surgery due to late diagnosis. Therefore, we should not only pay attention to treatment methods, but also pay more attention to early detection of lung cancer.

[0003] Traditional lung cancer detection relies more on biomarker detection. However, this method requires incision of biological tissues, and the detection time is long, the sensitivity is low, and it is extremely user-unfriendly. Further innovation and development of early detection methods are still needed. At this time, optical biological detection methods were proposed, and polarization optical technology has received considerable attention due to its potential in biomedical applications. Polarization imaging technology has the characteristics of non-contact, non-invasive, and high sensitivity. Compared with traditional light intensity imaging and infrared radiation imaging, it has unique advantages. Polarization imaging can also capture the polarization information of another dimension of the target object, which can reveal the microscopic structure information of the sample and is often used for the detection of various abnormal tissues.

[0004] Since Bickel et al. introduced polarization imaging technology into the field of biomedical sensing in 1976, the technology has made significant progress in biomedical detection. Quoc-Hung Phan used polarization imaging technology to analyze glucose tissue model solutions with different albumin concentrations, revealing the optical properties of Serum Albumin Protein Media. AngeloPierangelo combined multispectral and polarization imaging technology to detect human colon cancer, and the results showed that the technology can effectively distinguish normal tissue from diseased tissue. Alexander G.Ushenko used polarization imaging method and 3D Mueller matrix detection technology to analyze the polycrystalline structure of blood films, and the results showed that the accuracy of this technology in early cancer detection exceeded 90%. Among them, the polarization imaging system based on the principle of dual wave plate rotation is the most widely used. This principle was originally proposed by RMAAzzam in 1978. The Mueller matrix is ​​calculated by the operation rules of Fourier coefficients to obtain the polarization information of the image. Compared with the traditional 36-order HV and 49-order HV methods, the dual wave plate rotation method is favored because of its fewer rotating devices and rotation times. Minghao Sun used the dual-wave plate rotation polarization imaging system to measure unstained human cervical cancer, and the results showed that polarization parameters can significantly distinguish cancerous tissue from healthy tissue. More studies have combined the dual-wave plate rotation polarization imaging system with a microscope to measure some microscopic samples such as changes in the fiber structure of breast ductal carcinoma tissue and microscopic changes in nude mouse skin at different times, which have achieved significant results. However, the dual-wave plate rotation polarization imaging system still relies on two wave plates that rotate 30 times each in principle and during use. This multiple mechanical rotation may introduce unnecessary errors and is time-consuming, affecting the accuracy of the results.

[0005] As an electrically controlled liquid crystal device, the liquid crystal phase retarder (LCVR) has become an ideal choice to replace the rotating wave plate due to its good stability, easy operation and high sensitivity. By applying voltage to both ends of the LCVR to change the refractive index of the liquid crystal molecules inside it, the phase delay of the light can be modulated, and the response time is extremely short, which is particularly suitable as a polarization generating device. Laude-Boulesteix B, Antonello De Martino and others applied two sets of LCVR to the polarization imaging system to verify the feasibility of LCVR. However, using two sets of LCVR as polarization elements requires too many components in the system and the cost is relatively high. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a symmetrical single LCVR polarization imaging system and an imaging method.

[0007] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0008] A symmetrical single LCVR polarization imaging system comprises a light source and a camera, wherein the incident light path of the light source is provided with a filter and a system polarizing part in sequence, the system polarizing part is used to modulate the polarization state of the incident light irradiated on a sample to be tested, the camera is arranged on the outgoing light path of the sample to be tested, a system analyzing part is provided between the camera and the sample to be tested, the system analyzing part is used to modulate the polarization state of scattered light of the sample to be tested; the system polarizing part comprises a polarizer 1 and a liquid crystal phase retarder 1 arranged in sequence along the incident light path; the system analyzing part comprises a liquid crystal phase retarder 2 and a polarizer 2 arranged in sequence along the scattered light path.

