Surface inspection system and method based on polarimetric imaging

Abstract

The application relates to the technical field of imaging detection, and particularly provides a surface detection system and method based on polarization imaging. The system comprises a light source, a beam splitter, a reflection device, a beam combiner, a polarization analyzer and an imaging device; the light source can generate a light source beam along a first light path; the beam splitter can divide the light source beam into a second signal light and a first signal light; the reflection device reflects the second signal light to obtain a second reflected signal light; the beam combiner combines the detection signal light and the first signal light / second reflected signal light to obtain interference signal light; the polarization analyzer filters the non-polarization signal light in the interference signal light; and the imaging device obtains a detection image of a surface to be detected. The surface detection system based on polarization imaging provided by the application can improve the resolution of the detection image of the surface to be detected, thereby improving the surface detection precision under a lower photon flux.

Description

Technical Field

[0001] This application relates to the field of imaging detection technology, and more specifically, to a surface detection system and method based on polarization imaging. Background Technology

[0002] Polarization imaging is an important method for detecting surface cleanliness and defects. Targets reflect, scatter, refract, and transmit incident light. The reflected and refracted light contains the polarization characteristics of the target surface, and these characteristics change with variations in the degree of polarization, incident angle, and the target surface material. Therefore, polarization imaging contains rich information about the target surface. Compared to traditional imaging techniques, polarization imaging expands the information dimensions from light intensity, spectrum, and spatial location to multiple directions such as degree of polarization, polarization angle, and ellipticity. Furthermore, by changing the vibration direction between two polarized lights, polarization detection can reduce the intensity of reflected light, enhance its characteristics, and more clearly reveal the surface features of the target, effectively identifying objects of different materials and surface conditions. Therefore, polarization imaging technology has unparalleled advantages over other imaging techniques in material identification and detection, and has wide applications in various fields.

[0003] However, as illumination levels decrease, detector dark noise and electronic readout noise become significant factors that degrade the quality of the generated images. Consequently, existing polarization imaging detection methods exhibit low accuracy at lower photon fluxes. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a surface detection system and method based on polarization imaging to solve the technical problem that existing polarization imaging detection has low accuracy at low photon flux.

[0005] In a first aspect, embodiments of this application provide a surface detection system based on polarization imaging, the system comprising: a light source, a beam splitter, a reflective device, a beam combiner, a polarizer, and an imaging device;

[0006] The light source is configured as a light beam along the first optical path;

[0007] The beam splitter is configured to split the light source beam into a second signal light and a first signal light along the first optical path;

[0008] The reflective device is disposed in the optical path of the second signal light and configured to reflect and reverse the second signal light to obtain a second reflected signal light;

[0009] The beam combiner is disposed in the first optical path and configured to combine the detection signal light and the first signal light / second reflected signal light to obtain the combined interference signal light, wherein the detection signal light is configured to be obtained by the second reflected signal light / first signal light illuminating the surface to be detected and returning;

[0010] The analyzer is configured to filter out unpolarized signal light from the interference signal light;

[0011] The imaging device is configured to receive filtered interference signal light and obtain a detection image of the surface to be detected.

[0012] In the above implementation process, the polarization imaging-based surface detection system includes: a light source, a beam splitter, a reflector, a beam combiner, an analyzer, and an imaging device. The light source generates a light beam along a first optical path; the beam splitter splits the light beam into a second signal beam and a first signal beam; the reflector reverses the reflection of the second signal beam to obtain a second reflected signal beam; the beam combiner combines the detection signal beam and the first / second reflected signal beam to obtain a combined interference signal beam; the analyzer filters out unpolarized signal beams from the interference signal beam; and the imaging device acquires a detection image of the surface to be detected. Specifically, based on the surface detection system provided in this application, the original coherent image of the surface to be detected corresponding to the interference signal beam can be acquired, and a reference signal intensity image of the surface to be detected can be acquired by blocking the second / first signal beam; a zero-difference detection image of the surface to be detected can then be acquired based on the original coherent image and the reference signal intensity image. Furthermore, the analyzer filters out unpolarized signal beams from the interference signal beam to eliminate background light interference, thereby achieving zero-difference polarization imaging detection of the surface to be detected. Zero-difference detection enhances the signal light; combined with polarization imaging, it eliminates background light interference, enabling more accurate identification of particles or defects on the surface to be inspected. Therefore, the polarization imaging-based surface inspection system provided in this application improves the resolution of the inspected image of the surface through zero-difference polarization imaging, thereby enhancing surface inspection accuracy at lower photon fluxes. This solves the technical problem of low accuracy in existing polarization imaging detection at lower photon fluxes.

