CN111256818B - Calculation method for moon irradiance observed value of linear array push-broom type remote sensing imager - Google Patents
Calculation method for moon irradiance observed value of linear array push-broom type remote sensing imager Download PDFInfo
- Publication number
- CN111256818B CN111256818B CN202010081114.9A CN202010081114A CN111256818B CN 111256818 B CN111256818 B CN 111256818B CN 202010081114 A CN202010081114 A CN 202010081114A CN 111256818 B CN111256818 B CN 111256818B
- Authority
- CN
- China
- Prior art keywords
- moon
- irradiance
- pixel
- data
- remote sensing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 title claims abstract description 224
- 238000004364 calculation method Methods 0.000 title claims abstract description 34
- 238000000034 method Methods 0.000 claims abstract description 40
- 238000002360 preparation method Methods 0.000 claims abstract description 13
- 238000012545 processing Methods 0.000 claims abstract description 9
- 238000012937 correction Methods 0.000 claims description 27
- 230000005855 radiation Effects 0.000 claims description 19
- 239000000523 sample Substances 0.000 claims description 18
- 230000004044 response Effects 0.000 claims description 14
- 230000003068 static effect Effects 0.000 claims description 14
- 238000009533 lab test Methods 0.000 claims description 8
- 239000007787 solid Substances 0.000 claims description 8
- 230000008569 process Effects 0.000 claims description 7
- 238000005070 sampling Methods 0.000 claims description 5
- 239000011159 matrix material Substances 0.000 claims description 4
- 230000010287 polarization Effects 0.000 claims description 4
- 238000012216 screening Methods 0.000 claims description 4
- 239000000443 aerosol Substances 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 238000003384 imaging method Methods 0.000 description 15
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 210000001747 pupil Anatomy 0.000 description 1
- 238000002310 reflectometry Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
- G01J1/4257—Photometry, e.g. photographic exposure meter using electric radiation detectors applied to monitoring the characteristics of a beam, e.g. laser beam, headlamp beam
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
- G01J1/44—Electric circuits
- G01J2001/444—Compensating; Calibrating, e.g. dark current, temperature drift, noise reduction or baseline correction; Adjusting
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Abstract
The invention discloses a method for calculating a moon irradiance observed value of a linear array push-broom type remote sensing imager, which comprises the following steps of: s1: a data preparation stage, which is used for completing the acquisition and preparation of data required by lunar irradiance calculation; s2: in the data processing stage, the moon observation of the original data and the auxiliary parameters based on the remote sensing imager is completed, and the moon irradiance observation value is calculated; s3: and a result output stage, namely outputting and storing the calculation result of the moon irradiance observation value and the related auxiliary parameters into a file. The invention has the beneficial effects that: the method for calculating the moon irradiance observed value of the linear array push-broom remote sensing imager is suitable for calculating the moon irradiance of the large linear array push-broom remote sensing imager, and solves the problem of calculating the moon irradiance observed value of high-distortion moon image data.
Description
Technical Field
The invention relates to the technical field of remote sensing imaging, in particular to a method for calculating a linear array push-broom type remote sensing imager moon irradiance observed value.
Background
High-precision ground remote sensing data is an important basis for researching climate change and monitoring natural elements such as environment and weather. Radiometric calibration of the remote sensing imager is a key link for determining the precision of remote sensing data. The moon is used as a natural celestial body closest to the earth, the radiation characteristic of the moon is stable, the moon is very suitable for being used as a reference source for on-orbit radiation calibration, and a high-precision radiation calibration result can be obtained by comparing moon observation data of a remote sensing imager with a moon radiation model. The moon irradiance observation value is an important link for realizing moon calibration. The observation value of the moon irradiance of the remote sensing imager needs to be calculated by comprehensively considering the observation principle of the remote sensing imager, the imaging geometry of the moon observation and other factors, and a specific calculation method suitable for the imaging mode of the moon observation is constructed.
At present, satellite-borne monthly observation imaging mainly comprises two imaging modes:
(1) a multi-dimensional and scanning multi-frame monthly scan imaging mode typified by FY-3/MERSI. The lunar image obtained by the imaging mode is mainly expressed in the process that the moon slowly enters and moves out from the moon observation visual field, the lunar image has small distortion, and the main difficulties are complete identification of the lunar observation image and the influence of over-sampling in the cross-orbit direction and the along-orbit direction.
(2) A progressive scan imaging system typified by FY-2/VISSR. The moon image obtained by the imaging mode mainly shows the distortion of the moon image caused by the moon movement within the time required for completing the moon imaging due to the relative movement between the moon and the satellite. The main difficulty is that oversampling of the lunar image in the row and column directions affects rectification.
