Different-angle multi-point dynamic calibration system and method for scanning camera

Abstract

According to the different-angle multi-point dynamic calibration system and method for the scanning camera, the scanning camera is placed in the center of the two-dimensional rotary table platform, the surface source black body is placed at the specific angle position in the scanning view field range of the scanning camera, and when the scanning mirror of the scanning camera conducts dynamic rotary scanning, the surface source black body is located at the specific angle position; and sequentially scanning the surfaces of the on-satellite high-temperature black body, the surface source black body and the on-satellite low-temperature black body so as to obtain calibration radiation information of the on-satellite black body and the surface source black body. A calibration image is acquired by a calibration acquisition system, and a calibration coefficient at the angle position is obtained after image data processing. The two-dimensional rotary table drives the scanning camera to rotate integrally, so that the relative positions of the surface source black body and the scanning camera are changed, the scanning mirror scans the surface source black body at the new angle position when rotating dynamically, and the calibration coefficient of the new angle position is obtained by repeating the calibration image acquisition and processing process. And performing polynomial fitting on the calibration coefficients at the plurality of different angle positions to obtain a calibration coefficient fitting result at any angle position.

Description

Technical Field

[0001] The invention belongs to the technical field of quantitative detection of aerospace optical remote sensing, and relates to a multi-point dynamic calibration system and method for a scanning camera at different angles. Background Art

[0002] High-precision absolute calibration technology is the key to the quantitative acquisition of information by cameras, and directly determines the level of quantitative application of cameras. For scanning cameras, due to the differences in system transmittance at different scanning angles, the traditional static calibration method at fixed positions cannot meet the calibration accuracy requirements of different scanning fields of view. Dynamic calibration of scanning cameras at different angles is conducive to improving the accuracy of radiation calibration, reducing quantitative inversion errors, and improving the level of quantitative application.

[0003] At present, the aerospace field usually uses absolute radiometric calibration at a static fixed angle position for infrared camera systems, which is generally based on national standards and rarely considers calibration errors caused by different angle positions. However, this method cannot meet the absolute radiometric calibration accuracy requirements of better than 0.5K in different scanning fields of view for scanning, wide-width, and highly quantitative ocean remote sensing earth observation cameras in the mid- and long-wave infrared bands. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and provide a system and method for dynamic calibration of multiple points at different angles for a scanning camera. The method traverses multiple calibration positions and can obtain more effective calibration data. At the same time, the calibration accuracy at different angles is improved, and the calibration accuracy is better than 0.5K.

[0005] The technical solution of the present invention is: a multi-point dynamic calibration system for scanning cameras at different angles, comprising: a scanning camera system, a two-dimensional turntable system, a calibration source system and a calibration acquisition processing system;

[0006] The scanning camera system is installed at the center of the two-dimensional turntable system, and the two rotate on the same axis. When the scanning camera system scans the high-temperature black body on the satellite, the low-temperature black body on the satellite, and the calibration source system, the scanning camera system collects the corresponding radiation energy, converts the radiation energy into photoelectricity, and outputs the electrical signal of the image to the calibration acquisition system.

[0007] The two-dimensional turntable system is installed on the vacuum tank truss in the vacuum tank. The two-dimensional turntable system is controlled to rotate in the horizontal direction through instructions, thereby driving the scanning camera system installed on the two-dimensional turntable system to rotate horizontally to the corresponding angle position;

[0008] The calibration source system includes a surface source black body and a vacuum tank; the surface source black body is installed on a black body mounting seat in the vacuum tank to ensure that the scanning camera system can scan the surface of the surface source black body during the rotation process; by setting the temperature of the surface source black body, the black body surface emits black body radiation energy at the set temperature;

[0009] The calibration acquisition and processing system receives the electrical signal of the image sent by the scanning camera system, converts it into dynamic calibration image data of different scanning angle positions and different black body temperature values, calculates the calibration coefficients at different angle positions based on the data, and then performs polynomial fitting on the calibration coefficients at different angle positions according to the angle to complete the multi-point dynamic calibration at different angles.

