Underwater laser detection equipment

Abstract

A laser emission assembly of the underwater laser detection equipment comprises a plurality of emission sources and a wavelength beam combiner, each emission source emits different laser beams to the wavelength beam combiner at a repetition frequency, and the wavelength beam combiner combines the laser beams to form a combined beam; the pulse selection assembly is arranged in the irradiation direction of the combined light beam so as to form a pulse selection light beam emitted outwards; the receiving assembly comprises an acquisition structure and an analysis structure so as to analyze an echo light beam or an echo signal generated after the pulse selection light beam irradiates the underwater target object. According to the invention, the problems that when the laser beam is propagated in water, the laser beam is influenced by absorption and scattering, so that the reflection of the laser and the effect of collecting the reflected beam are greatly interfered, the influence of water body scattering is serious, and the distance measurement or imaging of the target object cannot be accurately carried out are effectively solved.

Description

Technical Field

[0001] The present application relates to the technical field of underwater detection equipment, and in particular, to an underwater laser detection equipment. Background Art

[0002] With the increasing importance of marine resources and the increasing complexity of the marine environment, higher and higher requirements are placed on the detection and perception technology of the underwater environment. With the continuous development of optical imaging technology, the performance of underwater detection equipment has been significantly improved, and the scope of application has gradually expanded.

[0003] Since water is a scattering medium, when laser is used for detection, the light propagates in the water and is affected by absorption and scattering, resulting in significant interference in the reflection of the laser and the collection of the reflected light beam. The influence of water scattering is more serious, and it is impossible to accurately measure the distance or image the target object.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present application, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Utility Model Content

[0005] The purpose of this application is to overcome the deficiencies of the above-mentioned prior art and to provide an underwater laser detection device that can analyze underwater physical information by emitting a wavelength-compounded laser beam and through a pulse selector, thereby improving the accuracy of underwater physical information collection.

[0006] According to one aspect of the present application, there is provided an underwater laser detection device, comprising: a laser emitting component, a pulse selection component and a receiving component, the laser emitting component comprising a plurality of emission sources and a wavelength beam combining device, each of the emission sources emitting a different laser beam to the wavelength beam combining device at a repetition frequency, the wavelength beam combining device combining the laser beams to form a combined beam; the pulse selection component is arranged in the irradiation direction of the combined beam to form a pulse selection beam emitted outward; the receiving component comprises a collection structure and an analysis structure, the collection structure collects an echo beam or an echo signal generated after the pulse selection beam is irradiated, and transmits it to the analysis structure to parse the echo beam or the echo signal.

[0007] According to some embodiments of the present application, the pulse selection component includes a first reflector and a pulse selector, wherein the pulse selector is located in the irradiation direction of the combined light beam, and the first reflector can be movably arranged to emit the pulse selection component light beam to different underwater positions.

[0008] According to some embodiments of the present application, the repetition frequency of the transmitting source is greater than or equal to 200 MHz.

[0009] According to some embodiments of the present application, the laser emitting assembly includes at least three emission sources, the spectral width of the laser light beams emitted by the emission sources are greater than or equal to 100 nm, and the wavelength λ is in the range of 450 nm to 550 nm.

[0010] According to some embodiments of the present application, the wavelength λ of the laser beam is one of 532 nm, 525 nm, 515 nm, 486 nm, and 473 nm.

[0011] According to some embodiments of the present application, the wavelength beam combining device is a grating, which combines the different laser light beams to form the combined light beam.

[0012] According to some embodiments of the present application, the collection structure includes a collector and a beam transfer structure, the analysis structure includes a plurality of different analysis instruments, and the beam transfer structure transmits the echo beam or echo signal collected by the collector to each of the analysis instruments respectively.

[0013] According to some embodiments of the present application, the plurality of analytical instruments include at least a first analytical instrument, and the first analytical instrument is an image intensifier with time gating or a streak camera with time gating.