For a large linear array push-broom imaging remote sensing imager, a moon observation image shows no distortion in the row direction, and a long and narrow moon image with serious oversampling in the column direction exists. The two types of oversampling calculation methods are not suitable for moon irradiance calculation of the large linear array push-broom remote sensing imaging instrument, and a complete method suitable for processing moon observation data of the remote sensing imaging instrument needs to be constructed.
Disclosure of Invention
Aiming at the technical problems in the related art, the invention provides a method for calculating the moon irradiance observed value of a linear array push-broom type remote sensing imager, which can overcome the defects in the prior art.
In order to achieve the technical purpose, the technical scheme of the invention is realized as follows:
a method for calculating a moon irradiance observed value of a linear array push-broom remote sensing imager comprises the following steps:
s1: a data preparation stage, which is used for completing the acquisition and preparation of data required by lunar irradiance calculation;
s2: in the data processing stage, the moon observation of the original data and the auxiliary parameters based on the remote sensing imager is completed, and the moon irradiance observation value is calculated;
s3: and a result output stage, namely outputting and storing the calculation result of the moon irradiance observation value and the related auxiliary parameters into a file.
Further, in step S1, the data required for calculating the lunar irradiance includes on-orbit monthly observation data of the remote sensing imager, static calibration parameters of the remote sensing imager, and relevant position data of the remote sensing imager during monthly observation.
The on-orbit monthly observation data of the remote sensing imager comprises all monthly observation original data of all wave bands and dark current meter numerical value observation data.
The static calibration parameters of the remote sensing imager are static calibration parameters of all wave bands of the remote sensing imager, and comprise a calibration slope, a calibration intercept, a radiation response uniformity correction coefficient, a linear array detector probe element length and equivalent focal lengths of all wave bands.
The relevant position data of the remote sensing imager during the moon observation comprises satellite position data, position data coordinate system information, moon observation time data and attitude data of the moon observation process.
Further, in step S2, the method for calculating the observed value of lunar irradiance is as follows:
s21: correcting all pixel count values of each channel of the remote sensing imager, namely eliminating dark current count values from monthly observation data, wherein the calculation formula is as follows:
wherein DN*The corrected pixel count value is DN, namely the moon observation data, of all pixel count values of each channel of the remote sensing imager, DC is a dark current meter value estimated from row data which is not influenced by moon pixels in the moon observation data, Band is a channel number, and pixels are pixel numbers;
s22: obtaining a relative radiation response uniformity correction coefficient between probe elements of the linear array detector by utilizing laboratory tests, correcting the radiation response difference of the on-orbit observation data of the remote sensing imager after eliminating the dark current count value, and specifically calculating the following formula:
DN' is the pixel count value after uniformity correction, fu is the uniformity correction coefficient;
s23: three forward scans and three reverse scans of the moon are realized in a single moon observation mode of the remote sensing imager by utilizing the pitching maneuver of the satellite, and all moon observation data are intercepted into 6 single moon observation image data according to satellite attitude angle data in the moon observation process:
{1…P1}，{P1+1…P2}，{P2+1…P3}，{P3+1…P4}，{P4+1…P5}，{P5+1…N}
wherein the content of the first and second substances,
further, can be in accordance with PkRespectively intercepting 6 moon observation images,
n is the number of rows of all the monthly observation data, sign function is a sign function, namely, when the independent variable is greater than 0, the independent variable returns to 1, when the independent variable is less than zero, the independent variable returns to-1, and omega is the pitch angle speed of the satellite pitching maneuver;
s24: according to the maximum value of the single-time monthly observation image data, all monthly observation data are divided into effective lunar pixels and non-lunar pixels, 5% of the maximum value of the single-time monthly observation image data is used as a threshold value for judging the effective lunar pixels, and a lunar pixel template matrix is as follows:
wherein M (i, j) is a moon template value of i rows and j columns, 1 represents a moon pixel, and 0 represents a non-moon pixel;
s25: the method comprises the following steps of converting an original count value of a moon pixel into radiance data by using a calibration slope and a calibration intercept obtained by laboratory tests, namely converting an original count value image observed for a month into a radiance image, wherein the specific calculation formula is as follows:
L＝Slope·DN″+Offset
wherein Slope is a calibration Slope, Offset is a calibration intercept, L is the brightness of the pixel, and the calculation formula of pixel irradiance is as follows:
Ipixel＝σLpixel，
wherein, σ is a solid angle formed by the lunar pixel, and I is the irradiance of the pixel;
s26: screening effective lunar pixels by using a lunar pixel template, accumulating single-pixel irradiance to obtain a lunar full-disc irradiance initial value, and calculating the lunar irradiance initial value according to the following formula:
wherein, ImoonIs the initial value of the lunar full disc irradiance;
