A near-infrared imaging optical visibility measurement system and method

Abstract

The present invention discloses a near-infrared imaging optical visibility measurement system and method. The system includes a near-infrared target, a dark channel target, a near-infrared imaging module and an information processing module; the near-infrared target and the dark channel target are placed in pairs and side by side to form a target unit, and multiple target units are placed at different positions in the field of view of the near-infrared imaging module, and all point to the near-infrared imaging module to form multiple measurement links, and the near-infrared imaging module is electrically connected to the information processing module; the near-infrared imaging module collects images in the near-infrared band and outputs image signals to the information processing module, and the information processing module extracts pixel values ​​from the image signal and loads a meteorological visibility calculation algorithm to obtain the meteorological visibility of each measurement link. The present invention can measure links under extremely low visibility and can simultaneously measure the visibility of multiple links in a large field of view, thereby improving the accuracy of meteorological visibility measurement and expanding the measurement coverage of meteorological visibility.

Description

Technical Field

[0001] The present invention relates to the technical field of meteorological visibility measurement, and more specifically, to a near-infrared imaging optical visibility measurement system and method. Background Art

[0002] Meteorological visibility is an important meteorological observation factor to ensure people's production and life. In low-visibility scenes such as clouds, smoke, fog, and haze, the detection and perception capabilities of the human eye and optoelectronic system to the environment will be adversely affected, thus affecting the correct decision-making of navigation, aviation, land transportation and military activities. At present, the equipment used for meteorological visibility measurement is mainly divided into two categories: transmission visibility meters and scattered visibility meters.

[0003] The transmission type visibility meter is a device that arranges the light source and the optical power detector oppositely at the two ends of a long measurement link without obstruction. The transmission type visibility meter inverts visibility based on the transmittance of light radiation transmitted in the atmospheric sample. The lower the transmittance, the lower the corresponding meteorological visibility. The light source of the transmission type visibility meter is a parallel beam emitted by an incandescent lamp with a color temperature of 2700K. The transmission type visibility meter can accurately measure the visibility of long link atmospheric samples. The atmosphere that the measurement link passes through is the atmospheric sample sampling area. However, the light source and optical power detector of the transmission type visibility meter are fixed after installation, and the measurement distance and direction cannot be adjusted. The transmission type visibility meter cannot measure visibility when there is an obstruction in the optical path, and it cannot measure visibility when the alignment of the light source or optical power detector is deviated. Therefore, the transmission type visibility meter is mostly used in open and less disturbed environments such as airports, railways, and laboratories, and is often not applicable in scenes with complex environments. Under extremely low visibility conditions, the attenuation intensity is large and is easily interfered by ambient light. It is difficult for the optical power detector to detect the correct signal. Therefore, the transmission-type visibility meter is not suitable under extremely low visibility conditions.

[0004] The scattering visibility meter is an integrated device of a light source and a receiver. The scattering visibility meter inverts visibility by measuring the scattered light intensity when light passes through an atmospheric sample. There is an overlapping area in space between the emission angle of the light source and the receiving angle of the receiver. The overlapping area is the atmospheric sample sampling area. The scattering visibility meter is compact and a single-ended device, which does not require the long interference-free link of the transmission visibility meter. When the visibility is lower, the scattering effect in the atmospheric sample is stronger, and the receiver can detect stronger scattered light. The scattering visibility meter has a small sampling area, compact equipment, and strong anti-interference ability, but it can only measure the visibility at a certain location and cannot characterize the visibility of a large area. Usually, multiple scattering visibility meters are used to measure visibility at multiple locations to obtain the equivalent visibility of the measurement link. However, under extremely low visibility, scattering particles are easy to agglomerate, and the atmospheric medium is often not uniform, so the error of the visibility of the reverse link measured at a single point is large. According to the different arrangement orientations of the light source and the receiver, the scattering type visibility meter can be divided into the forward scattering type and the backward scattering type. In the forward scattering type, the light source and the receiver are arranged on different sides; in the backward scattering type, the light source and the receiver are arranged on the same side.

