Underwater target polarization hyperspectral imaging detection device and detection method for cooperative active illumination

Abstract

The invention discloses an underwater target polarization hyperspectral imaging detection device and detection method for cooperative active illumination, and solves the technical problems of poor imaging quality caused by underwater light absorption and scattering and poor use flexibility caused by large size of an existing underwater optical imaging detection device. The system comprises an active illumination module and a polarization hyperspectral imaging module. The polarization hyperspectral imaging module comprises a waterproof protection shell with openings in the two ends. A front telescopic imaging unit, a polarization spectrum coupling unit, an embedded processing unit and a first watertight connector are sequentially arranged in the waterproof protection shell. The front telescopic imaging unit and the polarization spectrum coupling unit are connected; according to the invention, through the combination of cooperative active illumination and polarization hyperspectral technology, the detection precision of the underwater target is greatly improved, and the interference of underwater scattering can be effectively eliminated.

Description

Technical Field

[0001] The present invention relates to an underwater target imaging device and method, and in particular to an underwater target polarization hyperspectral imaging detection device and detection method in coordination with active illumination. Background Art

[0002] Compared with acoustic detection and other means, underwater target optical imaging detection technology has unique advantages: it can provide high-resolution images, intuitively display the shape, color, texture and other characteristics of underwater objects, and help the qualitative / quantitative analysis of underwater targets. However, the water body is a complex dispersion system composed of irregular particles with absorption ability and random orientation; generally speaking, natural light disappears below 200m underwater, and it will be pitch black underwater. At this time, optical imaging detection must rely on artificial active lighting sources. Most of the underwater artificial active lighting sources currently used are prepared for underwater color cameras, which can provide different lumen light output, color temperature, color rendering index, etc. There is almost no research on light sources adapted for multi-, hyperspectral and polarization detectors.

[0003] In addition, most underwater optical imaging detection devices are still at the stage of ordinary color cameras. Although these cameras can capture basic underwater images, they have limitations in identifying and analyzing underwater targets. Teams from Xidian University, Tianjin University and other universities have done a lot of research in the laboratory using polarization cameras, using polarization properties to increase the detectable distance of objects, but most of these research results are still at the laboratory stage. The underwater hyperspectral system (UHI) developed by the Norwegian University of Science and Technology and Ecotone has achieved commercial application and can provide richer spectral information than ordinary color cameras, which helps to more accurately identify and analyze underwater targets. However, its large size requires an external push-broom structure, which limits its flexible application in complex underwater environments. In addition, hyperspectral polarization imaging technology (SPI) is an emerging 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 remains at the laboratory stage. The entire device is large and bulky, making it difficult to be effectively used underwater. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problems of the existing underwater optical imaging detection devices, such as poor imaging quality due to the absorption and scattering of light underwater, and poor flexibility in use due to large size; and to provide an underwater target polarization hyperspectral imaging detection device and detection method with coordinated active illumination.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A polarization hyperspectral imaging device for underwater targets in coordination with active illumination, which is also characterized in that: it comprises an active illumination module and a polarization hyperspectral imaging module;

[0007] The active lighting module is used to provide an illuminated field of view for underwater targets, so that the detection imaging device of the present invention can adapt to a variety of complex underwater environments and improve the detection effect.

[0008] The polarization hyperspectral imaging module comprises a waterproof protective housing, in which a front telescopic imaging unit, a polarization spectrum coupling unit, an embedded processing unit and a first watertight connector are arranged;

[0009] The input end of the front telescopic imaging unit is sealed and connected to one end of the waterproof protective housing, and is electrically connected to the embedded processing unit to receive a control signal of the embedded processing unit and receive target imaging information of the underwater target in the illuminated field of view;

[0010] The polarization spectrum coupling unit is arranged relative to the output end of the front telescopic imaging unit, and is electrically connected to the embedded processing unit to receive the control signal of the embedded processing unit, and collect and reconstruct the target imaging information by push scanning to obtain a multi-dimensional target image;

[0011] The input end of the embedded processing unit is electrically connected to the output end of the polarized light coupling unit, and the output end is connected to the first watertight connector, and is used to filter, correct the posture information, stitch images, remove backscattered light, and remove forward scattered light on multiple multi-dimensional target images to obtain a hyperspectral image of the underwater target, and extract the reflectivity characteristics of the hyperspectral image;

[0012] The first watertight connector is electrically connected to the output end of the embedded processing unit and is sealed to the other end of the waterproof protection housing.