s27: in the linear array direction, the oversampling phenomenon does not exist, and the theoretical pixel number is calculated by utilizing the lunar aperture, the linear array detector probe element length and the equivalent focal length of each wave band; in the push-broom direction, an oversampling phenomenon exists, a moon pixel number is obtained by using a moon pixel template, and then an oversampling correction coefficient is calculated by using the ratio of the moon longitudinal pixel number to the moon transverse pixel number to correct the oversampling phenomenon;
the theoretical single-row lunar sampling point number is calculated by the following formula:
wherein, A is the length of a single probe element, NumsamplesThe number of pixels of the moon in the linear array direction, FocalLength equivalent focal length of the remote sensing imager, Moondiameter of the moon and Distancesatellite-MoonIs the satellite moon distance; the theoretical pixel number of the moon in the linear array direction is:
considering that the moon phase angle is close to full moon, the image is circular, so the number of moon pixels in the linear array direction is the same as the number of frames in the push-scan direction, i.e. the number of moon image frames should theoretically be:
NumFrames＝NumSamples，
wherein, NumFramesThe number of moon image frames in the push-broom direction;
in the actual moon observation image, the frame number of the moon image can be calculated by the difference between the maximum value and the minimum value of the pixel line number in the moon pixel template data, that is:
Num′Frames＝max(lines(M))-min(lines(M))，
wherein max (lines (m)) is the maximum line number of the moon pixel in the moon pixel template, and min (lines (m)) is the minimum line number of the moon pixel in the moon pixel template;
the oversampled correction factor f in the push-broom directionover-sampleComprises the following steps:
finally, the observed value of the irradiance of the lunar full-circle disc is obtained as follows:
wherein, the moon phase is close to the full moon condition when the moon is observed, namely, the moon image is circular.
The remote sensing imager is a cloud and aerosol polarization imager, namely CAPI.
Further, in step S3, the data to be output includes a calculation result of the lunar full disc irradiance observation value, an oversampling correction coefficient, and a satellite-moon distance during lunar observation.
The invention has the beneficial effects that: the method for calculating the moon irradiance observed value of the linear array push-broom remote sensing imager is suitable for calculating the moon irradiance of the large linear array push-broom remote sensing imager, and solves the problem of calculating the moon irradiance observed value of high-distortion moon image data.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a technical flowchart of a method for calculating a moon irradiance observed value of a linear array push-broom remote sensing imager according to an embodiment of the invention;
FIG. 2 is a schematic diagram of lunar imaging according to an embodiment of the invention, wherein the method is used for calculating a lunar irradiance observed value of a linear array push-broom remote sensing imager;
FIG. 3 is a dark current meter value of all pixels used for lunar calibration according to the method for calculating the moon irradiance observed value of the linear array push-broom remote sensing imager in the embodiment of the invention;
fig. 4 is a dark current count value of the first 59 pixels adopted in lunar calibration according to the method for calculating the lunar irradiance observed value of the linear array push-broom remote sensing imager in the embodiment of the invention;
FIG. 5 is a monthly observation data of all pixels after removing dark current count value according to the method for calculating the moon irradiance observation value of the linear array push-broom remote sensing imager in the embodiment of the invention;
FIG. 6 is the lunar observation data of the first 59 pixels after removing the dark current count value according to the method for calculating the moon irradiance observation value of the linear array push-broom remote sensing imager in the embodiment of the invention;
FIG. 7 is a distribution of the follow-up CAPI to the lunar observation data according to the method for calculating the lunar irradiance observed value of the linear array push-broom remote sensing imager in the embodiment of the invention;
FIG. 8 is a distribution of CAPI versus lunar observation data along columns according to a calculation method of a linear array push-broom remote sensing imager lunar irradiance observation value according to an embodiment of the invention;
fig. 9 is a row number of monthly observation data and a row number of a single lunar image intercepted by the CAPI according to the method for calculating the observed value of the lunar irradiance of the linear array push-broom remote sensing imager in the embodiment of the invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
As shown in fig. 1, the method for calculating the observed value of lunar irradiance of the linear array push-broom remote sensing imager according to the embodiment of the invention includes the following steps:
s1: a data preparation stage, which is used for completing the acquisition and preparation of data required by lunar irradiance calculation;
s2: in the data processing stage, the moon observation of the original data and the auxiliary parameters based on the remote sensing imager is completed, and the moon irradiance observation value is calculated;
s3: and a result output stage, namely outputting and storing the calculation result of the moon irradiance observation value and the related auxiliary parameters into a file.
In a specific embodiment, in step S1, the data required for calculating the lunar irradiance includes on-orbit monthly observation data of the remote sensing imager, static calibration parameters of the remote sensing imager, and relevant position data of the remote sensing imager during the monthly observation.
Preferably, the on-orbit monthly observation data of the remote sensing imager comprises all monthly observation original data and dark current meter numerical observation data of all wave bands.