[0005] However, neither the transmission type visibility meter nor the scatter type visibility meter can reliably and accurately measure the meteorological visibility of long links under extremely low visibility conditions while realizing the measurement of multi-link meteorological visibility in a large field of view. Therefore, this problem needs to be solved urgently. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a near-infrared imaging optical visibility measurement system and method, which can reliably realize effective measurement of long links under extremely low visibility and at the same time realize visibility measurement of multiple links in a large field of view, so as to improve the accuracy of meteorological visibility measurement.

[0007] The technical solution of the present invention is as follows:

[0008] A near-infrared imaging optical visibility measurement system, comprising a near-infrared target, a dark channel target, a near-infrared imaging module and an information processing module;

[0009] One of the near-infrared targets and one of the dark channel targets are placed in pairs and in parallel to form a target unit, a plurality of the target units are placed at different positions within the field of view of the near-infrared imaging module, and each of the target units points to the near-infrared imaging module to form a plurality of meteorological visibility measurement links relative to the near-infrared imaging module, and an output end of the near-infrared imaging module is electrically connected to an input end of the information processing module;

[0010] The near-infrared imaging module is used to collect the near-infrared band image of the target unit and output the image signal to the information processing module. The information processing module extracts the pixel value of the image signal and loads the meteorological visibility calculation algorithm to obtain the meteorological visibility of each measurement link.

[0011] Furthermore, the near-infrared target includes a light source array, which includes a plurality of light sources emitting light waves with wavelengths ranging from 750 to 1800 nm, and the light sources include light emitting diodes.

[0012] Furthermore, the dark channel target includes a matte material, the reflectivity of the matte material to light waves in the range of 750 to 1800 nm is less than 0.1%, and the matte material includes matte flannel.

[0013] Furthermore, the near-infrared imaging module includes: a near-infrared camera, a filter, a lens, a lens controller and a base;

[0014] The near-infrared camera is connected to the lens controller, and the lens controller is connected to the lens; the filter is inserted into the internal gap between the lens controller and the lens, and the near-infrared camera is placed on the base.

[0015] Furthermore, the central wavelength of the filter is consistent with the wavelength of the near-infrared target, and the filter is an optical bandpass filter with a bandwidth of 10 nm.

[0016] Furthermore, the lens controller can adjust the focus and aperture of the lens.

[0017] Furthermore, the information processing module controls the near-infrared imaging module to capture band images of all measurement links within the field of view to form an image signal, and extracts corresponding pixel values ​​of near-infrared target pixels and dark channel target pixels in each measurement link from the image signal.

[0018] Furthermore, the lateral and longitudinal field of view angles of the near-infrared imaging module are both greater than 4.6° to ensure that the field of view coverage of the near-infrared imaging module is large enough to achieve full coverage of the arrangement range of multiple target units, so as to achieve the measurement of meteorological visibility of multiple measurement links. The specific angle can be determined according to the arrangement range of the target units to be measured in actual need, and is not limited here.

[0019] Furthermore, the meteorological visibility measurement link is an unobstructed space passed by a straight line from the near-infrared imaging module to each of the target units.

[0020] The present invention also provides a near-infrared optical imaging meteorological visibility measurement method, comprising the above-mentioned near-infrared optical imaging meteorological visibility measurement system, and the steps are as follows:

[0021] S1. System construction: Set up the near-infrared imaging module, and respectively set up a plurality of target units at different positions within the measurement link range of 500 to 5000 m within the field of view of the near-infrared imaging module, and each of the target units points to the near-infrared imaging module to form a plurality of meteorological visibility measurement links relative to the near-infrared imaging module;

[0022] S2, alignment adjustment: adjusting the base of the near-infrared imaging module so that the lens of the near-infrared imaging module is aligned with the plurality of target units for simultaneous imaging;

[0023] S3, focus adjustment: using the lens controller to adjust the lens to focus so that the image is clear;

