Method and device for measuring intrinsic radiance of a non-sunlit terrestrial object at a distance

Abstract

The present application relates to the technical field of infrared radiation characteristic measurement, and discloses a method and device for measuring the intrinsic radiation characteristic of a ground object without direct sunlight, which comprises the following steps: selecting an open high observation base point, synchronously deploying an in-situ atmospheric parameter measuring device and an infrared characteristic measuring device, and arranging a standard target at the measured ground object point; using a blackbody radiation source to perform radiation calibration and derive an infrared calibration coefficient; then synchronously starting the in-situ meteorological equipment and the infrared thermal imager to collect target data; calculating the apparent radiation brightness based on the calibration data and real-time gray value; combining the in-situ meteorological parameters, the line-of-sight length calculated by inertial navigation, and the standard target reference radiation brightness, and obtaining the atmospheric path radiation of the corresponding wave band through an atmospheric radiation transmission model; and finally obtaining the intrinsic radiation characteristic through joint correction processing. The present application effectively reduces the uncertainty of atmospheric transmission correction and improves the engineering applicability of in-situ monitoring at a medium distance.

Description

Technical Field

[0001] This invention relates to the field of infrared radiation characteristic measurement technology, and in particular to a method and apparatus for measuring the intrinsic infrared radiation characteristics of ground objects without direct sunlight at a distance by staring. Background Technology

[0002] In infrared radiation characteristics research, the environmental characteristics of ground features are widely studied and applied as an important feature. Since ground features (grasslands, woodlands, deserts, roads, airports, etc.) are static objects, their geographical location and the surface being measured do not change due to measurement. Therefore, the gaze measurement method can be used to obtain the infrared radiation characteristics of ground features at the same location, at different times, and under different environmental parameters. When using gaze measurement to measure the infrared radiation characteristics of ground features, atmospheric transmission affects the radiation. This effect mainly includes attenuating the radiation energy of the ground features and increasing the radiation of the atmosphere itself, and the degree of influence increases with the transmission distance. Therefore, to obtain the inherent characteristics of the ground features, it is necessary to minimize or even eliminate the influence of atmospheric transmission during data processing. Relevant measured data also show that without accurate atmospheric correction, the measurement uncertainty caused by atmospheric transmission in infrared radiation characteristics data processing can reach 10% to 25%, and even higher in complex and variable environments and at medium to long distances (0.1 to 1 km for medium distances and 1 to 10 km for long distances).

[0003] To reduce the impact of atmospheric transmission on infrared radiation characteristics, atmospheric radiative transfer models are typically used in data processing to correct measurement results, allowing the intrinsic radiation characteristics of ground objects to be derived from apparent radiation properties. This process is highly dependent on sufficient atmospheric parameters (air temperature, air pressure, relative humidity, wind field, gas content, aerosol content, etc.) acquired along the measurement path. However, in actual measurements, it is difficult to obtain comprehensive and sufficient atmospheric parameters along the transmission path.

[0004] Currently, there are two main types of atmospheric parameter measurement equipment commonly used for infrared characteristic measurements: First, there are in-situ measurement devices, such as weather stations, handheld weather instruments, and temperature sensors, which can acquire atmospheric parameters at single or limited points.

[0005] Secondly, profile measurement devices, such as lidar, microwave radiometers, and temperature pulsometers, can acquire atmospheric parameters along the measurement path.

[0006] However, both types of measuring devices have certain limitations in practical applications: Although in-situ measurement devices can accurately measure various types of atmospheric parameters, their point-distribution characteristics mean they cannot cover atmospheric parameters along the path for obtaining infrared radiation characteristics.