Preferably, the dark current meter value is an output count value of the remote sensing imager when energy at the entrance pupil of the remote sensing imager is zero, and describes a local noise level of the remote sensing imager.
Preferably, the static calibration parameters of the remote sensing imager are static calibration parameters of all wave bands of the remote sensing imager, and include a calibration slope, a calibration intercept, a radiation response uniformity correction coefficient, a linear array detector probe element length and an equivalent focal length of each wave band.
Preferably, the relevant position data of the remote sensing imager during the moon observation comprises satellite position data, position data coordinate system information, moon observation time data and attitude data during the moon observation.
In one embodiment, in step S2, the method for calculating the lunar irradiance observation is as follows:
s21: correcting all pixel count values of each channel of the remote sensing imager, namely eliminating dark current count values from monthly observation data, wherein the calculation formula is as follows:
wherein DN*The corrected pixel count value is DN, namely the moon observation data, of all pixel count values of each channel of the remote sensing imager, DC is a dark current meter value estimated from row data which is not influenced by moon pixels in the moon observation data, Band is a channel number, and pixels are pixel numbers;
s22: obtaining a relative radiation response uniformity correction coefficient between probe elements of the linear array detector by utilizing laboratory tests, correcting the radiation response difference of the on-orbit observation data of the remote sensing imager after eliminating the dark current count value, and specifically calculating the following formula:
DN' is the pixel count value after uniformity correction, fu is the uniformity correction coefficient;
s23: three forward scans and three reverse scans of the moon are realized in a single moon observation mode of the remote sensing imager by utilizing the pitching maneuver of the satellite, and all moon observation data are intercepted into 6 single moon observation image data according to satellite attitude angle data in the moon observation process:
{1…P1}，{P1+1…P2}，{P2+1…P3}，{P3+1…P4}，{P4+1…P5}，{P5+1…N}
wherein the content of the first and second substances,
further, can be in accordance with PkRespectively intercepting 6 moon observation images,
n is the number of rows of all the monthly observation data, sign function is a sign function, namely, when the independent variable is greater than 0, the independent variable returns to 1, when the independent variable is less than zero, the independent variable returns to-1, and omega is the pitch angle speed of the satellite pitching maneuver;
s24: according to the maximum value of the single-time monthly observation image data, all monthly observation data are divided into effective lunar pixels and non-lunar pixels, 5% of the maximum value of the single-time monthly observation image data is used as a threshold value for judging the effective lunar pixels, and a lunar pixel template matrix is as follows:
wherein M (i, j) is a moon template value of i rows and j columns, 1 represents a moon pixel, and 0 represents a non-moon pixel;
s25: the method comprises the following steps of converting an original count value of a moon pixel into radiance data by using a calibration slope and a calibration intercept obtained by laboratory tests, namely converting an original count value image observed for a month into a radiance image, wherein the specific calculation formula is as follows:
L＝Slope·DN″+Offset
wherein Slope is a calibration Slope, Offset is a calibration intercept, L is the brightness of the pixel, and the calculation formula of pixel irradiance is as follows:
Ipixel＝σLpixel，
wherein, σ is a solid angle formed by the lunar pixel, and I is the irradiance of the pixel;
s26: screening effective lunar pixels by using a lunar pixel template, accumulating single-pixel irradiance to obtain a lunar full-disc irradiance initial value, and calculating the lunar irradiance initial value according to the following formula:
wherein, ImoonIs the initial value of the lunar full disc irradiance;
s27: in the linear array direction, the oversampling phenomenon does not exist, and the theoretical pixel number is calculated by utilizing the lunar aperture, the linear array detector probe element length and the equivalent focal length of each wave band; in the push-broom direction, an oversampling phenomenon exists, a moon pixel number is obtained by using a moon pixel template, and then an oversampling correction coefficient is calculated by using the ratio of the moon longitudinal pixel number to the moon transverse pixel number to correct the oversampling phenomenon; as shown in figure 2 of the drawings, in which,
the theoretical single-row lunar sampling point number is calculated by the following formula:
wherein, A is the length of a single probe element, NumsamplesIs the number of pixels of the moon in the line array direction,FocalLength is the equivalent focal length of the remote sensing imager, Moondiameter is the lunar diameter, DistanceSatellite-MoonIs the satellite moon distance; the theoretical pixel number of the moon in the linear array direction is:
considering that the moon phase angle is close to full moon, the image is circular, so the number of moon pixels in the linear array direction is the same as the number of frames in the push-scan direction, i.e. the number of moon image frames should theoretically be:
NumFrames＝NumSamples，
wherein, NumFramesThe number of moon image frames in the push-broom direction;
in the actual moon observation image, the frame number of the moon image can be calculated by the difference between the maximum value and the minimum value of the pixel line number in the moon pixel template data, that is:
Num′Frames＝max(lines(M))-min(lines(M))，
wherein max (lines (m)) is the maximum line number of the moon pixel in the moon pixel template, and min (lines (m)) is the minimum line number of the moon pixel in the moon pixel template;
the oversampled correction factor f in the push-broom directionover-sampleComprises the following steps:
finally, the observed value of the irradiance of the lunar full-circle disc is obtained as follows:
preferably, the phase of the moon is near full moon when viewed on the moon, i.e., the moon image is circular.