[0010] The scanning camera system includes a camera body and a video electronic device; the camera body is scanned by rotating 360° through a scanning mirror. When scanning the high-temperature black body on the satellite, the low-temperature black body on the satellite, and the calibration source system, the camera body collects the corresponding radiation energy and converts the radiation energy into an analog electrical signal through photoelectric conversion. The video electronic device amplifies, processes, and arranges the analog electrical signal and outputs the electrical signal of the digital image.

[0011] The two-dimensional turntable system includes a two-dimensional turntable platform and a two-dimensional turntable controller; the two-dimensional turntable platform is installed on a vacuum tank truss in a vacuum tank, and the two-dimensional turntable controller is placed outside the vacuum tank; the two-dimensional turntable platform is kept horizontal by adjusting the pitch direction of the two-dimensional turntable platform; the scanning camera system is installed on the two-dimensional turntable platform, and the installation position is adjusted so that the rotation axis of the scanning camera system is located on the rotation center axis of the two-dimensional turntable; the two-dimensional turntable controller sends instructions to control the two-dimensional turntable platform to rotate to any angle position in the horizontal direction, thereby driving the scanning camera body installed on the two-dimensional turntable platform to rotate to the corresponding angle position.

[0012] The calibration source system comprises a surface source blackbody, a blackbody controller for setting the temperature of the surface source blackbody, a blackbody mounting base for mounting the surface source blackbody, and a vacuum tank for maintaining a vacuum environment; the surface source blackbody is mounted on the blackbody mounting base and placed in the vacuum tank; after the door of the vacuum tank is closed, vacuuming is started, and after the required vacuum degree is reached, the blackbody controller is turned on and set to the required temperature point to control the temperature of the surface source blackbody, thereby emitting blackbody radiation energy at a specific temperature in a vacuum environment.

[0013] The height of the surface source blackbody mounting seat is consistent with the center height of the scanning mirror, ensuring that the scanning mirror can scan the surface of the surface source blackbody when rotating.

[0014] The orientation of the blackbody mounting seat is adjusted to ensure that when the scanning mirror scans the surface of the surface source blackbody, the optical axis direction of the scanning mirror is consistent with the normal direction of the surface source blackbody.

[0015] The distance between the surface source black body and the scanning mirror is adjusted to ensure that the effective aperture of the surface source black body completely covers the optical field of view of the scanning mirror.

[0016] A method for dynamic calibration of multiple points at different angles of a scanning camera, comprising:

[0017] The two-dimensional turntable platform is adjusted to a preset angle, the surface source blackbody is set to a preset temperature, and the scanning mirror dynamically scans the surface of the surface source blackbody to obtain the radiation energy of the surface source blackbody at different temperatures, thereby obtaining dynamic calibration image data of different scanning angle positions and different blackbody temperature values; calibration coefficients of different scanning angle positions and different blackbody temperature values ​​are calculated based on the data, and polynomial fitting is performed according to the angle to obtain multi-point dynamic calibration coefficients of different angles.

[0018] The calibration coefficients of different scanning angles and different blackbody temperature values ​​are calculated based on the dynamic calibration image data of different scanning angles and different blackbody temperature values, and polynomial fitting is performed according to the angle to obtain dynamic calibration coefficients of multiple points at different angles, including:

[0019] Calculate the radiance L corresponding to different blackbody temperatures T;

[0020] Calculate the DN value of the calibration image corresponding to the surface source blackbody at different blackbody temperatures T;

[0021] The least squares fitting of multiple sets of data DN values ​​and radiance L of the calibration image of the surface source blackbody at different blackbody temperatures T is performed DN = K w *L+C w , the external calibration coefficient K at a certain scanning angle A is obtained by linear fitting w , C w ;

[0022] The least squares fitting of multiple sets of data DN'=K is performed on the calibration images DN' value and radiance L' corresponding to the high-temperature black body and the low-temperature black body on the star. n *L`+C n , the internal calibration coefficient K at a certain scanning angle A is obtained by linear fitting n , C n ;

[0023] Establish the correlation between the high-temperature blackbody on the star, the low-temperature blackbody on the star and the surface source blackbody, and obtain the correlation between the external calibration coefficients The correlation relationship between the internal calibration coefficient and R2=(C n -C w ) / K w ;

[0024] A cubic polynomial fitting is performed on the relationship between R1, R2 and the scanning angle θ, and the calibration coefficients R1(θ) and E2(θ) at any angle position θ are calculated.