[0013] The present invention significantly improves the detection accuracy of underwater targets by combining an active lighting module with a polarization hyperspectral imaging module, that is, combining active lighting with polarization hyperspectral technology, and can effectively eliminate the interference of underwater scattering.

[0014] Furthermore, the front telescopic imaging unit includes a first window glass, an electrically adjustable lens, a mounting support plate, and a lens driving plate;

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

[0016] Furthermore, the polarization spectrum coupling unit includes a polarization spectrum camera and a sliding component, and the sliding component is used to drive the polarization spectrum camera to implement push scanning to collect target imaging information;

[0017] The fixed end of the sliding component is connected to the inner wall of the waterproof protection shell, and the sliding end is connected to the polarization spectrum camera. The input end of the polarization spectrum camera is arranged relative to the output end of the electrically adjustable 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 adjustable lens. After filtering, polarization and imaging, a multi-dimensional target image is obtained and transmitted to the embedded processing unit.

[0018] Furthermore, the polarization spectrum camera includes a camera body, a linear gradient filter and a micro-polarization focal plane array;

[0019] The camera body is arranged relative to the output end of the electrically adjustable lens, and a micro-polarization focal plane array and a linear gradient filter are arranged in the camera body 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 includes four linear polarization directions, namely 0°, 45°, 90°, and 135°;

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

[0022] Furthermore, the sliding assembly includes a screw stepper motor and a screw nut mechanism connected to the output end of the screw stepper motor, the 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 protection shell, the screw stepper motor is fixedly connected to the mounting support plate, the side wall of the screw stepper motor is fixedly connected to a slide rail, the slide rail is slidably connected to a slider, the slider is connected to a nut of the screw nut mechanism, the slider is fixedly connected to a polarization spectrum camera, and the push scanning of the polarization spectrum camera is achieved by controlling the screw stepper motor.

[0023] Furthermore, the polarization spectrum coupling unit also includes a heat dissipation fin and a flexible heat dissipation copper belt. 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 belt, and the other end of the flexible heat dissipation copper belt is fixedly connected to the waterproof protective shell.

[0024] Furthermore, the active lighting module comprises a lighting waterproof housing with openings at both ends, wherein the lighting waterproof housing is sequentially connected with a first filter wheel, a second filter wheel, a collimating element, a light emitting chip group, and a constant current source drive control board, and the constant current source drive control board is respectively connected with the light emitting chip group, the first filter wheel, and the second filter wheel;

[0025] The first filter wheel is fixedly connected to polarizers of multiple polarization states, the second filter wheel is connected to diffusers of multiple parameters, the second window glass is sealed at an opening at one end of the lighting waterproof housing close to the first filter wheel, the collimating element, one of the polarizers, one of the diffusers of uniform light engineering and the second window glass form an optical path, the light emitting chip group is located at the incident end of the collimating element, and the second watertight connector is sealed at the other end of the lighting waterproof housing;

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

[0027] Further, the dynamic lighting module includes a lighting waterproof shell with openings at both ends, and one of the openings is arranged away from the central axis of the lighting waterproof shell, the lighting waterproof shell is sequentially connected with a lens fixing ring, a collimating element, a light-emitting chipset, and a constant current source drive control board, the constant current source drive control board is connected to the light-emitting chipset, the lens fixing ring is sequentially provided with a first lens mounting slot and a second lens mounting slot, and the first lens mounting slot is close to the collimating element, the first lens mounting slot is provided with a uniform light engineering diffuser, and the second lens mounting slot is provided with a polarizer;

[0028] The second window glass is connected to the opening at one end of the lighting waterproof housing near the polarizer, and the collimating element, the polarizer, the uniform light engineering diffuser and the second window glass form an optical path. The light-emitting chip group is located at the incident end of the collimating element, and the constant current source drive control board is electrically connected to the second watertight connector, and the second watertight connector is sealed and connected to the opening at the other end of the lighting waterproof housing;

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

[0030] The present invention also provides a method for detecting underwater target polarization hyperspectral with coordinated active illumination, and the special feature of the method is that the underwater target polarization hyperspectral imaging detection device based on the above-mentioned coordinated active illumination specifically comprises the following steps:

[0031] S1, respectively connect the first watertight connector and the active lighting module to the computer through long cables, connect the active lighting module and the waterproof protective housing to the underwater submersible, place the underwater submersible underwater, turn on the active lighting module to emit a light signal, and provide an illuminated field of view for the underwater target;

[0032] S2. The reflected light signal of the target in the illumination field forms target imaging information in the front telescopic imaging unit, drives the polarization spectrum coupling unit to collect and reconstruct the target imaging information in a push-scan manner, and obtains a multi-dimensional target image at the location, and moves the waterproof protective housing to collect multi-dimensional target images at multiple locations to obtain multiple multi-dimensional target images;

[0033] S3, filtering, posture information correction, and image stitching of multiple multi-dimensional target images through an embedded processing unit to obtain a target image with a large field of view, using the polarization component information of the polarization spectrum coupling unit to remove the backscattered light of the underwater image, and combining the image edge information method and the estimated point spread function to remove the image forward scattered light, to obtain a hyperspectral image of the underwater target;

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

[0035]

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

[0037] S4. Extract the reflectivity features in the hyperspectral image of the underwater target through standard diffuse reflection plates or light source light field modeling, and perform qualitative analysis on the underwater target based on the reflectivity features to obtain the classification results of the underwater target; perform quantitative analysis on the underwater target based on the reflectivity features to obtain the parameter distribution results of the underwater target.

[0038] Beneficial effects of the present invention:

[0039] 1) The present invention provides a polarization hyperspectral imaging detection device and detection method for underwater targets with coordinated active illumination. By combining coordinated active illumination with polarization hyperspectral technology, the detection accuracy of underwater targets is greatly improved, and the interference of underwater scattering can be effectively eliminated.

[0040] 2) In the polarization hyperspectral imaging detection device for underwater targets with coordinated active illumination of the present invention, the polarization spectrum coupling unit has a built-in push-broom structure, and adopts a push-broom acquisition method to obtain target imaging information with a large field of view, which can realize the collection of spectral information of spatial target points on the entire target surface, and obtain accurate polarization hyperspectral images of underwater targets, that is, multi-dimensional target images.

[0041] 3) In a polarization hyperspectral imaging detection device for underwater targets with coordinated active illumination of the present invention, polarizers with multiple polarization states and uniform light engineering diffusers with multiple parameters are arranged, so that the light source emitted by the light-emitting chipset has adjustable polarization state, adjustable spectrum and intensity, can adapt to a variety of complex underwater environments, and improve the detection effect.

[0042] 4) In the underwater target polarization hyperspectral imaging detection device with coordinated active illumination of the present invention, the push-broom structure is arranged inside the waterproof protective shell, which avoids the inconvenience of using the external push-broom structure underwater, makes the design of each part inside the waterproof protective shell compact, and realizes the miniaturization of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of a first embodiment of a polarization hyperspectral imaging detection device for underwater targets in coordination with active illumination according to the present invention;

[0044] Figure 2 It is a structural schematic diagram of a micro-polarization focal plane array of a first embodiment of a polarization hyperspectral imaging detection device for underwater targets in coordination with active illumination of the present invention;

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

[0046] Figure 3 It is a schematic structural diagram of a waterproof protective housing in Embodiment 1 of a polarization hyperspectral imaging detection device for underwater targets with coordinated active illumination of the present invention;

[0047] Figure 4 It is a schematic diagram of the first viewing angle structure inside the polarization hyperspectral imaging module in the first embodiment of the underwater target polarization hyperspectral imaging detection device with coordinated active illumination of the present invention;

[0048] Figure 5 It is a schematic diagram of the second viewing angle structure inside the polarization hyperspectral imaging module in the first embodiment of the underwater target polarization hyperspectral imaging detection device with coordinated active illumination of the present invention;

[0049] Figure 6 It is a spectrum 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] Among them, the horizontal axis represents the wavelength and the vertical axis represents the light intensity;

[0051] Figure 7 It is a structural schematic diagram of a light-emitting chipset in Embodiment 1 of a polarization hyperspectral imaging detection device for underwater targets with coordinated active illumination of the present invention;

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

[0053] Fig. 9 It is a structural schematic diagram of an active illumination module in Embodiment 1 of a polarization hyperspectral imaging detection device for underwater targets in coordination with active illumination of the present invention;

[0054] Fig.10 It is a structural schematic diagram of the lighting waterproof housing in Embodiment 2 of the underwater target polarization hyperspectral imaging detection device with coordinated active illumination of the present invention;

[0055] Fig.11 It is a structural schematic diagram of an active illumination module in Embodiment 2 of a polarization hyperspectral imaging detection device for underwater targets in coordination with active illumination of the present invention;

[0056] Fig.12 It is a flow chart of Example 1 of a polarization hyperspectral imaging detection method for underwater targets in coordination with active illumination according to the present invention.