[0009] Furthermore, the system polarizing part and the system analyzing part are symmetrically distributed, and the angle between the fast axis of the first liquid crystal phase retarder and the second liquid crystal phase retarder and the horizontal direction is 45°.

[0010] Preferably, the light source is a laser light source.

[0011] Preferably, the camera is a CMOS camera.

[0012] In a second technical solution, the present invention proposes an imaging method, applied to the imaging system according to any of claims 1 to x, the method comprising:

[0013] Modulating the angle of the first polarizer P1, the angle of the second polarizer P2, the phase delay of the polarizing part PSG, and the phase delay of the analyzing part to control the imaging system to be in a predetermined polarization state;

[0014] Under a plurality of predetermined polarization states, respectively, image acquisition is performed on the target object to obtain polarization images corresponding to the respective polarization states, wherein the polarization information contained in each of the polarization images is different;

[0015] Based on each of the polarization images, a normalized Mueller matrix image is generated to obtain a target image.

[0016] In the second technical solution, as a preference, the angle of the first polarizer P1 is 0 degrees or 45 degrees; the angle of the second polarizer P2 is 0 degrees or 45 degrees;

[0017] When the first polarizer is at 0 degrees, the phase delay δ1 of the polarizing part LCVR1 is zero, π, or When the first polarizer is at 45 degrees, the phase delay δ1 of the polarizing part LCVR1 is a Random arbitrary value;

[0018] When the second polarizer is at 0 degrees, the phase delay δ2 of the polarizing part LCVR2 is zero, π, or When the second polarizer is at 45 degrees, the phase delay δ2 of the polarizing portion LCVR2 is a Random arbitrary value.

[0019] In the second technical solution, as preferably, the polarization states include 16 types, and the polarization images include HH image, HV image, HP image, HR image, VH image, VV image, VP image, VR image, PH image, PV image, PP image, PR image, RH image, RV image, RP image and RR image;

[0020] The step of generating a normalized Mueller matrix image based on each of the polarization images comprises:

[0021] Based on the HH image, the HV image, the VH image, and the VV image, the first matrix element m is generated respectively. 11 , the second matrix element m 12 And the fifth matrix m 21 ;

[0022] Based on the PH image, the PV image and the first matrix element, the third matrix element m is generated. 13 ;

[0023] Based on the RH image, the RV image and the first matrix element, a fourth matrix element m is generated. 14 ;

[0024] Based on the HH image, the HV image, and the VH image, the sixth matrix element m is generated. 22 ;

[0025] Based on the PH image, the PV image and the fifth matrix element, the seventh matrix element m is generated. 22 ;

[0026] Based on the RH image, the RV image and the fifth matrix element, an eighth matrix element m is generated. 24 ;

[0027] Based on the HP image, the VP image and the first matrix element, a ninth matrix element m is generated. 31 ;

[0028] Based on the HP image, the VP image and the second matrix element, a tenth matrix element m is generated. 32 ;

[0029] Based on the PP image, the PH image, the PV image and the ninth matrix element, an eleventh matrix element m is generated. 33 ;

[0030] Based on the RP image, the RH image, the RV image and the ninth matrix element, the twelfth matrix element m is generated. 34 ;

[0031] Based on the HR image, the VR image and the first matrix element, a thirteenth matrix element m is generated. 41 ;

[0032] Based on the HR image, the VR image and the second matrix element, a fourteenth matrix element m is generated. 42 ;

[0033] Based on the PR image, the PH image, the PV image and the thirteenth matrix element, a fifteenth matrix element m is generated. 43 ;

[0034] Based on the RR image, the RH image, the RV image and the thirteenth matrix element, a sixteenth matrix element m is generated. 44 ;

[0035] A normalized Mueller matrix image is generated based on each matrix element.