[0013] Optionally, in this embodiment, the optical path of the second signal light and the first optical path of the first signal light are perpendicular to each other; the reflecting device includes a first reflecting mirror and a second reflecting mirror; the first reflecting mirror is configured to reflect the second signal light to obtain signal reflected light; the second reflecting mirror is configured to reflect the signal reflected light to obtain the second reflected signal light.

[0014] In the above implementation process, by setting up the first and second reflectors, the difficulty of setting up the beam combiner can be reduced, a better beam combining effect can be obtained, and the surface detection accuracy of the polarization imaging-based surface detection system under low photon flux can be further improved.

[0015] Optionally, in this embodiment of the application, the reflective device further includes: a filter; the filter is disposed between the first reflector and the second reflector.

[0016] In the above implementation process, the intensity of the second reflected signal light can be controlled by the filter, thereby reducing the probability of overexposure of the imaging device.

[0017] Optionally, in this embodiment of the application, when the surface to be detected is disposed in the first optical path, the first signal light illuminates the surface to be detected and returns to obtain the detection signal light; the beam combiner is specifically configured to combine the detection signal light and the second reflected signal light to obtain the combined interference signal light.

[0018] Optionally, in this embodiment of the application, when the surface to be tested is disposed in the optical path of the second reflected signal light, the second reflected signal light irradiates the surface to be tested and returns to obtain the detection signal light; the beam combiner is specifically configured to combine the detection signal light and the first signal light to obtain the combined interference signal light.

[0019] Optionally, in this embodiment of the application, the system further includes: an imaging lens; the imaging lens is disposed between the beam combiner and the imaging device, or between the beam combiner and the surface to be detected.

[0020] In the above implementation process, the specific position of the imaging lens can be adjusted to avoid the presence of irrelevant objects such as beam combiners in the detection image, thereby further improving the surface detection accuracy of the system at low photon flux.

[0021] Optionally, in this embodiment of the application, the system further includes: a first aperture and a second aperture; the first aperture and the second aperture are disposed along the first optical path, the first aperture is specifically disposed between the light source and the beam splitter, and the second aperture is specifically disposed between the beam splitter and the beam combiner.

[0022] In the above implementation process, the intensity of the light beam received by the beam splitter can be controlled by the first aperture, and the intensity of the first signal light received by the beam combiner can be controlled by the second aperture, thereby reducing the overexposure probability of the imaging device.

[0023] In a second aspect, embodiments of this application provide a surface detection method based on polarization imaging, the method being applied to a surface detection system based on polarization imaging as described in any of the first aspects above; the surface to be detected is disposed in the optical path of the first optical path / second reflected signal light;

[0024] The method includes:

[0025] Based on the imaging device in the surface detection system, the original coherent image of the surface to be detected is obtained using interference signal light;

[0026] The first signal light / second signal light is blocked, and a reference signal intensity image is obtained based on the imaging device;

[0027] Based on the original coherent image and the reference signal intensity image, the surface detection result of the surface to be detected is determined.

[0028] In the above implementation process, this polarization imaging-based surface detection method can acquire the original coherent image of the surface to be detected using an imaging device in the surface detection system and interference signal light; by blocking the first / second signal light and based on the imaging device, a reference signal intensity image is obtained; and based on the original coherent image and the reference signal intensity image, the surface detection result of the surface to be detected is determined. This polarization imaging-based surface detection method can achieve zero-difference polarization imaging detection of the surface to be detected based on the original coherent image and the reference signal intensity image; and improves the resolution of the detection image of the surface to be detected through zero-difference polarization imaging, thereby improving the surface detection accuracy at low photon flux. It solves the technical problem of low accuracy detection of existing polarization imaging detection at low photon flux.

[0029] Optionally, in this embodiment of the application, determining the surface detection result of the surface to be detected based on the original coherent image and the reference signal intensity image includes: obtaining a zero-difference polarization detection image of the surface to be detected by subtracting the reference signal intensity image from the original coherent image; and determining the surface detection result of the surface to be detected based on the zero-difference polarization detection image.