[0057] In the figure, 1-waterproof protective shell; 2-front telescopic imaging unit, 201-first window glass, 202-electric adjustment lens, 203-installation support plate, 204-lens drive board; 3-polarization spectrum coupling unit, 301-polarization spectrum camera, 302-screw stepper motor, 303-slide rail, 304-slider, 305-motor drive board, 306-heat dissipation fins, 307-flexible heat dissipation copper belt; 4-embedded processing unit; 5-first watertight Connectors; 6-active lighting module, 601-lighting waterproof housing, 602-first filter wheel, 603-second filter wheel, 604-collimation element, 605-light-emitting chipset, 606-polarizer, 607-uniform light engineering diffuser, 608-constant current source drive control board, 609-second watertight connector, 610-second window glass, 611-lens fixing ring, 612-first lens mounting slot, 613-second lens mounting slot. DETAILED DESCRIPTION

[0058] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] Embodiment 1

[0060] This embodiment constructs a polarization spectrum coupling unit 3 based on linear gradient filtering and pixel polarization modulation method, which can synchronously acquire polarization hyperspectral images of four different linear polarization directions (0°, 45°, 90°, and 135°). The imaging principle is as follows: Figure 1 and Figure 2 As shown. The incident light of the front telescopic 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. After entering the embedded processing unit 4, it undergoes steps such as information reconstruction and fusion, and is output to the link and terminal through the first watertight connector 5. In view of the characteristics of the linear gradient filter, a motion structure needs to be added to ensure the complete output of the spectral image; in this embodiment, an internal push-scan structure is proposed, which utilizes the relative motion between the polarization spectrum camera and the lens to realize the spectral information collection of the target points in the entire target space.

[0061] This embodiment provides a polarization hyperspectral imaging detection device for underwater targets in cooperation with active illumination, and the specific structure includes an active illumination module 6 and a polarization hyperspectral imaging module; Figure 3 As shown, the polarization hyperspectral imaging module includes a waterproof protective housing 1 with openings at both ends, which is a cylindrical pressure-resistant shell. The specific material can be aluminum, titanium alloy, etc. The opening at one end of the waterproof protective housing 1 is sealed and connected to the first window glass 201. The first window glass 201 is made of flat glass and needs to have a high transmittance in the range of 400nm-700nm. Figure 4 As shown, the interior of the waterproof protective housing 1 is connected with a mounting support plate 203 and a 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, and 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 Corporation.

[0062] In this embodiment, the embedded processing unit 4 controls the lens driving board 204 to adjust the electrically adjustable lens 202, and the embedded processing unit 4 controls the electrically adjustable lens 202 to image the target light signal entering the electrically adjustable lens 202 to obtain imaging information. Figure 5 As shown, a motor driving board 305 is fixedly connected inside the waterproof protective shell 1, a screw stepping motor 302 is fixedly connected to the mounting support plate 203 at one side of the imaging end of the electrically adjustable lens 202, a screw nut mechanism is connected to the output end of the screw stepping motor 302, the screw stepping motor 302 is electrically connected to the motor driving board 305, a side wall of the screw stepping 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 fixedly connected to the output end of the screw stepping motor 302 through a connecting piece, and a polarization spectrum camera 301 is fixedly connected to the slider 304. The input end of the polarization spectrum camera 301 is arranged relative to the output end of the electrically adjustable lens 202. The polarization spectrum camera 301 is electrically connected to the embedded processing unit 4. The polarization spectrum camera 301 receives the control signal of the embedded processing unit 4, collects the imaging information output by the electrically adjustable lens 202, filters, polarizes, and images the imaging information, obtains the polarization hyperspectral image of the underwater target, that is, the multi-dimensional target image, and transmits the multi-dimensional target image to the embedded processing unit 4.

