Apparatus and method for measuring atmospheric transmittance

Abstract

The application relates to the technical field of atmospheric detection, and particularly provides a device and a method for measuring atmospheric transmittance, the device comprising a sensing and executing layer and a supporting layer, wherein the sensing and executing layer comprises a long-distance subsystem, a short-distance subsystem and a meteorological detection device; the distance between the long-distance subsystem and a measurement target is equal to a to-be-measured distance of the atmospheric transmittance; the distance between the long-distance subsystem and the measurement target is greater than the distance between the short-distance subsystem and the measurement target; the long-distance subsystem and the short-distance subsystem both comprise a multi-spectrum device; the multi-spectrum device of the long-distance subsystem collects a first multi-spectrum radiation image of the measurement target; at the same time, the multi-spectrum device of the short-distance subsystem collects a second multi-spectrum image of the measurement target; the atmospheric transmittance is calculated based on the radiation path difference of the first and second multi-spectrum radiation images; and the meteorological detection device is used for collecting meteorological data of a measurement environment, and the meteorological data is used for compensating for the environmental error of the atmospheric transmittance.

Description

Technical Field

[0001] This invention belongs to the field of atmospheric detection technology, and in particular relates to a device and method for measuring atmospheric transmittance. Background Technology

[0002] Atmospheric transmittance is a key parameter in atmospheric observation and target characteristic research, and it is widely used in aerospace, environmental monitoring and other fields.

[0003] Currently, existing technologies face numerous bottlenecks in practical applications: single devices struggle to simultaneously meet the measurement needs of both visible and infrared multi-bands; fixed-position measurements cannot avoid interference from local atmospheric environments; and the lack of a unified collaborative control and data integration mechanism results in measurement accuracy, efficiency, and environmental adaptability failing to meet the requirements of complex scenarios. Achieving accurate atmospheric transmittance through combined infrared and visible optics measurement technologies, and subsequently retrieving the target's characteristics in both bands, has become a core research direction in this field. Summary of the Invention

[0004] In view of this, the present invention aims to provide an apparatus and method for measuring atmospheric transmittance. The present invention revolves around "multi-band coverage, multi-distance coordination, all-weather adaptability, and high integration", constructs a hierarchical collaborative structure of "support layer + sensing and execution layer", and achieves high-precision, all-weather measurement of atmospheric transmittance and target multi-dimensional radiation characteristics through substation modular design and multispectral measurement technology.

[0005] To achieve the above objectives, the technical solution created by this invention is implemented as follows: This invention provides an apparatus for measuring atmospheric transmittance, comprising: The perception and execution layer includes a long-range subsystem, a short-range subsystem, and meteorological detection equipment; The support layer is used to control the perception and execution layer; The distance between the long-range subsystem and the target is equal to the distance at which atmospheric transmittance is measured, and the distance between the long-range subsystem and the target is greater than the distance between the short-range subsystem and the target. Both the long-range and short-range subsystems include multispectral equipment; The multispectral equipment of the long-range subsystem acquires the first multispectral radiometric image of the target being measured; at the same time, the multispectral equipment of the short-range subsystem acquires the second multispectral image of the target being measured. Atmospheric transmittance is calculated based on the difference in radiation paths between the first and second multispectral radiation images. Meteorological detection equipment is used to collect and measure meteorological data of the environment, and the meteorological data is used to compensate for environmental errors in atmospheric transmittance.

[0006] Preferably, the spectral range of the multispectral device includes visible and near-infrared, short and mid-wave infrared, and long-wave infrared.

[0007] Preferably, the meteorological data includes temperature, humidity, air pressure, and visibility.

[0008] Preferably, both the first and second multispectral radiation images include infrared radiation images and visible light radiation images.

[0009] In another aspect, the present invention provides a method for measuring atmospheric transmittance, comprising: Choose to measure atmospheric transmittance based on either infrared radiation or visible light radiation, depending on environmental conditions. Infrared radiation measurements of atmospheric transmittance include: S1: Acquire the first infrared radiation image of the target using the multispectral equipment of the long-range subsystem; at the same time, acquire the second infrared radiation image of the target using the multispectral equipment of the short-range subsystem; at the same time, acquire meteorological data of the measurement environment using meteorological detection equipment, and calculate the infrared band atmospheric scattering coefficient and the infrared radiation brightness of the atmosphere itself using the meteorological data. S2: Calculate the first infrared radiation brightness using the first infrared radiation image, and calculate the second infrared radiation brightness using the second infrared radiation image; S3: Calculate the distance attenuation coefficient by using the ratio of the distance between the long-range subsystem and the target to the distance between the short-range subsystem and the target; S4: The atmospheric transmittance τ_ir in the infrared band is calculated as follows: τ_ir=[Lir,2-L_air×(1-exp(-σ_ir×L2))] / [Lir,1-L_air×(1-exp(-σ_ir×L1))]×(L1 / L2)^k; Where: L1 is the distance between the near-range subsystem and the measurement target, L2 is the distance between the far-range subsystem and the measurement target, Lir,1 is the second infrared radiance obtained at the L1 distance, Lir,2 is the first infrared radiance obtained at the L2 distance, L_air is the infrared radiance of the atmosphere itself, σ_ir is the atmospheric scattering coefficient in the infrared band, and k is the distance attenuation coefficient. Atmospheric transmittance based on visible light radiation measurement: A1: The multispectral equipment of the long-range subsystem acquires the first visible light radiation image of the target being measured; at the same time, the multispectral equipment of the short-range subsystem acquires the second visible light radiation image of the target being measured; at the same time, meteorological data of the measurement environment is acquired using meteorological detection equipment, and the meteorological data is used to calculate the atmospheric scattering coefficient in the visible light band and the visible light radiance of the atmosphere itself. A2: The first visible light radiation brightness is calculated using the first multi-visible light radiation image, and the second visible light radiation brightness is calculated using the second visible light radiation image; A3: The atmospheric transmittance τ_v in the visible light band is calculated as follows: τ_v=[L_v2-L_air_v×(1-exp(-σ×L2))] / [L_v1-L_air_v×(1-exp(-σ×L1))]×(L1 / L2)^n; Where: L1 is the distance between the near-range subsystem and the measurement target, L2 is the distance between the far-range subsystem and the measurement target, L_v1 is the second visible light radiance obtained at distance L1, L_v2 is the first visible light radiance measured at distance L2, L_air_v is the visible light radiance of the atmosphere itself, σ is the atmospheric scattering coefficient in the visible light band, and n is the atmospheric attenuation index.