[0036] Compared with the prior art, the entire system of the present invention has fewer components and is more convenient to build; the entire image acquisition time used is shorter, with each measurement consuming only 150 seconds on average; the system has higher accuracy, and the overall accuracy for lung cancer detection can reach more than 90%; the detected lung cancer image has smaller errors, so the generated Mueller matrix has more array elements with distinguishing significance; compared with the traditional LCVR imaging system, the present invention uses fewer LCVRs and has lower costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the structure of a symmetrical single LCVR polarization imaging system according to an embodiment of the present invention.

[0038] Figure 2 LCVR calibration curve diagram of the embodiment of the present invention.

[0039] Figure 3 The lung cancer slices according to the embodiment of the present invention are: (a) is slice No. 18, and (b) is slice No. 23.

[0040] Figure 4 The normalized Mueller matrix result diagrams of the embodiments of the present invention are as follows: (a) is the normalized Mueller matrix of the polarization imaging system of the dual wave plate rotation method, and (b) is the normalized Mueller matrix of the symmetric single LCVR polarization imaging system.

[0041] Figure 5 This is a 3D data set of lung cancer slice No. 18 collected by the symmetrical single LCVR polarization imaging system according to the embodiment of the present invention.

[0042] Figure 6 1 and 2 are polarization information intensity curves and radar diagrams according to an embodiment of the present invention: (a) is the polarization information intensity curve, and (b) is the corresponding radar diagram.

[0043] Figure 7 This is a precision analysis diagram of the acquisition results of lung cancer slice No. 23 by the symmetrical single LCVR polarization imaging system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the invention.

[0045] Example 1

[0046] like Figure 1 As shown, this embodiment exemplarily shows a symmetrical single LCVR polarization imaging system, including a light source 1 and a camera 8, wherein the incident light path of the light source 1 is provided with a filter 2 and a system polarizing part in sequence, and the system polarizing part is used to modulate the polarization state of the incident light irradiated on the sample to be tested, and the camera 8 is arranged on the outgoing light path of the sample to be tested 5, and a system analyzing part is provided between the camera 8 and the sample to be tested 5, and the system analyzing part is used to modulate the polarization state of the scattered light of the sample to be tested; the system polarizing part includes a polarizer 1 3 and a liquid crystal phase retarder 1 4 arranged in sequence along the incident light path; the system analyzing part includes a liquid crystal phase retarder 2 6 and a polarizer 2 7 arranged in sequence along the scattered light path.

[0047] It should be noted that the liquid crystal variable phase retarder (LCVR) is a precision polarization device made using the electrically controlled birefringence characteristics of nematic liquid crystals. The phase modulation of light is achieved by changing the refractive index of the liquid crystal molecules by applying a voltage to both ends of the LCVR. The basic structure of the LCVR is to fill liquid crystal material between two pieces of flat glass and coat the glass with a conductive film. Normally, applying a voltage to both ends will change the arrangement order of the liquid crystal molecules inside, thereby changing the phase delay of light. However, we only know that the phase delay can be adjusted by changing the voltage, but we do not know the specific correspondence between the voltage and the phase delay. Therefore, in this embodiment, the LCVR must be calibrated before using it to obtain a voltage-phase delay curve, such as Figure 2 shown.

[0048] Furthermore, the system polarizing part and the system analyzing part are symmetrically distributed, and the angle between the fast axis of the liquid crystal phase retarder 1 4 and the liquid crystal phase retarder 2 6 and the horizontal direction is 45°.

[0049] Example 2

[0050] This embodiment proposes an imaging method, which is completed by the symmetrical single LCVR polarization imaging system described in the above embodiment 1.

[0051] Specifically, the above method includes:

[0052] Modulating the angle of the first polarizer P1, the angle of the second polarizer P2, the phase delay of the polarizing part PSG, and the phase delay of the analyzing part to control the imaging system to be in a predetermined polarization state;

[0053] Under a plurality of predetermined polarization states, respectively, image acquisition is performed on the target object to obtain polarization images corresponding to the respective polarization states, wherein the polarization information contained in each of the polarization images is different;

[0054] Based on each of the polarization images, a normalized Mueller matrix image is generated to obtain a target image.