[0030] Optionally, in this embodiment of the application, determining the surface detection result of the surface to be detected based on the zero-difference polarization detection image includes: performing a Fourier transform on the zero-difference polarization detection image to obtain a spectral detection image; filtering the spectral detection image to obtain a filtered detection image; and performing an inverse Fourier transform on the filtered detection image to obtain a surface detection image of the surface to be detected; wherein the surface detection image includes the surface detection result of the surface to be detected.

[0031] The beneficial effects of this application include at least the following:

[0032] This polarization-based surface detection system includes a light source, a beam splitter, a reflector, a beam combiner, an analyzer, and an imaging device. The light source generates a light beam along a first optical path; the beam splitter splits the light beam into a second signal beam and a first signal beam; the reflector reverses the second signal beam to obtain a second reflected signal beam; the beam combiner combines the detection signal beam and the first / second reflected signal beam to obtain a combined interference signal beam; the analyzer filters out unpolarized signal beams from the interference signal beam; and the imaging device acquires a detection image of the surface to be detected. Specifically, based on the surface detection system provided in this application, the system can acquire the original coherent image of the surface to be detected corresponding to the interference signal beam, and then acquire a reference signal intensity image of the surface to be detected by blocking the second / first signal beam; and finally acquire a zero-difference detection image of the surface to be detected based on the original coherent image and the reference signal intensity image. Furthermore, the analyzer filters out unpolarized signal beams from the interference signal beam to eliminate background light interference, thereby achieving zero-difference polarization imaging detection of the surface to be detected. Zero-difference detection enhances the signal light; combined with polarization imaging, it eliminates background light interference, enabling a more accurate determination of particles or defects on the surface to be inspected. Therefore, the polarization imaging-based surface inspection system provided in this application improves the resolution of the inspection image of the surface by using zero-difference polarization imaging, thereby increasing the surface inspection accuracy at lower photon fluxes and solving the technical problem of low accuracy in existing polarization imaging detection at lower photon fluxes. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of a first type of surface detection system based on polarization imaging provided in an embodiment of this application;

[0035] Figure 2 This is a schematic diagram of the structure of a second surface detection system based on polarization imaging provided in an embodiment of this application;

[0036] Figure 3 This is a schematic diagram of the structure of a third surface detection system based on polarization imaging provided in an embodiment of this application;

[0037] Figure 4A schematic flowchart of a surface detection method based on polarization imaging provided in an embodiment of this application;

[0038] Figure 5 A schematic flowchart of another surface detection method based on polarization imaging provided in this application embodiment;

[0039] Figure 6 A schematic diagram of a surface inspection image provided in an embodiment of this application;

[0040] Figure 7 This is a schematic diagram of another surface inspection image provided in an embodiment of this application.

[0041] Reference numerals: 01-Light source; 02-Beam splitter; 03-Reflecting device; 031-First reflecting mirror; 032-Second reflecting mirror; 033-Filter; 04-Beam combiner; 05-Analyzer; 06-Imaging device; 07-Imaging lens. Detailed Implementation

[0042] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this application.

[0044] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0045] Please see Figure 1 The diagram shown is a schematic representation of a surface detection system based on polarization imaging according to an embodiment of this application. The system includes: a light source 01, a beam splitter 02, a reflective device 03, a beam combiner 04, a polarizer 05, and an imaging device 06.

[0046] Light source 01 is configured to generate a light beam along the first optical path;

[0047] Beam splitter 02 is configured to split the light source beam into a second signal light and a first signal light along the first optical path;

[0048] The reflective device 03 is disposed in the optical path of the second signal light, and the reflective device 03 is configured to reflect and reverse the second signal light to obtain the second reflected signal light;

[0049] A beam combiner 04 is disposed in the first optical path. The beam combiner 04 is configured to combine the detection signal light and the first signal light / second reflected signal light to obtain the combined interference signal light. The detection signal light is configured to be obtained by the second reflected signal light / first signal light illuminating the surface to be detected and returning.

[0050] Analyzer 05 is configured to filter out undepolarized signal light from the interference signal light;

[0051] Imaging device 06 is configured to receive filtered interference signal light and obtain a detection image of the surface to be detected.

[0052] The light source 01 can be a laser source, such as a gas laser source, a semiconductor laser source, or a fiber laser source. The beam splitter 02 can be implemented using a dielectric film mirror or a cubic beam splitter. The optical path of the second signal light can be adjusted according to the actual application. Figure 1 This is merely an example illustrating the case where the optical path of the second signal light is perpendicular to the first optical path. The reflecting device 03 can be implemented using one or more mirrors. Figure 1 This example only illustrates the case where the reflective device 03 is implemented using a single mirror. The beam combiner 04 can be implemented using a dielectric film mirror or a cubic beam splitter, etc. The implementation of the beam combiner 04 can be the same as or different from that of the beam splitter 02. Figure 1 The diagram shows the polarizer 05 positioned in the optical path of the interference signal light. By rotating the polarizer 05, the unpolarized signal light in the interference signal light can be filtered out, thus enabling polarization imaging of the surface to be inspected in conjunction with the imaging device 06.

[0053] Among them, such as Figure 1 As shown, the surface to be tested can be placed in the first optical path (specifically, on the side of the combiner 04 away from the light source 01; correspondingly, the imaging device 06 can be placed in the optical path of the second reflected signal light). In this case, the light reflected by the surface to be tested from the first signal light can be used as the detection signal light. The combiner 04 is specifically configured to combine the detection signal light and the second reflected signal light to obtain interference signal light. Alternatively, the surface to be tested can be placed in the optical path of the second reflected signal light (specifically, on the side of the combiner 04 away from the reflecting device 03; correspondingly, the imaging device 06 can be placed in the first optical path). In this case, the light reflected by the surface to be tested from the second reflected signal light can be used as the detection signal light. The combiner 04 is specifically configured to combine the detection signal light and the first signal light to obtain interference signal light.

[0054] In this process, after the light source 01 emits a light beam, it is split into two polarized beams, a first signal beam and a second signal beam, by the beam splitter 02. For example, when the surface to be tested is positioned in the first optical path, the first signal beam illuminates the surface. Dust / particles / defects on the surface cause depolarization, absorption, and scattering effects on the polarized light (first signal beam), resulting in a polarization state different from the light reflected from other parts of the surface. In this case, the second signal beam serves as a reference beam, and the optical path difference is adjusted by the reflector 03. The beam combiner 04 combines the "first signal beam returned from the surface to be tested" and the second reflected signal beam. The "first signal beam returned from the surface to be tested" includes: reflected light (undepolarized signal beam) from the surface and depolarized light scattered by dust / particles / defects (including some undepolarized signal beam). By rotating the analyzer 05, the undepolarized signal beam in the "reflected light from the surface to be tested" and the "depolarized light scattered by dust / particles / defects" can be filtered out; thus, polarization imaging of the surface to be tested is achieved based on the imaging device 06.

[0055] Therefore, the surface inspection system based on polarization imaging provided in this application includes: a light source 01, a beam splitter 02, a reflector 03, a beam combiner 04, a polarizer 05, and an imaging device 06; it can acquire a high-precision inspection image of the surface to be inspected based on the imaging device 06. Specifically, based on the surface inspection system provided in this application, the original coherent image of the surface to be inspected corresponding to the interference signal light can be acquired, and then a reference signal intensity image of the surface to be inspected can be acquired by blocking the second signal light / first signal light; a zero-difference inspection image of the surface to be inspected can be acquired based on the original coherent image and the reference signal intensity image. Furthermore, the polarizer 05 filters out the undepolarized signal light in the interference signal light, eliminating the interference of background light, thereby realizing zero-difference polarization imaging inspection of the surface to be inspected. Zero-difference inspection can enhance the signal light; combined with polarization imaging, the interference of background light can be eliminated, so as to more accurately determine the particle or defect situation of the surface to be inspected. Therefore, the surface detection system based on polarization imaging provided in this application can improve the resolution of the detection image of the surface to be detected through zero-difference polarization imaging, thereby improving the surface detection accuracy at low photon fluxes. This solves the technical problem of low accuracy in existing polarization imaging detection at low photon fluxes.

[0056] Please refer to Figure 2 , Figure 2 This is a schematic diagram of the structure of a second polarization imaging-based surface detection system provided in an embodiment of this application. Figure 2 Specifically, it shows the case where the reflective device 03 is implemented by two reflectors (first reflector 031 and second reflector 032).