[0014] According to some embodiments of the present application, the multiple analytical instruments also include a spectrometer and an oscilloscope, and the beam transfer structure includes a second reflector, a first half mirror, a second half mirror and a third reflector arranged in sequence, the echo beam or the echo signal passes through the second reflector and is emitted toward the first half mirror, the echo beam or the echo signal passes through the first half mirror and is emitted toward the second half mirror and the first analytical instrument respectively, the echo beam or the echo signal passes through the second half mirror and is emitted toward the third reflector and the spectrometer respectively, and the echo beam or the echo signal passes through the third reflector and is emitted toward the oscilloscope.

[0015] According to some embodiments of the present application, the underwater laser detection equipment also includes a control component, and each of the emission sources, the pulse selection component, the acquisition structure and each of the analysis instruments are electrically connected to the control component.

[0016] An underwater laser detection device of the present application includes: a laser emission component, a pulse selection component and a receiving component, wherein the laser emission component includes a plurality of emission sources and a wavelength beam combining device, wherein each emission source emits a different laser beam to the wavelength beam combining device at a repetitive frequency, and the wavelength beam combining device combines each laser beam to form a combined beam; the pulse selection component is arranged in the irradiation direction of the combined beam to form a pulse selection beam emitted outward; the receiving component includes a collection structure and an analysis structure, wherein the collection structure collects the echo beam or echo signal generated after the pulse selection beam is irradiated, and transmits it to the analysis structure to analyze the echo beam or echo signal. After the different laser beams are aggregated, the combined beam is split by the pulse selection component to form a beam of pulse combinations of different frequencies, and the echo beam or echo signal generated by such a beam contacting an underwater object is easy to synchronize with the time gating of the underwater laser detection device, and effectively separates the high-frequency target reflection signal and the low-frequency backscattered noise signal. The present application effectively solves the problem that when a laser beam propagates in water, it is affected by absorption and scattering, resulting in significant interference in the reflection of the laser and the collection of the reflected beam, and the influence of water scattering is more serious, making it impossible to accurately measure the distance or image the target object.

[0017] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A schematic diagram of the internal structure of an underwater laser detection device provided in an embodiment of the present application is shown;

[0020] Figure 2 Shows Figure 1 Schematic diagram of electrical signals and optical connections of underwater laser detection equipment;

[0021] Figure 3 Shows Figure 1 Schematic diagram of the architecture of underwater laser detection equipment.

[0022] The above drawings contain the following reference numerals:

[0023] 10. Laser emission component; 11. Emission source; 12. Wavelength beam combining device; 13. Fourth reflector; 20. Pulse selection component; 21. First reflector; 22. Pulse selector; 23. Rotating seat; 30. Receiving component; 31. Collection structure; 311. Collector; 312. Beam transfer structure; 313. Second reflector; 314. First half mirror; 315. Second half mirror; 316. Third reflector; 32. Analysis structure; 321. Analysis instrument; 322. First analysis instrument; 323. Spectrometer; 324. Oscilloscope; 40. Control component. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0025] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention may repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0026] For ease of description, spatial relative terms may be used herein to describe the relative positional relationship or movement of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", "front", "back", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure undergoes a position flip or a posture change or a motion state change, then these directional indications also change accordingly, for example: an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative descriptors used herein are interpreted accordingly.

[0027] like Figures 1 to 3 As shown, the embodiment of the present application provides an underwater laser detection device, including: a laser emitting component 10, a pulse selection component 20 and a receiving component 30, the laser emitting component 10 includes a plurality of emission sources 11 and a wavelength beam combining device 12, each emission source 11 emits a different laser beam to the wavelength beam combining device 12 at a repetition frequency, and the wavelength beam combining device 12 combines each laser beam to form a combined beam; the pulse selection component 20 is arranged in the irradiation direction of the combined beam to form a pulse selection beam emitted outward; the receiving component 30 includes a collection structure 31 and an analysis structure 32, the collection structure 31 collects the echo beam or echo signal generated after the pulse selection beam is irradiated, and transmits it to the analysis structure 32 to analyze the echo beam or echo signal. Each emission source 11 emits a different laser beam to the wavelength beam combining device 12, including a laser beam with different parameter combinations of wavelength, frequency, and spectral width, so as to meet the operation requirements of the pulse selection component 20.