[0010] Preferably, an illumination threshold is set to divide the environmental conditions into at least three illumination intervals, including: low illumination environment, medium illumination environment and high illumination environment; atmospheric transmittance in the low illumination environment is measured based on infrared radiation; atmospheric transmittance in the high illumination environment is measured based on visible light radiation; and atmospheric transmittance in the medium illumination environment is measured based on a weighted average of infrared and visible light radiation.

[0011] Preferably, the atmospheric scattering coefficient is calculated using visibility, and the atmospheric radiance is calculated using temperature, humidity, and air pressure.

[0012] Preferably, a standard blackbody is used to calibrate the measurement link of the multispectral equipment in the process of measuring atmospheric transmittance of infrared radiation, and a diffuse reflection standard plate is used to calibrate the measurement link of the multispectral equipment in the process of measuring atmospheric transmittance of visible light radiation, in order to eliminate equipment errors.

[0013] Compared with the prior art, the present invention can achieve the following beneficial effects: To address the problems of poor system integration and coordination, limited spectral coverage, insufficient measurement accuracy, and inability to operate in all weather conditions associated with traditional atmospheric transmittance measurement equipment, this invention employs a dual-station collaborative measurement system consisting of a near-range subsystem and a far-range subsystem. Combining multispectral imaging technology, dual-range calibration methods, time synchronization, and spatial positioning technology, and integrating environmental parameters such as temperature and visibility, it achieves accurate, all-weather measurement of atmospheric transmittance and the multi-dimensional radiation characteristics of the target. This invention simultaneously acquires the infrared and visible light radiance of the target at different distances (near-range L1, far-range L2, where L2 is the distance to be measured) using the near-range and far-range subsystems, obtaining differences in atmospheric radiation paths. Meteorological data from the measurement environment is collected using meteorological detection equipment to compensate for environmental errors in atmospheric transmittance. Combined with standard source calibration correction, the atmospheric transmittance at the measured distance is calculated. Simultaneously, it supports automatic switching between infrared and visible light measurement modes, ensuring all-weather measurement capability. Attached Figure Description

[0014] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of an apparatus for measuring atmospheric transmittance according to an embodiment of the present invention; Figure 2 This is a specific calibration flowchart based on an infrared camera measurement link provided according to an embodiment of the present invention; Figure 3 This is a flowchart of measuring atmospheric transmittance based on infrared radiation, provided according to an embodiment of the present invention; Figure 4 This is a specific calibration flowchart based on a visible light camera measurement link provided according to an embodiment of the present invention; Figure 5 This is a flowchart of atmospheric transmittance measurement based on visible light radiation, provided according to an embodiment of the present invention; Detailed Implementation To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and do not constitute a limitation thereof. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; the relevant operations can be fully understood based on the description in the specification and general technical knowledge in the art.

[0015] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined to form various implementations. Furthermore, the order of the steps or actions in the method description can be changed or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a mandatory order, unless otherwise stated that a particular order must be followed.

[0016] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0017] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0018] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] Please see Figure 1 In one embodiment of the present invention, an apparatus for measuring atmospheric transmittance is provided, wherein the sensing and execution layer includes a long-range subsystem, a short-range subsystem, and a meteorological detection device; The support layer is used to control the perception and execution layer; The distance between the long-range subsystem and the target is equal to the distance at which atmospheric transmittance is measured, and the distance between the long-range subsystem and the target is greater than the distance between the short-range subsystem and the target. Both the long-range and short-range subsystems include multispectral equipment; The multispectral equipment of the long-range subsystem acquires the first multispectral radiometric image of the target being measured; at the same time, the multispectral equipment of the short-range subsystem acquires the second multispectral image of the target being measured. Atmospheric transmittance is calculated based on the difference in radiation paths between the first and second multispectral radiation images. Meteorological detection equipment is used to collect and measure meteorological data of the environment, and the meteorological data is used to compensate for environmental errors in atmospheric transmittance.