[0057] In some optional embodiments, the optical path of the second signal light and the first optical path of the first signal light are perpendicular to each other; the reflecting device 03 includes a first reflecting mirror 031 and a second reflecting mirror 032; the first reflecting mirror 031 is configured to reflect the second signal light to obtain signal reflected light; the second reflecting mirror 032 is configured to reflect the signal reflected light to obtain the second reflected signal light.

[0058] By setting the first reflector 031 and the second reflector 032, the difficulty of setting up the beam combiner 04 can be reduced, a better beam combining effect can be obtained, and the surface detection accuracy of the polarization imaging-based surface detection system under low photon flux can be further improved.

[0059] In some optional embodiments, the reflective device 03 further includes a filter 033; the filter 033 is disposed between the first reflector 031 and the second reflector 032.

[0060] The filter 033 can be implemented using an absorption filter or an interference filter, etc., and this application does not specifically limit it. The intensity of the second reflected signal light can be controlled by the filter 033, thereby reducing the probability of overexposure of the imaging device 06.

[0061] In some optional embodiments, when the surface to be detected is disposed in the first optical path, the first signal light illuminates the surface to be detected and returns to obtain the detection signal light; the beam combiner 04 is specifically configured to combine the detection signal light and the second reflected signal light to obtain the combined interference signal light.

[0062] in, Figure 2 An illustrative example is shown where the surface to be detected is positioned in the first optical path. When the surface to be detected is positioned in the first optical path, the imaging device 06 can be positioned in the optical path of the second reflected signal light. In this case, the first signal light can be blocked, and a reference signal intensity image of the surface to be detected can be acquired based on the imaging device 06.

[0063] Please refer to Figure 3 , Figure 3 This is a schematic diagram of the structure of a third type of surface detection system based on polarization imaging provided in this application embodiment. Figure 3 The specific example shows the case where the analyzer 05 is placed in the optical path of the interference signal light.

[0064] In some optional embodiments, when the surface to be tested is disposed in the optical path of the second reflected signal light, the second reflected signal light illuminates the surface to be tested and returns to obtain the detection signal light; the beam combiner 04 is specifically configured to combine the detection signal light and the first signal light to obtain the combined interference signal light.

[0065] in, Figure 3 An illustrative example is shown where the surface to be detected is positioned within the optical path of the second reflected signal light. When the surface to be detected is positioned within the optical path of the second reflected signal light, the imaging device 06 can be positioned within the first optical path. In this case, the second signal light can be blocked, and a reference signal intensity image of the surface to be detected can be acquired based on the imaging device 06.

[0066] In some optional embodiments, the system further includes an imaging lens 07; the imaging lens 07 is disposed between the beam combiner 04 and the imaging device 06, or between the beam combiner 04 and the surface to be detected.

[0067] In this system, the imaging device 06 may not include an imaging lens, but instead works with the imaging lens 07 to achieve polarization imaging of the surface to be inspected. In this case, by adjusting the specific position of the imaging lens 07, irrelevant objects such as the beam combiner 04 can be avoided in the detection image, further improving the surface detection accuracy of the system at lower photon fluxes. Figure 2 An exemplary illustration shows the imaging lens 07, the beam combiner 04, and the imaging device 06, specifically illustrating the configuration of the imaging lens 07 between the beam combiner 04 and the analyzer 05. It should be noted that the imaging lens 07 may also be configured between the analyzer 05 and the imaging device 06. Figure 3 An illustrative example is shown where the imaging lens 07 is positioned between the surface to be inspected and the beam combiner 04. The specific position of the imaging lens 07 can be adjusted according to its actual focal length.

[0068] In some optional embodiments, the system further includes: a first aperture and a second aperture; the first aperture and the second aperture are disposed along the first optical path, the first aperture is specifically disposed between the light source 01 and the beam splitter 02, and the second aperture is specifically disposed between the beam splitter 02 and the beam combiner 04.

[0069] The intensity of the light beam received by the beam splitter 02 can be controlled by the first aperture, and the intensity of the first signal light received by the beam combiner 04 can be controlled by the second aperture, so as to reduce the overexposure probability of the imaging device.

[0070] Please refer to Figure 4 , Figure 4 This is a schematic flowchart illustrating a surface detection method based on polarization imaging, provided in an embodiment of this application. This polarization imaging-based surface detection method is applied to a surface detection system based on polarization imaging as described in any of the first aspects above; the surface to be detected is positioned within the optical path of the first optical path / second reflected signal light.