[0025] The Planck blackbody formula is used to calculate the radiance L corresponding to different blackbody temperatures T, as follows:

[0026]

[0027] Where:

[0028] μ——blackbody emissivity;

[0029] L——spectral radiance;

[0030] T——absolute temperature;

[0031] λ——wavelength;

[0032] Constant c1=3.7415×10 8 ;

[0033] Constant c2 = 1.43879 × 10 4 .

[0034] The calculation obtains the calibration coefficients R1(θ) and R2(θ) at any angle position θ as follows:

[0035] R1(θ)=a3θ 3 +a2θ 2 +a1θ+a0

[0036] R2(θ)=b3θ 3 +b2θ 2 +b1θ+b0

[0037] Where:

[0038] θ is the scanning angle; a2, a1, a0, b3, b2, b1, and b0 are the fitting coefficients respectively.

[0039] The advantages of the present invention compared with the prior art are:

[0040] The multi-point dynamic calibration method at different angles of the present invention adopts the high-temperature black body and low-temperature black body on the satellite for internal calibration, adopts the high-precision surface source black body on the ground for multi-point dynamic calibration at different angles, and adopts the method of multi-point dynamic calibration image data processing. Compared with the traditional single-point static calibration method at a specific position, this method adds dynamic calibration of the scanning dimension, and the calibration data is greatly increased. Through the real-time processing of the calibration image data, the external calibration coefficients at different angles are calculated and associated with the internal calibration coefficients of the high and low temperature black bodies on the satellite to obtain the calibration coefficients at different angles. Finally, the calibration coefficients within all angle ranges are obtained by a multi-term fitting method. This method greatly improves the calibration accuracy of the scanning camera, and the calibration accuracy of all positions within the scanning range reaches 0.5K. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a diagram of the composition of the multi-point dynamic calibration system at different angles.

[0042] Figure 2 Calibrate the blackbody position on the scanning camera body.

[0043] Figure 3 This is a calibration diagram of the multi-point dynamic calibration system at different angles. DETAILED DESCRIPTION

[0044] The embodiments of the present invention are described in detail below with reference to the accompanying drawings:

[0045] The invention relates to a calibration system, comprising: a scanning camera system, a two-dimensional turntable system, a calibration source system and a calibration acquisition and processing system.

[0046] The composition of the multi-point dynamic calibration system at different angles is detailed in the attached Figure 1 and attached Figure 2 As shown:

[0047] The scanning camera system includes a camera body 25 and a video electronic device 26. The camera body 25 mainly realizes the functions of splitting light and converging it to the focal plane, and the video electronic device 26 is used to control the timing and logic of camera imaging, and output the electrical signal of the image after amplifying, processing, and arranging the analog electrical signal. The camera body 25 is installed at the center of the two-dimensional turntable platform 31, and the two share a common rotation axis. The scanning mirror 22 can rotate and scan at a constant speed of 360° throughout the whole circle. When the scanning mirror 22 scans the high-temperature black body 10 on the star, the low-temperature black body 11 on the star, and the surface source black body 21, the scanning camera system collects the radiation energy of the corresponding black body, converts the radiation energy into photoelectricity, and outputs a digital image signal. The scanning mirror entrance pupil diameter of the scanning camera system is 96mm, the optical field of view of the scanning mirror is 3°, and the scanning mirror has the ability to rotate at a constant speed of 360°. The calibration spectrum is B16: 3.645μm~3.835μm, B17: 10.3μm~11.3μm, B18: 11.5μm~12.5μm. The angular position of the high-temperature black body on the satellite is -90°, the angular position of the high-temperature black body on the satellite is 90°, the scanning field angle is -57.5°~57.5°, and the scanning mirror rotates for a scanning cycle of 5.2s.