[0024] S4, exposure adjustment: synchronously controlling the exposure time of the near-infrared camera and the aperture of the lens so that all pixels in the image are not overexposed;

[0025] S5, image acquisition: the near-infrared imaging module acquires images of near-infrared bands corresponding to multiple measurement links, and sends image signals composed of images of multiple near-infrared bands to the information processing module, and the information processing module obtains near-infrared target pixel points and dark channel target pixel points corresponding to each measurement link, and pixel values ​​corresponding to the two pixel points;

[0026] S51, initial pixel value calibration: when the visibility of each measurement link is greater than or equal to 9999m, the information processing module sets the pixel values ​​corresponding to the near-infrared target pixel points and the dark channel target pixel points as the initial pixel values ​​of the near-infrared target and the dark channel target respectively;

[0027] S52, test pixel value calibration: when each measurement link is in extremely low visibility, the information processing module sets the pixel values ​​corresponding to the near-infrared target pixel points and the dark channel target pixel points as the test pixel values ​​of the near-infrared target and the dark channel target respectively;

[0028] S6. Visibility calculation: The information processing module obtains the meteorological visibility of each measurement link according to the initial pixel value, test pixel value and length corresponding to each measurement link through the meteorological visibility calculation algorithm output.

[0029] Further, in step S6, the process of obtaining the meteorological visibility through the output of the meteorological visibility calculation algorithm is as follows:

[0030] S61, first calculate the near infrared transmittance:

[0031] Near-infrared transmittance refers to the atmospheric transmittance corresponding to the wavelength of the light source of the measurement link. The formula is as follows:

[0032]

[0033] S62. Calculation of meteorological visibility:

[0034] The obtained near-infrared transmittance of the measurement link is input into the wavelength transmission visibility conversion formula, and the meteorological visibility of the measurement link is output.

[0035] Further, in step S52, the extremely low visibility means: when the meteorological visibility is less than the length of the measurement link, the meteorological visibility at this time is extremely low visibility.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The near-infrared band emitted by the near-infrared light target used in the present invention has high transmittance and low attenuation in fog, which greatly improves the measurement capability of meteorological visibility of long measurement links in extremely low visibility.

[0038] 2. The field of view angle range of the near-infrared imaging module of the present invention is much larger than the arrangement range of the near-infrared target, and the required alignment accuracy is low; the problem of easily losing the ability to measure meteorological visibility when irresistible disturbances occur is avoided.

[0039] 3. The present invention uses a dark channel target and a near-infrared target in pairs to form a target unit, which corrects the influence of environmental interference light in the near-infrared band on the near-infrared target, so that the atmospheric transmittance measurement accuracy corresponding to the light source wavelength of the near-infrared target is high, thereby improving the measurement accuracy of the meteorological visibility of the continuous link.

[0040] 4. The present invention arranges several target units consisting of near-infrared targets and dark channel targets at several positions, which can form several measurement links relative to the near-infrared imaging module, and can realize the simultaneous measurement of meteorological visibility of multiple links in a large field of view, effectively improving the measurement range. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic diagram of a near-infrared imaging optical visibility measurement system of the present invention;

[0042] Figure 2 This is a schematic diagram of an image in the near-infrared band;

[0043] Figure 3 The present invention is a flowchart of the near-infrared imaging optical visibility measurement method.

[0044] In the figure: near-infrared target 1, dark channel target 2, near-infrared imaging module 3, near-infrared camera 31, filter 32, lens 33, lens controller 34, base 35, information processing module 4. DETAILED DESCRIPTION

[0045] The drawings are only for illustrative purposes and cannot be construed as limiting the present invention. To better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are only for illustrative purposes and cannot be construed as limiting the present invention.