[0055] The angle of the first polarizer P1 is 0 degrees or 45 degrees; the angle of the second polarizer P2 is 0 degrees or 45 degrees;

[0056] When the first polarizer is at 0 degrees, the phase delay δ1 of the polarizing part LCVR1 is zero, π, or When the first polarizer is at 45 degrees, the phase delay δ1 of the polarizing part LCVR1 is a Random arbitrary value;

[0057] When the second polarizer is at 0 degrees, the phase delay δ2 of the polarizing part LCVR2 is zero, π, or When the second polarizer is at 45 degrees, the phase delay δ2 of the polarizing portion LCVR2 is a Random arbitrary value.

[0058] The above method is described in detail through the following technical solution.

[0059] according to Figure 1 As shown, the Stokes vector relationship between the incident light and the outgoing light of the polarization imaging system is:

[0060] S out =M P2 M LC2 M S M LC1 M P1 S in ;

[0061] Among them, S out represents the Stokes vector of the system's outgoing light, M P2 The Mueller matrix of the polarizer P2 of PSA, M S Represents the Mueller matrix of the sample to be tested, M P1Represents the Mueller matrix of the polarizer P1 of PSG. In this experiment, the target Mueller matrix measured last was normalized, so the transmittance of each optical element does not need to be considered. Since the polarizer placed in front of the light source is horizontally polarized, the Stokes vector of the incident light is S in =[1 1 0 0] T , so the Stokes vector of PSG is expressed as:

[0062]

[0063] Therefore, the Stokes vector relationship can change the polarization state of the output light by modulating the phase delay δ of LC1.

[0064] If we want to modulate the outgoing light into horizontally polarized light S out =[1 1 0 0] T , then δ=0;

[0065] If we want to modulate the outgoing light into vertical linear polarized light S out =[1 -1 0 0] T , then δ=π;

[0066] If we want to modulate the outgoing light into right-handed circularly polarized light S out =[1 0 0 1] T ,but

[0067] From the above vector relationship, it can be seen that no matter how the phase delay δ of LC1 is adjusted, there is no way to modulate the outgoing light of PSG into 45° linearly polarized light S out =[1 0 1 0] T Because the third element of the Stokes vector of the PSG output light is 0, there is no δ as a variable, and the modulation cannot be 1. If you want to modulate 45° linear polarized light, you need to make some adjustments to the polarizer.

[0068] The Mueller matrix of the 45° polarizer is:

[0069]

[0070] The coefficient 1 / 2 of the Mueller matrix does not affect the result of calculating the polarization state of the light, so it can be ignored during the calculation. Therefore, the Stokes vector of the PSG output light is expressed as:

[0071]

[0072] From the Stokes vector result in the above formula, it can be known that this combination can modulate the outgoing light of PSG into 45° linear polarized light. PSA and PSG have the same structural composition, so the modulation principle of polarized light is also the same, which will not be elaborated here.

[0073] This embodiment is mainly used for lung cancer detection, with in vitro lung cancer slices as the sample to be detected. According to Table 1, 16 different polarization states of light can be obtained by modulating the combination of PSG and PSA. 16 polarization images of lung cancer containing different information are collected through these 16 combinations.

[0074] Table 1

[0075]

[0076] H represents horizontal linear polarization, V represents vertical linear polarization, P represents 45° linear polarization, R represents right-handed circular polarization, HH represents polarization as H and analysis as H, and the other combinations have the same meaning. The δ1 column represents the phase delay modulated by LCVR1, the P1 column represents the rotation angle of polarizer 1, and the δ2 ​​and P2 columns are the same. (Take the first row as an example, to capture an image with HH polarization information, the phase delay δ1 of the polarization part LCVR1 needs to be modulated to 0, and the angle of polarizer P1 needs to be modulated to 0°. The phase delay δ2 of the analysis part LCVR2 needs to be modulated to 0, and the angle of polarizer P2 needs to be modulated to 0°.).