[0020] The support layer and the sensing and execution layer are connected via a wireless bridge. The support layer, centered on the control and display computers, is responsible for receiving, preprocessing, and storing various data collected by the sensing and execution layer, calculating atmospheric transmittance, and displaying the results. The sensing and execution layer includes a long-range subsystem, a short-range subsystem, a positioning and orientation device, a weather station, and a visibility meter.

[0021] Among them, the positioning and orientation instrument provides a unified spatial coordinate reference and attitude information for the entire measurement system by combining inertial navigation and satellite positioning, ensuring that measurement equipment on different distances and different carriers can be aligned with the same target, thus guaranteeing the spatiotemporal consistency of the measurement.

[0022] Weather stations and visibility meters are deployed in open areas between the long-range and short-range subsystems to ensure accurate collection of environmental meteorological data for the measurement area. The environmental meteorological data includes temperature, humidity, air pressure, and visibility. The collected meteorological data is used to compensate for environmental errors in atmospheric transmittance.

[0023] The long-range subsystem is equipped with multispectral equipment, a laser rangefinder, a communication board, a data acquisition card, a servo platform, and a timing terminal. The laser rangefinder is used to calibrate the distances from the long-range and short-range subsystems to the target. The communication board includes a wireless bridge and a serial port. By sending commands through the control computer, the long-range subsystem can be locally controlled and remotely controlled via the wireless bridge. Simultaneously, environmental parameters from the positioning and orientation instrument, weather station, and visibility meter are acquired via the serial port. The distance between the long-range subsystem and the target is equal to the atmospheric transmittance of the target distance. The multispectral equipment includes a visible and near-infrared zoom camera, a short- and mid-wave infrared zoom camera, and a long-wave infrared zoom camera, used to acquire the first multispectral radiation image. The data acquisition card is used to convert the first multispectral radiation image acquired by the multispectral equipment into a digital signal that the computer can recognize and process in real time, and then transmit it to memory or forward it. The servo platform is used to precisely rotate the multispectral equipment on both the long-range and short-range subsystems, enabling the multispectral equipment to measure the same target simultaneously, ensuring that the multispectral equipment is jitter-free during the measurement process.

[0024] The near-range subsystem is a portable device deployed near the measurement target. It is equipped with a multispectral device in the same band as the long-range subsystem, a portable power supply, a communication board, a data acquisition card, a support frame, and a timing terminal. It is responsible for acquiring near-range radiation data of the measurement target and transmitting keyframes in encrypted form. The multispectral device also includes a visible / near-infrared fixed-focus camera, a short / mid-wave infrared fixed-focus camera, and a long-wave infrared fixed-focus camera, used to acquire second multispectral radiation images. The portable power supply provides an independent and portable power supply for the near-range imaging subsystem, enabling it to operate without mains power. The data acquisition card converts the second multispectral radiation images acquired by the multispectral device into digital signals that can be recognized and processed by a computer in real time, and stores or forwards them. The communication board receives control commands from the long-range subsystem and sends the second multispectral radiation images acquired by the data acquisition card back to the long-range subsystem. The support frame supports the multispectral device, communication board, data acquisition card, portable power supply, and timing terminal, placing them securely at the measurement location.

[0025] The timing terminals on both the long-range and short-range subsystems employ GPS / BeiDou dual-mode timing to provide a unified timestamp for all cameras. The distance between the long-range subsystem and the target is greater than that between the short-range subsystem and the target. At different distances, the timing terminals synchronize the timing for both subsystems. The multispectral equipment of the long-range subsystem acquires the first multispectral radiation image of the target, while the multispectral equipment of the short-range subsystem acquires the second multispectral radiation image. Both the first and second multispectral radiation images include infrared and visible light radiation images. By simultaneously acquiring infrared and visible light images of the target at different distances, the infrared and visible light brightness of the target at these distances is determined. Utilizing differences in atmospheric radiation paths and combining collected meteorological data to compensate for environmental errors in atmospheric transmittance, a specific algorithm calculates the atmospheric transmittance at the measured distance. Automatic switching between infrared and visible light measurement modes is also supported, ensuring all-weather measurement capabilities.