[0048] The two-dimensional turntable system includes a two-dimensional turntable platform 31 and a two-dimensional turntable controller 32. The two-dimensional turntable platform 31 is installed on the vacuum tank truss 27 in the vacuum tank, and its position can be adjusted through the vacuum tank guide rail 30. The two-dimensional turntable platform 31 is mainly used for the installation of the main body of the scanning camera, and the two rotate together with the central axis. The two-dimensional turntable controller 32 is placed outside the vacuum tank, and controls the two-dimensional turntable platform 31 to rotate to a specific angle position in the horizontal direction by sending an angle position instruction, thereby driving the camera body 25 installed on the two-dimensional turntable platform to rotate to the corresponding angle position. The settable angle range of the two-dimensional turntable platform 31 is -60° to 60°, which can cover the scanning field angle of -57.5° to 57.5°.

[0049] The calibration source system includes a surface source blackbody 21, a blackbody mounting base 24, a blackbody controller 33 and a vacuum tank 29. The surface source blackbody 21 is mounted on the blackbody mounting base 24, and the blackbody mounting base 24 is mounted on the vacuum tank truss 27. The height of the blackbody mounting base 24 is adjusted so that the height of the surface source blackbody 21 is consistent with the center height of the scanning mirror 22, thereby ensuring that the scanning mirror 22 can scan the surface of the surface source blackbody 21 during rotation. When the light inlet of the scanning mirror points to the center of the blackbody radiation surface, the angle between the normal of the blackbody radiation surface and the optical axis of the scanning mirror is ≤1°, and the distance between the blackbody radiation surface and the scanning mirror is ≤500mm, thereby ensuring that the effective size of the surface source blackbody 21 can completely cover the optical field of view 23 of the scanning mirror. The surface source blackbody can emit radiation energy corresponding to a specific temperature, and its effective size is The normal emissivity μ is 0.99, the temperature adjustable range is 110K~400K, and the temperature instability is better than ±0.1K / h. The blackbody controller 33 is used to set the temperature of the surface source blackbody 21. The blackbody controller 33 is placed outside the vacuum tank and connected to the surface source blackbody 21 through the tank cable to set the blackbody temperature. The vacuum tank truss 27 and the vacuum tank guide rail 30 are installed at the bottom of the vacuum tank 29 to provide an installation interface and operation of the equipment in the vacuum tank.

[0050] The calibration acquisition system mainly includes an image acquisition workstation and image acquisition software, wherein the image acquisition workstation 28 receives the image electronic signal sent by the video electronic device 26 through the board card, converts it into dynamic calibration image data of different scanning angle positions and different black body temperature values, calculates the calibration coefficients at different angle positions based on the data, and then performs polynomial fitting on the calibration coefficients at different angle positions according to the angle to complete the dynamic calibration of multiple points at different angles. The output bit number of the image acquisition is 14bit, the data transmission clock is 50MHz±400Hz, the duty cycle is 45%~55%, and the clock is continuous and uninterrupted. A total of 3527 lines of image data are transmitted in one scanning cycle, and the data rate is 4.05316Mbps.