In one embodiment, the remote sensing imager is a Cloud and Aerosol Polarization Imager (CAPI) on the first global carbon dioxide monitoring experimental satellite (carbon satellite, TanSat) in china.
Preferably, a sub-channel linear array push-broom type imaging scheme is adopted through CAPI to obtain the reflectivity of 5 wave bands and the polarization information of 2 wave bands of the ground object target.
Preferably, 1600-element linear array detectors are adopted in 380nm, 670nm and 870nm wave bands, and the spatial resolution is 250 m; 400-element linear array detectors are adopted in 1375nm and 1640nm wave bands, and the spatial resolution is 1000 m.
In one embodiment, the lunar full disc irradiance is the cumulative sum of the lunar irradiance over all the energy in the solid angle spanned by the remote imager.
In one embodiment, in step S3, the data to be output includes the calculation result of the lunar full disc irradiance observation, the over-sampling correction coefficient, and the distance between stars and months during the lunar observation.
In one embodiment, this observation of lunar irradiance is calculated, taking as an example the CAPI versus lunar observation data of 8, 7, 2017.
Preferably, 870nm channel data is taken as an example, and the data file name is:
TAN1_CAPIX_1A_PIX_MS_1K250_ORBT_03337_20170807_0000_NUL_170113.HDF。
preferably, as shown in fig. 3-4, the average value of the observed data in a short period of time at the beginning of the monthly observation is used as the data used for the calculation of the irradiance of the moon, and the dark current meter value observed in each month has a weak change.
Preferably, as shown in fig. 5 to 6, after removing the dark current count value, the 1372 th frame image data is used for the monthly observation image.
Preferably, as shown in fig. 7-8, effective pixels of the lunar observation data are selected through the lunar pixel template matrix, and the distribution of the effective pixels in the row direction and the column direction is obtained.
Preferably, as shown in fig. 9, the pitch angle speed of the satellite pitching machine is used for calculation, a row number interception number is obtained, and 6 parts of the raw monthly observation data are intercepted by the CAPI.
Preferably, the oversampling factor of the lunar image is 36.25, the effective pixel number of the single lunar image is 19526, the average pixel count value is 332.9, the total pixel count value is 6500265, the initial value of the lunar irradiance is 8.736E-5W/m2nm, and the oversampled and corrected lunar irradiance value is 2.41F-6W/m2 nm.
In order to facilitate understanding of the above-described technical aspects of the present invention, the above-described technical aspects of the present invention will be described in detail below in terms of specific usage.
When the method is used specifically, the method for calculating the moon irradiance observed value of the linear array push-broom remote sensing imager mainly comprises three continuous processing stages, namely a data preparation stage, a data processing stage and a result output stage. The data preparation stage mainly finishes the acquisition and preparation of data required by lunar irradiance calculation, and comprises a lunar observation data acquisition module, a static calibration parameter preparation module and a position information acquisition module of the remote sensing imager. The remote sensing imager moon observation data acquisition module acquires on-orbit moon observation data of the remote sensing imager, wherein the on-orbit moon observation data comprise all moon observation original data of all wave bands, dark current count value observation data and the like; the static calibration parameter preparation module acquires static calibration parameters of all wave bands of the remote sensing imager, wherein the static calibration parameters comprise a calibration slope, a calibration intercept, a radiation response uniformity correction coefficient, a linear array detector probe element length, equivalent focal lengths of all wave bands and the like; the position information acquisition module acquires relevant position information of the remote sensing imager during the moon observation, including satellite positions, position data coordinate system information, moon observation time, attitude data of the moon observation process and the like.