[0077] The image data in this embodiment is mainly processed and analyzed using the imaging method of the Mueller matrix. In 1943, Hans Mueller developed a matrix that links the Stokes vector of the incident sample light with the Stokes vector of the outgoing sample light. A 4×4 matrix is ​​calculated by calculating the Stokes vectors of two known light rays, which is called the Mueller matrix. The calculation relationship is shown in the following formula. The polarization characteristics of the sample can be described by the 4×4 Mueller matrix.

[0078] S out =M sampls ·S in ;

[0079] The polarization image is calculated in Table 2 to obtain the Mueller matrix of the sample. For simplicity, the Mueller matrix can be normalized by dividing all array elements by the 00 array element. In the normalized matrix, the value of the 00 array element is 1, and the values ​​of the remaining array elements are between 1 and -1. Normalizing the Mueller matrix can facilitate the determination of the polarization characteristics in the sample tissue and has a better effect on lung cancer identification.

[0080] Table 2

[0081]

[0082] So far, the above-mentioned symmetrical single LCVR polarization imaging system is collected in the manner of Table 1, and the result is calculated in the manner of Table 2. The detection of lung cancer tissue can be achieved through the generated Mueller matrix.

[0083] In order to verify the feasibility of the present invention, a polarization imaging system of the dual wave plate rotation method was built as the reference group of the present invention, and the system performance, Mueller matrix results, and system accuracy were compared respectively:

[0084] 1. System performance;

[0085] The hardware comparison results between the system of this embodiment and the reference group are shown in Table 3. Table 3 clearly shows the advantages of the symmetrical single LCVR polarization imaging system. The system uses two polarizers and a set of LCVR as the modulation elements of polarized light, which simplifies the construction of the system. The modulation method combining electrically controlled liquid crystal with a small amount of mechanical rotation also simplifies the operation process. Since the modulation mainly relies on electrically controlled liquid crystal, the error introduced by mechanical rotation is greatly reduced. In addition, the liquid crystal switching time is only 60ms, which further speeds up the acquisition speed. Combined with a small amount of mechanical rotation, the symmetrical single LCVR polarization imaging system can complete all acquisitions in about 150s per measurement on average. From the above analysis, the symmetrical single LCVR polarization imaging system shows good performance advantages.

[0086] Table 3

[0087]

[0088] 2. Mueller matrix results:

[0089] The samples used in this example are Figure 3 The 20 μm thick dewaxed, unstained lung cancer section shown. The section sample was provided by the First Medical College of Jilin University, and this work was approved by the Ethics Committee of the First Hospital of Jilin University. The cancerous part used in the section study has been manually annotated by a professional pathologist.

[0090] By using the Mueller matrix to represent the polarization image, we can distinguish the cancerous area from the non-cancerous area based on the significant difference in polarization characteristics by observing the numerical changes in the array elements in the Mueller matrix. Take the lung cancer slice No. 18 as an example. Figure 4As shown in the figure, the normalized Mueller matrix calculated by the symmetrical single LCVR polarization imaging system reveals significant polarization characteristics. The experimental results show that an average of 7 array elements with obvious polarization characteristics can be identified in each measurement, which is more than the measurement results of the polarization imaging system using the dual wave plate rotation method. In addition, the symmetrical single LCVR polarization imaging system performs well in characterizing the characteristic information of the edge area of ​​the cancerous part in the array element, and the clear numerical color distribution makes the positioning of the cancerous area more accurate. This is because the system error is smaller, and the polarization information calculated with a more accurate image is also more significant.