[0026] In another embodiment of the present invention, a method for measuring atmospheric transmittance is provided, which uses an apparatus for measuring atmospheric transmittance to measure atmospheric transmittance, including: selecting whether to measure atmospheric transmittance based on infrared radiation or based on visible light radiation according to environmental conditions. Infrared radiation measurements of atmospheric transmittance include: S1: Acquire the first infrared radiation image of the target using the multispectral equipment of the long-range subsystem; at the same time, acquire the second infrared radiation image of the target using the multispectral equipment of the short-range subsystem; at the same time, acquire meteorological data of the measurement environment using meteorological detection equipment, and calculate the infrared band atmospheric scattering coefficient and the infrared radiation brightness of the atmosphere itself using the meteorological data. S2: Calculate the first infrared radiation brightness using the first infrared radiation image, and calculate the second infrared radiation brightness using the second infrared radiation image; S3: Calculate the distance attenuation coefficient by using the ratio of the distance between the long-range subsystem and the target to the distance between the short-range subsystem and the target; S4: The atmospheric transmittance τ_ir in the infrared band is calculated as follows: τ_ir=[Lir,2-L_air×(1-exp(-σ_ir×L2))] / [Lir,1-L_air×(1-exp(-σ_ir×L1))]×(L1 / L2)^k; Where: L1 is the distance between the near-range subsystem and the measurement target, L2 is the distance between the far-range subsystem and the measurement target, Lir,1 is the second infrared radiance obtained at the L1 distance, Lir,2 is the first infrared radiance obtained at the L2 distance, L_air is the infrared radiance of the atmosphere itself, σ_ir is the atmospheric scattering coefficient in the infrared band, and k is the distance attenuation coefficient. Atmospheric transmittance based on visible light radiation measurement: A1: The multispectral equipment of the long-range subsystem acquires the first visible light radiation image of the target being measured; at the same time, the multispectral equipment of the short-range subsystem acquires the second visible light radiation image of the target being measured; at the same time, meteorological data of the measurement environment is acquired using meteorological detection equipment, and the meteorological data is used to calculate the atmospheric scattering coefficient in the visible light band and the visible light radiance of the atmosphere itself. A2: The first visible light radiation brightness is calculated using the first multi-visible light radiation image, and the second visible light radiation brightness is calculated using the second visible light radiation image; A3: The atmospheric transmittance τ_v in the visible light band is calculated as follows: τ_v=[L_v2-L_air_v×(1-exp(-σ×L2))] / [L_v1-L_air_v×(1-exp(-σ×L1))]×(L1 / L2)^n; Where: L1 is the distance between the near-range subsystem and the measurement target, L2 is the distance between the far-range subsystem and the measurement target, L_v1 is the second visible light radiance obtained at distance L1, L_v2 is the first visible light radiance measured at distance L2, L_air_v is the visible light radiance of the atmosphere itself, σ is the atmospheric scattering coefficient in the visible light band, and n is the atmospheric attenuation index.

[0027] Before taking measurements with multispectral equipment, the infrared camera measurement link needs to be calibrated using a standard blackbody, and the visible light camera measurement link needs to be calibrated using a diffuse reflection standard plate to eliminate the inherent bias of the multispectral equipment, i.e., equipment error.

[0028] Based on multiple preset illumination thresholds, the measurement conditions are divided into at least three intervals: low illumination, medium illumination, and high illumination, each corresponding to a different measurement link (infrared or visible light). In the low illumination environment, the measurement link is calibrated using a standard blackbody, and atmospheric transmittance is measured based on infrared radiation. Image acquisition during this process is mainly performed using short-wave and mid-wave infrared cameras and long-wave infrared cameras in the multispectral equipment. In the medium illumination environment, the measurement link is calibrated using a standard blackbody and a diffuse reflection standard plate, and atmospheric transmittance is measured based on a weighted average of infrared and visible light radiation. Image acquisition during this process is mainly performed using visible and near-infrared cameras, short-wave and mid-wave infrared cameras, and long-wave infrared cameras in the multispectral equipment. In the high illumination environment, the measurement link is calibrated using a diffuse reflection standard plate, and atmospheric transmittance is measured based on visible light radiation. Image acquisition during this process is mainly performed using visible and near-infrared cameras in the multispectral equipment.

[0029] When measurements are primarily performed using infrared cameras, the calibration of the infrared camera measurement link is a crucial step in ensuring the accuracy of infrared radiance measurements. Please refer to [link to relevant documentation]. Figure 2 In this embodiment, a standard blackbody is used as the calibration device for the infrared camera. The calibration establishes a mapping relationship between the camera output signal and the actual infrared radiation brightness, thereby eliminating the influence of the device's own response deviation on the measurement results.

[0030] The specific calibration procedure for the infrared camera measurement link: B1: Completely block the infrared camera lens with a lens hood to ensure no external radiation enters the camera. Set the camera's operating parameters (such as exposure time, gain, etc.) to the default parameters for subsequent measurements. Acquire 10 frames of dark field images, calculate the grayscale value of each pixel in each frame, and take the average value as the camera's dark current grayscale value (denoted as D), which will be used for dark current compensation in subsequent images.

[0031] B2: According to the calibration requirements, set the target temperature of the standard blackbody and select 5 typical temperature points: 30℃, 45℃, 60℃, 75℃, and 90℃. Start the temperature control system of the standard blackbody. After the standard blackbody temperature reaches the target temperature, keep it constant for 30 minutes to ensure its radiation brightness is stable (radiation brightness fluctuation ≤ 0.1%).

[0032] B3: After the standard blackbody temperature stabilizes, infrared radiation images of the standard blackbody are acquired using infrared cameras (short-wave and mid-wave infrared cameras) from the near-range and long-range subsystems, respectively. Twenty frames are acquired for each of the five temperature points. During the acquisition process, ensure that the measurement link between the infrared cameras and the standard blackbody is unobstructed and that the infrared camera parameters remain constant.

[0033] B4: Preprocess the acquired infrared radiation image, including dark current compensation (subtracting the dark field calibration value D from the image grayscale value), bad pixel removal (removing pixels with abnormal grayscale values ​​and replacing them with the neighborhood mean), and mean filtering (filtering window size of 3×3 to eliminate image noise). After preprocessing, extract the average grayscale value (denoted as G) of the standard blackbody radiation surface region in the image, as the output grayscale value of the infrared camera at that temperature point.