The data processing stage mainly finishes moon observation original data and auxiliary parameters based on a remote sensing imager, calculates a moon irradiance observation value, comprises 7 modules of dark current count value removal, probe element uniformity correction, single-time moon scanning effective data interception, moon image template generation, count value radiance conversion, moon irradiance conversion, oversampling correction and the like, and firstly removes a dark current count value from the moon observation data; because the actual optical system of the remote sensing imager is not an ideal perfect system and the difference among the detecting elements of the linear array detector causes the radiation response of each detecting element of the linear array detector to have difference, and the result shows that the observation output result of a uniform target has longitudinal stripe phenomenon, the relative radiation response correction coefficient among the detecting elements obtained by laboratory test is needed to be utilized to correct the radiation response difference of the on-orbit observation data of the remote sensing imager; then, according to the instruction of a ground system, the satellite remote sensing imager continuously scans the moon in the forward direction and the reverse direction for a plurality of times, and according to the satellite attitude data in the moon observation process, all the moon observation data is intercepted into a plurality of single-time moon observation image data; a moon pixel template is regenerated, because the moon effective pixels of the moon observation image of the large linear array remote sensing imager generally occupy a low proportion of all pixels, in order to improve the processing efficiency, the effective moon pixels need to be marked for subsequent moon irradiance calculation, according to the maximum value of single moon observation image data, 5% of the maximum value is used as a threshold value for judging the moon effective pixels, and all data are divided into effective moon pixels and non-moon pixels; then pixel irradiance is converted, because the original output result of the remote sensing imager is a digital count value, a laboratory test result is required to be utilized, the original count value of the moon pixel is converted into radiance data, the irradiance is the sum of all radiances in a certain solid angle range, for the pixel irradiance, because the solid angle formed by the pixel is small, the radiance can be considered to be kept unchanged in the solid angle, therefore, the pixel irradiance can be calculated by the product of the solid angle formed by the pixel and the radiance of the pixel, and the conversion of the count value and the radiance is generally expressed as that the radiance is equal to the sum of the count value and the calibration slope plus the calibration intercept; then, integrating the irradiance of the lunar full-disc, screening effective lunar pixels by using a lunar pixel template in order to reduce the influence of stray light of the instrument, and accumulating the irradiance of a single pixel to obtain an initial value of the irradiance of the lunar full-disc; and finally, correcting the oversampling phenomenon, wherein the oversampling phenomenon exists in the moon observed image due to the fact that the speed-height ratio of the earth remote sensing imager during the moon observation is not matched, namely the moon image has distortion, the oversampling factor needs to be calculated by using position information and instrument parameters, the oversampling of the moon irradiance is corrected, the oversampling phenomenon does not exist in the linear array direction, the theoretical pixel number is calculated by using the moon field angle, the probe element length and the focal length, the oversampling phenomenon exists in the push-broom direction, the moon pixel number is acquired by using a moon pixel template, the oversampling factor is calculated by using the ratio of the longitudinal pixel number and the transverse pixel number of the moon, the oversampling phenomenon is corrected, and the moon full-disc irradiance observed value is calculated.
And the result output stage is mainly used for outputting and storing the calculation result of the lunar irradiance observation value and related auxiliary parameters into a file, and comprises a result output module, wherein data to be output comprise a lunar irradiance observation value calculation result, an oversampling correction coefficient, a satellite-moon distance during lunar observation and the like, and are output into a result file of the lunar irradiance calculation result, the related correction parameters and the like.
In summary, the invention provides a calculation method for calculating the moon irradiance observation value aiming at the on-orbit and on-month observation data of a large linear array push-broom imager, the on-orbit and on-month observation can be realized through a remote sensing imager by utilizing the attitude mobility of a satellite, and then the moon is used as an on-orbit radiation calibration source to realize the on-orbit tracking monitoring of the radiation response attenuation; the method is suitable for calculating the lunar irradiance of the large linear array push-broom remote sensing imager, and solves the problem of calculating the lunar irradiance observed value of high-distortion lunar image data.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (8)
1. A method for calculating a moon irradiance observed value of a linear array push-broom type remote sensing imager is characterized by comprising the following steps:
s1: a data preparation stage, which is used for completing the acquisition and preparation of data required by lunar irradiance calculation;
s2: in the data processing stage, the moon observation of the original data and the auxiliary parameters based on the remote sensing imager is completed, and the moon irradiance observation value is calculated; in step S2, the method for calculating the observed value of lunar irradiance is as follows:
s21: correcting all pixel count values of each channel of the remote sensing imager, namely eliminating dark current count values from monthly observation data, wherein the calculation formula is as follows:
wherein DN*The corrected pixel count value is DN, namely the moon observation data, of all pixel count values of each channel of the remote sensing imager, DC is a dark current meter value estimated from row data which is not influenced by moon pixels in the moon observation data, Band is a channel number, and pixels are pixel numbers;