[0046] Embodiment 1:

[0047] like Figure 1-Figure 2 As shown, this embodiment provides a near-infrared imaging optical visibility measurement system, including a near-infrared target 1, a dark channel target 2, a near-infrared imaging module 3 and an information processing module 4;

[0048] A near-infrared target 1 and a dark channel target 2 are placed in pairs and in parallel to form a target unit, and a plurality of target units are placed at different positions in the field of view of the near-infrared imaging module 3, and each target unit points to the near-infrared imaging module 3 to form a plurality of meteorological visibility measurement links relative to the near-infrared imaging module 3, and the output end of the near-infrared imaging module 3 is electrically connected to the input end of the information processing module 4;

[0049] The near-infrared imaging module 3 is used to collect near-infrared band images of the target unit and output image signals to the information processing module 4. The information processing module 4 extracts pixel values ​​from the image signals and loads a meteorological visibility calculation algorithm to obtain the meteorological visibility of each measurement link.

[0050] In this embodiment, the near-infrared target 1 includes a light source array, which includes a plurality of light sources emitting light waves with wavelengths ranging from 750 to 1800 nm, and the light sources include light emitting diodes.

[0051] In this embodiment, the dark channel target 2 includes a matte material, the reflectivity of the matte material to light waves in the range of 750 to 1800 nm is less than 0.1%, and the matte material includes a matte flannel.

[0052] In this embodiment, the near-infrared imaging module 3 includes: a near-infrared camera 31, a filter 32, a lens 33, a lens controller 34 and a base 35;

[0053] The near-infrared camera 31 is connected to the lens controller 34 , and the lens controller 34 is connected to the lens 33 ; the filter 32 is inserted into the internal gap between the lens controller 34 and the lens 33 , and the near-infrared camera 31 is placed on the base 35 .

[0054] Among them, the central wavelength of the filter 32 is consistent with the wavelength of the near-infrared target 1, and the filter 32 adopts an optical bandpass filter with a bandwidth of 10nm; the lens controller 34 can adjust the focus and aperture of the lens 33; the base 35 can adjust the direction and position of the near-infrared camera 31.

[0055] In this embodiment, the information processing module 4 controls the near-infrared imaging module 3 to capture the band images of all measurement links within the field of view to form an image signal, and extracts the near-infrared target pixel points and dark channel target pixel points in each measurement link, as well as the pixel values ​​corresponding to the two pixel points, from the image signal.

[0056] In this embodiment, the information processing module 4 may adopt a processor or a microcomputer, and may output the calculation results through a display screen for display.

[0057] In this embodiment, the lateral and longitudinal viewing angles of the near-infrared imaging module 3 are both greater than 4.6° to ensure that the viewing angle coverage of the near-infrared imaging module 3 is large enough to achieve full coverage of the arrangement range of multiple target units, so as to achieve the measurement of the meteorological visibility of multiple measurement links. The specific angle can be determined according to the arrangement range of the target units to be measured in actual need, and is not limited here.

[0058] In this embodiment, the meteorological visibility measurement link is an unobstructed space passed by a straight line from the near-infrared imaging module 3 to each target unit.

[0059] Embodiment 2:

[0060] This embodiment also provides a near-infrared optical imaging meteorological visibility measurement method, including the near-infrared optical imaging meteorological visibility measurement system of the above-mentioned embodiment 1, and the steps are as follows:

[0061] S1. System construction: Set up the near-infrared imaging module 3, and set up multiple target units at different positions within the measurement link range of 500 to 5000m within the field of view of the near-infrared imaging module 3, and each target unit points to the near-infrared imaging module 3 to form multiple meteorological visibility measurement links relative to the near-infrared imaging module 3;

[0062] S2, alignment adjustment: adjusting the base 35 of the near-infrared imaging module 3 so that the lens 33 of the near-infrared imaging module 3 is aligned with multiple target units for simultaneous imaging;

[0063] S3, focus adjustment: use the lens controller 34 to adjust the lens 33 to focus so that the image is clear;

[0064] S4, exposure adjustment: synchronously controlling the exposure time of the near-infrared camera 31 and the aperture of the lens 33 so that all pixels in the image are not overexposed;

[0065] S5, image acquisition: the near-infrared imaging module 3 acquires images of near-infrared bands corresponding to multiple measurement links, and sends image signals composed of images of multiple near-infrared bands to the information processing module 4, and the information processing module 4 obtains near-infrared target pixel points and dark channel target pixel points corresponding to each measurement link, and pixel values ​​corresponding to the two pixel points;