[0071] The surface detection method based on polarization imaging may include the following steps:

[0072] S101. Based on the imaging device in the surface detection system, the original coherent image of the surface to be detected is obtained using interference signal light;

[0073] S102, Block the first signal light / second signal light, and obtain a reference signal intensity image based on the imaging device;

[0074] S103. Based on the original coherent image and the reference signal intensity image, determine the surface detection result of the surface to be detected.

[0075] In steps S101-S103, the original coherent image is a polarization image of the surface to be detected obtained without obstruction. The reference signal intensity image, however, is obtained when the first signal light / second signal light is obstructed. Specifically, when the surface to be detected is positioned in the first optical path, the reference signal intensity image can be obtained by obstructing the first signal light and based on the imaging device. When the surface to be detected is positioned in the optical path of the second reflected signal light, the reference signal intensity image can be obtained by obstructing the second signal light and based on the imaging device. The surface detection result of the surface to be detected can be determined based on the original coherent image, the reference signal intensity image, and the zero-difference interferometry principle. The polarization imaging-based surface detection method provided in this application, based on polarization imaging and combined with the zero-difference interferometry method, can solve the problem of detecting extremely weak light information such as particle size (accuracy of 1μm and below) and lens surface defects (achieving first-class smoothness).

[0076] It should be understood that the surface detection method based on polarization imaging corresponds to the above-described embodiment of the surface detection system based on polarization imaging. The specific implementation of the above steps in the surface detection method based on polarization imaging can be found in the relevant description above. To avoid repetition, detailed descriptions are omitted here.

[0077] Please refer to Figure 5 , Figure 5 This is a schematic flowchart of another surface detection method based on polarization imaging provided in an embodiment of this application.

[0078] In some optional embodiments, S103, determining the surface detection result of the surface to be detected based on the original coherent image and the reference signal intensity image, includes: S1031, obtaining a zero-difference polarization detection image of the surface to be detected by subtracting the reference signal intensity image from the original coherent image; S1032, determining the surface detection result of the surface to be detected based on the zero-difference polarization detection image.

[0079] This process involves blocking the first / second signal light and continuously acquiring multiple reference images using an imaging device. The average of these reference images is then taken to obtain the reference signal intensity image. Finally, the reference signal intensity image is subtracted from the original coherent image to obtain the zero-difference polarization detection image of the surface to be detected. The number of acquired reference images can be 5, 10, or other reasonable values.

[0080] In some optional embodiments, S1032, determining the surface detection result of the surface to be detected based on the zero-difference polarization detection image, includes: performing a Fourier transform on the zero-difference polarization detection image to obtain a spectral detection image; filtering the spectral detection image to obtain a filtered detection image; and performing an inverse Fourier transform on the filtered detection image to obtain a surface detection image of the surface to be detected; wherein the surface detection image includes the surface detection result of the surface to be detected.

[0081] Please refer to Figure 6 , Figure 6 This is a schematic diagram of a surface inspection image provided in an embodiment of this application. Figure 6 Specifically, the diagram illustrates the detection image obtained by contaminating a lens with a 200nm monodisperse polystyrene microsphere dilution solution and then detecting the contaminated lens surface using the polarization imaging-based surface detection system provided in this application. Figure 6 The following images are shown: the original coherent image, the reference signal intensity image, the zero-difference polarization detection image obtained by subtracting the reference signal intensity image from the original coherent image, the filtered detection image obtained by filtering the spectrum detection image, the filtered detection image obtained by filtering the spectrum detection image, and the surface detection image obtained by performing an inverse Fourier transform on the filtered detection image.

[0082] Please refer to Figure 7 , Figure 7 This is a schematic diagram of another surface inspection image provided in an embodiment of this application. Figure 7 Specifically, the image shown is a surface inspection image obtained by inspecting the surface of a contaminated lens using existing polarization imaging detection methods.

[0083] from Figure 6 , Figure 7 As can be seen, the surface detection system and method based on polarization imaging provided in this application can improve the resolution of the detection image of the surface to be detected, thereby improving the surface detection accuracy under low photon flux and solving the technical problem of low accuracy detection under low photon flux in existing polarization imaging detection.