[0051] The present invention also relates to a method for dynamic calibration of multiple points at different angles, as shown in the attached Figure 3 As shown: The multi-point dynamic calibration process, through the rotation of the scanning mirror of the scanning camera system, the scanning mirror dynamically scans the positions of the high-temperature black body on the star, the surface source black body, and the low-temperature black body on the star in turn, and obtains the radiation energy of the black body on the star and the surface source black body at different temperatures. Among them, the positions of the high-temperature black body on the star and the low-temperature black body on the star are fixed, and the position of the surface source black body within the scanning field angle range of the scanning mirror can be adjusted arbitrarily. This is achieved by rotating the two-dimensional turntable platform in the horizontal direction, driving the scanning camera body installed on the two-dimensional turntable platform to rotate horizontally to the corresponding angle position, realizing the change of the surface source black body within the scanning field angle range of the scanning mirror, thereby obtaining the dynamic scanning calibration image data of the scanning mirror at different scanning angle positions and different black body temperature values. The specific steps are as follows:

[0052] 1) The two-dimensional turntable rotates to the set angle position;

[0053] 2) The blackbody controller sets the temperature of the surface source blackbody;

[0054] 3) The scanning camera system sets the scanning mirror to dynamically rotate and scan;

[0055] 4) The calibration acquisition system acquires calibration image data of a set angle position and a set black body temperature;

[0056] 5) The blackbody controller sets a new blackbody temperature and repeats steps 2) to 4);

[0057] 6) The two-dimensional turntable rotates to the newly set angle position and repeats steps 1) to 5).

[0058] First, according to step 1), set the two-dimensional turntable to rotate to the initial angle of -50° position, according to step 2), set the temperature of the surface source blackbody to the initial temperature of 220K, and according to steps 2) to 4), perform the -50° position to complete the calibration image data acquisition of the surface source blackbody 220K. According to step 5), repeat steps 2) to 4), and set the temperature points of the surface source blackbody to 220K, 230K, 243K, 256K, 268K, 279K, 285K, 293K, 300K, 308K, 317K, 323K, 330K, 340K, 350K, and 360K in sequence to complete the calibration image data acquisition of all temperature points. According to step 6), start the calibration data acquisition at the next angle position -40° position. All the implemented two-dimensional turntable angles are shown in Table 1:

[0059] Table 1 Angular position of the two-dimensional turntable

[0060] Serial number 2D turntable angle 1 -50° 2 -40° 3 -20° 4 0° 5 20° 6 40°

[0061] During the multi-point dynamic calibration process, the two-dimensional turntable selects the above-mentioned six angle positions. Compared with the traditional single-point static calibration method at a specific angle position, the number of calibration positions in the scanning dimension is increased, more positions are traversed, and more valid calibration data can be obtained, which naturally has the advantage of improving the calibration accuracy at different angle positions.

[0062] The calculation of the multi-point dynamic calibration coefficients implemented is to process the dynamic calibration image data at different angles, calculate the calibration coefficients at different angles, and then perform polynomial fitting on the calibration coefficients at different angles to complete the multi-point dynamic calibration at different angles. The following takes the B18 (11.5um~12.5um) band as an example to calculate the calibration coefficients, and the specific calculation process is as follows:

[0063] 1) Calculate the radiance L corresponding to different blackbody temperatures T using the Planck blackbody formula as follows:

[0064]

[0065] Where:

[0066] μ——blackbody emissivity;

[0067] L——spectral radiance (W / m 2 .Sr.μm);

[0068] T——absolute temperature (K);

[0069] λ——wavelength (μm);

[0070] c1=3.7415×10 8 Wm －2 .μm 4 ;

[0071] c2=1.43879×10 4 μm.K.

[0072] In the above formula, the blackbody emissivity μ is 0.99, the wavelength range is 11.5um to 12.5um in the B18 band, and the temperature point is 220K to 360K. The spectral radiance L of the surface source blackbody at different temperatures can be calculated. The calculation results are shown in Table 2:

[0073] Table 2 Spectral radiance of surface source blackbody at different temperatures

[0074]

[0075] 2) Calculate the DN value of the calibration image corresponding to different blackbody temperatures T, and select the average DN value of all pixels in the image area corresponding to the center position of the blackbody at a certain temperature from the calibration image as the image DN value at that temperature. In this embodiment, the scanning mirror scans the surface of the high-temperature blackbody on the star, the low-temperature blackbody on the star, and the surface source blackbody, and takes the image area corresponding to the center position of the blackbody and the average DN value of all pixels to participate in the calculation. Since the detector pixel is 80, the image DN value of 80 is taken as the calculated DN value.

[0076] 3) Perform the least squares fitting of multiple sets of data on the calibration image DN value and radiance L corresponding to the surface source black body, and calculate the external calibration coefficient at the angle position. Where DN = K w *L+C w , the external calibration coefficient K at this angle is obtained by linear fitting w , C w .

[0077] 4) Perform the least squares fitting of multiple sets of data on the calibration image DN' value and radiance L' corresponding to the high-temperature black body and low-temperature black body on the star, and calculate the internal calibration coefficient at the angle position. Where DN' = K n *L`+C n , the internal calibration coefficient K at this angle is obtained by linear fitting n , C n .

[0078] 5) Due to the difference between the camera's on-star high-temperature black body, on-star low-temperature black body and the external surface source black body, the radiance at the on-star high-temperature black body and on-star low-temperature black body cannot be directly equivalent to the radiance of the entrance pupil spectrum at the camera scanning mirror position. Therefore, it is necessary to establish the internal and external correlation relationship between the on-star high-temperature black body, on-star low-temperature black body and the external surface source black body. The internal and external correlation relationship can be used to calculate the camera entrance pupil spectrum radiance corresponding to the internal calibration black body temperature. The internal and external correlation relationship reflects the calibration coefficient of the infrared band. When the DN value of the internal calibration image is the same as the DN value of the external calibration image, the following conversion relationship can be established according to the formula:

[0079] K w L w +C w =K n L n +C n

[0080] make R2=(C n -C w ) / K w , we can get:

[0081] L w =R1L n +R2

[0082] In the above formula: R1 and R2 are the internal and external correlation calibration coefficients of infrared calibration.

[0083] According to the K at different turntable angle positions calculated in step 3) and step 4) n , C n and K w , C w , substitute into the above R1, R2 formula to calculate the calibration coefficient, as shown in Table 3:

[0084] Table 3B18 band calibration coefficient changes with turntable angle

[0085] Angle (°) <![CDATA[K w ]]> <![CDATA[C w ]]> <![CDATA[K n ]]> <![CDATA[C n ]]> <![CDATA[R1]]> <![CDATA[R2]]> -50 184.249 10416.289 129.451 10806.690 0.7026 2.1189 -40 204.994 10236.157 129.458 10787.053 0.6315 2.6874 -20 233.0671 10026.2 129.5435 10773.87 0.5558 3.2079 0 265.417 9775.988 129.635 10759.047 0.4884 3.7038 20 267.706 9759.491 129.560 10757.482 0.4840 3.7279 40 235.674 9990.169 129.569 10756.073 0.5498 3.2498

[0086] 6) Perform cubic polynomial fitting on the relationship between the calibration coefficients R1, R2 and the scanning angle θ, and calculate the calibration coefficients R1(θ) and R2(θ) at any angle position θ. The fitting formula is as follows:

[0087] R1(θ)=a3θ 3 +a2θ 2 +a1θ+a0

[0088] R2(θ)=b3θ 3 +b2θ 2 +b1θ+b0

[0089] Where:

[0090] θ is the scanning angle;

[0091] a3, a2, a1, a0, b3, b2, b1, and b0 are the fitting coefficients respectively.

[0092] According to the values ​​of the calibration correlation coefficients R1 and R2 of the B18 band at different angles, a cubic polynomial fitting is performed, as shown in Table 4:

[0093] Table 4. Fitting results of cubic polynomials for calibration coefficients at different angles in the B18 band

[0094] coefficient Fitted values Fitting coefficients Fitted values <![CDATA[a3]]> 0.00000033 <![CDATA[b3]]> -0.00000200 <![CDATA[a2]]> 0.00006563 <![CDATA[b2]]> -0.00047739 <![CDATA[a1]]> -0.00169037 <![CDATA[b1]]> 0.01154635 <![CDATA[a0]]> 0.49041030 <![CDATA[b0]]> 3.68765208

[0095] The calibration coefficient is obtained by fitting, and the calibration coefficient fitting formula is obtained by substituting it into the fitting formula:

[0096] R1(θ)=0.00000033θ 3 +0.00006563θ 2 -0.00169037θ+0.49041030

[0097] R2(θ)=-0.00000200θ 3 -0.00047739θ 2 +0.01154635θ+3.68765208

[0098] In the above implementation process, the external calibration coefficients at different angles and the internal calibration coefficients of the high-temperature black body and the low-temperature black body on the satellite are calculated, and the internal calibration coefficients and the external calibration coefficients are associated to obtain the calibration coefficients at different angles. Finally, the calibration coefficients within all angle ranges are obtained by multi-term fitting. This method greatly improves the calibration accuracy of the scanning camera, and the calibration accuracy of all positions within the scanning range reaches 0.5K.

[0099] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A multi-point dynamic calibration system for scanning cameras at different angles, characterized in that: include: Scanning camera system, 2D turntable system, calibration source system and calibration acquisition and processing system; The scanning camera system is installed at the center of the two-dimensional turntable system, and the two rotate on the same axis. When the scanning camera system scans the high-temperature black body on the satellite, the low-temperature black body on the satellite, and the calibration source system, the scanning camera system collects the corresponding radiation energy, converts the radiation energy into photoelectricity, and outputs the electrical signal of the image to the calibration acquisition system. The two-dimensional turntable system is installed on the vacuum tank truss in the vacuum tank. The two-dimensional turntable system is controlled to rotate in the horizontal direction through instructions, thereby driving the scanning camera system installed on the two-dimensional turntable system to rotate horizontally to the corresponding angle position; The calibration source system includes a surface source black body and a vacuum tank; the surface source black body is installed on a black body mounting seat in the vacuum tank to ensure that the scanning camera system can scan the surface of the surface source black body during the rotation process; By setting the temperature of the surface source black body, the black body surface emits black body radiation energy at the set temperature; The calibration acquisition and processing system receives the electrical signal of the image sent by the scanning camera system, converts it into dynamic calibration image data of different scanning angle positions and different black body temperature values, calculates the calibration coefficients at different angle positions based on the data, and then performs polynomial fitting on the calibration coefficients at different angle positions according to the angle to complete the multi-point dynamic calibration at different angles.

2. The multi-point dynamic calibration system for scanning cameras at different angles according to claim 1, characterized in that: The scanning camera system includes a camera body and a video electronic device; the camera body is scanned by rotating 360° through a scanning mirror. When scanning the high-temperature black body on the satellite, the low-temperature black body on the satellite, and the calibration source system, the camera body collects the corresponding radiation energy and converts the radiation energy into an analog electrical signal through photoelectric conversion. The video electronic device amplifies, processes, and arranges the analog electrical signal and outputs the electrical signal of the digital image.

3. The multi-point dynamic calibration system for scanning cameras at different angles according to claim 2, characterized in that: The two-dimensional turntable system includes a two-dimensional turntable platform and a two-dimensional turntable controller; the two-dimensional turntable platform is installed on a vacuum tank truss in a vacuum tank, and the two-dimensional turntable controller is placed outside the vacuum tank; the two-dimensional turntable platform is kept horizontal by adjusting the pitch direction of the two-dimensional turntable platform; the scanning camera system is installed on the two-dimensional turntable platform, and the installation position is adjusted so that the rotation axis of the scanning camera system is located on the rotation center axis of the two-dimensional turntable; the two-dimensional turntable controller sends instructions to control the two-dimensional turntable platform to rotate to any angle position in the horizontal direction, thereby driving the scanning camera body installed on the two-dimensional turntable platform to rotate to the corresponding angle position.