[0007] While most profile measurement devices can acquire atmospheric parameters along the measurement path, the types or bands of parameters acquired are limited, and the equipment is relatively complex, bulky, and difficult to deploy in the field. Particularly in ground-based environmental monitoring, lidar, a typical profile device, is unsuitable for ground illumination due to its measurement principle and usage constraints, making it difficult to directly meet the requirements for acquiring slant path atmospheric parameters. These limitations are further amplified in the absence of direct sunlight, as atmospheric transmittance is more significantly affected by environmental parameter fluctuations than atmospheric path radiation. Therefore, when sufficient atmospheric parameters along the measurement path cannot be obtained, relying on extrapolation or single-point data will lead to distortion of the correction model, resulting in significant errors in atmospheric transmission correction, which accumulate nonlinearly with increasing observation distance. Summary of the Invention

[0008] The purpose of this invention is to provide a method and device for mid-range staring measurement of the intrinsic infrared radiation characteristics of ground objects without direct sunlight. By synchronously and collaboratively deploying a standard target and atmospheric parameter measurement equipment, the measured correction data on the slant path can be directly obtained, thereby overcoming the problems of radiation correction model distortion and nonlinear amplification of error with distance caused by insufficient sampling of atmospheric parameters within the existing slant line of sight.

[0009] To achieve the above objectives, in a first aspect, the present invention provides a method for mid-range staring measurement of the infrared intrinsic radiation characteristics of ground objects without direct sunlight, comprising the following steps: Select measurement stations that are in open space and relatively high in position to the ground features being measured as observation base points; Atmospheric parameter measurement equipment and infrared characteristic measurement equipment are set up at the measurement site, and a standard target is deployed at the measured ground object point; In the radiometric calibration stage, the surface temperature of the blackbody radiation source is adjusted to reach multiple known nominal temperature values. Infrared grayscale images at corresponding time points are acquired. The pixel grayscale values ​​at the corresponding nominal temperature extracted from the infrared grayscale images are linearly fitted with the theoretical radiance value of the blackbody radiation source at the corresponding nominal temperature to generate and derive infrared calibration coefficients for converting real-time image grayscale into radiance. The field of view center of the infrared characteristic measurement device is aligned with the ground object to be measured, the orientation of the standard target is adjusted so that its surface is perpendicular to the measurement optical axis, and the atmospheric parameter measurement device and the infrared characteristic measurement device are turned on simultaneously to collect data. Based on the infrared calibration coefficients and the grayscale values ​​of the infrared grayscale images of the measured ground objects, the apparent radiance of the measured ground objects is calculated; combined with the synchronously acquired atmospheric parameters, the calculated transmission distance, and the environmental latitude, longitude, and altitude coordinates, the atmospheric path radiation of the corresponding band is calculated by inputting them into the atmospheric radiation transmission model. The reference radiance of the standard target is calculated based on the true temperature and surface emissivity of the standard target. The apparent radiance, atmospheric path radiance, and reference radiance of the standard target are then combined for correction to eliminate the influence of atmospheric transmission, and the intrinsic radiance of the measured object is calculated. Based on the intrinsic radiance and the known surface emissivity, the infrared intrinsic radiation characteristics of the measured object are determined.

[0010] Optionally, the selection of a measurement station that is open and relatively higher than the location of the measured object point as the observation base point specifically involves selecting an open, high-level platform that is free from significant gas or aerosol emissions, strong heat source interference, and moving obstructions between and around the measured object point.

[0011] Optionally, the standard target includes a position information box, an azimuth level box, an angle scale frame, adjustable feet, and multiple temperature sensors distributed on the back of the standard target. The specific steps for adjusting the orientation of the standard target are as follows: adjust the target surface posture by means of the orientation level box and the included angle scale frame, and use the adjustable feet to calibrate the levelness so that the standard target is stable and the target surface is approximately perpendicular to the measurement optical axis.

[0012] Optionally, the infrared characteristic measurement device includes a mid-wave infrared thermal imager and a long-wave infrared thermal imager, wherein the measurement band of the mid-wave infrared thermal imager is 3.7~4.8μm, and the measurement band of the long-wave infrared thermal imager is 7.7~9.3μm.

[0013] Optionally, the calculation of atmospheric path radiation specifically includes: The position information and pitch / azimuth angle data of the measuring device are obtained by inertial navigation gyroscope, and the mid-range line-of-sight length is calculated by combining the position information of the standard target. The atmospheric parameters, line-of-sight length, and environmental latitude, longitude, and altitude coordinates are input into the atmospheric radiation transfer model, and the atmospheric path radiation of the corresponding band is output.

[0014] Optionally, the linear fitting adopts the least squares method; wherein, the side length of the preprocessing region of the selected blackbody radiation source image is N1 pixels, the side length of the preprocessing region of the selected ground object image is N2 pixels, and N1≥2N2 is satisfied.

[0015] Optionally, the intrinsic radiance of the measured object is calculated using the following formula: The apparent radiance of the measured ground object. Atmospheric path radiation, The apparent radiance of the standard target. The reference radiance is the standard target radiance.

[0016] In a second aspect, the present invention also provides a mid-range staring measurement device for measuring the infrared intrinsic radiation characteristics of ground objects without direct sunlight, for implementing any of the implementation methods in the first aspect, comprising: An infrared characteristic measurement device includes a support unit and an infrared radiation measurement unit. The support unit is configured to provide a stable mounting base at the observation base point and support precise two-dimensional adjustment of the field of view angle. The infrared radiation measurement unit is fixed to the load end of the support unit and integrates a mid-wave infrared thermal imager, a long-wave infrared thermal imager, and an inertial navigation gyroscope. It is used to synchronously lock the field of view of the target under test, acquire continuous frame infrared grayscale images, and receive control commands and infrared grayscale image data through a data interface. Before measurement, radiometric calibration is performed using a blackbody radiation source to generate and store infrared calibration coefficients that convert real-time grayscale into radiance. Atmospheric parameter measurement equipment is independently arranged at the observation base point and communicates in coordination with the infrared radiation measurement unit to acquire air temperature, air pressure, humidity and wind field elements along the transmission path in real time in situ; A standard target, placed at the point of measurement, has a target surface with a known emissivity and multiple temperature sensors distributed on the back of the target surface. It serves as a reference source to simultaneously provide the standard target reference radiance and the calibration data required for path radiance correction within the measurement line of sight.

[0017] Optionally, the atmospheric parameter measuring equipment includes a meteorological station, a visibility meter, and a data storage box for storing data, all installed in layers along the support frame; The multiple temperature sensors on the back of the target surface of the standard target are arranged in an X-shape. The support unit includes a tripod base and a two-dimensional servo turntable, and the infrared radiation measurement unit is connected to the output end of the two-dimensional servo turntable via an adapter plate.

[0018] Optionally, the standard target further includes a position information box, an orientation level box, an angle scale frame, and an adjustable foot. One end of the target surface is hinged to one end of the angle scale frame. The angle scale frame can display the angle between the target surface and the ground. The adjustable foot is provided at the other end of the target surface and the angle scale frame, and is used to adjust the height of the target surface and the angle scale frame.

[0019] The above-described technical solution of the present invention has the following advantages: This invention provides a method and apparatus for mid-range staring measurement of the intrinsic infrared radiation characteristics of ground objects without direct sunlight. It involves the synchronous deployment of a standard target assembly and in-situ atmospheric parameter measurement equipment at the observation base point. The measured transmission distance is calculated using the three-dimensional coordinates fed back by an inertial gyroscope and the target position information. Furthermore, the reference radiance of the standard target is directly calculated using the true temperature of the target surface and the known surface emissivity, providing accurate geometric boundary conditions and physical input parameters for the atmospheric radiative transfer model. The measured data stream is directly input into the atmospheric radiative transfer model for joint correction, effectively deducting atmospheric attenuation and path radiation interference. This makes the intrinsic infrared radiation characteristics of ground objects calculated through joint correction closer to the actual physical state, reducing the uncertainty of apparent radiation inversion, and improving the data reliability of mid-range staring measurements. It effectively overcomes the correction bias caused by traditional reliance on spatial extrapolation or single meteorological parameter assumptions, eliminates the need for cross-regional coordination and on-site deployment of complex profile equipment, and improves the efficiency and engineering applicability of the system in in-situ field monitoring under conditions without direct sunlight. Attached Figure Description

[0020] The accompanying drawings are provided for illustrative purposes only, and the proportions and quantities of the components in the drawings may not be consistent with the actual product.

[0021] Figure 1 This is a schematic diagram of the method for measuring the infrared intrinsic radiation characteristics of ground objects without direct sunlight in an embodiment of the present invention. Figure 2 This is a schematic diagram of a mid-range staring measurement device for infrared intrinsic radiation characteristics of ground objects without direct sunlight, as described in an embodiment of the present invention. Figure 3 This is a schematic diagram of the structure of an atmospheric parameter measuring device according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of an infrared characteristic measuring device according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of a standard target in an embodiment of the present invention; Figure 6 This is a schematic diagram of the arrangement of temperature sensors on the back of a standard target surface in an embodiment of the present invention.

[0022] In the picture: 1: Atmospheric parameter measuring equipment; 11: Support frame; 12: Weather station; 13: Visibility meter; 14: Data storage box; 15: Power supply for atmospheric parameter measuring equipment; 2: Infrared characteristic measurement equipment; 21: Support unit; 211: Tripod base; 212: Two-dimensional servo turntable; 22: Adapter board; 23: Mid-wave infrared thermal imager; 24: Long-wave infrared thermal imager; 25: Inertial navigation gyroscope; 26: Computer; 27: Power supply for infrared characteristic measurement equipment; 3: Standard target; 31: Target surface; 32: Temperature sensor; 33: Position information box; 34: Azimuth level box; 35: Angle scale frame; 351: Scale bar assembly; 36: Adjustable feet. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] In this application, "medium-distance gaze measurement" refers to in-situ monitoring scenarios with a measurement range of 0.1km to 1km.

[0026] See Figure 1 The method for mid-range staring measurement of the intrinsic infrared radiation characteristics of ground objects without direct sunlight provided in this embodiment of the invention is applicable to mid-range staring measurement of the intrinsic infrared radiation characteristics of ground objects under conditions without direct sunlight. The method includes the following steps: S1: Selecting the observation base point In environments without direct sunlight, a station with an open space and a relatively higher position than the target feature should be selected as the observation base point. Preferably, there should be no significant gas or aerosol emissions, strong heat sources, or moving obstructions between the observation base point and the target feature point, in or around the site, to ensure stable and measurable atmospheric transmission conditions for the slant path line-of-sight.

[0027] In this application, "significant emissions" refers to pollution sources (such as industrial chimneys, dense vehicle exhaust, etc.) that may cause sudden changes in local energy wind or interference with specific absorption bands, and whose impact is sufficient to distort the boundary conditions of the atmospheric radiation transfer model.

[0028] In this application, "no strong heat source interference" means that there are no heat sources with surface temperatures significantly higher than the ambient temperature and radiation levels sufficient to directly superimpose thermal radiation or reflect clutter on infrared imaging along the observation line of sight and around the measurement station.

[0029] In this application, "no moving obstructions" means that there are no moving physical targets in the observation line of sight and the surrounding buffer space, such as motor vehicles, drones, fast-moving pedestrians, etc.

[0030] S2: Set up the measuring device and deploy the standard target See Figure 2 At the observation base point, atmospheric parameter measurement device 1 and infrared characteristic measurement device 2 were set up, and a standard target 3 was deployed at the ground object to be measured. Initial debugging was completed to ensure the stable spatial coordination of subsequent multi-source equipment.

[0031] See Figure 3 The atmospheric parameter measuring device 1 includes a support frame 11 and a weather station 12 and a visibility meter 13, which are layered and mounted on the support frame 11. The atmospheric parameter measuring device 1 also includes a data storage box 14 for automatically storing atmospheric parameter measurement data and an atmospheric parameter measuring device power supply 15 for providing power to the atmospheric parameter measuring device 1. Specifically, a solar-powered rechargeable battery can be used. The support frame 11 provides stable support for the weather station 12 and the visibility meter 13, placing them at a relatively high position. When installing the atmospheric parameter measuring device 1, the support frame 11 is placed at the selected observation point, the weather station 12 is installed on top of the support frame 11, and the visibility meter 13 is installed near and below the weather station 12. The data storage box 14 and the atmospheric parameter measuring device power supply 15 are then connected.

[0032] See Figure 4 The infrared characteristic measurement device 2 includes a support unit 21 and an infrared radiation measurement unit. The support unit 21 is configured to provide a stable mounting base at the observation base point and support precise two-dimensional adjustment of the field of view angle. The infrared radiation measurement unit is fixed to the load end of the support unit and integrates a mid-wave infrared thermal imager 23, a long-wave infrared thermal imager 24, and an inertial navigation gyroscope 25, forming a whole with synchronous attitude changes. It is used to synchronously lock the field of view of the target under test, acquire continuous frame infrared grayscale images, and receive control commands and infrared grayscale image data through a data interface. Before measurement, radiometric calibration is performed using a blackbody radiation source to generate and store infrared calibration coefficients that convert real-time grayscale into radiance.

[0033] In a specific example, the support unit 21 includes a tripod base 211 and a two-dimensional servo turntable 212. The infrared radiation measurement unit is connected to the output end of the two-dimensional servo turntable 212 via an adapter plate 22. By adjusting the two-dimensional servo turntable 212, precise adjustment of the azimuth and pitch angles of the measurement field of view can be achieved. During staring measurement, the center position of the measurement field of view can be locked to avoid drifting or shaking of the measurement field of view due to strong winds. The tripod base 211 is used to mount the entire set of equipment and adjust the horizontal state of the adapter plate 22. The infrared characteristic measurement device 2 is powered by the infrared characteristic measurement device power supply 27. In this embodiment, a 220V / 10A AC power supply is used. In this embodiment, a computer 26 controls the mid-wave infrared thermal imager 23, the long-wave infrared thermal imager 24, the inertial navigation gyroscope 25, and the two-dimensional servo turntable 212, and receives the measurement data (infrared measurement data, position and attitude information) from the infrared characteristic measurement device 2. In this embodiment, the computer 26 is a laptop computer, which is convenient for portability and field use.

[0034] The control logic, data calibration, and radiation transmission processing involved in this embodiment can be implemented by a general-purpose computer configured with corresponding program instructions, or by application-specific integrated circuits (ASICs) in the prior art. Each data processing module can be centrally deployed in the built-in industrial control computer of the infrared characteristic measurement equipment, or it can be distributed between a cloud server and the end-side equipment.

[0035] When setting up the infrared characteristic measurement device 2, the tripod base 211 is connected to the two-dimensional servo turntable 212 and placed at the measurement station. The mid-wave infrared thermal imager 23, the long-wave infrared thermal imager 24 and the inertial navigation gyroscope 25 are installed on the adapter plate 22 and the adapter plate 22 is connected to the two-dimensional servo turntable 212.

[0036] Mid-wave infrared thermal imager 23 is used to acquire mid-wave infrared measurement data (continuous frame mid-wave infrared grayscale images). It is configured with a cooled mercury cadmium telluride detector, a measurement band of 3.7–4.8 μm, 640 × 512 pixels, a pixel size of 15 μm, and lens focal length and measurement distance are related to the size of the area being measured. Long-wave infrared thermal imager 24 is used to acquire long-wave infrared measurement data (continuous frame long-wave infrared grayscale images). It is configured with a measurement band of 7.7–9.3 μm, and other specifications are the same as the mid-wave infrared thermal imager.

[0037] See Figure 5 and Figure 6A standard target 3 is assembled at the location of the target feature. The standard target 3 mainly consists of a target surface 31, a position information box 33, an azimuth / level box 34, an angle scale frame 35, and adjustable feet 36. The position information box 33 is used to measure and record the target's position information (longitude, latitude, and altitude). It can be a low-power device based on GPS or BeiDou positioning, and information is collected and recorded only once when the target 3 is placed. The azimuth / level box 34 displays the orientation and level of the target surface 31. It adopts a passive design, with a compass for azimuth and a bubble jet for level. The target surface 31 provides a reference radiation source. The emissivity of the surface coating is known, and in this embodiment, it is 0.7. Five temperature sensors 32 are embedded in the back in an X-shape to collect and record the true temperature data of the target surface 31 in real time. The angle scale frame 35 displays the angle between the target surface 31 and the ground. In one example, one end of the target surface 31 is hinged to one end of the included angle scale frame 35, which can display the included angle between the target surface 31 and the ground.

[0038] See Figure 6 As shown, in a specific example, there is a scale bar assembly 351 between the target surface 31 and the included angle scale frame 35. The scale bar assembly 351 includes two parts that can slide relative to each other. These two parts are fixedly connected to the target surface 31 and the included angle scale frame 35, respectively. When the included angle between the target surface 31 and the included angle scale frame 35 changes, the two parts of the scale bar assembly 351 slide relative to each other synchronously. One part is engraved with angle scale, and the other part has an indicator mark to indicate the current angle position.

[0039] The adjustable feet 36 are used to adjust the horizontal height and levelness of the standard target. Based on the horizontal orientation box 34 and the angle scale frame 35, the orientation and angle of the target surface 31 are adjusted. By adjusting the height of some or all of the adjustable feet 36, the standard target is stabilized and the target surface is as perpendicular as possible to the infrared characteristic measuring device. The adjustable feet 36 can use existing structures and will not be described in detail here.

[0040] S3: Radiation calibration and measurement experiments Before formally commencing ground feature staring measurements, the infrared characteristic measurement equipment 2 needs to be radiometrically calibrated. The specific procedures are as follows: Adjust the blackbody radiation source so that its surface temperature is sequentially stabilized at several known nominal temperature values ​​T1, T2, ... T nThe nominal temperature range should cover the expected maximum and minimum radiation temperatures of the measured ground object. Set the integration time for the mid-wave thermal imager to 23 (e.g., 4000 μs) and the long-wave infrared thermal imager to 24 (e.g., 500 μs), and the measurement frequency to 0.1 Hz. Start automatic measurement, acquiring infrared grayscale images at the corresponding time points. Acquire n infrared grayscale images continuously for each temperature (n≥10). Based on the acquired multi-temperature grayscale images and the known theoretical radiance values ​​corresponding to the nominal temperatures of the blackbody radiation sources, perform linear fitting using the least squares method to generate and derive infrared calibration coefficients (slope) used to achieve a linear mapping between grayscale values ​​and radiance. k and intercept b The calibration coefficient data is saved and used as the basis for the quantification of radiance in the subsequent S4 step.

[0041] After completing the above calibration, see Figure 2 and Figure 5 The infrared characteristic measurement device 2 is positioned so that its field of view is aligned with the target object, and the orientation of the standard target 3 is adjusted so that its target surface 31 is approximately perpendicular to the measurement optical axis. Simultaneously, the atmospheric parameter measurement device 1 and the infrared characteristic measurement device 2 are activated to enter synchronous data acquisition mode. The atmospheric parameter measurement device 1 is set to acquire one image per minute. The infrared characteristic measurement device 2 locks its field of view and continuously acquires a sequence of infrared grayscale images of the target object and the standard target within its field of view at a measurement frequency of 0.1 Hz. After completing the required duration of staring measurement, the infrared characteristic measurement device 2 and the atmospheric parameter measurement device 1 are sequentially turned off.

[0042] S4: Processing measurement data Based on the derived infrared calibration coefficients, n infrared images corresponding to the nominal temperatures of different blackbody radiation sources are selected. An N1×N1 pixel region is chosen at the center of each image as the processing object, and the mean grayscale value of the pixel region in each infrared grayscale image is calculated. Then, the average of the mean grayscale values ​​of the n infrared grayscale images is calculated to obtain the grayscale value corresponding to the nominal temperature. DN C Using Planck's formula, calculate the theoretical radiance value at the corresponding nominal temperature. L C The blackbody radiation source is an independently set standard radiation source with known emissivity (not shown in the figure).

[0043] Based on the measurement data from the infrared characteristic measurement device 2, an N2×N2 pixel region within the measured ground feature area at the center of the image is selected as the processing object. Here, N1 is no less than twice N2 to balance the signal-to-noise ratio requirements of blackbody calibration with the spatial flexibility of ground feature sampling. The average grayscale value of each infrared image pixel region is calculated. DN T Combined with infrared calibration coefficients k ,b ,Will DN T Converted to apparent radiance of the measured ground object L The conversion formula is as follows: .

[0044] Export the synchronously acquired in-situ atmospheric measurement data to obtain in-situ parameters such as temperature, air pressure, and humidity. Acquire the position information and elevation / azimuth data of the infrared characteristic measurement device 2 via the inertial gyroscope 25. Combine this with the latitude, longitude, and altitude coordinates recorded by the standard target 3's position information box 33, and calculate the transmission distance (i.e., mid-range line-of-sight length) between the two points using a spatial geometric algorithm. Input the synchronously acquired in-situ atmospheric parameters, transmission distance, and environmental latitude, longitude, and altitude coordinates into an atmospheric radiative transfer model (such as CART or an equivalent radiative transfer model), and output the atmospheric path radiation for the corresponding band. p .

[0045] S5: Correct processing results Using the same processing method as the ground background, the apparent radiance of the standard target corresponding to target surface 31 was calculated. L S The emissivity radiance reference (i.e., the standard target reference radiance, denoted as ) is calculated based on the true temperature and surface emissivity of the target surface. L S ').

[0046] In this process, the standard target is used as a reference source with known radiation characteristics. The atmospheric path-dependent radiation is obtained by simultaneously measuring its apparent radiance. This additional radiation is used to subtract the atmospheric interference component from the apparent radiance of the measured ground object, and combined with the reference radiance of the standard target for joint correction, to calculate the corrected intrinsic radiance of the measured ground object. L '.

[0047] Specifically, this is achieved through the following modified formula: L The apparent radiance of the measured ground object. p Atmospheric path radiation, L S The apparent radiance of the standard target. L S 'Refractory radiance of the standard target.'

[0048] Subsequently, based on the surface emissivity parameters, conventional table lookup methods or radiative transfer algorithms are used to determine the infrared intrinsic radiation characteristics of the measured ground object.

[0049] In this embodiment, a joint calibration method based on measured data from a standard target is used to correct for the influence of atmospheric transport; the apparent radiance of the standard target measured simultaneously is used. L S Compared with the reference radiance of the standard target L S The ratio of ' to ' is used as a path transmittance calibration coefficient to overcome the errors that may be introduced by directly relying on a single atmospheric transmittance parameter output by the model.

[0050] By consulting data or measuring the background emissivity of ground features in the laboratory / field, and given the radiance, the radiant temperature of typical landforms can be obtained using a lookup table method.

[0051] Any aspects not described in detail in this invention are common knowledge or existing technology in the field.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that not every embodiment contains only one independent technical solution, and in the absence of conflict between solutions, the various technical features mentioned in each embodiment can be combined in any way to form other implementation methods that can be understood by those skilled in the art.

[0053] Furthermore, without departing from the scope of the present invention, modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some of the technical features, shall not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for mid-range staring measurement of the infrared intrinsic radiation characteristics of ground objects without direct sunlight, characterized in that, Includes the following steps: Select measurement stations that are in open space and relatively high in position to the ground features being measured as observation base points; Atmospheric parameter measurement equipment and infrared characteristic measurement equipment are set up at the measurement site, and a standard target is deployed at the measured ground object point; In the radiometric calibration stage, the surface temperature of the blackbody radiation source is adjusted to reach multiple known nominal temperature values. Infrared grayscale images at corresponding time points are acquired. The pixel grayscale values ​​at the corresponding nominal temperature extracted from the infrared grayscale images are linearly fitted with the theoretical radiance value of the blackbody radiation source at the corresponding nominal temperature to generate and derive infrared calibration coefficients for converting real-time image grayscale into radiance. The field of view center of the infrared characteristic measurement device is aligned with the ground object to be measured, the orientation of the standard target is adjusted so that its surface is perpendicular to the measurement optical axis, and the atmospheric parameter measurement device and the infrared characteristic measurement device are turned on simultaneously to collect data. Based on the infrared calibration coefficients and the grayscale values ​​of the infrared grayscale images of the measured ground objects, the apparent radiance of the measured ground objects is calculated; combined with the synchronously acquired atmospheric parameters, the calculated transmission distance, and the environmental latitude, longitude, and altitude coordinates, the atmospheric path radiation of the corresponding band is calculated by inputting them into the atmospheric radiation transmission model. The reference radiance of the standard target was calculated based on the true temperature and surface emissivity of the standard target. The apparent radiance, atmospheric path radiance, and standard target reference radiance are used for joint correction processing to eliminate the influence of atmospheric transmission, and the intrinsic radiance of the measured object is calculated. Based on the intrinsic radiance and known surface emissivity, the infrared intrinsic radiation characteristics of the measured object are determined.

2. The method according to claim 1, characterized in that, The selection of a measurement station that is open and higher than the location of the ground object being measured as the observation base point specifically means: selecting an open, high-level platform with no significant gas or aerosol emissions, no strong heat source interference, and no moving obstructions between and around the ground object being measured.

3. The method according to claim 1, characterized in that, The standard target includes a position information box, an azimuth level box, an angle scale frame, adjustable feet, and multiple temperature sensors distributed on the back of the standard target. The specific steps for adjusting the orientation of the standard target are as follows: adjust the target surface posture by means of the orientation level box and the included angle scale frame, and use the adjustable feet to calibrate the levelness so that the standard target is stable and the target surface is approximately perpendicular to the measurement optical axis.

4. The method according to claim 1, characterized in that, The infrared characteristic measurement device includes a mid-wave infrared thermal imager and a long-wave infrared thermal imager, wherein the measurement band of the mid-wave infrared thermal imager is 3.7~4.8μm, and the measurement band of the long-wave infrared thermal imager is 7.7~9.3μm.

5. The method according to claim 1, characterized in that, The calculation of atmospheric path radiation specifically includes: The position information and pitch / azimuth angle data of the measuring device are obtained by inertial navigation gyroscope, and the mid-range line-of-sight length is calculated by combining the position information of the standard target. The atmospheric parameters, line-of-sight length, and environmental latitude, longitude, and altitude coordinates are input into the atmospheric radiation transfer model, and the atmospheric path radiation of the corresponding band is output.

6. The method according to claim 1, characterized in that, The linear fitting adopts the least squares method; wherein, the side length of the preprocessing region of the selected blackbody radiation source image is N1 pixels, the side length of the preprocessing region of the selected ground object image is N2 pixels, and N1≥2N2 is satisfied.

7. The method according to claim 1, characterized in that, The intrinsic radiance of the measured ground object is calculated using the following formula: The apparent radiance of the measured ground object. Atmospheric path radiation, The apparent radiance of the standard target. The reference radiance is the standard target radiance.

8. A mid-range staring measurement device for the infrared intrinsic radiation characteristics of ground objects without direct sunlight, used to implement the method as described in any one of claims 1 to 7, characterized in that, include: An infrared characteristic measurement device includes a support unit and an infrared radiation measurement unit. The support unit is configured to provide a stable mounting base at the observation base point and support precise two-dimensional adjustment of the field of view angle. The infrared radiation measurement unit is fixed to the load end of the support unit and integrates a mid-wave infrared thermal imager, a long-wave infrared thermal imager, and an inertial navigation gyroscope. It is used to synchronously lock the field of view of the target under test, acquire continuous frame infrared grayscale images, and receive control commands and infrared grayscale image data through a data interface. Before measurement, radiometric calibration is performed using a blackbody radiation source to generate and store infrared calibration coefficients used to convert the grayscale values ​​of the acquired infrared images into radiance. Atmospheric parameter measurement equipment is independently arranged at the observation base point and communicates in coordination with the infrared radiation measurement unit to acquire air temperature, air pressure, humidity and wind field elements along the transmission path in real time in situ; A standard target, placed at the point of measurement, has a target surface with a known emissivity and multiple temperature sensors distributed on the back of the target surface. It serves as a reference source to simultaneously provide the standard target reference radiance and the calibration data required for path radiance correction within the measurement line of sight.

9. The apparatus according to claim 8, characterized in that, The atmospheric parameter measuring equipment includes a meteorological station, a visibility meter, and a data storage box for storing data, all installed in layers along the support frame. The multiple temperature sensors on the back of the target surface of the standard target are arranged in an X-shape. The support unit includes a tripod base and a two-dimensional servo turntable, and the infrared radiation measurement unit is connected to the output end of the two-dimensional servo turntable via an adapter plate.

10. The apparatus according to claim 8, characterized in that, The standard target also includes a position information box, an orientation level box, an angle scale frame, and an adjustable base. One end of the target surface is hinged to one end of the angle scale frame. The angle scale frame can display the angle between the target surface and the ground. The adjustable base is located at the other end of the target surface and the angle scale frame, and is used to adjust the height of the target surface and the angle scale frame.

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