An underwater target polarization hyperspectral imaging detection device and method with synergistic active illumination

Abstract

The application discloses a kind of underwater target polarization hyperspectral imaging detection device and detection method of cooperative active illumination, solve the technical problems that the existing underwater optical imaging detection device is due to the absorption and scattering of light under water, resulting in poor imaging quality and large volume, leading to poor flexibility of use;The present application comprises an active illumination module and a polarization hyperspectral imaging module;The polarization hyperspectral imaging module comprises a waterproof protective shell with two open ends, a front-mounted telescopic imaging unit, a polarization spectrum coupling unit, an embedded processing unit and a first water-tight connector are sequentially arranged in the waterproof protective shell;Connect the front-mounted telescopic imaging unit, polarization spectrum coupling unit;The present application greatly improves the detection accuracy of underwater target by combining active illumination and polarization hyperspectral technology, which can effectively eliminate the interference of underwater scattering.

Description

TECHNICAL FIELD

[0001] The present application relates to underwater target imaging device and method, specifically relates to a kind of underwater target polarization hyperspectral imaging detection device and detection method of cooperative active illumination. BACKGROUND

[0002] Compared with acoustic detection, underwater target optical imaging detection technology has unique advantages: it can provide high-resolution images, intuitively display the shape, color and texture of underwater objects, and help qualitative / quantitative analysis of underwater targets.However, water is a complex dispersive system composed of irregular particles with absorption and random orientation;Generally speaking, natural light disappears below 200m underwater, and it is pitch black underwater at this time.Optical imaging detection must rely on artificial active illumination source at this time.The underwater artificial active illumination sources currently used are mostly prepared for underwater color cameras, which can provide different lumen light output, color temperature and color rendering index.The research on light source suitable for multi-hyperspectral and polarization detector is almost none.

[0003] In addition, most underwater optical imaging detection devices are still at the stage of ordinary color cameras.These cameras can capture basic images underwater, but have limitations in identifying and analyzing underwater targets.Xi'an University of Electronic Science and Technology, Tianjin University and other teams have done a lot of research in the laboratory using polarization cameras, which increase the detectable distance of objects using polarization properties, but most of these research results are still at the laboratory stage.The underwater hyperspectral system (UHI) developed by the University of Science and Technology of Norway and Ecotone Company has achieved commercial application, and can provide more spectral information than ordinary color cameras, which helps to identify and analyze underwater targets more accurately.However, it is bulky and needs external push-scan structure, which limits its flexible application in complex underwater environment.In addition, hyperspectral polarization imaging technology (SPI) is a new technology that combines hyperspectral imaging technology and polarization imaging technology.In recent years, research on this technology has gradually increased at home and abroad, but most of the research is still at the laboratory stage, and the whole device is bulky and difficult to apply effectively underwater. SUMMARY

[0004] The purpose of the present application is to solve the technical problems of poor imaging quality and poor flexibility due to the volume of existing underwater optical imaging detection devices caused by light absorption and scattering underwater;And provide a kind of underwater target polarization hyperspectral imaging detection device and detection method of cooperative active illumination.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] The application discloses a kind of underwater target polarization hyperspectral imaging devices of cooperative active illumination, it is characterized by further comprising active illumination module and polarization hyperspectral imaging module.

[0007] The active illumination module is used to provide the illumination field of view of the underwater target; the present application detection imaging device can adapt to various complex underwater environments, and the detection effect is improved.

[0008] The polarization hyperspectral imaging module includes a waterproof protective shell, a front-mounted telescopic imaging unit, a polarization spectrum coupling unit, an embedded processing unit, and a first water-tight connector are arranged in the waterproof protective shell.

[0009] The input end of the front-mounted telescopic imaging unit is sealingly connected to one end of the waterproof protective shell and is electrically connected to the embedded processing unit, for receiving the control signal of the embedded processing unit and receiving the target imaging information of the underwater target in the illumination field of view.

[0010] The polarization spectrum coupling unit is arranged opposite to the output end of the front-mounted telescopic imaging unit and is electrically connected to the embedded processing unit, for receiving the control signal of the embedded processing unit and collecting and reconstructing the target imaging information in a push-broom manner to obtain multi-dimensional target images.

[0011] The input end of the embedded processing unit is electrically connected to the output end of the polarization light coupling unit, and the output end is connected to the first water-tight connector, for filtering, pose information correction, image stitching, removing backscattering light, and removing forward scattering light on the multiple multi-dimensional target images to obtain the hyperspectral image of the underwater target and extract the reflectivity characteristics of the hyperspectral image.

[0012] The first water-tight connector is electrically connected to the output end of the embedded processing unit and is sealingly connected to the other end of the waterproof protective shell.

[0013] The present application greatly improves the detection accuracy of the underwater target by combining the active illumination module with the polarization hyperspectral imaging module, i.e., combining the active illumination and polarization hyperspectral technology, which can effectively eliminate the interference of underwater scattering.

[0014] Further, the front-mounted telescopic imaging unit includes a first window glass, an electrically adjustable lens, a mounting support plate, and a lens driving board.

[0015] The first window glass is fixedly connected to the opening at one end of the waterproof protective shell, the mounting support plate and the lens driving board are fixedly connected inside the waterproof protective shell, the electrically adjustable lens is fixedly connected to the mounting support plate, the electrically adjustable lens is arranged opposite to the first window glass, the lens driving board is electrically connected to the electrically adjustable lens, and the lens driving board is used to adjust the focal length and aperture of the electrically adjustable lens; the lens driving board is electrically connected to the embedded processing unit, and the embedded processing unit transmits control signals to the lens driving board.

[0016] Further, the polarization spectrum coupling unit comprises a polarization spectrum camera and a sliding assembly for driving the polarization spectrum camera to realize push scanning to collect target imaging information.

[0017] The fixed end of the sliding assembly is connected to the inner wall of the waterproof protective shell, and the sliding end is connected to the polarization spectrum camera. The input end of the polarization spectrum camera is arranged opposite to the output end of the electrically tunable lens. The polarization spectrum camera is electrically connected to the embedded processing unit. The polarization spectrum camera receives the control signal of the embedded processing unit and collects the imaging information output by the electrically tunable lens. After filtering, polarization and imaging, multi-dimensional target images are obtained and transmitted to the embedded processing unit.

[0018] Further, the polarization spectrum camera comprises a camera body, a linear gradient filter and a micro-polarization focal plane array.

[0019] The camera body is arranged opposite to the output end of the electrically tunable lens. The micro-polarization focal plane array and the linear gradient filter are arranged in the camera body and used for filtering, polarizing and imaging the received target imaging information. The camera body is electrically connected to the embedded processing unit.

[0020] Further, the micro-polarization focal plane array comprises four linear polarization directions, i.e. 0°, 45°, 90° and 135°.

[0021] The spectral range of the linear gradient filter is 400nm-1000nm, and the spectral resolution is 1.5%-2% of the center wavelength.

[0022] Further, the sliding assembly comprises a lead screw stepper motor and a lead screw nut mechanism connected to the output end of the lead screw stepper motor. The lead screw stepper motor is electrically connected to a motor drive board. The motor drive board is fixedly connected to the inner wall of the waterproof protective shell. The lead screw stepper motor is fixedly connected to the mounting support plate. The sidewall of the lead screw stepper motor is fixedly connected to a sliding rail. A sliding block is slidingly connected to the sliding rail. The sliding block is connected to the nut of the lead screw nut mechanism. The polarization spectrum camera is fixedly connected to the sliding block. The push scanning of the polarization spectrum camera is realized by controlling the lead screw stepper motor.

[0023] Further, the polarization spectrum coupling unit further comprises a heat dissipation fin and a flexible heat dissipation copper strip. The heat dissipation fin is sleeved on the outer wall of the camera body. One side of the heat dissipation fin is fixedly connected to one end of the flexible heat dissipation copper strip. The other end of the flexible heat dissipation copper strip is fixedly connected to the waterproof protective shell.

[0024] Further, the active lighting module comprises a lighting waterproof shell with two open ends, and a first light filtering rotating wheel, a second light filtering rotating wheel, a collimating element, a light emitting chip group and a constant current source driving control board are sequentially connected in the lighting waterproof shell, and the constant current source driving control board is connected with the light emitting chip group, the first light filtering rotating wheel and the second light filtering rotating wheel respectively.

[0025] A plurality of polarizing plates of polarization states are fixedly connected to the first light filtering rotating wheel, a plurality of uniform light engineering diffusion plates of parameters are connected to the second light filtering rotating wheel, a second window glass is sealingly connected to the end opening of the lighting waterproof shell close to the first light filtering rotating wheel, the collimating element, one of the polarizing plates and one of the uniform light engineering diffusion plates form an optical path with the second window glass, and the light emitting chip group is located at the incident end of the collimating element.

[0026] The light emitting chip group comprises a white light LED chip, a 405nm-412nm violet light emitting chip and a 685nm-693nm red light emitting chip.

[0027] Further, the active lighting module comprises a lighting waterproof shell with two open ends, and one of the open ends is arranged away from the central axis of the lighting waterproof shell, a lens fixing ring, a collimating element, a light emitting chip group and a constant current source driving control board are sequentially connected in the lighting waterproof shell, the constant current source driving control board is connected with the light emitting chip group, a first lens mounting clamping groove and a second lens mounting clamping groove are sequentially arranged on the lens fixing ring, and the first lens mounting clamping groove is close to the collimating element, a uniform light engineering diffusion plate is arranged in the first lens mounting clamping groove, and a polarizing plate is arranged in the second lens mounting clamping groove.

[0028] A second window glass is connected to the end opening of the lighting waterproof shell close to the polarizing plate, the collimating element, the polarizing plate and the uniform light engineering diffusion plate form an optical path with the second window glass, the light emitting chip group is located at the incident end of the collimating element, the constant current source driving control board is electrically connected with a second watertight connector, and the second watertight connector is sealingly connected to the other end opening of the lighting waterproof shell.

[0029] The light emitting chip group comprises a white light LED chip, a 405nm-412nm violet light emitting chip and a 685nm-693nm red light emitting chip.

[0030] The application also provides a method for detecting an underwater target polarization hyperspectrum in cooperation with an active lighting, and the method comprises the following steps based on the above-mentioned device for detecting an underwater target polarization hyperspectrum in cooperation with an active lighting.

[0031] S1, connect the first water-tight connector, the active illumination module and the computer through long cables respectively, connect the active illumination module and the waterproof protective shell on the underwater submersible, place the underwater submersible underwater, turn on the active illumination module to emit light signals, and provide an illumination field of view of the underwater target;

[0032] S2, the reflected light signals of the target in the illumination field of view form target imaging information in the front-mounted telescopic imaging unit, the polarization spectrum coupling unit is driven to collect and reconstruct the target imaging information in a push-scan manner, obtain the multi-dimensional target image at the place, and move the waterproof protective shell to collect multi-dimensional target images at multiple places to obtain multiple multi-dimensional target images;

[0033] S3, filter, pose information correction and image stitching are performed on the multiple multi-dimensional target images by the embedded processing unit to obtain a target image of a large field of view, the polarization component information of the polarization spectrum coupling unit is used to remove the backscattering light of the underwater image, and the image edge information method and the estimated point spread function are combined to remove the forward scattering light of the image, so that a hyperspectral image of the underwater target is obtained;

[0034] The formula for removing the backscattering light of the underwater image by using the polarization component information of the polarization spectrum coupling unit is:

[0035]

[0036] Wherein, S(x,y,λ) is the target information light obtained at (x,y), λ represents the wavelength passing through a specific spectral channel, p scat (λ) is the polarization degree of the backscattering light in the image obtained after image stitching, p obj (λ) is the polarization degree of the target in the image obtained after image stitching, I(x,y,λ) is the sum of the light intensities at (x,y,λ) of the specific spectral channel 0° polarization direction and 90° polarization direction, Q(x,y,λ) is the difference between the light intensities at (x,y,λ) of the specific spectral channel 0° polarization direction and 90° polarization direction, and U(x,y,λ) is the difference between the light intensities at (x,y,λ) of the specific spectral channel 45° polarization direction and 135° polarization direction;

[0037] S4, the reflectance characteristics in the hyperspectral image of the underwater target are extracted by using a standard diffuse reflection plate or a light source light field modeling, qualitative analysis of the underwater target is performed according to the reflectance characteristics to obtain a classification result of the underwater target, and quantitative analysis of the underwater target is performed according to the reflectance characteristics to obtain a parameter distribution result of the underwater target.

[0038] The beneficial effects of the present application are:

[0039] 1) The application is a kind of underwater target polarization hyperspectral imaging detection device and detection method of cooperative active illumination, which greatly improves the detection accuracy of underwater target by combining active illumination and polarization hyperspectral technology, and can effectively eliminate the interference of underwater scattering.

[0040] 2) In the application, the polarization spectrum coupling unit is built-in push-scan structure, which adopts push-scan acquisition to obtain large field of view target imaging information, can realize spectral information collection of full target space target points, and obtain accurate underwater target polarization hyperspectral image, i.e. multi-dimensional target image.

[0041] 3) In the application, a plurality of polarization plates of multiple polarization states and a plurality of parameter uniform light engineering diffusion plates are arranged, so that the light source emitted by the light-emitting chip group has adjustable polarization state, adjustable spectrum and intensity, which can adapt to various complex underwater environments and improve the detection effect.

[0042] 4) In the application, the push-scan structure is arranged inside the waterproof protective shell, which avoids the inconvenience of external push-scan structure in underwater use, makes the design of each part in the waterproof protective shell compact, and realizes the miniaturization of the structure. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a principle diagram of the application, a kind of underwater target polarization hyperspectral imaging detection device of cooperative active illumination embodiment one;

[0044] Figure 2 is the structure diagram of the micro-polarization focal plane array of the application, a kind of underwater target polarization hyperspectral imaging detection device of cooperative active illumination embodiment one;

[0045] Wherein, (a) is a micro-polarization focal plane array three-dimensional schematic view;(b) is the polarization direction schematic view of micro-polarization focal plane array;

[0046] Figure 3 is the structure diagram of the waterproof protective shell in the application, a kind of underwater target polarization hyperspectral imaging detection device of cooperative active illumination embodiment one;

[0047] Figure 4 is the first view angle structure schematic view in the polarization hyperspectral imaging module of the application, a kind of underwater target polarization hyperspectral imaging detection device of cooperative active illumination embodiment one;

[0048] Figure 5 is the second view angle structure schematic view in the polarization hyperspectral imaging module of the application, a kind of underwater target polarization hyperspectral imaging detection device of cooperative active illumination embodiment one;

[0049] Figure 6 This is a spectral curve diagram corresponding to different color temperatures of the central white light in Embodiment 1 of the underwater target polarization hyperspectral imaging detection device with coordinated active illumination of the present invention;

[0050] Where the horizontal axis represents wavelength and the vertical axis represents light intensity;

[0051] Figure 7 This is a schematic diagram of the structure of the light-emitting chip group in Embodiment 1 of the underwater target polarization hyperspectral imaging detection device with coordinated active illumination according to the present invention.

[0052] Figure 8 This is a schematic diagram of the waterproof outer shell of the underwater target polarization hyperspectral imaging detection device with coordinated active illumination in Embodiment 1 of the present invention;

[0053] Figure 9 This is a schematic diagram of the active illumination module in Embodiment 1 of the underwater target polarization hyperspectral imaging detection device with cooperative active illumination according to the present invention;

[0054] Figure 10 This is a schematic diagram of the waterproof outer shell for illumination in Embodiment 2 of the underwater target polarization hyperspectral imaging detection device with coordinated active illumination according to the present invention;

[0055] Figure 11 This is a schematic diagram of the active illumination module in Embodiment 2 of the underwater target polarization hyperspectral imaging detection device with cooperative active illumination according to the present invention;

[0056] Figure 12 This is a flowchart of an embodiment of the underwater target polarization hyperspectral imaging detection method with coordinated active illumination according to the present invention.

[0057] In the diagram, 1-waterproof protective housing; 2-front-mounted telescope imaging unit, 201-first window glass, 202-electrically adjustable lens, 203-mounting support plate, 204-lens drive board; 3-polarization spectral coupling unit, 301-polarization spectral camera, 302-lead screw stepper motor, 303-slide rail, 304-slider, 305-motor drive board, 306-heat sink, 307-flexible heat dissipation copper strip; 4-embedded processing unit; 5-first watertight Connectors; 6-Active lighting module, 601-Waterproof lighting housing, 602-First filter wheel, 603-Second filter wheel, 604-Collimating element, 605-Light-emitting chip group, 606-Polarizer, 607-Light-diffusing engineering diffuser, 608-Constant current source drive control board, 609-Second watertight connector, 610-Second window glass, 611-Lens retaining ring, 612-First lens mounting slot, 613-Second lens mounting slot. Detailed Implementation

[0058] The technical solutions of the present application will be described clearly and completely in combination with the drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0059] Embodiment one

[0060] The embodiment is based on a linear gradient filter and a pixel polarization modulation method to construct a polarization spectral coupling unit 3, which can synchronously acquire polarization hyperspectral images of four different linear polarization directions (0°, 45°, 90°, 135°). The imaging principle is shown in Figure 1 and Figure 2 The light incident on the front imaging unit 2 is first split by the linear gradient filter, then incident on the micro-polarization focal plane array, and then collected by the camera body to obtain a multi-dimensional target image, which is output to the link and terminal through the first water-tight connector 5 after information reconstruction and fusion in the embedded processing unit 4. Due to the characteristics of the linear gradient filter, a motion structure is also needed to ensure the complete output of the spectral image; in this embodiment, an internal push scanning structure is proposed, which uses the relative motion between the polarization spectral camera and the lens to realize the collection of spectral information of the target points in the whole target space.

[0061] The embodiment is a kind of underwater target polarization hyperspectral imaging detection device cooperated with active illumination, and the specific structure includes an active illumination module 6 and a polarization hyperspectral imaging module; as shown in Figure 3 , the polarization hyperspectral imaging module includes a waterproof protective shell 1 with two open ends, which adopts a cylindrical pressure-resistant shell, and the specific material can be selected from aluminum, titanium alloy, etc. The first window glass 201 is sealingly connected to the open end of the waterproof protective shell 1, and the first window glass 201 is selected from flat glass, which needs to have high transmittance in the range of 400nm-700nm. As shown in Figure 4 , the waterproof protective shell 1 is connected to the mounting support plate 203 and the lens driving plate 204 in sequence, the electrically adjustable lens 202 is fixedly connected to the mounting support plate 203, the electrically adjustable lens 202 is arranged opposite to the first window glass 201, the lens driving plate 204 is electrically connected to the electrically adjustable lens 202, the lens driving plate 204 is used to adjust the focal length and aperture of the electrically adjustable lens 202, the lens driving plate 204 is electrically connected to the embedded processing unit 4, and the embedded processing unit 4 can select the NUC series of Intel company.

[0062] In this embodiment, the lens driving board 204 controls the electrically adjustable lens 202 through the embedded processing unit 4, and the imaging information is obtained by controlling the electrically adjustable lens 202 to enter the target optical signal in the electrically adjustable lens 202 for imaging. Figure 5 As shown in the figure, the waterproof protective shell 1 is fixedly connected with the motor driving board 305. The lead screw stepper motor 302 is fixedly connected on the imaging end of the electrically adjustable lens 202. The lead screw stepper motor 302 is connected with the lead screw nut mechanism at the output end. The lead screw stepper motor 302 is electrically connected with the motor driving board 305. The side wall of the lead screw stepper motor 302 is fixedly connected with the sliding rail 303. The sliding block 304 is slidably connected with the sliding rail 303. The sliding block 304 is fixedly connected with the output end of the lead screw stepper motor 302 through the connecting piece. The polarized spectral camera 301 is fixedly connected with the sliding block 304. The input end of the polarized spectral camera 301 is arranged opposite to the output end of the electrically adjustable lens 202. The polarized spectral camera 301 is electrically connected with the embedded processing unit 4. The polarized spectral camera 301 receives the control signal of the embedded processing unit 4 and collects the imaging information output by the electrically adjustable lens 202. The imaging information is filtered, polarized and imaged to obtain the polarized hyperspectral image of the underwater target, that is, the multi-dimensional target image, and the multi-dimensional target image is transmitted to the embedded processing unit 4.

[0063] In view of the characteristics of the linear variable filter, in this embodiment, the lead screw stepper motor 302 is repeatedly driven and controlled by the motor driving board 305 to drive the polarized spectral camera 301 to collect the imaging information output by the electrically adjustable lens 202 in the waterproof protective shell 1 in a push-scan manner. The push-scan speed is determined by the frame frequency of the polarized spectral camera. The precision lead screw stepper motor 302 can be selected from the products of Shanghai Yanneng Automation Technology Co., Ltd. The motor driving board can be selected from the CL3-E-1-0F series products of Nanotec, Germany. By using the relative movement between the polarized spectral camera 301 and the electrically adjustable lens 202, the spectral information of the target points in the whole target space can be collected, and the accurate polarized hyperspectral image of the underwater target can be obtained.

[0064] In this embodiment, the polarized spectral camera 301 includes a camera body, a linear variable filter and a micro-polarized focal plane array. The micro-polarized focal plane array includes four linear polarization directions, which are 0°, 45°, 90° and 135°, respectively. The spectral range of the linear variable filter is 400nm-1000nm, and the spectral resolution is 1.5%-2% of the center wavelength. The camera body is arranged opposite to the output end of the electrically adjustable lens 202. The micro-polarized focal plane array and the linear variable filter are arranged in the camera body, which are used for filtering, polarizing and imaging the received target imaging information. The camera body is electrically connected with the embedded processing unit 4.

[0065] In this embodiment, the outer wall of the camera body is also connected with the heat dissipation fins 306, one side of the heat dissipation fins 306 is fixedly connected with the flexible heat dissipation copper strip 307, and the flexible heat dissipation copper strip 307 is fixedly connected with the waterproof protective shell 1. The heat dissipation fins 306 and the flexible heat dissipation copper strip 307 conduct heat to the waterproof protective shell 1, thereby accelerating heat circulation and achieving the purpose of cooling.

[0066] The input end of the embedded processing unit 4 is electrically connected with the output end of the camera body, the output end is connected with the first watertight connector 5, receives a plurality of multi-dimensional target images of a plurality of fields of view, and performs the following preprocessing on the plurality of multi-dimensional target images: removes random noise by using median filtering, corrects the distortion that may occur in the image acquisition process due to the instability of the platform caused by environmental factors such as underwater turbulence by using pose information, and finally splices the obtained images by using image splicing technology, removes back scattering light, removes forward scattering light, obtains a hyperspectral image of an underwater target, and extracts reflectivity features of the hyperspectral image.

[0067] The first watertight connector 5 is electrically connected with the output end of the embedded processing unit 4 and is sealingly connected at the other end opening of the waterproof protective shell 1.

[0068] In order to adapt to various complex underwater environments and improve the detection effect, the active illumination module 6 is adopted in this embodiment, which can provide an underwater active illumination light source to provide an illumination field of view for the acquisition of target images. As for the selection of the light-emitting light source in the active illumination module 6, LED technology is selected first, which has the advantages of small volume, light weight, low electrical specification requirement, high luminous efficiency, etc. The COB packaging process integrated LED light source (COB packaging refers to chip on board, that is, the bare chip is adhered to the interconnection substrate by conductive or non-conductive adhesive, and then wire bonding is performed to realize electrical connection, that is, LED chip and substrate integration technology) is selected, which has the advantages of high integration, small space occupation, high light efficiency, etc. A variety of light-emitting chips are used to excite mixed fluorescent powder to realize a white spectral line similar to sunlight spectrum, and the color rendering index can be greater than 95. The white light color temperature is selected to be 5000K (high Kelvin). The maximum light output is greater than 3000lm.

[0069] According to the specific curve of the white light selection, it is found that the relative light intensity at 400nm and 700nm is relatively low, such as Figure 6As shown, considering the strong total attenuation of the red, blue and purple regions of the turbid water body, additional "bilateral" light compensation is also needed, i.e. separate monochromatic light emitting chips are arranged around the white light LED, and the difficulties brought by this work are obvious. Not only the adaptability of various light emitting chips needs to be considered, but also the overall circuit design and miniaturized arrangement. Finally, 410nm violet light emitting chips (2235 size, normal process, horizontal chip) and 690nm red light emitting chips (4242 size, normal process, vertical chip) are selected for additional light compensation, as shown in Figure 7 .

[0070] In this embodiment, by continuously controlling the current, the light intensity and spectrum of the light source can be adjusted. A constant current source driving design is adopted to realize three-way independent continuous control of white light, red light and violet light. When the maximum rated current of the three ways is reached at the same time, the ideal light source should have a "camel hump" shape, and by controlling the relative power of the three ways, the spectrum can be adjusted, which has high robustness in different underwater environments.

[0071] In addition, considering the actual underwater application and the detection technology system in this embodiment, the uniformity of the light emitting chip group exit light source also needs to be considered, and it is designed as a point-like light source, i.e. the light within the exit angle is flat-top light. In this embodiment, a collimating element is used to collimate the light beam, which can be a custom-made reflective cup or a TIR lens. Then, through the light homogenization engineering diffusion sheet (GDF series of Hainan Optical Co., Ltd. is selected), a uniform light beam with a certain divergence angle is emitted. Considering the demand for underwater active polarized light source and the influence of light homogenization engineering diffusion sheet on polarization state, a polarizing sheet (polarizing element of Edmund optics company is selected) is installed after the light homogenization diffusion sheet, and finally a uniform light beam with polarization state is emitted.

[0072] As shown in Figure 8 and Figure 9 The active illumination module 6 is an electrically switched type, and the specific structure includes an illumination waterproof housing 601 with two open ends, a first filter rotating wheel 602, a second filter rotating wheel 603, a collimating element 604, a light emitting chip group 605, and a constant current source driving control board 608 connected in turn in the illumination waterproof housing 601. The constant current source driving control board 608 is connected with the light emitting chip group 605, the first filter rotating wheel 602 and the second filter rotating wheel 603 respectively.

[0073] In the embodiment, a plurality of polarizers 606 of polarization states (circular polarization, linear polarization, no polarization) are fixedly connected to the first light filtering rotating wheel 602, a plurality of uniform light engineering diffusers 607 of parameters (different beam angles, different shapes) are connected to the second light filtering rotating wheel 603, the second window glass 610 is sealingly connected to the opening at one end of the illumination waterproof shell 601 close to the first light filtering rotating wheel 602, the collimating element 604, one of the polarizers 606, one of the uniform light engineering diffusers 607 and the second window glass 610 form an optical path, and the light emitting chip group 605 is located at the incident end of the collimating element 604 on the optical path; in order to realize that the second window glass 610 and the polarizer 606 and the uniform light engineering diffuser 607 are on the same optical path, the position of the second window glass 610 deviates from the center of the illumination waterproof shell 601 in the embodiment; in use, the switching of the polarizer 606 is realized through the first light filtering rotating wheel 602, and the switching of the uniform light engineering diffuser 607 is realized through the second light filtering rotating wheel 603, without the need to disassemble the shell for manual replacement.

[0074] The light emitting chip group 605 includes white light LED chips, 405nm-412nm violet light emitting chips and 685nm-693nm red light emitting chips.

[0075] In the embodiment, the embedded processing unit 4 is connected to the first water-proof connector 5 at the output end and is sealingly connected to the opening at the other end of the waterproof protective shell 1, for power supply and communication with the device.

[0076] The embodiment also provides a kind of underwater target polarization hyperspectral detection method of cooperative active illumination, as shown in Figure 6, based on the underwater target polarization hyperspectral imaging detection device of cooperative active illumination in embodiment two, specifically comprising the following steps: Figure 12

[0077] S1, the first water-proof connector 5 in the second water-proof connector 609 in the active illumination module 6 is connected to the computer by long cable respectively, the active illumination module 6 and the waterproof protective shell 1 are connected to the underwater submersible vehicle, the underwater submersible vehicle is placed underwater, the active illumination module is turned on to emit light signal, and the illumination field of view of underwater target is provided;

[0078] S2, the reflected light signal of the target in the illumination field of view forms target imaging information in the front-mounted telescopic imaging unit 2, the target imaging information is collected by polarization spectrum coupling unit 3 and push-scan, and the target imaging information is filtered, polarized and imaged to obtain the multi-dimensional target image at the place, the waterproof protective shell 1 is moved to collect multi-dimensional target images at multiple places to obtain a plurality of multi-dimensional target images; in the embodiment, the multi-dimensional target image is collected in the gazing type observation mode each time.

[0079] ​S3, due to the instability of the platform caused by underwater turbulence and other environmental factors, distortion may occur during image acquisition, and geometric correction is needed using pose information. The embedded processing unit 4 filters multiple multi-dimensional target images, corrects the pose information, and splices the images to obtain a large field-of-view target image. The polarization component information is used to remove the backscattering light of the underwater image, and the image edge information method and the estimated point spread function are used to remove the forward scattering light of the image to obtain the hyperspectral image of the underwater target. Among them, the use of polarization information to remove the backscattering light of the underwater image is based on the active polarization despeckling model proposed by Treibitz et al. in 2008, and four-channel polarization component information is used to remove the backscattering light of the underwater image,

[0080] The formula for removing the backscattering light of the underwater image using the polarization component information of the polarization spectral coupling unit 3 is:

[0081]

[0082] Where S(x, y, λ) is the target information light obtained at (x, y), λ represents the wavelength through a specific spectral channel, p scat (λ) is the degree of polarization of the backscattering light in the image obtained after image splicing, and the degree of polarization is determined according to the polarization information of the multi-dimensional target image, p obj (λ) is the degree of polarization of the target in the image obtained after image splicing, I(x, y, λ) is the sum of the light intensities at (x, y, λ) of the specific spectral channel 0° polarization direction and 90° polarization direction, Q(x, y, λ) is the difference between the light intensities at (x, y, λ) of the specific spectral channel 0° polarization direction and 90° polarization direction, and U(x, y, λ) is the difference between the light intensities at (x, y, λ) of the specific spectral channel 45° polarization direction and 135° polarization direction.

[0083] S4, the reflectance characteristics in the hyperspectral image of the underwater target are extracted by standard diffuse reflection plate or light field modeling of the light source, and the classification results of the underwater target are obtained by qualitative analysis of the reflectance characteristics. The parameter distribution results of the underwater target are obtained by quantitative analysis of the reflectance characteristics of the underwater target.

[0084] Example Two

[0085] The difference between this embodiment and Example One is that, as shown in FIG. 2, the polarization spectral coupling unit 3 is replaced by a polarization spectral coupling unit 3' in the embodiment. Figure 10 , Figure 11As shown, the active illumination module 6 is manually switched, and specifically comprises a lighting waterproof shell 601 with two open ends, a lens fixing ring 611, a collimating element 604, a light emitting chip set 605, a constant current source driving control board 608 connected in sequence in the lighting waterproof shell 601, the constant current source driving control board 608 connected with the light emitting chip set 605, a first lens mounting clamping groove 612 and a second lens mounting clamping groove 613 opened in sequence on the lens fixing ring 611, the first lens mounting clamping groove 612 close to the collimating element 604, an optical engineering diffuser 607 arranged in the first lens mounting clamping groove 612, and a polarizer 606 arranged in the second lens mounting clamping groove 613;

[0086] The second window glass 610 is sealingly connected to the opening end of the lighting waterproof shell 601 close to the polarizer 606, the collimating element 604, the polarizer 606, the optical engineering diffuser 607 and the second window glass 610 form a light path, the light emitting chip set 605 is located at the incident end of the collimating element 604 on the light path, the constant current source driving control board 608 is electrically connected with a second water-tight connector 609, and the second water-tight connector 609 is sealingly connected to the other opening end of the lighting waterproof shell 601.

[0087] The light emitting chip set 605 comprises a white light LED chip, a 405nm-412nm violet light emitting chip and a 685nm-693nm red light emitting chip.

[0088] In the embodiment, the polarization state of the polarizer 606 is selected and replaced according to actual requirements, and the beam angle and shape of the optical engineering diffuser 607 are also selected and replaced according to actual requirements.

[0089] The underwater target polarization hyperspectral detection method in cooperation with the active illumination in the embodiment is the same as that in Embodiment 1.

[0090] The above is only a specific embodiment of the present application, and the effect of the related specific embodiment and the comparative example is compared, but the protection scope of the present application is not limited to this, any change or replacement within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A polarization hyperspectral imaging detection device for underwater targets with coordinated active illumination, characterized in that: It includes an active illumination module (6) and a polarization hyperspectral imaging module; The active illumination module (6) is used to provide an illumination field of view for underwater targets; The polarization hyperspectral imaging module includes a waterproof protective housing (1), and the waterproof protective housing (1) is provided with a front-mounted telescope imaging unit (2), a polarization spectral coupling unit (3), an embedded processing unit (4), and a first watertight connector (5). The front-mounted telephoto imaging unit (2) includes a first window glass (201), an electrically adjustable lens (202), a mounting support plate (203), and a lens drive plate (204). The first window glass (201) is fixedly connected to one end opening of the waterproof protective housing (1). The mounting support plate (203) and lens drive plate (204) are fixedly connected inside the waterproof protective housing (1). The electrically adjustable lens (202) is fixedly connected to the mounting support plate (203). The electrically adjustable lens (202) is arranged opposite to the first window glass (201). The lens drive plate (204) is electrically connected to the electrically adjustable lens (202). The lens drive plate (204) is used to adjust the focal length and aperture of the electrically adjustable lens (202). The lens drive plate (204) is electrically connected to the embedded processing unit (4). The front-mounted telephoto imaging unit (2) is used to receive the control signal from the embedded processing unit (4) and receive the target imaging information of the underwater target in the illumination field of view. The polarization spectral coupling unit (3) includes a polarization spectral camera (301) and a sliding component; The fixed end of the sliding component is connected to the inner wall of the waterproof protective housing (1), and the sliding end is connected to the polarization spectral camera (301). The input end of the polarization spectral camera (301) is set relative to the output end of the electrically adjustable lens (202). The polarization spectral camera (301) is electrically connected to the embedded processing unit (4). The polarization spectral camera (301) receives the control signal of the embedded processing unit (4) and collects the imaging information output by the electrically adjustable lens (202) to obtain a multidimensional target image, which is then transmitted to the embedded processing unit (4). The polarization spectral coupling unit (3) is used to receive the control signal of the embedded processing unit (4) and collects and reconstructs the target imaging information by push-broom method to obtain a multidimensional target image. The polarization spectral camera (301) includes a camera body, a linear gradient filter, and a micro-polarization focal plane array; The camera body is positioned relative to the output end of the electrically adjustable lens (202). The camera body is equipped with a micro-polarization focal plane array and a linear gradient filter for filtering, polarizing, and imaging the received target imaging information. The camera body is electrically connected to the embedded processing unit (4). The micro-polarization focal plane array includes four linear polarization directions, namely 0°, 45°, 90°, and 135°. The linear graded filter has a spectral range of 400nm-1000nm and a spectral resolution of 1.5%-2% of the center wavelength. The sliding assembly includes a lead screw stepper motor (302) and a lead screw nut mechanism connected to the output end of the lead screw stepper motor (302). The lead screw stepper motor (302) is electrically connected to a motor drive board (305). The motor drive board (305) is fixedly connected to the inner wall of the waterproof protective housing (1). The lead screw stepper motor (302) is fixedly connected to the mounting support plate (203). The side wall of the lead screw stepper motor (302) is fixedly connected to a slide rail (303). A slider (304) is slidably connected to the slide rail (303). The slider (304) is connected to the nut motor of the lead screw nut mechanism. A polarization spectral camera (301) is fixedly connected to the slider (304). The input end of the embedded processing unit (4) is electrically connected to the output end of the polarization coupling unit (3), and the output end is connected to the first watertight connector (5). The embedded processing unit (4) is used to filter, correct pose information, stitch images, remove backscattered light, remove forward scattered light, obtain a hyperspectral image of the underwater target, and extract the reflectance features of the hyperspectral image. The first watertight connector (5) is electrically connected to the output end of the embedded processing unit (4) and is sealed to the other end of the waterproof protective housing (1).

2. The underwater target polarization hyperspectral imaging detection device with cooperative active illumination according to claim 1, characterized in that: The polarization spectral coupling unit (3) also includes a heat dissipation fin (306) and a flexible heat dissipation copper strip (307). The heat dissipation fin (306) is sleeved on the outer wall of the camera body. One side of the heat dissipation fin (306) is fixedly connected to one end of the flexible heat dissipation copper strip (307), and the other end of the flexible heat dissipation copper strip (307) is fixedly connected to the waterproof protective shell (1).

3. The underwater target polarization hyperspectral imaging detection device with cooperative active illumination according to claim 1, characterized in that: The active lighting module (6) includes a waterproof lighting housing (601) with openings at both ends, and one of the openings is offset from the central axis of the waterproof lighting housing (601); the waterproof lighting housing (601) is connected in sequence to a first filter wheel (602), a second filter wheel (603), a collimating element (604), a light-emitting chip group (605), and a constant current source drive control board (608), and the constant current source drive control board (608) is connected to the light-emitting chip group (605), the first filter wheel (602), and the second filter wheel (603); Multiple polarizers (606) with polarization states are fixedly connected to the first filter wheel (602). Multiple uniform light diffusers (607) with multiple parameters are connected to the second filter wheel (603). The second window glass (610) is sealed at one end of the lighting waterproof housing (601) off the central axis. The collimating element (604), one of the polarizers (606), one of the uniform light diffusers (607) and the second window glass (610) form an optical path. The light-emitting chip group (605) is located at the incident end of the collimating element (604). The constant current source drive control board (608) is electrically connected to the second watertight connector (609). The second watertight connector (609) is sealed at the other end of the lighting waterproof housing (601). The light-emitting chip group (605) includes a white LED chip, a 405nm-412nm purple light-emitting chip, and a 685nm-693nm red light-emitting chip.

4. The underwater target polarization hyperspectral imaging detection device with cooperative active illumination according to claim 1, characterized in that: The dynamic lighting module (7) includes a waterproof lighting housing (601) with openings at both ends. Inside the waterproof lighting housing (601), a lens fixing ring (611), a collimating element (604), a light-emitting chip group (605), and a constant current source drive control board (608) are connected in sequence. The constant current source drive control board (608) is connected to the light-emitting chip group (605). The lens fixing ring (611) has a first lens mounting slot (612) and a second lens mounting slot (613) in sequence. The first lens mounting slot (612) is close to the collimating element (604). A light-diffusing engineering diffuser (607) is provided in the first lens mounting slot (612), and a polarizer (606) is provided in the second lens mounting slot (613). The lighting waterproof housing (601) is connected to a second window glass (610) at one end near the polarizer (606). The collimating element (604), polarizer (606), light-diffusing sheet (607) and the second window glass (610) form an optical path. The light-emitting chip group (605) is located at the incident end of the collimating element (604). The constant current source drive control board (608) is electrically connected to the second watertight connector (609). The second watertight connector (609) is sealed to the other end of the lighting waterproof housing (601). The light-emitting chip group (605) includes a white LED chip, a 405nm-412nm purple light-emitting chip, and a 685nm-693nm red light-emitting chip.

5. A method for detecting underwater targets using coordinated active illumination polarization hyperspectral imaging, characterized in that, The underwater target polarization hyperspectral imaging detection device based on any one of claims 1-4 specifically includes the following steps: S1. Connect the first watertight connector (5) and the active lighting module (6) to the computer via long cables. Connect the active lighting module (6) and the waterproof protective shell (1) to the underwater vehicle. Place the underwater vehicle underwater and turn on the active lighting module (6) to emit light signals to provide an illumination field of view for the underwater target. S2. The reflected light signal of the target in the illumination field of view forms target imaging information in the front telescope imaging unit (2). The polarization spectral coupling unit (3) is driven to collect and reconstruct the target imaging information by push-broom method, and obtain multi-dimensional target images at the push-broom position. The waterproof protective shell (1) is moved to collect multi-dimensional target images at multiple locations, and obtain multiple multi-dimensional target images. S3. The embedded processing unit (4) filters, corrects pose information, and stitches images of multiple multidimensional target images to obtain a target image with a large field of view. The polarization component information of the polarization spectral coupling unit (3) is used to remove the backscattered light of the underwater image from the target image with a large field of view. The image edge information method and the estimated point diffusion function are combined to remove the forward scattered light of the image to obtain a hyperspectral image of the underwater target. The formula for removing backscattered light from underwater images using polarization component information from polarization spectral coupling unit (3) is as follows: in, In order to be in The target information light obtained at the point, Indicates the wavelength passing through a specific spectral channel. This refers to the degree of polarization of the backscattered light in the image obtained after image stitching. To obtain the polarization degree of the target in the image after image stitching. For a specific spectral channel, the 0° polarization direction and the 90° polarization direction are in The sum of light intensities at a point, For a specific spectral channel, the 0° polarization direction and the 90° polarization direction are in The difference in light intensity at a point For specific spectral channels, the 45° polarization direction and the 135° polarization direction are in The difference in light intensity at a point; S4. Extract reflectance features from the hyperspectral images of underwater targets by modeling the light field of a standard diffuse reflector or light source. Perform qualitative analysis on the underwater targets based on the reflectance features to obtain the classification results of the underwater targets. Perform quantitative analysis on the underwater targets based on the reflectance features to obtain the parameter distribution results of the underwater targets.

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