[0034] B5: Using Planck's blackbody radiation law, calculate the theoretical infrared radiance L_blackbody of a standard blackbody at each target temperature. Planck's formula L(λ,T) is expressed as: L(λ,T)=C1 / [λ 5 )]; Where: L is the theoretical infrared radiance of a standard blackbody at the target temperature, i.e., infrared radiance L_blackbody, C1=3.7418×10 8 W·μm 4 / m² is the first radiation constant, λ is the center wavelength of the infrared camera, and C² = 1.4388 × 10⁻⁶. 4 μm·K is the second radiation constant, and T is the absolute temperature of the standard blackbody.

[0035] Using the average grayscale value G output by the camera as the x-axis and the theoretical infrared radiance L of a standard blackbody as the y-axis, the radiation calibration curve of the infrared camera is obtained by fitting using the least squares method (linear fitting equation: Lir = k × G + b, where k is the gain coefficient, b is the offset coefficient, and Lir is the radiation calibration curve), thus completing the calibration of the infrared camera measurement link. Each infrared camera (a total of 4, including 2 near-range and 2 long-range cameras) must undergo the above calibration process individually to ensure the measurement accuracy of each camera.

[0036] B6: Verification of calibration results. Select a temperature point that was not involved in the calibration (e.g., 52℃), set the standard blackbody to this temperature and stabilize it, then collect its radiation image using an infrared camera. Compare the radiance calculated based on the calibration curve with the theoretical radiance. The error must be ≤2%. If the error exceeds the range, recalibration is required.

[0037] In low-light conditions, infrared cameras dominate the measurements; please refer to [link / reference needed]. Figure 3 By utilizing the target's own thermal radiation characteristics, combined with dual-distance infrared radiation brightness acquisition and calibration curve correction, and meteorological parameter compensation, high-precision measurement of atmospheric transmittance in the infrared band is achieved, ensuring the system's continuous observation capability in low-light environments.

[0038] Measurement procedure for atmospheric transmittance based on infrared radiation: S1: First, a standard test vehicle is selected as the measurement target. A high emissivity coating (emissivity ≥ 0.9) is sprayed onto the vehicle's surface. The target is placed at the center of the measurement area, ensuring it is completely within the measurement field of view of both the near-range and far-range subsystems. Control commands are sent from the computer to control the infrared cameras (short-wave / mid-wave and long-wave infrared cameras) of the near-range subsystem, acquiring infrared radiation images of the target at a distance L1 from the near-range subsystem, according to pre-calibrated parameters (exposure time, gain, etc.). Keeping the target position and infrared camera parameters (exposure time, gain, focal length, etc.) unchanged, control commands are sent from the computer to control the infrared cameras (short-wave / mid-wave and long-wave infrared cameras) of the far-range subsystem, acquiring infrared radiation images of the target at a distance L2 from the far-range subsystem. During acquisition, the timing terminal synchronously triggers the infrared cameras of both subsystems to ensure consistent acquisition time and avoid the influence of temperature changes or environmental radiation changes on the measurement results. At the same time, meteorological parameters of the measurement environment are collected in real-time from a weather station for environmental compensation in subsequent atmospheric transmittance calculations.

[0039] S2: The acquired near-range infrared radiation image, after preprocessing, calculates the infrared radiation brightness of the target based on the infrared radiation calibration curve, denoted as Lir,1; the acquired far-range infrared radiation image, after preprocessing, calculates the infrared radiation brightness of the target based on the infrared radiation calibration curve, denoted as Lir,2.

[0040] S3: Calculate the distance attenuation coefficient by using the ratio of the distance between the long-range subsystem and the target to the distance between the short-range subsystem and the target.

[0041] S4: In the specific calculation process, the infrared camera gain coefficient and intercept obtained during calibration need to be combined to correct the measured infrared radiance and eliminate equipment errors; at the same time, the environmental parameters collected by the meteorological station are substituted to compensate for the atmospheric radiance itself, further improving the calculation accuracy. The calculated infrared atmospheric transmittance τ_ir is expressed as: τ_ir=[Lir,2-L_air×(1-exp(-σ_ir×L2))] / [Lir,1-L_air×(1-exp(-σ_ir×L1))]×(L1 / L2)^k; Where: L1 is the distance between the near-range subsystem and the measurement target, L2 is the distance between the far-range subsystem and the measurement target, Lir,1 is the second infrared radiance obtained at the L1 distance, Lir,2 is the first infrared radiance obtained at the L2 distance, L_air is the infrared radiance of the atmosphere itself, σ_ir is the atmospheric scattering coefficient in the infrared band, and k is the distance attenuation coefficient.

[0042] After the calculation is completed, the computer automatically stores the measurement results and generates curves showing the change of atmospheric transmittance over time and wavelength for subsequent analysis.

[0043] When measurements are primarily performed using a visible light camera, the calibration of the visible light camera measurement link is a critical step in ensuring the accuracy of visible light brightness measurements. Please refer to [link to relevant documentation]. Figure 4 In this embodiment, a diffuse reflection standard plate is used as a calibration device for the visible light camera. The calibration establishes a mapping relationship between the camera output signal and the actual visible light brightness, thereby eliminating the influence of the device's own response deviation on the measurement results.

