A backlight imaging device based on polarized light

Abstract

The present invention discloses a backlight imaging device based on polarized light, which is used for an optical detection system to perform detection imaging in a strong backlight environment in space. Since sunlight does not show polarization, the polarization degree and polarization angle are both 0. When polarization technology is used to image the sun, its polarization degree and polarization angle images will appear completely black; at the same time, the target's own radiation / reflected light has polarization characteristics, and the characteristics are obvious during imaging. The backlight imaging device based on polarized light of the present invention can filter out background strong light interference, realize detection imaging of the target in a backlight environment, have clear imaging effect, and have a laser ranging function, which is suitable for multi-scenario applications.

Description

Technical Field

[0001] The present invention belongs to the field of target feature detection and recognition, and particularly relates to a backlight imaging device based on polarized light. Background Art

[0002] The optical detection system applied to space vehicles is usually restricted by the orbital position. In the backlight orbital position, it will be interfered by strong light such as the sun, resulting in overexposure, and causing the problem that the target is submerged by the strong light. The existing space optical detection system cannot solve the problem of effective detection in the backlight orbital position, which restricts the working time and efficiency of the space vehicle detection system. Studying a device that can effectively perform optical detection in the full-directional orbital positions of front light and backlight has become an urgent technical requirement for breakthrough.

[0003] Backlight detection is a bottleneck problem in current space optical detection technology. For the problem of backlight imaging, the main solutions of current optical detectors are through the following technical means: 1. Close the optical detector within the backlight angle range to avoid strong light interference; 2. Adjust the light passing aperture of the detector to reduce the light passing amount and weaken the strong light interference; 3. Use a spectral filter to cut the imaging spectrum into a narrow-band spectrum and reduce the light passing amount. The above methods avoid the technical obstacles of space backlight detection to a certain extent. However, they do not fundamentally solve the problem of space backlight detection. Closing the detector within the backlight angle to avoid strong light interference will cause a detection blind area, which is particularly disadvantageous in the field of space game confrontation; adjusting the light passing aperture of the detector to reduce the light passing amount will seriously weaken the irradiation intensity of the detection target, and may cause the loss of the target or the detailed features of the target; the method of using a spectral filter to cut strong stray light interference has a certain effect on the specific spectral optical features of specific targets, but is limited by the single reflection characteristics of specific targets and has great limitations. From the research status at home and abroad, there is currently no space backlight detection technology with strong adaptability successfully applied. Therefore, it is necessary to study a backlight imaging system that can image the target within the 360° space around the target. Summary of the Invention

[0004] The present invention discloses a backlight imaging device based on polarized light, which realizes backlight imaging by means of laser supplementary light and polarized imaging. Its basic principle is that sunlight does not show polarization, and both the degree of polarization and the polarization angle are 0. The irradiated light of the sun is converted into polarization, and the polarization technology is used to image the sun, and its degree of polarization and polarization angle images will present a completely black state. At the same time, the light radiated / reflected by the target itself has polarization characteristics, and the characteristics are obvious during imaging. When the polarized imaging device of the present invention is used in space backlight detection, it can completely eliminate the influence of the sun and realize imaging in a completely backlight environment.

[0005] A backlight imaging device based on polarized light, characterized in that it comprises:

[0006] The imaging subsystem is used to implement polarized light imaging;

[0007] The laser subsystem is used to emit a laser beam to the imaging subsystem to supplement light to the target;

[0008] The information processing subsystem receives the imaging signal transmitted by the imaging subsystem, processes and generates backlight imaging data, and transmits the signal to the master control unit.

[0009] Preferably, the imaging subsystem includes: a galvanometer and a reflecting mirror for changing the optical path of the target beam; a beam splitter for splitting the target beam; a polarization imaging unit for converting the irradiated light of part of the target beam into polarized light and transmitting it to the information processing subsystem; a beam splitter for turning part of the target reflected beam towards the laser subsystem.

[0010] Preferably, the polarization imaging unit includes: a polarization detector for receiving the polarized light signal and transmitting it to the information processing subsystem.

[0011] Preferably, the imaging subsystem further includes: a precise tracking imaging unit for receiving part of the target beam and outputting a feedback signal to the galvanometer.

[0012] Preferably, the precise tracking imaging unit includes: an imaging system for receiving the optical signal and imaging; a precise tracking detector for receiving the imaging signal and feedback-adjusting the galvanometer.

[0013] Preferably, the laser subsystem includes: a duplex reflecting mirror for changing the directions of the laser beam and the target reflected light; a power driver for providing electrical energy; an illumination laser for emitting a laser beam towards the target.

[0014] Preferably, the laser subsystem further includes: an APD detector for amplifying the target reflected light; a ranging processing unit for ranging the target reflected light and transmitting the result to the information processing subsystem.

[0015] Preferably, the information processing subsystem includes: an information input interface for receiving the imaging signal of the polarization detector and the ranging signal of the ranging processing unit, a data processing unit for resolving the polarized light signal, an information output interface for transmitting the polarized light data, and a display for receiving the polarized light data signal and imaging.

[0016] A backlight imaging method based on polarized light, including the above-mentioned backlight imaging device based on polarized light, includes the following steps:

[0017] (1) The target beam enters the imaging subsystem and outputs a polarized light signal to the information processing subsystem;

[0018] (2) The laser subsystem emits a laser beam to supplement light to the imaging subsystem and performs ranging;

[0019] (3) The information processing subsystem receives the polarized light signal and the ranging signal, displays the backlight imaging signal, and transmits the backlight imaging data to the master control unit.

[0020] Preferably, the implementation method of step (1) is as follows: The target beam enters the imaging subsystem through the Cassegrain optical antenna, passes through the collimating mirror, galvanometer, and reflecting mirror in sequence, and reaches the beam splitter; part of the beam passes through the beam splitter and turns to the polarization imaging unit to reach the polarization detector; the other part of the beam passes through the beam splitter and turns to the fine tracking imaging unit, passes through the switchable filter and imaging system in sequence, and reaches the fine tracking detector, and the fine tracking detector feeds back to adjust the galvanometer to achieve stable tracking of the target.

[0021] Preferably, the implementation method of step (2) is as follows: The laser illuminator emits a laser beam, and the beam passes through the optical system, duplex reflector, beam splitter, reflecting mirror, collimating mirror, and Cassegrain optical antenna in sequence and is emitted to the target; part of the target reflected beam passes through the beam splitter, passes through the duplex mirror and APD detector in sequence, and reaches the ranging processing unit to achieve the ranging function of the target.

[0022] Preferably, the implementation method of step (3) is as follows: The imaging signal transmitted by the polarization detector is received by the information input interface and transmitted to the data processing unit; the data processing unit resolves the polarized light signal of the target, filters out the non-polarized signal of the strong light background, and transmits the signal with the strong background light filtered through the information output interface to the display to achieve the display of the target backlight imaging.

[0023] A backlight test method for a satellite model includes the above backlight imaging device based on polarized light.

[0024] An optical detection system for a space vehicle includes the above backlight imaging device based on polarized light.

[0025] The backlight imaging device based on polarized light disclosed by the present invention can eliminate the influence of sunlight and achieve imaging in a completely backlight environment, and specifically includes the following beneficial effects:

[0026] (1) Break through the angle limitation of imaging in the space backlight environment, be able to image the target within the 360° space around the target, achieve imaging in a completely backlight environment, and the imaging effect is clear;

[0027] (2) The backlight detection device retains the non-polarized imaging ability through mechanism and optical path control, and retains the ranging ability of the original system under non-backlight conditions, adapting to multi-scene applications. Description of the Drawings

[0028] Figure 1 It is a connection schematic diagram of the polarized backlight imaging device in the first embodiment of the application;

[0029] Figure 2It is the layout diagram of the backlight imaging test for Embodiment 3 of the application;

[0030] Figure 3 It is the comparison diagram of the imaging effects for Embodiment 3 of the application.

[0031] Attached drawing reference signs:

[0032] I - Imaging subsystem, 1 - Target beam, 2 - Cassegrain optical antenna, 3 - Collimator, 4 - Galvanometer, 5 - Reflecting mirror, 6 - Beam splitter, 7 - Polarization imaging unit, 8 - Polarization detector, 9 - Precision tracking imaging unit, 10 - Switchable filter, 11 - Imaging system, 12 - Precision tracking detector, 13 - Beam splitter, II - Laser subsystem, 14 - Duplex mirror, 15 - APD detector, 16 - Ranging processing unit, 17 - Optical system, 18 - Illumination laser, 19 - Power driver, III - Information processing subsystem, 20 - Information input interface, 21 - Data processing unit, 22 - Information output interface, 23 - Display Detailed implementation manners

[0033] The technical solutions of the present invention will be further described in detail below in conjunction with the attached drawings and specific implementation manners. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0034] Embodiment 1

[0035] A backlight imaging device based on polarized light disclosed in an embodiment of the present application includes:

[0036] An imaging subsystem I for realizing polarized light imaging;

[0037] A laser subsystem II for emitting a laser beam to the imaging subsystem I to supplement light to the target;

[0038] An information processing subsystem III that receives the imaging signal transmitted by the imaging subsystem I, processes and generates backlight imaging data, and transmits the signal to the master control unit.

[0039] The imaging subsystem I includes: a galvanometer 4 and a reflecting mirror 5 that change the optical path of the target beam 1; a beam splitter 6 that splits the target beam 1; a polarization imaging unit 7 that converts the irradiated light of part of the target beam 1 into polarized light and sends it to the information processing subsystem III; a beam splitter 13 that turns part of the target reflected beam to the laser subsystem II.

[0040] The polarization imaging unit 7 includes: a polarization detector 8 that receives the polarized light signal and sends it to the information processing subsystem III.

[0041] The imaging subsystem I further includes: a fine tracking imaging unit 9 that receives a part of the target beam 1 and outputs a feedback signal to the galvanometer 4.

[0042] The fine tracking imaging unit 9 includes: an imaging system 11 that receives an optical signal and forms an image; a fine tracking detector 12 that receives the imaging signal and feeds back to adjust the galvanometer 4.

[0043] The laser subsystem II includes: a duplex mirror 14 that changes the directions of the laser beam and the target reflected light; a power driver 19 that provides electrical energy; an illumination laser 18 that emits a laser beam towards the target.

[0044] The laser subsystem II further includes: an APD detector 15 that amplifies the target reflected light; a ranging processing unit 16 that ranges the target reflected light and sends the result to the information processing subsystem III.

[0045] The information processing subsystem III includes: an information input interface 20 that receives the imaging signal of the polarization detector 8 and the ranging signal of the ranging processing unit 16, a data processing unit 21 that resolves the polarized light signal, an information output interface 22 that sends the polarized light data, and a display 23 that receives the polarized light data signal and forms an image.

[0046] Embodiment 2

[0047] A backlight imaging method based on polarized light disclosed in an embodiment of the present application includes the backlight imaging device based on polarized light in Embodiment 1 of the application, and includes the following steps:

[0048] (1) The target beam 1 enters the imaging subsystem I and outputs a polarized light signal to the information processing subsystem III;

[0049] (2) The laser subsystem II emits a laser beam, fills light for the imaging subsystem I, and ranges;

[0050] (3) The information processing subsystem III receives the polarized light signal and the ranging signal, displays the backlight imaging signal, and transfers the backlight imaging data to the master control unit.

[0051] The implementation method of step (1) is: The target beam 1 enters the interior of the imaging subsystem I through the Cassegrain optical antenna 2, and successively passes through the collimating mirror 3, the galvanometer 4, the reflecting mirror 5, and reaches the beam splitter 6; a part of the beam passes through the beam splitter 6 and turns to the polarization imaging unit 7 and reaches the polarization detector 8; another part of the beam passes through the beam splitter 6 and turns to the fine tracking imaging unit 9, successively passes through the switchable filter 10 and the imaging system 11, and reaches the fine tracking detector 12. The fine tracking detector 12 feeds back to adjust the galvanometer 4 to achieve stable tracking of the target.

[0052] The implementation method of step (2) is as follows: The laser illuminator 18 emits a laser beam, which successively passes through the optical system 17, the duplex reflector 14, the beam splitter 13, the reflector 5, the collimator 3, and the Cassegrain optical antenna 2 and is emitted towards the target; a part of the target reflected beam passes through the beam splitter 13, successively passes through the duplex mirror 14, the APD detector 15, and reaches the ranging processing unit 16 to realize the ranging function for the target.

[0053] The implementation method of step (3) is as follows: The imaging signal transmitted by the polarization detector 8 is received by the information input interface 20 and is transmitted to the data processing unit 21; the data processing unit 21 resolves the polarized light signal of the target, filters out the non-polarized signals of the strong light background, and transmits the signal with the strong background light filtered through the information output interface 22 to the display 23 to realize the backlight imaging display of the target.

[0054] Embodiment III

[0055] The backlight test method for the satellite model disclosed in the embodiments of the present application includes the backlight imaging device based on polarized light in Embodiment I of the application, and detects the satellite model in a completely backlight environment. As Figure 2 shown, the light integrating sphere is used as the target beam 1 to simulate the backlight interference source of sunlight.

[0056] The imaging effect without using the backlight polarization imaging method is as Figure 3 shown. Under the completely backlight condition, the intensity image of the target appears black and the details of the target surface cannot be distinguished; after adopting the backlight polarization imaging method in Embodiment II of the application, the details of the satellite model surface are clearly visible, and clear imaging in the completely backlight state is realized.

[0057] The polarization characteristics of light are described by the Stokes vector. Among them, S0 describes the self-light intensity of the incident light, S1 describes the horizontal polarization intensity of the incident light, S2 describes the polarization intensity of the incident light in the oblique 45° direction, S3 describes the circular polarization intensity of the incident light, and the definition of the Stokes vector is as follows:

[0058]

[0059] In the formula: I(ζ,η) represents the radiation power received by the detector, ζ is the polarization direction, and η is the angle between the fast axis of the wave plate and the reference axis; S0 is related to the incident light intensity; S1 is related to the linear polarization information in the 0° and 90° directions; S2 is related to the linear polarization information in the 45° and 135° directions; S3 is related to the left / right circular polarization information.

[0060] The polarization state of the image can be represented by the degree of polarization p(DoP), and the expression is as follows:

[0061]

[0062] Example 4

[0063] An optical detection system for a space vehicle disclosed in an embodiment of the present application includes a backlight imaging device based on polarized light in Embodiment 1 of the application.

[0064] As described above, the above is only the best specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. The content not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims

1. A backlight imaging device based on polarized light, characterized in that, Comprising: An imaging subsystem (I) for implementing polarized light imaging; A laser subsystem (II) for emitting a laser beam to the imaging subsystem (I) to supplement light to the target; An information processing subsystem (III) for receiving the imaging signal transmitted by the imaging subsystem (I), processing to generate backlight imaging data, and transmitting the signal to the master control unit; The imaging subsystem (I) includes: a galvanometer (4) and a reflector (5) for changing the optical path of the target beam (1); a beam splitter (6) for splitting the target beam (1); a polarization imaging unit (7) for converting the irradiated light of part of the target beam (1) into polarized light and transmitting it to the information processing subsystem (III); a beam splitter (13) for deflecting part of the target reflected beam towards the laser subsystem (II); The polarization imaging unit (7) includes: a polarization detector (8) for receiving the polarized light signal and transmitting it to the information processing subsystem (III); The imaging subsystem (I) further includes: a fine tracking imaging unit (9) for receiving part of the target beam (1) and outputting a feedback signal to the galvanometer (4); The fine tracking imaging unit (9) includes: an imaging system (11) for receiving the optical signal and imaging; a fine tracking detector (12) for receiving the imaging signal and feedback-adjusting the galvanometer (4); The laser subsystem (II) includes: a duplex reflector (14) for changing the directions of the laser beam and the target reflected light; a power driver (19) for providing electric energy; a laser illuminator (18) for emitting a laser beam towards the target; The laser subsystem (II) further includes: an APD detector (15) for amplifying the target reflected light; a ranging processing unit (16) for ranging the target reflected light and transmitting the result to the information processing subsystem (III); The information processing subsystem (III) includes: an information input interface (20) for receiving the imaging signal of the polarization detector (8) and the ranging signal of the ranging processing unit (16), a data processing unit (21) for resolving the polarized light signal, an information output interface (22) for transmitting the polarized light data, and a display (23) for receiving the polarized light data signal and imaging.

2. A backlight imaging method based on polarized light, comprising the backlight imaging device based on polarized light described in claim 1, characterized in that, Including the following steps: Step 1: The target beam (1) enters the imaging subsystem (I), and outputs a polarized light signal to the information processing subsystem (III); Step 2: The laser subsystem (II) emits a laser beam to supplement light to the imaging subsystem (I) and performs ranging; Step 3: The information processing subsystem (III) receives the polarized light signal and the ranging signal, displays the backlight imaging signal, and transmits the backlight imaging data to the master control unit.

3. The backlight imaging method based on polarized light according to claim 2, wherein, The implementation method of step 1 is as follows: The target beam (1) enters the internal of the imaging subsystem (I) through the Cassegrain optical antenna (2), and successively passes through the collimating mirror (3), the galvanometer (4), the reflecting mirror (5), and reaches the beam splitter (6); A part of the beam passes through the beam splitter (6) and turns to the polarization imaging unit (7) and reaches the polarization detector (8); Another part of the beam passes through the beam splitter (6) and turns to the fine tracking imaging unit (9), successively passes through the switchable filter (10) and the imaging system (11), and reaches the fine tracking detector (12), and the galvanometer (4) is feedback - adjusted by the fine tracking detector (12) to achieve stable tracking of the target.

4. The backlight imaging method based on polarized light according to claim 2, wherein The implementation method of step 2 is as follows: The laser illuminator (18) emits a laser beam, and the beam successively passes through the optical system (17), the duplex mirror (14), the beam splitter (13), the reflecting mirror (5), the collimating mirror (3), and the Cassegrain optical antenna (2) and is emitted to irradiate the target; A part of the target - reflected beam passes through the beam splitter (13), successively passes through the duplex mirror (14) and the APD detector (15), and reaches the ranging processing unit (16) to achieve the function of ranging the target.

5. The backlight imaging method based on polarized light according to claim 2, characterized in that The implementation method of step 3 is as follows: The imaging signal transmitted by the polarization detector (8) is received by the information input interface (20) and the signal is transmitted to the data processing unit (21); The data processing unit (21) resolves the polarized light signal of the target, filters out the non - polarized signals of the strong light background, and transmits the signal with the strong background light filtered through the information output interface (22) to the display (23) to achieve the backlight imaging display of the target.

6. A backlighting test method for a satellite model, characterized in that, It includes the backlight imaging device based on polarized light described in claim 1.

7. An optical detection system for a space vehicle, characterized in that, It includes the backlight imaging device based on polarized light described in claim 1.

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