[0028] After different laser beams are aggregated, the combined beams are split by the pulse selection component 20 to form beams of different frequency pulse combinations. When such beams contact the echo beams or echo signals generated by underwater objects, they are easily synchronized with the time gating of underwater laser detection equipment, and can effectively separate high-frequency target reflection signals and low-frequency backscattered noise signals. The present application effectively solves the problem that when the laser beam propagates in water, it is affected by absorption and scattering, resulting in significant interference in the reflection of the laser and the effect of collecting the reflected beam, and the scattering effect of the water body is more serious, making it impossible to accurately measure the distance or image the target object.

[0029] Underwater laser detection equipment, commonly known as underwater laser radar, is a device that uses laser beams to scan and measure the distance of underwater targets. Its basic principle is: the transmitting source emits a laser pulse (laser beam). When the laser pulse encounters the target object, part of the light energy is reflected back and received by the receiving component. By measuring the time difference between the emission and reception of the laser pulse, the distance between the target and the detector can be calculated. At the same time, the laser beam is scanned in the horizontal or vertical direction through the scanning device to achieve the distance measurement or imaging of underwater targets. As a high-precision and high-efficiency underwater detection technology, underwater laser radar has broad application prospects in the fields of marine resource development, underwater archaeology, marine environment monitoring, underwater topographic mapping, etc. With the continuous advancement of technology and the reduction of costs, underwater laser radar is expected to be used in more fields.

[0030] It should be noted that the underwater environment is complex and changeable. Factors such as water temperature, salinity, and flow rate will affect the propagation of laser beams, electromagnetic waves, etc. In addition, the visibility of the underwater environment is low, and light is affected by absorption and scattering when propagating in the water, which limits the application of traditional optical equipment underwater. However, this application effectively enhances the penetration ability of laser beams underwater by aggregating different laser beams, and effectively separates high-frequency target signals and low-frequency noise signals.

[0031] After different laser beams are aggregated, the combined beam is split through the pulse selection component 20 to form a beam of light with different frequency pulse combinations. When such a beam contacts the underwater object, the echo beam or echo signal generated is easy to synchronize with the time gating of the underwater laser detection equipment, and effectively separate the high-frequency target reflection signal and the low-frequency backscattered noise signal, so that the underwater identification and detection work is more accurate.

[0032] like Figure 1 and Figure 2 As shown, in the technical solution of this embodiment, the pulse selection component 20 includes a first reflector 21 and a pulse selector 22. The pulse selector 22 is located in the irradiation direction of the combined light beam, and the first reflector 21 can be movably arranged to emit a pulse selection light beam to different underwater positions.

[0033] After being reflected by the fourth reflector 13, the laser beam enters the wavelength beam combining device 12 to achieve beam combining, and then enters the pulse selector 22 to split the laser beam of the repetition frequency, so that the laser beam of a specific frequency is emitted outward, which greatly reduces the emission of laser beams of other frequencies, and the measurement accuracy is more accurate and reliable. The first reflector 21 can be movably arranged to realize the emission of the pulse selection beam in different directions, thereby realizing more comprehensive physical quantity detection.

[0034] Specifically, Figure 1 and Figure 2 As shown, in the technical solution of this embodiment, the first reflector 21 is fixedly set on a rotating seat 23. The direction of the reflected pulse selection light beam is adjusted by the setting of the rotating seat 23. It can be better adapted when detecting larger underwater objects, with a wider detection range. It can also reduce the components that emit laser beams, thereby saving costs.

[0035] In the technical solution of this embodiment (not shown in the figure), the repetition frequency of the emission source 11 is greater than or equal to 200MHz. Such a setting can be used to split the laser beam, and a laser giant pulse train (i.e., pulse selection beam) with a repetition frequency of the order of hundreds of hertz can be obtained. For example, by splitting a laser beam with a repetition frequency of 200MHz, a laser giant pulse train (i.e., pulse selection beam) with a repetition frequency of the order of hundreds of hertz can be obtained, and the repetition frequency of each giant pulse train is 200MHz. This is conducive to the penetration of water bodies and the emission of laser beams. At the same time, the frequency of the generated echo beam or echo signal will be higher, and the measurement accuracy will also be higher.

[0036] In the technical solution of this embodiment (not shown in the figure), the laser emission assembly 10 includes at least three emission sources 11, and the spectral width of the laser beam emitted by the emission source 11 is greater than or equal to 100nm, and the range of wavelength λ is between 450nm and 550nm. At least three emission sources 11 can provide laser beams of different frequency ranges at different angles, and the laser beams of multiple wavelengths are combined into one laser beam through the wavelength beam combining device 12, so that the laser has multiple wavelengths at the same time, which can concentrate the laser beam and reduce the loss of laser beam propagation. The spectral width of the laser beam emitted by the emission source 11 is greater than or equal to 100nm, and the range of wavelength λ is between 450nm and 550nm, which belongs to the wavelength range of blue light and part of green light. It can be understood that blue light is less absorbed in water, especially in seawater, so the transmission range is longer, and the accuracy requirements of underwater detection and even processing requirements can be met. Its power is also higher than that of infrared laser beams, and it is easy to convert into white light, which can be used for underwater lighting, etc. Blue light also has higher energy conversion efficiency.

[0037] In the technical solution of this embodiment (not shown in the figure), the wavelength λ of the laser beam is one of 532nm, 525nm, 515nm, 486nm, and 473nm. The above laser beams are easy to obtain and belong to commonly used laser beam wavelengths, among which the 486nm laser beam and the 532nm laser beam are more suitable for underwater detection operations.

[0038] like Figure 1 and Figure 2 As shown, in the technical solution of this embodiment, the wavelength beam combining device 12 is a grating, which combines different laser beams to form a combined beam. With multiple high repetition rate emission sources 11 of different wavelengths as detection or imaging light sources, the multi-wavelength laser beams are incident on the grating at a fixed angle, and the grating diffraction angle difference of lasers of different wavelengths is used to combine the laser beams of multiple wavelengths into one combined beam, which can concentrate the laser beams and reduce the loss of laser beam propagation.

[0039] like Figures 1 to 3As shown, in the technical solution of this embodiment, the collection structure 31 includes a collector 311 and a beam transfer structure 312, the analysis structure 32 includes a plurality of different analysis instruments 321, and the beam transfer structure 312 transmits the echo beam or echo signal collected by the collector 311 to each analysis instrument 321 respectively.

[0040] After the pulse selection light beam reaches the target to be measured, an echo light beam or an echo signal is generated. The echo light beam or the echo signal is collected by the collector 311, and the echo light beam or the echo signal is transmitted to different analysis instruments 321 through the beam transmission structure 312. After comprehensive analysis of the echo light beam or the echo signal, the spatial coordinate information of the characteristic points of the collected object is obtained, and then the three-dimensional point cloud data of the target is obtained, which can realize the simulation reconstruction of the three-dimensional object, thereby realizing the accurate detection of underwater objects.

[0041] It should be noted that since the optical transmission channel of the scattering medium has a low-pass characteristic (such as 2-100MHz in water), a filter is set at the position of the collector 311, and the echo light beam or echo signal is filtered using a bandpass filtering method. The high-frequency target reflection signal and the low-frequency backscattered noise signal can be separated, thereby reducing the impact of water scattering and significantly improving the signal-to-noise ratio of the target echo signal.

[0042] like Figures 1 to 3 As shown, in the technical solution of this embodiment, the multiple analysis instruments 321 include at least a first analysis instrument 322, and the first analysis instrument 322 is an image intensifier with time gating or a streak camera with time gating. The image intensifier with time gating or the streak camera with time gating can use an imaging lens to capture the echo signal of the target to be measured, obtain the target echo signal at different times, and then better simulate the three-dimensional point cloud data.

[0043] like Figures 1 to 3 As shown, in the technical solution of this embodiment, the multiple analysis instruments 321 also include a spectrometer 323 and an oscilloscope 324, the beam transfer structure 312 includes a second reflector 313, a first half mirror 314, a second half mirror 315 and a third reflector 316 arranged in sequence, the echo beam or the echo signal passes through the second reflector 313 and is emitted to the first half mirror 314, the echo beam or the echo signal passes through the first half mirror 314 and is emitted to the second half mirror 315 and the first analysis instrument 322 respectively, the echo beam or the echo signal passes through the second half mirror 315 and is emitted to the third reflector 316 and the spectrometer 323 respectively, and the echo beam or the echo signal passes through the third reflector 316 and is emitted to the oscilloscope 324.

[0044] The combination of the second reflector 313, the first semi-mirror 314, the second semi-mirror 315 and the third reflector 316 realizes the transmission of the echo light beam or the echo signal, and can cooperate with a plurality of different analysis instruments 321 to realize multi-faceted data analysis of the echo light beam or the echo signal, thereby making the detection results more accurate and stable.

[0045] Specifically, the echo beam or echo signal enters the spectrometer 323 to obtain the spectrum information of the target echo signal. The difference in reflection information of the target echo signal in different water environments is used to improve the environmental adaptability of laser detection or imaging.

[0046] Furthermore, the echo beam or echo signal enters the oscilloscope 324 to obtain the pulse waveform information of the target echo signal, thereby improving the time accuracy of the laser pulse and further improving the distance accuracy of laser detection or imaging.

[0047] In summary, the specific principles of this embodiment are as follows: multiple high repetition frequency emission sources 11 with different wavelengths are used as detection or imaging light sources, and the multi-wavelength laser beam is incident on the grating (wavelength beam combining device 12) at a fixed angle. The laser beams of multiple wavelengths are combined into one laser beam (combined beam) by utilizing the difference in grating diffraction angles of laser beams of different wavelengths. The laser passes through a pulse selector 22 to cut and select the high repetition frequency laser pulses to obtain a string of giant pulse trains with a low repetition frequency (pulse selection beam), and each giant pulse train still retains the repetition frequency of the initial laser pulse. Laser beams of different wavelengths are directed to the target through the first reflector 21 installed on the rotating seat 23. The echo beam or echo signal of the target to be measured is captured by an imaging lens (collector 311). The echo signal passes through the second reflector 313 and enters the image intensifier with time gating to obtain target echo signals at different times. Afterwards, the first half mirror 314, the second half mirror 315 and the third reflector 316 are used to make the echo signal enter the spectrometer 323 and the oscilloscope 324, respectively obtaining the spectrum information and pulse waveform information of the target echo signal. Finally, the echo signal is subjected to bandpass filtering denoising and three-dimensional image reconstruction using a computer (control component 40). The advantages of the laser in terms of multi-wavelength, high repetition rate and narrow pulse are fully utilized to effectively suppress scattering and improve the underwater target detection or imaging capability.

[0048] like Figures 1 to 3 As shown, in the technical solution of this embodiment, the underwater laser detection device also includes a control component 40, and each emission source 11, pulse selection component 20, acquisition structure 31 and each analysis instrument 321 are electrically connected to the control component 40. The control component 40 is used to operate and control each electrical component, and specifically can be a processor, computer, etc. with data processing and transmission functions.

[0049] Furthermore, the control component 40 can adjust the laser beam emitted by the transmitting source 11 according to actual needs, and based on the echo signal received by the receiving component 30, after being processed by the first analysis instrument 322, the spectrometer 323 and the oscilloscope 324, comprehensively perform bandpass filtering denoising and three-dimensional image reconstruction, thereby realizing underwater detection operations.

[0050] The advantage of this embodiment is that it combines the advantages of multi-wavelength lasers, and achieves high-precision detection and imaging of underwater targets by separating and processing the spectrum and pulse waveform information of the target echo signal. It has strong environmental adaptability and imaging or detection accuracy.

[0051] It should be understood that the utility model does not limit its application to the detailed structure and arrangement of the components proposed in the utility model. The utility model can have other embodiments and can be implemented and executed in a variety of ways. The aforementioned deformation forms and modified forms fall within the scope of the utility model. It should be understood that the utility model disclosed and defined in the utility model extends to all alternative combinations of two or more individual features mentioned or evident in the text and / or the drawings. All these different combinations constitute multiple alternative aspects of the utility model. The embodiments described in the utility model illustrate the best known methods for implementing the utility model and will enable those skilled in the art to utilize the utility model.

Claims

1. An underwater laser detection device, characterized in that: include: A laser emission assembly, comprising a plurality of emission sources and a wavelength beam combining device, wherein each of the emission sources emits a different laser beam to the wavelength beam combining device at a repetition frequency, and the wavelength beam combining device combines each of the laser beams to form a combined beam; A pulse selection component is arranged in the irradiation direction of the combined light beam to form a pulse selection light beam emitted outward; The receiving component includes a collection structure and an analysis structure. The collection structure collects the echo beam or echo signal generated after the pulse selection beam is irradiated, and transmits it to the analysis structure to analyze the echo beam or echo signal.

2. The underwater laser detection device according to claim 1, characterized in that: The pulse selection component includes a first reflector and a pulse selector. The pulse selector is located in the irradiation direction of the combined light beam. The first reflector can be movably arranged to emit the pulse selection light beam to different underwater positions.

3. The underwater laser detection device according to claim 2, characterized in that: The repetition frequency of the transmitting source is greater than or equal to 200 MHz.

4. The underwater laser detection device according to claim 3, characterized in that: The laser emission assembly includes at least three emission sources, and the spectrum width of the laser light beams emitted by the emission sources is greater than or equal to 100 nm, and the wavelength λ is in the range of 450 nm to 550 nm.

5. The underwater laser detection device according to claim 4, characterized in that: The wavelength λ of the laser beam is one of 532nm, 525nm, 515nm, 486nm, and 473nm.

6. The underwater laser detection device according to claim 1, characterized in that: The wavelength beam combining device is a grating, which combines different laser beams to form the combined beam.

7. The underwater laser detection device according to any one of claims 1 to 6, characterized in that: The collection structure includes a collector and a beam transfer structure, the analysis structure includes a plurality of different analysis instruments, and the beam transfer structure transmits the echo beam or echo signal collected by the collector to each of the analysis instruments respectively.

8. The underwater laser detection device according to claim 7, characterized in that: The plurality of analytical instruments include at least a first analytical instrument, which is an image intensifier with time gating or a streak camera with time gating.

9. The underwater laser detection device according to claim 8, characterized in that: The multiple analytical instruments also include a spectrometer and an oscilloscope. The beam transfer structure includes a second reflector, a first half mirror, a second half mirror and a third reflector arranged in sequence. The echo beam or echo signal passes through the second reflector and is directed toward the first half mirror. The echo beam or echo signal passes through the first half mirror and is directed toward the second half mirror and the first analytical instrument respectively. The echo beam or echo signal passes through the second half mirror and is directed toward the third reflector and the spectrometer respectively. The echo beam or echo signal passes through the third reflector and is directed toward the oscilloscope.

10. The underwater laser detection device according to claim 7, characterized in that: The underwater laser detection equipment also includes a control component, and each of the emission sources, the pulse selection component, the collection structure and each of the analysis instruments are electrically connected to the control component.

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