[0063] In view of the characteristics of the linear gradient filter, in this embodiment, the motor drive board 305 drives the screw stepper motor 302 to push and sweep repeatedly, driving the polarization spectrum camera 301 to collect the imaging information output by the electric adjustment lens 202 in the waterproof protective housing 1 in a push-sweep manner. The push-sweep speed is determined by the frame rate of the polarization spectrum camera. The precision screw stepper motor 302 can be selected from the products of Shanghai Yanlan Automation Technology Co., Ltd., and the motor drive board can be selected from the CL3-E-1-0F series products of Nanotec of Germany. The relative movement between the polarization spectrum camera 301 and the electric adjustment lens 202 can realize the collection of spectral information of the target points in the entire target space, thereby obtaining an accurate polarization hyperspectral image of the underwater target.

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

[0065] In this embodiment, the outer wall of the camera body is also connected to the heat dissipation fin 306, one side of the heat dissipation fin 306 is fixedly connected to the flexible heat dissipation copper belt 307, and the flexible heat dissipation copper belt 307 is fixedly connected to the waterproof protective housing 1. The heat dissipation fin 306 and the flexible heat dissipation copper belt 307 conduct heat to the waterproof protective housing 1, thereby accelerating the thermal cycle and achieving the purpose of cooling.

[0066] The input end of the embedded processing unit 4 is electrically connected to the output end of the camera body, and the output end is connected to the first watertight connector 5, receiving multi-dimensional target images of multiple fields of view, and performing the following preprocessing on the multiple multi-dimensional target images: for example, using median filtering to remove random noise, and because the platform is unstable due to environmental factors such as underwater turbulence, distortion and deformation may occur during the image acquisition process, and it is necessary to use posture information for geometric correction, and finally using image stitching technology to stitch the obtained images, remove backscattered light, remove forward scattered light, obtain a hyperspectral image of the underwater target, and extract the reflectivity characteristics of the hyperspectral image;

[0067] The first watertight connector 5 is electrically connected to the output end of the embedded processing unit 4 , and is sealed and connected to the other end opening of the waterproof protection housing 1 .

[0068] In order to adapt to various complex underwater environments and improve the detection effect, this embodiment adopts an active lighting module 6, which can provide an underwater active lighting light source and provide an illumination field for the acquisition of the target image; for the selection of the light source in the active lighting module 6, first select the LED system technology, which has the advantages of small size, light weight, low electrical specification requirements, and high luminous efficiency; select the LED integrated light source of the COB packaging process (COB packaging is chip on board, which is to adhere the bare chip to the interconnection substrate with conductive or non-conductive glue, and then perform wire bonding to achieve electrical connection, that is, LED chip and substrate integration technology), which has the advantages of high integration, small space occupation, and high light efficiency; use a variety of light-emitting chips to excite mixed phosphors to achieve white spectrum lines that imitate the solar spectrum, and its 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 white light selection, it is found that the relative light intensity at 400nm and 700nm is low, such as Figure 6As shown, considering the strong total attenuation of the red, blue and purple regions in turbid water, "bilateral" fill light is also required, that is, a separate monochrome light-emitting chip is set around the white light LED. The difficulties brought about 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 miniaturization arrangement are factors that need to be considered. In the end, a 410nm purple light-emitting chip (2235 size, upright process, horizontal chip) and a 690nm red light-emitting chip (4242 size, upright process, vertical chip) were selected for additional fill light, as shown in the figure. Figure 7 shown.

[0070] In this embodiment, the light intensity and spectrum of the light source are adjustable by continuous control of the current. A constant current source drive design is adopted to realize independent and continuous control of three channels of white light, red light and purple light. When the three channels reach the maximum rated current at the same time, the emission effect of the ideal light source should be "hump" shaped. By controlling the relative power of the three channels, the spectrum can be adjusted, which has high robustness in different underwater environments.

[0071] In addition, in combination with the practical underwater application and the detection technology system in this embodiment, the uniformity of the light source emitted by the light-emitting chipset must also be considered, and it is designed to be a point-like light source, that is, the light within the emission angle is a flat-top light. This embodiment uses a collimating element to collimate the light beam, and the collimating element can be a customized reflector cup or a TIR lens. Then, through the uniform light engineering diffuser (the GDF series of Haina Optics Co., Ltd. is selected), a uniform light beam with a certain divergence angle is emitted. Considering the demand for underwater active polarized light sources and the fact that the uniform light engineering diffuser will affect the polarization state, a polarizer is installed after the uniform light diffuser (the polarization element of Edmund Optics is selected), and finally a uniform light beam with a polarization state is emitted.

