A staring type fast hyperspectral pulsed laser radar system

Abstract

The application discloses a kind of gaze type fast hyperspectral pulse laser radar systems, including pulse laser, beam expander module, two-dimensional galvanometer unit, excitation light plane mirror, signal receiving unit, information control unit;Pulse laser emits laser beam through beam expander module, two-dimensional galvanometer unit, excitation light plane mirror reaches to be measured object, and the scattering light and excited fluorescence of measured object are received by signal receiving unit, output scattering light and fluorescence (or emission) spectral data to information control unit, obtain the three-dimensional topographic data and fluorescence (or emission) spectral data of measured object.The application combines traditional distance detection and spectrum detection, overcomes the single point cloud data, near field noise is strong, and the problems such as low work efficiency.The system effectively improves the signal-to-noise ratio of detection signal in combination with gate technology, increases spectral information on the basis of detecting geometric appearance, to enhance the means of discriminant analysis to the detected object, and has great application value in multiple fields.

Description

Technical Field

[0001] This invention belongs to the field of optical technology, specifically relating to a staring-type fast hyperspectral pulsed lidar system. Background Technology

[0002] LiDAR is not only an important means of acquiring three-dimensional geographic information, but the data obtained through this method is also widely used in resource exploration, urban planning, agricultural development, water conservancy projects, land use, environmental monitoring, transportation and communication, and earthquake disaster prevention and mitigation. It provides crucial raw data for national economic and social development and scientific research, achieving significant economic benefits and demonstrating promising application prospects. However, traditional lidar systems suffer from low scanning efficiency, relying solely on a displacement stage to mechanically scan three-dimensional spatial points, and lacking information on optical characteristics to identify and analyze the target object. Sonar utilizes the propagation and reflection characteristics of sound waves in water, employing electroacoustic conversion and information processing for navigation and ranging. It is a common electronic device for detecting underwater targets. Traditional sonar imaging mostly uses towed imaging. This results in low imaging efficiency and low imaging accuracy, failing to detect details of the sample, let alone analyze changes in the sample's type or biological information. Summary of the Invention

[0003] In order to overcome the problems in the prior art, the purpose of this invention is to provide a staring-type fast hyperspectral pulsed lidar system.

[0004] A staring-type fast hyperspectral pulsed lidar system includes a pulsed laser, a beam expander module, a two-dimensional galvanometer unit, an excitation light plane reflector, a signal receiving unit, and an information control unit. The laser beam emitted by the pulsed laser passes through the beam expander module, the two-dimensional galvanometer unit, and the excitation light plane reflector to reach the object under test. The scattered light and excited fluorescence of the object under test are received by the signal receiving unit, which outputs the scattered light and fluorescence (or emission) spectral data to the information control unit to obtain the three-dimensional morphology data and fluorescence (or emission) spectral data of the object under test.

[0005] The beam expander module includes a first lens and a second lens.

[0006] The two-dimensional galvanometer unit is used to continuously change the angle of laser beam reflection to achieve two-dimensional scanning of the laser beam on the object under test.

[0007] The signal receiving unit includes, in sequence, a concave reflector, a receiving plane reflector, a tunable filter, and a photodetector; wherein the tunable filter is used for spectral scanning, and the photodetector is used to convert the scattered light signal and the fluorescence signal into an electrical signal.

[0008] The information control unit includes a pulse delay unit, a data acquisition card, and a computer; the pulse delay unit is used to control the delayed activation of the photodetector; the data acquisition card is used to acquire the electrical signals output by the photodetector and to control the two-dimensional galvanometer unit with the output voltage; the computer is used to process and obtain the three-dimensional morphology data and fluorescence (or emission) spectrum data of the object under test.

[0009] The beneficial effects of this invention: The staring-type fast hyperspectral pulsed lidar system disclosed in this invention combines traditional distance detection and spectral detection, overcoming the problems of single point cloud data, strong near-field noise, and low working efficiency. The system incorporates gating technology to effectively improve the signal-to-noise ratio of the detected signal. By adding spectral information to the detected geometric shape, it enhances the means of object identification and analysis, and has significant application value in fields such as environmental remote sensing monitoring. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of a staring-type fast hyperspectral pulsed lidar system.

[0011] In the figure, the components are: 1. Pulsed laser; 2. Beam expander module; 3. First lens; 4. Second lens; 5. Two-dimensional galvanometer unit; 6. Excitation light plane mirror; 7. Receiving plane mirror; 8. Concave mirror; 9. Tunable filter; 10. Photodetector; 11. Signal receiving unit; 12. Pulse delayer; 13. Data acquisition card; 14. Computer; and 15. Information control unit. Detailed Implementation

[0012] The present invention will now be described in conjunction with the accompanying drawings and specific examples.

[0013] like Figure 1 As shown, a staring-type fast hyperspectral pulsed lidar system includes a pulsed laser 1, a beam expander 2, a two-dimensional galvanometer unit 5, an excitation light plane reflector 6, a signal receiving unit 11, and an information control unit 15. The pulsed laser 1 emits a laser beam that passes through the beam expander 2, the two-dimensional galvanometer unit 5, and the excitation light plane reflector 6 to reach the object under test. The scattered light and excited fluorescence of the object under test are received by the signal receiving unit 11, which outputs the scattered light and fluorescence spectral data to the information control unit 15 to obtain the three-dimensional morphology data and fluorescence (or emission) spectral data of the object under test.

[0014] The beam expander module 2 includes a first lens 3 and a second lens 4.

[0015] The two-dimensional galvanometer unit 5 is used to continuously change the angle of laser beam reflection to achieve two-dimensional scanning of the laser beam on the object under test.

[0016] The signal receiving unit 11 includes, in sequence, a concave reflector 8, a receiving plane reflector 7, a tunable filter 9, and a photodetector 10; wherein the tunable filter 9 is used for spectral scanning, and the photodetector 10 is used to convert the scattered light signal and the fluorescence signal into an electrical signal.

[0017] The information control unit 15 includes a pulse delay unit 12, a data acquisition card 13, and a computer 14. The pulse delay unit 12 controls the delayed activation of the photodetector 10. The data acquisition card 13 acquires the electrical signals output by the photodetector 10 and controls the output voltage of the two-dimensional galvanometer unit 5. The computer 14 processes the obtained three-dimensional morphology data and fluorescence (or emission) spectrum data of the object under test. In some scenarios, such as foggy weather or underwater, the laser beam will produce large scattering when passing through the fog or water medium, thus interfering with signal acquisition. The system combines gating technology, triggering the data acquisition card to acquire data from the photodetector in the signal receiving unit at a specific time set by the pulse delay unit, and keeping the photodetector off and not acquiring data during other times, thereby improving the signal-to-noise ratio of the acquired data.

[0018] The gating technology described above allows the photodetector to detect light at a time calculated from the distance between the object and the system. In special environments such as the ocean, where the distance between the object and the system is unknown, measurement techniques such as acoustic waves can be used to measure the distance, and then the specific time can be calculated for gating the photodetector.

[0019] Application Example 1

[0020] This invention discloses a staring-type fast hyperspectral pulse radar system that can be installed on an underwater detector (such as a submarine) to create seabed maps. The underwater detector first emits ultrasonic sonar to detect a rough distance from itself to the seabed. This distance information is applied to the gating technology of this invention to eliminate scattering noise along the optical path. This allows the photodetector to detect echo pulse signals with a high signal-to-noise ratio, thereby extending the detection range. A two-dimensional galvanometer unit provides staring scanning. The system processes the echo signals to obtain a high-precision three-dimensional topography of the seabed below the underwater detector. Furthermore, the spectral data detected based on this data can be used for analysis of seabed materials and organisms. Currently, underwater detectors (such as submarines) only use ultrasonic sonar technology, resulting in very coarse ocean mapping and low efficiency in detecting three-dimensional topography, providing limited seabed mapping information. This invention's staring-type fast hyperspectral pulse radar system, however, can obtain high-precision four-dimensional spectral images of the seabed topography.

[0021] Application Example 2

[0022] The staring-type fast hyperspectral pulse radar system of this invention can also be used in real-time navigation applications for underwater detectors (such as submarines). The underwater detector using this system employs gating technology to accurately detect the distance to surrounding obstacles, and the corresponding spectral information can be used for obstacle category identification, thereby helping the underwater detector better avoid obstacles. Traditional underwater detectors mostly rely on echolocation using ultrasonic sonar for underwater positioning; however, the accuracy is still limited, and it is difficult to detect the type of obstacle from the echo.

[0023] Application Example 3

[0024] This invention provides a staring-type fast hyperspectral pulse radar system that can also be used to monitor coral reefs or fixed targets at known distances. The invention employs gating technology based on the distance to underwater coral reefs or fixed targets to eliminate scattering noise in the laser path, thereby improving the contrast of the detected signal. This invention can detect the four-dimensional morphological spectral information of coral reefs. The morphological information of coral reefs can be used to analyze their growth status, and the point cloud information on the morphology can be used to detect the health status of various parts of the coral reef (e.g., whether there is bleaching, and whether the species and density of symbiotic algae are normal).

[0025] Application Example 4

[0026] The staring-type fast hyperspectral pulse radar system of this invention can also be used for underwater detectors to monitor mariculture, enabling early monitoring of density, species, size, and disease presence. The underwater detector equipped with this invention can cyclically perform optical morphology and spectral detection in mariculture areas. The combination of three-dimensional morphology and spectral data can be used for early monitoring of the density, species, size, and disease presence of organisms in the aquaculture area.

[0027] The embodiments described above can be further combined or replaced, and these embodiments are merely descriptions of preferred embodiments of the present invention, not limitations on the concept and scope of the present invention. Various changes and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the inventive concept are all within the protection scope of the present invention. The protection scope of the present invention is given by the appended claims and any equivalents.

Claims

1. A staring-type fast hyperspectral pulsed lidar system, characterized in that: The system includes a pulsed laser (1), a beam expander (2), a two-dimensional galvanometer (5), an excitation light plane mirror (6), a signal receiving unit (11), and an information control unit (15). The pulsed laser (1) emits a laser beam that passes through the beam expander (2), the two-dimensional galvanometer (5), and the excitation light plane mirror (6) to reach the object under test. The scattered light and the excitation fluorescence of the object under test are received by the signal receiving unit (11), which outputs the scattered light and fluorescence or reflection spectrum data to the information control unit (15) to obtain the three-dimensional morphology data and fluorescence or reflection spectrum data of the object under test. The signal receiving unit (11) includes, in sequence, a concave reflector (8), a receiving plane reflector (7), a tunable filter (9), and a photodetector (10); wherein the tunable filter (9) is used for spectral scanning, and the photodetector (10) is used to convert the scattered light signal and the fluorescence signal into an electrical signal; The information control unit (15) includes a pulse delay unit (12), a data acquisition card (13), and a computer (14); the pulse delay unit (12) is used to control the delayed activation of the photodetector (10); the data acquisition card (13) is used to acquire the electrical signal output by the photodetector (10) and to control the two-dimensional galvanometer unit (5) with the output voltage; the computer (14) is used to process and obtain the three-dimensional morphology data and fluorescence or reflectance spectral data of the object under test. The beam expander module (2) includes a first lens (3) and a second lens (4); The two-dimensional galvanometer unit (5) is used to continuously change the angle of laser beam reflection to realize two-dimensional scanning of the laser beam on the object to be tested.

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