[0091] 3. System accuracy analysis:

[0092] In order to further evaluate the measurement accuracy of the system, this embodiment adopts data processing technology in the field of remote sensing. Using spectral curve generation technology, we analyze the longitudinal polarization information of the Mueller matrix data set. Through this analysis, we can evaluate the accuracy of the system's data collection. Taking the lung cancer tissue slice numbered 18 as an example, Figure 5 The normalized Mueller matrix of 16 array elements collected by the symmetrical single LCVR polarization imaging system is shown, and the corresponding 3D data set image is constructed. In the constructed 3D Mueller matrix data set, we selected the regions of interest of cancerous tissue and normal tissue according to the annotation of the slices, and drew the corresponding characteristic curves. Figure 5 In the figure, the red area identifies the region of interest of cancerous tissue, while the blue area corresponds to normal tissue.

[0093] The characteristic curves of the region of interest are shown in Figure 6 In (a), the ordinate represents the intensity of polarization information, and the 16 points on the abscissa correspond to the Mueller matrix elements from m00 to m33. Figure 6 (a) in Figure 1 clearly shows the contrast between the polarization information intensity of different array elements in cancerous tissue and normal tissue. In order to present these differences more intuitively, we convert the characteristic curve into Figure 6 The radar chart format shown in (b) in the figure.

[0094] This embodiment adopts the spectral angle mapping method to classify the data set according to the polarization information intensity curve, and compares it with the standard template annotated by the physician to evaluate the accuracy of the symmetrical single LCVR polarization imaging system in detecting cancerous tissue. The classification results are detailed in Table 4. The accuracy of the symmetrical single LCVR polarization imaging system in the classification of cancerous tissue reached 96.4%, the classification accuracy of normal tissue was 92.08%, and the overall accuracy was about 93.92%. In addition, we also processed the Mueller matrix of the No. 18 lung cancer image collected by the polarization imaging system of the dual wave plate rotation method to compare the accuracy of the two systems. The analysis results show that the classification accuracy of the polarization imaging system of the dual wave plate rotation method in cancerous tissue is 83.68%, the accuracy of normal tissue is 87.06%, and the overall accuracy is 85.15%, which are lower than the symmetrical single LCVR polarization imaging system, thereby highlighting the superiority of the symmetrical single LCVR polarization imaging system in terms of accuracy.

[0095] Table 4

[0096]

[0097] To verify that the high accuracy of the symmetrical single LCVR polarization imaging system is not an isolated case, we further tested other lung cancer slices. The overall accuracy of all test results exceeded 90%. Taking lung cancer slice No. 23 as an example, Figure 7 As shown, the classification accuracy of the cancer region is 84.25%, and the overall accuracy reaches about 90.42%. These results further confirm the high accuracy of the SSLPIS system in lung cancer tissue detection.

[0098] In summary, the present invention utilizes the stability of LCVR to solve the problems of complex operation and large number of mechanical rotation errors in the traditional dual-wave plate rotation polarization imaging system. It also solves the problem that a single LCVR combined with a polarizer can modulate all vector information of polarized light. The accuracy of the present invention is also much higher than that of the traditional dual-wave plate rotation polarization imaging system. Connection method and spatial layout of the symmetrical single LCVR polarization imaging system: A special connection method has been developed, which greatly reduces the time consumption of the entire acquisition process and reflects high precision, with an average overall accuracy of more than 90%.

[0099] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A symmetrical single LCVR polarization imaging system, comprising a light source and a camera, characterized in that: The incident light path of the light source is provided with a filter and a system polarizing part in sequence, the system polarizing part is used to modulate the polarization state of the incident light shining on the sample to be tested, the camera is arranged on the outgoing light path of the sample to be tested, and a system analyzing part is provided between the camera and the sample to be tested, the system analyzing part is used to modulate the polarization state of the scattered light of the sample to be tested; the system polarizing part includes a polarizing plate 1 and a liquid crystal phase retarder 1 arranged in sequence along the incident light path; the system analyzing part includes a liquid crystal phase retarder 2 and a polarizing plate 2 arranged in sequence along the scattered light path.

2. The symmetrical single LCVR polarization imaging system according to claim 1, characterized in that: The system polarizing part and the system analyzing part are symmetrically distributed, and the angles between the fast axes of the first liquid crystal phase retarder and the second liquid crystal phase retarder and the horizontal direction are both 45 degrees.

3. The symmetrical single LCVR polarization imaging system according to claim 1, characterized in that: The light source is a laser light source.

4. The symmetrical single LCVR polarization imaging system according to claim 1, characterized in that: The camera is a CMOS camera.

5. An imaging method, characterized in that: Applied to the imaging system according to any one of claims 1 to 4, the method comprises: Modulating the angle of the first polarizer P1, the angle of the second polarizer P2, the phase delay of the polarizing part PSG, and the phase delay of the analyzing part to control the imaging system to be in a predetermined polarization state; Under a plurality of predetermined polarization states, respectively, image acquisition is performed on the target object to obtain polarization images corresponding to the respective polarization states, wherein the polarization information contained in each of the polarization images is different; Based on each of the polarization images, a normalized Mueller matrix image is generated to obtain a target image.

6. The imaging method according to claim 5, characterized in that: The angle of the first polarizer P1 is 0 degrees or 45 degrees; the angle of the second polarizer P1 is 0 degrees or 45 degrees. P 2's angle is 0 or 45 degrees; When the first polarizer is at 0 degrees, the phase delay δ1 of the polarizing part LCVR1 is zero, π, or When the first polarizer is at 45 degrees, the phase delay δ1 of the polarizing part LCVR1 is a Random arbitrary value; When the second polarizer is at 0 degrees, the phase delay δ2 of the polarizing part LCVR2 is zero, π, or When the second polarizer is at 45 degrees, the phase delay δ2 of the polarizing portion LCVR2 is a Random arbitrary value.

7. The imaging method according to claim 5, characterized in that: The polarization states include 16 types, and the polarization images include HH image, HV image, HP image, HR image, VH image, VV image, VP image, VR image, PH image, PV image, PP image, PR image, RH image, RV image, RP image and RR image; The step of generating a normalized Mueller matrix image based on each of the polarization images comprises: Based on the HH image, the HV image, the VH image, and the VV image, the first matrix element m is generated respectively. 11 , the second matrix element m 12 And the fifth matrix m 21 ; Based on the PH image, the PV image and the first matrix element, the third matrix element m is generated. 13 ; Based on the RH image, the RV image and the first matrix element, a fourth matrix element m is generated. 14 ; Based on the HH image, the HV image, and the VH image, the sixth matrix element m is generated. 22 ; Based on the PH image, the PV image and the fifth matrix element, the seventh matrix element m is generated. 22 ; Based on the RH image, the RV image and the fifth matrix element, an eighth matrix element m is generated. 24 ; Based on the HP image, the VP image and the first matrix element, a ninth matrix element m is generated. 31 ; Based on the HP image, the VP image and the second matrix element, a tenth matrix element m is generated. 32 ; Based on the PP image, the PH image, the PV image and the ninth matrix element, an eleventh matrix element m is generated. 33 ; Based on the RP image, the RH image, the RV image and the ninth matrix element, the twelfth matrix element m is generated. 34 ; Based on the HR image, the VR image and the first matrix element, a thirteenth matrix element m is generated. 41 ; Based on the HR image, the VR image and the second matrix element, a fourteenth matrix element m is generated. 42 ; Based on the PR image, the PH image, the PV image and the thirteenth matrix element, a fifteenth matrix element m is generated. 43 ; Based on the RR image, the RH image, the RV image and the thirteenth matrix element, a sixteenth matrix element m is generated. 44 ; A normalized Mueller matrix image is generated based on each matrix element.

Images