[0072] like Figure 8 and Fig. 9 As shown, the active lighting module 6 is of electric switching type, and its specific structure includes a lighting waterproof housing 601 with openings at both ends, and the lighting waterproof housing 601 is sequentially connected with 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 respectively connected to the light-emitting chip group 605, the first filter wheel 602, and the second filter wheel 603.

[0073] In this embodiment, the first filter wheel 602 is fixedly connected to a plurality of polarization states (circular polarization, linear polarization, no polarization) of polarizers 606, the second filter wheel 603 is connected to a plurality of parameters (different beam angles, different shapes) of uniform light engineering diffusers 607, the lighting waterproof housing 601 is sealed and connected to a second window glass 610 at an opening at one end close to the first filter 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. An optical path is formed, and the light-emitting chipset 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, the polarizing plate 606, and the light-uniforming engineering diffuser 607 are on the same optical path, the position of the second window glass 610 in this embodiment is offset from the center of the lighting waterproof housing 601; when in use, the polarizing plate 606 is switched by the first filter wheel 602, and the light-uniforming engineering diffuser 607 is switched by the second filter wheel 603, without the need to disassemble the housing for manual replacement.

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

[0075] In this embodiment, the output end of the embedded processing unit 4 is connected to the first watertight connector 5 and is sealed to the other end opening of the waterproof protective housing 1 for power supply and communication with the device.

[0076] This embodiment also provides a polarization hyperspectral detection method for underwater targets in coordination with active illumination, such as Fig.12 As shown, a polarization hyperspectral imaging detection device for underwater targets with coordinated active illumination in Embodiment 2 specifically includes the following steps:

[0077] S1, respectively connect the first watertight connector 5 and the second watertight connector 609 in the active lighting module 6 to the computer through long cables, connect the active lighting module 6 and the waterproof protection housing 1 to the underwater submersible, place the underwater submersible underwater, turn on the active lighting module to emit a light signal, and provide an illuminated field of view for the underwater target;

[0078] S2. The reflected light signal of the target in the illuminated field of view forms target imaging information in the front telescopic imaging unit 2. The target imaging information is collected by push-scanning through the polarization spectrum coupling unit 3, and the target imaging information is filtered, polarized, and imaged to obtain a multi-dimensional target image at that location. The mobile waterproof protective shell 1 collects multi-dimensional target images at multiple locations to obtain multiple multi-dimensional target images. In this embodiment, each time a multi-dimensional target image is collected, a staring-type observation method is adopted.

[0079] S3. Due to the instability of the platform caused by environmental factors such as underwater turbulence, distortion and deformation may occur during the image acquisition process, and it is necessary to use the posture information for geometric correction. The embedded processing unit 4 is used to filter multiple multi-dimensional target images, correct the posture information, and stitch the images to obtain a target image with a large field of view. The polarization component information is used to remove the backscattered light of the underwater image for the target image with a large field of view, and the image edge information method and the estimated point spread function are combined to remove the image forward scattered light to obtain a hyperspectral image of the underwater target. Among them, the use of polarization information to remove the backscattered light of the underwater image is based on the active polarization descattering model proposed by Treibitz et al. in 2008, which proposes the use of four-channel polarization component information to remove the backscattered light of the underwater image.

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

[0081]

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

[0083] S4. Extract the reflectivity features in the hyperspectral image of the underwater target through standard diffuse reflection plates or light source light field modeling, and perform qualitative analysis on the underwater target based on the reflectivity features to obtain the classification results of the underwater target; perform quantitative analysis on the underwater target based on the reflectivity features to obtain the parameter distribution results of the underwater target.