[0044] The specific calibration process for the visible light camera measurement link: C1: Determine the standard reflectivity ρ of the diffuse reflection standard plate (0.94 in this embodiment), select a standard light source (such as a standard D65 light source) to illuminate the diffuse reflection standard plate, and know the incident illuminance E0 (cd / m², obtained by measuring with a standard illuminance meter) of the standard light source on the surface of the diffuse reflection standard plate. Calculate the standard visible light luminance L0 of the diffuse reflection standard plate according to Lambert's law, as follows: L0 = ρE0 / π; Where: ρ is the standard reflectivity of the diffuse reflection standard plate, E0 is the incident illuminance of the standard light source on the surface of the diffuse reflection standard plate, and π is pi.

[0045] C2: Acquire image grayscale values: The visible light camera takes pictures of the diffuse reflection standard plate and obtains the average grayscale value G_avg of the standard plate area in the image (by removing edge noise pixels and selecting the central 200×200 pixel area to calculate the average value).

[0046] C3: Establishing a mapping model between grayscale values ​​and visible light brightness: Since the grayscale values ​​of a visible light camera have a linear relationship with the received visible light brightness, a linear fitting method is used to establish the mapping equation: L = kG_avg + b; Where: L is the visible light luminance, G_avg is the average gray value, k is the gain coefficient, and b is the offset coefficient.

[0047] C4: Solve the mapping equation parameters: Substitute the known standard visible light brightness L0 and the acquired average gray value G_avg into the mapping equation, and combine it with the dark field gray value G_dark of the visible light camera (the average gray value of the dark field image acquired by the lens, at which time the received brightness is 0), to obtain the equation system: L0=kG_avg+b, 0=kG_dark+b; solve the simultaneous equation system to obtain the gain coefficient k and offset coefficient b, where k=L0 / (G_avg-G_dark), b=-kG_dark, and use the least squares method to obtain the radiometric calibration curve of the visible light camera, thus completing the calibration of the visible light camera measurement link.

[0048] C5: Calibration Verification: Replace with another diffuse reflection standard plate with a reflectivity ρ1 (e.g., 0.5), repeat steps C1 to C3, calculate the calibrated visible light luminance L1, and compare it with the standard visible light luminance L1_std of the diffuse reflection standard plate. If the error is ≤2%, the calibration is valid.

[0049] In high-light conditions, the visible light characteristics of the target are significantly different; please refer to [link / reference needed]. Figure 5 The visible light radiation measurement process can fully utilize the high resolution advantage of the visible light band to improve the accuracy of atmospheric transmittance measurement. This process is based on dual-distance visible light brightness acquisition and calibration curve correction, combined with ambient light compensation, to achieve accurate calculation of atmospheric transmittance in the visible light band.

[0050] Measurement procedure for atmospheric transmittance based on visible light radiation: A1: First, assess the lighting conditions of the measurement environment. Collect real-time environmental parameters using a visibility meter to ensure that the ambient illuminance is within the range of 500 lux-10000 lux and that there are no interfering factors such as strong backlighting or shadows. If there are local shadows or uneven lighting, adjust the target placement to an open, unobstructed area, or select a period of stable lighting for measurement. Select a standard diffuse reflection target as the measurement target. The target board is 1m×1m in size, with a highly uniform diffuse reflection coating sprayed on its surface. The reflectivity is selected as 0.5 (medium reflectivity, accommodating both high and low brightness measurements), and its bidirectional reflectance distribution function (BRDF) varies by ≤1% within the 0°-30° observation angle range to ensure brightness stability at different distances. Fix the diffuse reflection target board on an adjustable bracket, and adjust the surface of the diffuse reflection target board to be perpendicular to the visible light camera lenses of the two subsystems, and align the center of the diffuse reflection target board with the center of the camera's measurement field of view to ensure that the camera can acquire the complete and effective area of ​​the diffuse reflection target board.

[0051] A2: By sending synchronous control commands through the computer, the timing terminal triggers the infrared cameras (visible and near-infrared cameras) of the near-range and far-range subsystems to simultaneously image, ensuring consistent acquisition time. First, the infrared camera (visible and near-infrared camera) of the near-range subsystem is controlled to acquire visible light images of the diffuse reflective target board at near-range L1 according to pre-calibrated parameters (aperture f / 4.0, exposure time 10ms, gain 1.0x), acquiring 15 frames to reduce the impact of random noise. Keeping the position of the diffuse reflective target board, the infrared camera parameters, and the ambient lighting conditions unchanged, the infrared camera of the far-range subsystem is controlled to acquire visible light images of the target board at far-range L2 (adjusting the focal length to the corresponding value to ensure the target board's proportion is consistent with the near-range image), also acquiring 15 frames. During acquisition, changes in ambient illuminance are monitored in real time. If the illuminance fluctuation exceeds ±5%, acquisition must be paused and restarted after the lighting stabilizes. Simultaneously, real-time environmental parameters (temperature, humidity, air pressure, visibility) collected by the weather station are recorded for subsequent illumination compensation calculations.

[0052] A3: The acquired near- and far-range visible light images are preprocessed. First, Zhang Zhengyou's calibration method is used to correct lens distortion and eliminate the influence of lens optical distortion on brightness measurement. Then, a 5×5 Gaussian filter is used to remove image noise and improve the accuracy of brightness extraction. Finally, a 100×100 pixel region of interest is selected in the center of the target board, and the average gray value of each region of interest is calculated. The average gray value of 15 frames is taken as the final output brightness value, denoted as B_out1 (L1 distance) and B_out2 (L2 distance), respectively. Based on the photometric calibration curve obtained during the visible light camera calibration process (fitting equation: L_v=a×B_out²+b×B_out+c), the output brightness values ​​B_out1 and B_out2 are substituted into the equation to calculate the actual visible light brightness L_v1 of the target board at L1 distance and the actual visible light brightness L_v2 of the target board at L2 distance, completing the conversion from camera output signal to actual brightness.

[0053] A4: Under high light conditions, atmospheric scattering significantly affects visible light propagation, necessitating light compensation based on environmental parameters. First, based on visibility data (V) collected from a weather station, the atmospheric scattering coefficient σ is calculated using Koschmieder's law, expressed as: σ = 3.912 / V; Where: V represents visibility.

[0054] By combining temperature (T), humidity (RH), and air pressure (P) parameters, the visible light radiance L_air_v of the atmosphere itself is calculated using an atmospheric radiative transfer model (such as the MODTRAN model), thus eliminating the interference of atmospheric radiation on the measurement results. The atmospheric transmittance τ_v in the visible light band is expressed as: τ_v=[L_v2-L_air_v×(1-exp(-σ×L2))] / [L_v1-L_air_v×(1-exp(-σ×L1))]×(L1 / L2)^n; Where: L1 is the distance between the near-range subsystem and the measurement target, L2 is the distance between the far-range subsystem and the measurement target, L_v1 is the second visible light radiance obtained at distance L1, L_v2 is the first visible light radiance measured at distance L2, L_air_v is the visible light radiance of the atmosphere itself, σ is the atmospheric scattering coefficient, and n is the atmospheric attenuation index.

[0055] As an optional embodiment, the present invention adopts a two-level architecture of "support layer + perception and execution layer", which can be changed to a four-level architecture of "presentation layer + application layer + support layer + perception and execution layer". The application layer adds a data fusion module and an intelligent decision-making module, and supports multi-scenario adaptive algorithm switching (such as path planning algorithm under complex terrain and measurement mode adjustment logic under extreme weather). The presentation layer can be expanded to multiple terminal display forms such as mobile APP and web platform, covering more usage scenarios.

[0056] As an optional embodiment, the short-range subsystem is deployed as a portable design mounted on a support frame, which can be replaced by a drone-mounted type or a ground robot-autonomous mobile type. The drone-mounted type supports close-range aerial observation, while the ground robot type has autonomous navigation and obstacle avoidance functions and can automatically adjust the distance and angle with the target, thereby improving deployment flexibility.

[0057] As an optional embodiment, the long-distance subsystem carrier can be vehicle-mounted, ship-mounted, airborne, or fixed-platform. Ship-mounted carriers are suitable for marine atmospheric transmittance measurement, airborne carriers support high-altitude long-distance observation, and fixed-platform carriers are suitable for long-term fixed-point monitoring scenarios, thus broadening the application fields of the system.

[0058] As an optional embodiment, multispectral equipment can be replaced by spectrometers or hyperspectral imagers. Spectrometers support finer band division, while hyperspectral imagers can simultaneously acquire the spatial and spectral information of the target, thereby enhancing the richness of target characteristic inversion.

[0059] As an optional embodiment, in addition to standard blackbody calibration, the infrared measuring equipment can be replaced by an infrared integrating sphere light source or an infrared LED array light source. The infrared integrating sphere light source is suitable for small target calibration, while the infrared LED array light source has the advantages of high portability and low energy consumption, making it suitable for rapid field calibration scenarios.

[0060] As an optional embodiment, the present invention adopts GPS / BeiDou dual-mode timing, which can be replaced by GPS / BeiDou / Galileo / GLONASS quad-mode timing, or by adding an atomic clock local timing module. Even in environments where satellite signals are blocked (such as indoors or underground projects), the time synchronization accuracy can still be guaranteed (≤100ns), thus improving the system's environmental adaptability.

[0061] As an optional embodiment, the inertial navigation + satellite positioning of the present invention can be replaced by a combination of visual positioning + lidar positioning. Visual positioning achieves high-precision positioning through ground markers, while lidar positioning is suitable for complex environments without satellite signals or markers, ensuring the stability of the spatial reference.

[0062] As an optional embodiment, alternative solutions can be adopted for data acquisition and calculation methods. The L1 and L2 of the present invention can be extended to multi-distance acquisition, such as three distances: L1, L2, and L3. By fitting the atmospheric transmittance curve with multiple sets of distance data, the measurement accuracy and distance adaptation range can be improved.

[0063] In summary, the above description is merely a preferred embodiment of this specification and is not intended to limit the scope of protection of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of protection of this specification.