[0066] S51, initial pixel value calibration: when the visibility of each measurement link is greater than or equal to 9999m, the information processing module 4 sets the pixel values ​​corresponding to the near-infrared target pixel points and the dark channel target pixel points as the initial pixel values ​​of the near-infrared target 1 and the dark channel target 2 respectively;

[0067] S52, test pixel value calibration: when each measurement link is in extremely low visibility, the information processing module 4 sets the pixel values ​​corresponding to the near-infrared target pixel points and the dark channel target pixel points as the test pixel values ​​of the near-infrared target 1 and the dark channel target 2 respectively;

[0068] S6. Visibility calculation: The information processing module 4 obtains the meteorological visibility of each measurement link according to the initial pixel value, test pixel value and length corresponding to each measurement link through the output of the meteorological visibility calculation algorithm.

[0069] In step S6 of this embodiment, the process of obtaining the meteorological visibility through the output of the meteorological visibility calculation algorithm is as follows:

[0070] S61, first calculate the near infrared transmittance:

[0071] Near-infrared transmittance refers to the atmospheric transmittance corresponding to the wavelength of the light source of the measurement link. The formula is as follows:

[0072]

[0073] S62. Calculation of meteorological visibility:

[0074] The obtained near-infrared transmittance of the measurement link is input into the wavelength transmission visibility conversion formula, and the meteorological visibility of the measurement link is output.

[0075] It should be noted that the wavelength transmission visibility conversion formula is a formula known to those skilled in the art for calculating meteorological visibility and will not be described here.

[0076] In step S52 of this embodiment, extremely low visibility means that when the meteorological visibility is less than the length of the measurement link, the meteorological visibility at this time is extremely low visibility.

[0077] The near-infrared band emitted by the near-infrared light target 1 used in the present invention has high transmittance and low attenuation in fog, which greatly improves the measurement capability of meteorological visibility of long measurement links in extremely low visibility.

[0078] The field of view angle range of the near-infrared imaging module 3 of the present invention is much larger than the arrangement range of the near-infrared target, and the required alignment accuracy is low; thus, the problem of easily losing the ability to measure meteorological visibility when irresistible disturbances occur is avoided.

[0079] The present invention uses a dark channel target 2 and a near-infrared target 1 in pairs to form a target unit, corrects the influence of environmental interference light in the near-infrared band on the near-infrared target 1, and makes the atmospheric transmittance measurement accuracy corresponding to the light source wavelength of the near-infrared target 1 high, thereby improving the measurement accuracy of the meteorological visibility of the link.

[0080] The present invention arranges several target units consisting of near-infrared targets 1 and dark channel targets 2 at several positions, which can form several measurement links relative to the near-infrared imaging module 3, and can realize the simultaneous measurement of meteorological visibility of multiple links, effectively improving the measurement range.

[0081] Embodiment 3:

[0082] This embodiment uses a specific example to illustrate the near-infrared imaging optical visibility measurement method of the present invention.

[0083] First, set the parameters of each component:

[0084] The light source array of the near-infrared target 1 includes a plurality of light sources emitting light waves at a wavelength of 900nm, and the dark channel target 2 uses matte flannel cloth, and the reflectivity of the 900nm light wave is less than 0.1%;

[0085] The imaging wavelength range of the near-infrared camera 31 includes 750 to 1800 nm; the central wavelength of the filter 32 is 900 nm and the bandwidth is 10 nm; the resolution of the near-infrared camera 31 is 2560×2160 pixels and the pixel size is 6.5 μm; the focal length of the lens 33 is 100 mm; the lateral and longitudinal field of view angles of the near-infrared imaging module 3 are 9.5° and 8.0°.

[0086] The specific implementation steps of the method are as follows:

[0087] S1. System construction: Set up the near-infrared imaging module 3, and set up three target units at the measurement link distances of 500m, 1500m, and 3000m within the field of view of the near-infrared imaging module 3, respectively. Turn on all light sources of the near-infrared target 1 in the target unit, and each target unit points to the near-infrared imaging module 3 to form three meteorological visibility measurement links relative to the near-infrared imaging module 3;

[0088] S2, alignment adjustment: adjusting the base 35 of the near-infrared imaging module 3 so that the lens 33 of the near-infrared imaging module 3 is aligned with multiple target units for simultaneous imaging;

[0089] S3, focus adjustment: use the lens controller 34 to adjust the lens 33 to focus, so that the image of each near-infrared target 1 output by the near-infrared camera 31 is clear;

[0090] S4, exposure adjustment: synchronously controlling the exposure time of the near-infrared camera 31 and the aperture of the lens 33 so that all pixels in the image are not overexposed;

[0091] S5, image acquisition: the near-infrared imaging module 3 acquires images of the near-infrared bands corresponding to the three measurement links, and sends an image signal composed of the images of the three near-infrared bands to the information processing module 4, and the information processing module 4 obtains the near-infrared target pixel points and the dark channel target pixel points corresponding to each measurement link, and the pixel values ​​corresponding to the two pixel points;

[0092] S51, initial pixel value calibration: when the visibility of the three measurement links is greater than or equal to 9999m, the information processing module sets the pixel values ​​corresponding to the near-infrared target pixel points and the dark channel target pixel points as the initial pixel values ​​of the near-infrared target and the dark channel target, respectively; here, the initial pixel values ​​of the measurement links of 500m, 1500m, and 3000m are (60538, 3), (42402, 4), and (39874, 3), respectively;

[0093] S52, test pixel value calibration: when the three measurement links are in extremely low visibility, the information processing module 4 sets the pixel values ​​corresponding to the near-infrared target pixel points and the dark channel target pixel points as the test pixel values ​​of the near-infrared target and the dark channel target, respectively; here, the test pixel values ​​of the measurement links of 500m, 1500m, and 3000m are (650, 529), (1221, 468), and (743, 597), respectively;

[0094] S6, visibility calculation: the information processing module 4 obtains the meteorological visibility of each measurement link through the meteorological visibility calculation algorithm output according to the initial pixel value, test pixel value and length (i.e., the above-mentioned 500m, 1500m, 3000) corresponding to each measurement link;

[0095] Specifically, the meteorological visibility of the measurement links of 500m, 1500m and 3000m are 213m, 985m and 1577m respectively.

[0096] It can be seen that the near-infrared imaging optical visibility measurement system and method of the present invention can effectively and accurately measure the meteorological visibility of multiple long measurement links simultaneously under extremely low visibility, avoiding the interference of ambient light on the measurement and reducing the alignment accuracy requirements for visibility measurement.

[0097] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A near-infrared imaging optical visibility measurement system, characterized in that: It includes a near-infrared target (1), a dark channel target (2), a near-infrared imaging module (3) and an information processing module (4); One of the near-infrared targets (1) and one of the dark channel targets (2) are placed in parallel in a pair to form a target unit; a plurality of the target units are placed at different positions within the field of view of the near-infrared imaging module (3); and each of the target units points to the near-infrared imaging module (3) to form a plurality of meteorological visibility measurement links relative to the near-infrared imaging module (3); and an output end of the near-infrared imaging module (3) is electrically connected to an input end of the information processing module (4); The near-infrared imaging module (3) is used to collect an image of the target unit in the near-infrared band and output an image signal to the information processing module (4); the information processing module (4) extracts pixel values ​​from the image signal and loads a meteorological visibility calculation algorithm to obtain the meteorological visibility of each measurement link; The near-infrared target (1) comprises a light source array, the light source array comprises a plurality of light sources emitting light waves with wavelengths in the range of 750 to 1800 nm, the light sources comprising light emitting diodes; the dark channel target (2) comprises a light extinction material, the reflectivity of the light extinction material to light waves in the range of 750 to 1800 nm is less than 0.1%, the light extinction material comprises a light extinction velvet cloth; the near-infrared imaging module (3) comprises: a near-infrared camera (31), a filter (32), a lens (33), a lens controller (34) and a base (35); the near-infrared camera (31) is connected to the lens controller (34), the lens controller (34) is connected to the lens (33); the filter (32) is inserted into the internal gap between the lens controller (34) and the lens (33), and the near-infrared camera (31) is placed on the base (35).

2. A near-infrared imaging optical visibility measurement system according to claim 1, characterized in that: The central wavelength of the optical filter (32) is consistent with the wavelength of the near-infrared target (1), and the optical filter (32) is an optical bandpass filter with a bandwidth of 10 nm.

3. A near-infrared imaging optical visibility measurement system according to claim 1, characterized in that: The lateral and longitudinal viewing angles of the near-infrared imaging module (3) are both greater than 4.6°.

4. A near-infrared imaging optical visibility measurement system according to claim 1, characterized in that: The meteorological visibility measurement link is an unobstructed space passed by a straight line from the near-infrared imaging module (3) to each of the target units.

5. A near-infrared imaging optical visibility measurement method, characterized in that: The near-infrared imaging optical visibility measurement system described in claim 1 is used, and the steps are as follows: S1. System construction: The near-infrared imaging module (3) is set up, and a plurality of target units are respectively set up at different positions within a measurement link range of 500 to 5000 m within the field of view of the near-infrared imaging module (3), and each of the target units points to the near-infrared imaging module (3), so as to form a plurality of meteorological visibility measurement links relative to the near-infrared imaging module (3); S2, alignment adjustment: adjusting the base (35) of the near-infrared imaging module (3) so that the lens (33) of the near-infrared imaging module (3) is aligned with the plurality of target units for simultaneous imaging; S3, focus adjustment: using the lens controller (34) to adjust the lens (33) to focus so that the image is clear; S4, exposure adjustment: synchronously controlling the exposure time of the near-infrared camera (31) and the aperture of the lens (33) so that all pixels in the image are not overexposed; S5, image acquisition: the near-infrared imaging module (3) acquires images of near-infrared bands corresponding to the multiple measurement links, and sends an image signal composed of the images of the multiple near-infrared bands to the information processing module (4), and the information processing module (4) obtains near-infrared target pixel points and dark channel target pixel points corresponding to each measurement link, and pixel values ​​corresponding to the two pixel points; S51, initial pixel value calibration: when the visibility of each measurement link is greater than or equal to 9999 m, the information processing module (4) sets the pixel values ​​corresponding to the near-infrared target pixel points and the dark channel target pixel points as the initial pixel values ​​of the near-infrared target (1) and the dark channel target (2), respectively; S52, test pixel value calibration: when each measurement link is in extremely low visibility, the information processing module (4) sets the pixel values ​​corresponding to the near-infrared target pixel points and the dark channel target pixel points as the test pixel values ​​of the near-infrared target (1) and the dark channel target (2), respectively; S6, visibility calculation: the information processing module (4) obtains the meteorological visibility of each measurement link according to the initial pixel value, test pixel value and length corresponding to each measurement link through the output of the meteorological visibility calculation algorithm.

6. A near-infrared imaging optical visibility measurement method according to claim 5, characterized in that: In step S6, the process of obtaining the meteorological visibility through the output of the meteorological visibility calculation algorithm is as follows: S61, first calculate the near infrared transmittance: Near-infrared transmittance refers to the atmospheric transmittance corresponding to the wavelength of the light source of the measurement link. The formula is as follows: S62. Calculation of meteorological visibility: The obtained near-infrared transmittance of the measurement link is input into the wavelength transmission visibility calculation formula, and the meteorological visibility of the measurement link is output.

7. A near-infrared imaging optical visibility measurement method according to claim 5, characterized in that: In step S52, the extremely low visibility means that when the meteorological visibility is less than the length of the measurement link, the meteorological visibility at this time is extremely low visibility.

Images