[0084] Embodiment 2

[0085] The difference between this embodiment and the first embodiment is that: Fig.10 , Fig.11As shown, the active lighting module 6 is a manually switched type, and the specific structure includes a lighting waterproof housing 601 with openings at both ends, and the lighting waterproof housing 601 is sequentially connected with a lens fixing ring 611, a collimating element 604, a light-emitting chipset 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 chipset 605. The lens fixing ring 611 is sequentially provided with a first lens mounting slot 612 and a second lens mounting slot 613, and the first lens mounting slot 612 is close to the collimating element 604, and a uniform light 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;

[0086] The opening at one end of the lighting waterproof housing 601 near the polarizer 606 is sealed and connected to the second window glass 610, the collimating element 604, the polarizer 606, the uniform light engineering diffuser 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 on the optical path, the constant current source drive control board 608 is electrically connected to the second watertight connector 609, and the second watertight connector 609 is sealed and connected to the opening at the other end of the lighting waterproof housing 601;

[0087] The light emitting chip group 605 includes a white light LED chip, a 405nm-412nm purple light emitting chip, and a 685nm-693nm red light emitting chip.

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

[0089] A polarization hyperspectral detection method for underwater targets in coordination with active illumination in this embodiment is the same as that in the first embodiment.

[0090] The above description is only a specific embodiment of the present invention, and a comparison of the effects of the specific embodiments and the related comparative examples, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A polarization hyperspectral imaging detection device for underwater targets in coordination with active illumination, characterized in that: It includes an active lighting module (6) and a polarization hyperspectral imaging module; The active lighting module (6) is used to provide an illuminated field of view for an underwater target; The polarization hyperspectral imaging module comprises a waterproof protective housing (1), wherein a front telescopic imaging unit (2), a polarization spectrum coupling unit (3), an embedded processing unit (4) and a first watertight connector (5) are arranged in the waterproof protective housing (1); The input end of the front telescopic imaging unit (2) is sealed and connected to one end of the waterproof protective housing (1), and is electrically connected to the embedded processing unit (4) to receive control signals from the embedded processing unit (4) and receive target imaging information of underwater targets in the illuminated field of view; The polarization spectrum coupling unit (3) is arranged relative to the output end of the front telescopic imaging unit (2), and is electrically connected to the embedded processing unit (4), so as to receive the control signal of the embedded processing unit (4), and to collect and reconstruct the target imaging information by a push-scan method, so as to obtain a multi-dimensional target image; The input end of the embedded processing unit (4) is electrically connected to the output end of the polarized light 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 position information, stitch images, remove backscattered light, and remove forward scattered light on multiple multi-dimensional target images to obtain a hyperspectral image of the underwater target, and extract reflectivity characteristics 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. According to claim 1, a polarization hyperspectral imaging detection device for underwater targets in cooperation with active illumination, characterized in that: The front telescopic imaging unit (2) comprises a first window glass (201), an electrically adjustable lens (202), a mounting support plate (203), and a lens driving plate (204); The first window glass (201) is fixedly connected to an opening at one end of the waterproof protective housing (1); the mounting support plate (203) and the lens driving 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) and the first window glass (201) are arranged opposite to each other; 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); and the lens driving plate (204) is electrically connected to the embedded processing unit (4).

3. According to claim 2, a polarization hyperspectral imaging detection device for underwater targets in coordination with active illumination, characterized in that: The polarization spectrum coupling unit (3) comprises a polarization spectrum 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 a polarization spectrum camera (301). The input end of the polarization spectrum camera (301) is arranged relative to the output end of the electrically adjustable lens (202). The polarization spectrum camera (301) is electrically connected to an embedded processing unit (4). The polarization spectrum camera (301) receives a control signal from the embedded processing unit (4), collects imaging information output by the electrically adjustable lens (202), obtains a multi-dimensional target image, and transmits the multi-dimensional target image to the embedded processing unit (4).

4. According to claim 3, a polarization hyperspectral imaging detection device for underwater targets in cooperation with active illumination, characterized in that: The polarization spectrum camera (301) comprises a camera body, a linear gradient filter and a micro-polarization focal plane array; The camera body is arranged relative to the output end of the electrically adjustable lens (202), and a micro-polarization focal plane array and a linear gradient filter are arranged in the camera body for filtering, polarizing and imaging received target imaging information; the camera body is electrically connected to an embedded processing unit (4).

5. According to claim 4, a polarization hyperspectral imaging detection device for underwater targets in cooperation with active illumination, characterized in that: The micro-polarization focal plane array includes four linear polarization directions, namely 0°, 45°, 90°, and 135°; The spectrum range of the linear gradient filter is 400nm-1000nm, and the spectrum resolution is 1.5%-2% of the central wavelength.

6. According to claim 3, a polarization hyperspectral imaging detection device for underwater targets in coordination with active illumination, characterized in that: The sliding assembly comprises a screw stepper motor (302) and a screw nut mechanism connected to the output end of the screw stepper motor (302); the 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 protection housing (1); the screw stepper motor (302) is fixedly connected to a mounting support plate (203); the side wall of the 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 a nut motor of the screw nut mechanism; and the slider (304) is fixedly connected to a polarization spectrum camera (301).

7. The underwater target polarization hyperspectral imaging detection device in cooperation with active illumination according to claim 4, characterized in that: The polarization spectrum coupling unit (3) further comprises a heat dissipation fin (306) and a flexible heat dissipation copper belt (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 belt (307); and the other end of the flexible heat dissipation copper belt (307) is fixedly connected to the waterproof protective housing (1).

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

9. The underwater target polarization hyperspectral imaging detection device in cooperation with active illumination according to claim 1, characterized in that: The dynamic lighting module (7) comprises a lighting waterproof shell (601) with openings at both ends, wherein 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 sequentially connected inside the lighting waterproof shell (601), wherein the constant current source drive control board (608) is connected to the light-emitting chip group (605), wherein a first lens mounting slot (612) and a second lens mounting slot (613) are sequentially provided on the lens fixing ring (611), wherein the first lens mounting slot (612) is close to the collimating element (604), wherein a light-homogenizing engineering diffuser (607) is provided inside the first lens mounting slot (612), and wherein a polarizing plate (606) is provided inside the second lens mounting slot (613); The second window glass (610) is connected to an opening at one end of the lighting waterproof housing (601) close to the polarizer (606); the collimating element (604), the polarizer (606), the light-uniform engineering diffuser (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 a second watertight connector (609); and the second watertight connector (609) is sealed and connected to the other opening of the lighting waterproof housing (601); The light-emitting chip group (605) includes a white light LED chip, a 405nm-412nm purple light-emitting chip, and a 685nm-693nm red light-emitting chip.

10. A polarization hyperspectral detection method for underwater targets in coordination with active illumination, characterized in that: A polarization hyperspectral imaging detection device for underwater targets with coordinated active illumination according to any one of claims 1 to 9 specifically comprises the following steps: S1, respectively connecting the first watertight connector (5) and the active lighting module (6) to a computer through long cables, connecting the active lighting module (6) and the waterproof protective housing (1) to an underwater submersible, placing the underwater submersible underwater, turning on the active lighting module (6) to emit a light signal, and providing an illuminated field of view of the underwater target; S2, the reflected light signal of the target in the illumination field forms target imaging information in the front telescopic imaging unit (2), drives the polarization spectrum coupling unit (3) to collect and reconstruct the target imaging information by push-scanning, and obtains a multi-dimensional target image at the location, and moves the waterproof protective housing (1) to collect multi-dimensional target images at multiple locations, and obtains multiple multi-dimensional target images; S3, filtering, correcting the position information, and stitching the multiple multi-dimensional target images by means of an embedded processing unit (4) to obtain a target image with a large field of view, using the polarization component information of the polarization spectrum coupling unit (3) to remove the backscattered light of the underwater image, and combining the image edge information method and the estimated point spread function to remove the forward scattered light of the image to obtain a hyperspectral image of the underwater target; The formula for removing the backscattered light of the underwater image by using the polarization component information of the polarization spectrum coupling unit (3) is: Among them, S(x,y,λ) is the target information light obtained at point (x,y), λ represents the wavelength passing through a specific spectral channel, and p scat (λ) is the polarization degree of the backscattered light in the image obtained after image splicing, p obj (λ) is the polarization degree of the target in the image after image stitching, I(x, y, λ) is the sum of the light intensities at the point (x, y, λ) of the 0° polarization direction and the 90° polarization direction of the specific spectral channel, Q(x, y, λ) is the difference in light intensities at the point (x, y, λ) of the 0° polarization direction and the 90° polarization direction of the specific spectral channel, and U(x, y, λ) is the difference in light intensities at the point (x, y, λ) of the 45° polarization direction and the 135° polarization direction of the specific spectral channel; S4. Extract the reflectivity features in the hyperspectral image of the underwater target through standard diffuse reflection plates or light source light field modeling, and perform qualitative analysis on the underwater target based on the reflectivity features to obtain the classification results of the underwater target; perform quantitative analysis on the underwater target based on the reflectivity features to obtain the parameter distribution results of the underwater target.

Images