[0064] The systems, apparatuses, modules, or units described in one or more of the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. A typical implementation device is a computer. Specifically, a computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0065] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0066] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

Claims

1. A device for measuring atmospheric transmittance, comprising a support layer and a sensing and execution layer, characterized in that, The perception and execution layer includes a long-range subsystem, a short-range subsystem, and meteorological detection equipment; The support layer is used to control the perception and execution layer; The distance between the long-range subsystem and the measurement target is equal to the distance at which the atmospheric transmittance is to be measured, and the distance between the long-range subsystem and the measurement target is greater than the distance between the short-range subsystem and the measurement target; Both the long-range subsystem and the short-range subsystem include multispectral devices; The multispectral device of the long-range subsystem acquires a first multispectral radiometric image of the target being measured; at the same time, the multispectral device of the short-range subsystem acquires a second multispectral image of the target being measured. Atmospheric transmittance is calculated based on the difference in radiation paths between the first and second multispectral radiation images. The meteorological detection equipment is used to collect meteorological data of the measurement environment, and the meteorological data is used to compensate for environmental errors in the atmospheric transmittance.

2. The apparatus for measuring atmospheric transmittance according to claim 1, characterized in that, The spectral range of the multispectral device includes visible and near-infrared, short and mid-wave infrared, and long-wave infrared.

3. The apparatus for measuring atmospheric transmittance according to claim 1, characterized in that, The meteorological data includes temperature, humidity, air pressure, and visibility.

4. The apparatus for measuring atmospheric transmittance according to claim 1, characterized in that, Both the first multispectral radiation image and the second multispectral radiation image include infrared radiation images and visible light radiation images.

5. A method for measuring atmospheric transmittance, comprising measuring atmospheric transmittance using the apparatus for measuring atmospheric transmittance as described in any one of claims 1 to 4, characterized in that, include: Choose to measure atmospheric transmittance based on either infrared radiation or visible light radiation, depending on environmental conditions. Infrared radiation measurements of atmospheric transmittance include: S1: Acquire a first infrared radiation image of the target using the multispectral equipment of the long-range subsystem; at the same time, acquire a second infrared radiation image of the target using the multispectral equipment of the short-range subsystem; at the same time, acquire meteorological data of the measurement environment using the meteorological detection equipment, and calculate the infrared band atmospheric scattering coefficient and the infrared radiance of the atmosphere itself using the meteorological data. S2: Calculate the first infrared radiation brightness using the first infrared radiation image, and calculate the second infrared radiation brightness using the second infrared radiation image; S3: Calculate the distance attenuation coefficient using the ratio of the distance between the long-range subsystem and the target to the distance between the short-range subsystem and the target; S4: The atmospheric transmittance τ_ir in the infrared band is calculated as follows: τ_ir=[Lir,2-L_air×(1-exp(-σ_ir×L2))] / [Lir,1-L_air×(1-exp(-σ_ir×L1))]×(L1 / L2)^k; Where: L1 is the distance between the near-range subsystem and the measurement target, L2 is the distance between the far-range subsystem and the measurement target, Lir,1 is the second infrared radiance obtained at distance L1, Lir,2 is the first infrared radiance obtained at distance L2, L_air is the infrared radiance of the atmosphere itself, σ_ir is the infrared band atmospheric scattering coefficient, and k is the distance attenuation coefficient; Atmospheric transmittance based on visible light radiation measurement: A1: The multispectral device of the long-range subsystem acquires a first visible light radiation image of the target being measured; at the same time, the multispectral device of the short-range subsystem acquires a second visible light radiation image of the target being measured; at the same time, the meteorological detection device acquires meteorological data of the measurement environment, which is used to calculate the atmospheric scattering coefficient in the visible light band and the visible light radiance of the atmosphere itself. A2: The first visible light radiation brightness is calculated using the first multi-visible light radiation image, and the second visible light radiation brightness is calculated using the second visible light radiation image; A3: The atmospheric transmittance τ_v in the visible light band is expressed as: τ_v=[L_v2-L_air_v×(1-exp(-σ×L2))] / [L_v1-L_air_v×(1-exp(-σ×L1))]×(L1 / L2)^n; Where: L1 is the distance between the near-range subsystem and the measurement target, L2 is the distance between the far-range subsystem and the measurement target, L_v1 is the second visible light radiance obtained at distance L1, L_v2 is the first visible light radiance measured at distance L2, L_air_v is the visible light radiance of the atmosphere itself, σ is the atmospheric scattering coefficient in the visible light band, and n is the atmospheric attenuation index.

6. The method for measuring atmospheric transmittance according to claim 5, characterized in that, A light threshold is set to divide the environmental conditions into at least three light intervals, including: low light environment, medium light environment and high light environment; the atmospheric transmittance in the low light environment is measured based on infrared radiation; the atmospheric transmittance in the high light environment is measured based on visible light radiation; and the atmospheric transmittance in the medium light environment is measured based on a weighted average of infrared and visible light radiation.

7. The method for measuring atmospheric transmittance according to claim 5, characterized in that, Atmospheric scattering coefficient is calculated using visibility, and atmospheric radiance is calculated using temperature, humidity, and air pressure.

8. The method for measuring atmospheric transmittance according to claim 5, characterized in that, The measurement link of the multispectral equipment in the process of measuring atmospheric transmittance by infrared radiation is calibrated using a standard blackbody, and the measurement link of the multispectral equipment in the process of measuring atmospheric transmittance by visible light radiation is calibrated using a diffuse reflection standard plate to eliminate equipment errors.

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