s22: obtaining a relative radiation response uniformity correction coefficient between probe elements of the linear array detector by utilizing laboratory tests, correcting the radiation response difference of the on-orbit observation data of the remote sensing imager after eliminating the dark current count value, and specifically calculating the following formula:
DN' is the pixel count value after uniformity correction, fu is the uniformity correction coefficient;
s23: three forward scans and three reverse scans of the moon are realized in a single moon observation mode of the remote sensing imager by utilizing the pitching maneuver of the satellite, and all moon observation data are intercepted into 6 single moon observation image data according to satellite attitude angle data in the moon observation process:
{1…P1}，{P1+1…P2}，{P2+1…P3}，{P3+1…P4}，{P4+1…P5}，{P5+1…N}，
wherein the content of the first and second substances,
further, can be in accordance with PkRespectively intercepting 6 moon observation images,
n is the number of rows of all the monthly observation data, sign function is a sign function, namely, when the independent variable is greater than 0, the independent variable returns to 1, when the independent variable is less than zero, the independent variable returns to-1, and omega is the pitch angle speed of the satellite pitching maneuver;
s24: according to the maximum value of the single-time monthly observation image data, all monthly observation data are divided into effective lunar pixels and non-lunar pixels, 5% of the maximum value of the single-time monthly observation image data is used as a threshold value for judging the effective lunar pixels, and a lunar pixel template matrix is as follows:
wherein M (i, j) is a moon template value of i rows and j columns, 1 represents a moon pixel, and 0 represents a non-moon pixel;
s25: the method comprises the following steps of converting an original count value of a moon pixel into radiance data by using a calibration slope and a calibration intercept obtained by laboratory tests, namely converting an original count value image observed for a month into a radiance image, wherein the specific calculation formula is as follows:
L＝Slope·DN″+Offset，
wherein Slope is a calibration Slope, Offset is a calibration intercept, L is the brightness of the pixel, and the calculation formula of pixel irradiance is as follows:
Ipixel＝σLpixel，
wherein, σ is a solid angle formed by the lunar pixel, and I is the irradiance of the pixel;
s26: screening effective lunar pixels by using a lunar pixel template, accumulating single-pixel irradiance to obtain a lunar full-disc irradiance initial value, and calculating the lunar irradiance initial value according to the following formula:
wherein, ImoonIs the moon wholeThe initial value of the disc irradiance;
s27: in the linear array direction, the oversampling phenomenon does not exist, and the theoretical pixel number is calculated by utilizing the lunar aperture, the linear array detector probe element length and the equivalent focal length of each wave band; in the push-broom direction, an oversampling phenomenon exists, a moon pixel number is obtained by using a moon pixel template, and then an oversampling correction coefficient is calculated by using the ratio of the moon longitudinal pixel number to the moon transverse pixel number to correct the oversampling phenomenon;
the theoretical single-row lunar sampling point number is calculated by the following formula:
wherein, A is the length of a single probe element, NumSamplesThe number of pixels of the moon in the linear array direction, FocalLength equivalent focal length of the remote sensing imager, Moondiameter of the moon and DistanceSatellite-MoonIs the satellite moon distance; the theoretical pixel number of the moon in the linear array direction is:
considering that the moon phase angle is close to full moon, the image is circular, so the number of moon pixels in the linear array direction is the same as the number of frames in the push-scan direction, i.e. the number of moon image frames should theoretically be:
NumFrames＝NumSamples，
wherein, NumFramesThe number of moon image frames in the push-broom direction;
in the actual moon observation image, the frame number of the moon image can be calculated by the difference between the maximum value and the minimum value of the pixel line number in the moon pixel template data, that is:
Num′Frames＝max(lines(M))-min(lines(M))，
wherein max (lines (m)) is the maximum line number of the moon pixel in the moon pixel template, and min (lines (m)) is the minimum line number of the moon pixel in the moon pixel template;
the oversampled correction factor f in the push-broom directionover-sampleComprises the following steps:
finally, the observed value of the irradiance of the lunar full-circle disc is obtained as follows:
s3: and a result output stage, namely outputting and saving the calculation result of the moon irradiance observation value and the related auxiliary parameters into a file.
2. The method for calculating the moon irradiance observed value of the linear array push-broom remote sensing imager according to claim 1, wherein in the step S1, the data required for calculating the moon irradiance comprises on-orbit moon observation data of the remote sensing imager, static calibration parameters of the remote sensing imager, and relevant position data of the remote sensing imager during the moon observation.
3. The method for calculating the moon irradiance observed value of the linear array push-broom remote sensing imager according to claim 2, wherein the on-orbit moon-to-moon observed data of the remote sensing imager comprises all-moon-to-moon observed original data and dark current meter numerical value observed data of all wave bands.
4. The method for calculating the moon irradiance observed value of the linear array push-broom remote sensing imager according to claim 2, wherein the static calibration parameters of the remote sensing imager are static calibration parameters of all wave bands of the remote sensing imager, and the static calibration parameters comprise a calibration slope, a calibration intercept, a radiation response uniformity correction coefficient, a linear array detector probe length and an equivalent focal length of each wave band.
5. The method for calculating the moon irradiance observed value of the linear array push-broom remote sensing imager according to claim 2, wherein the relevant position data of the remote sensing imager during the moon observation comprises satellite position data, position data coordinate system information, moon observation time data and attitude data during the moon observation.
6. The method for calculating the moon irradiance observed value of the linear array push-broom remote sensing imager according to claim 1, wherein a moon phase is close to a full moon condition when a moon is observed, namely a moon image is circular.