4. The multi-point dynamic calibration system for scanning cameras at different angles according to claim 3, characterized in that: The calibration source system comprises a surface source blackbody, a blackbody controller for setting the temperature of the surface source blackbody, a blackbody mounting base for mounting the surface source blackbody, and a vacuum tank for maintaining a vacuum environment; the surface source blackbody is mounted on the blackbody mounting base and placed in the vacuum tank; after the door of the vacuum tank is closed, vacuuming is started, and after the required vacuum degree is reached, the blackbody controller is turned on and set to the required temperature point to control the temperature of the surface source blackbody, thereby emitting blackbody radiation energy at a specific temperature in a vacuum environment.

5. The multi-point dynamic calibration system for scanning cameras at different angles according to claim 4, characterized in that: The height of the surface source blackbody mounting seat is consistent with the center height of the scanning mirror, ensuring that the scanning mirror can scan the surface of the surface source blackbody when rotating.

6. The multi-point dynamic calibration system for scanning cameras at different angles according to claim 4, characterized in that: The orientation of the blackbody mounting seat is adjusted to ensure that when the scanning mirror scans the surface of the surface source blackbody, the optical axis direction of the scanning mirror is consistent with the normal direction of the surface source blackbody.

7. The multi-point dynamic calibration system for scanning cameras at different angles according to claim 4, characterized in that: The distance between the surface source black body and the scanning mirror is adjusted to ensure that the effective aperture of the surface source black body completely covers the optical field of view of the scanning mirror.

8. A method for dynamic calibration of multiple points at different angles of a scanning camera, characterized in that: include: The two-dimensional turntable platform is adjusted to a preset angle, the surface source black body is set to a preset temperature, and the scanning mirror dynamically scans the surface of the surface source black body to obtain the radiation energy of the surface source black body at different temperatures, thereby obtaining dynamic calibration image data at different scanning angles and different black body temperature values; The calibration coefficients for different scanning angles and blackbody temperature values ​​are calculated based on the data, and polynomial fitting is performed according to the angle to obtain dynamic calibration coefficients for multiple points at different angles.

9. The method according to claim 8, characterized in that The calibration coefficients of different scanning angles and different blackbody temperature values ​​are calculated based on the dynamic calibration image data of different scanning angles and different blackbody temperature values, and polynomial fitting is performed according to the angle to obtain dynamic calibration coefficients of multiple points at different angles, including: Calculate the radiance L corresponding to different blackbody temperatures T; Calculate the DN value of the calibration image corresponding to the surface source blackbody at different blackbody temperatures T; The least squares fitting of multiple sets of data DN values ​​and radiance L of the calibration image of the surface source blackbody at different blackbody temperatures T is performed DN = K w *L+C w , the external calibration coefficient K at a certain scanning angle A is obtained by linear fitting w , C w ; The least squares fitting of multiple sets of data DN'=K is performed on the calibration images DN' value and radiance L' corresponding to the high-temperature black body and the low-temperature black body on the star. n *L`+C n , the internal calibration coefficient K at a certain scanning angle A is obtained by linear fitting n , C n ; Establish the correlation between the high-temperature blackbody on the star, the low-temperature blackbody on the star and the surface source blackbody, and obtain the correlation between the external calibration coefficients The correlation relationship between the internal calibration coefficient and R2=(C n -C w ) / K w ; A cubic polynomial fitting is performed on the relationship between R1, R2 and the scanning angle θ, and the calibration coefficients R1(θ) and R2(θ) at any angle position θ are calculated.

10. The method according to claim 9, characterized in that The Planck blackbody formula is used to calculate the radiance L corresponding to different blackbody temperatures T, as follows: Where: μ——blackbody emissivity; L——spectral radiance; T——absolute temperature; λ——wavelength; Constant c1=3.7415×10 8 ; Constant c2 = 1.43879 × 10 4 .

11. The method according to claim 9, characterized in that The calculation obtains the calibration coefficients R1(θ) and R2(θ) at any angle position θ as follows: R1(θ)=a3θ 3 +a2θ 2 +a1θ+a0 R2(θ)=b3θ 3 +b2θ 2 +b1θ+b0 Where: θ is the scanning angle; a2, a1, a0, b3, b2, b1, and b0 are the fitting coefficients respectively.

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