[0084] It should be understood that the disclosed apparatus / systems and methods can also be implemented in other ways, as provided in the embodiments of this application. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, or they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0085] In addition, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0086] The above description is only an optional implementation of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application should be covered within the protection scope of the embodiments of this application.

Claims

1. A surface detection system based on polarization imaging, characterized in that, The system includes: a light source, a beam splitter, a reflector, a beam combiner, a polarizer, and an imaging device; The light source is configured to generate a light beam along the first optical path; The beam splitter is configured to split the light source beam into a second signal light and a first signal light along the first optical path; The reflective device is disposed in the optical path of the second signal light and configured to reflect and reverse the second signal light to obtain a second reflected signal light; The beam combiner is disposed in the first optical path and configured to combine the detection signal light and the first signal light / second reflected signal light to obtain the combined interference signal light, wherein the detection signal light is configured to be obtained by the second reflected signal light / first signal light illuminating the surface to be detected and returning; The analyzer is configured to filter out undepolarized signal light from the interference signal light; wherein, the undepolarized signal light includes undepolarized signal light from the reflected light from the surface to be tested and from the depolarized light scattered by dust / particles / defects; The imaging device is configured to receive filtered interference signal light and obtain an original coherent image of the surface to be detected; and to receive the second reflected signal light / the first signal light and obtain a corresponding reference signal intensity image when the first signal light / the second signal light is blocked; wherein, the original coherent image is subtracted from the reference signal intensity image to obtain a zero-difference polarization detection image of the surface to be detected. The system further includes: an imaging lens; The imaging lens is disposed between the beam combiner and the analyzer, or between the beam combiner and the surface to be inspected.

2. The system according to claim 1, characterized in that, in, The optical path of the second signal light is perpendicular to the first optical path of the first signal light; the reflecting device includes a first reflecting mirror and a second reflecting mirror; The first reflector is configured to reflect the second signal light to obtain the reflected signal light; The second reflector is configured to reflect the signal reflected light to obtain the second reflected signal light.

3. The system according to claim 2, characterized in that, in, The reflective device further includes: a filter; The filter is disposed between the first reflector and the second reflector.

4. The system according to claim 1, characterized in that, in, When the surface to be detected is disposed in the first optical path, the first signal light illuminates the surface to be detected and returns to obtain the detection signal light; The beam combiner is specifically configured to combine the detection signal light and the second reflected signal light to obtain the combined interference signal light.

5. The system according to claim 1, characterized in that, in, When the surface to be detected is placed in the optical path of the second reflected signal light, the second reflected signal light illuminates the surface to be detected and returns to obtain the detection signal light; The beam combiner is specifically configured to combine the detection signal light and the first signal light to obtain the combined interference signal light.

6. The system according to claim 1, characterized in that, The system also includes: a first aperture and a second aperture; The first aperture and the second aperture are arranged along the first optical path. The first aperture is specifically arranged between the light source and the beam splitter, and the second aperture is specifically arranged between the beam splitter and the beam combiner.

7. A surface detection method based on polarization imaging, characterized in that, The method is applied to the surface detection system based on polarization imaging as described in any one of claims 1-6 above; The surface to be detected is placed in the optical path of the first optical path / second reflected signal light; The method includes: Based on the imaging device in the surface detection system, the original coherent image of the surface to be detected is obtained using interference signal light; The first signal light / second signal light is blocked, and a reference signal intensity image is obtained based on the imaging device; Based on the original coherent image and the reference signal intensity image, the surface detection result of the surface to be detected is determined.

8. The method according to claim 7, characterized in that, The step of determining the surface detection result of the surface to be detected based on the original coherent image and the reference signal intensity image includes: The zero-difference polarization detection image of the surface to be detected is obtained by subtracting the reference signal intensity image from the original coherent image. Based on the zero-difference polarization detection image, the surface detection result of the surface to be detected is determined.

9. The method according to claim 8, characterized in that, The step of determining the surface detection result of the surface to be detected based on the zero-difference polarization detection image includes: Perform a Fourier transform on the zero-difference polarization detection image to obtain a spectrum detection image; The spectrum detection image is filtered to obtain a filtered detection image; The filtered detection image is subjected to inverse Fourier transform to obtain a surface detection image of the surface to be detected; wherein, the surface detection image includes the surface detection result of the surface to be detected.

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