7. The method for calculating the moon irradiance observed value of the linear array push-broom remote sensing imager according to claim 1, wherein the remote sensing imager is a cloud and aerosol polarization imager, CAPI.
8. The method for calculating the moon irradiance observed value of the linear array push-broom remote sensing imager according to claim 1, wherein in the step S3, the data to be output comprise a moon full disc irradiance observed value calculation result, an oversampling correction coefficient and a star-moon distance during moon observation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010081114.9A CN111256818B (en) | 2020-02-05 | 2020-02-05 | Calculation method for moon irradiance observed value of linear array push-broom type remote sensing imager |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010081114.9A CN111256818B (en) | 2020-02-05 | 2020-02-05 | Calculation method for moon irradiance observed value of linear array push-broom type remote sensing imager |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111256818A CN111256818A (en) | 2020-06-09 |
| CN111256818B true CN111256818B (en) | 2022-04-15 |
Family
ID=70945464
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010081114.9A Active CN111256818B (en) | 2020-02-05 | 2020-02-05 | Calculation method for moon irradiance observed value of linear array push-broom type remote sensing imager |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111256818B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112381769B (en) * | 2020-10-30 | 2022-09-27 | 青岛科技大学 | Oversampling correction method and system based on functional fitting of lunar phase graph |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104462776B (en) * | 2014-11-06 | 2017-07-28 | 中国空间技术研究院 | A kind of low orbit earth observation satellite is to moon absolute radiation calibration method |
| CN106908813B (en) * | 2017-04-28 | 2019-08-27 | 国家卫星气象中心 | A kind of satellite remote sensor Calibration Method and device |
| CN109163801A (en) * | 2018-07-09 | 2019-01-08 | 国家卫星气象中心 | The in-orbit Calibration Method in Atmospheric Absorption channel and robot scaling equipment in a kind of remote sensor |
-
2020
- 2020-02-05 CN CN202010081114.9A patent/CN111256818B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN111256818A (en) | 2020-06-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Tubiana et al. | Scientific assessment of the quality of OSIRIS images | |
| Bruegge et al. | Early validation of the Multi-angle Imaging SpectroRadiometer (MISR) radiometric scale | |
| Lee et al. | A new method for SUOMI-NPP VIIRS day–night band on-orbit radiometric calibration | |
| CN103413272A (en) | Low-spatial-resolution multisource remote sensing image space consistency correction method | |
| Anderson et al. | Radiometric correction of RapidEye imagery using the on-orbit side-slither method | |
| Okuyama et al. | Validation of Himawari-8/AHI radiometric calibration based on two years of in-orbit data | |
| CN110006452B (en) | Relative geometric calibration method and system for high-resolution six-size wide-view-field camera | |
| Uprety et al. | Calibration improvements in S-NPP VIIRS DNB sensor data record using version 2 reprocessing | |
| Montojo et al. | Astrometric positioning and orbit determination of geostationary satellites | |
| Geuder et al. | Long-term behavior, accuracy and drift of LI-200 pyranometers as radiation sensors in Rotating Shadowband Irradiometers (RSI) | |
| CN115265783B (en) | Multi-platform understar instantaneous cross calibration method based on hyperspectral data | |
| Howett et al. | Inflight radiometric calibration of New Horizons’ multispectral visible imaging camera (MVIC) | |
| CN104977024A (en) | Solar blind ultraviolet remote sensing camera absolute radiometric calibration coefficient in-orbit correction method | |
| CN108226059B (en) | Satellite hyperspectral CO2On-orbit radiation calibration method for detector | |
| CN110689505B (en) | Scene-based satellite-borne remote sensing instrument self-adaptive correction method and system | |
| CN111256818B (en) | Calculation method for moon irradiance observed value of linear array push-broom type remote sensing imager | |
| Li et al. | An improved on-orbit relative radiometric calibration method for agile high-resolution optical remote-sensing satellites with sensor geometric distortion | |
| Meng et al. | Data processing pipeline for pointing observations of Lunar-based Ultraviolet Telescope | |
| JP2833861B2 (en) | Real-time image correction method | |
| Cede et al. | Raw EPIC data calibration | |
| Doelling et al. | Inter-calibration of the OSIRIS-REx NavCams with Earth-viewing imagers | |
| Böker et al. | The spectro-photometric calibration of the JWST NIRSpec instrument | |
| Wu et al. | Vicarious calibration of GOES Imager visible channel using the Moon | |
| CN112630174A (en) | Gas detection strip effect correction method for satellite-borne hyperspectral imager | |
| Iovenitti et al. | A new observing season for the ASTRI-Horn Cherenkov telescope: enhanced techniques for pointing calibration, astrometry, and PSF monitoring |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |