CN111735538A - Airborne area array staring type hyperspectral image illumination correction method - Google Patents
Airborne area array staring type hyperspectral image illumination correction method Download PDFInfo
- Publication number
- CN111735538A CN111735538A CN202010499645.XA CN202010499645A CN111735538A CN 111735538 A CN111735538 A CN 111735538A CN 202010499645 A CN202010499645 A CN 202010499645A CN 111735538 A CN111735538 A CN 111735538A
- Authority
- CN
- China
- Prior art keywords
- area array
- wave band
- corrected
- type hyperspectral
- staring type
- 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.)
- Granted
Links
- 238000005286 illumination Methods 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims abstract description 23
- 230000003595 spectral effect Effects 0.000 claims abstract description 43
- 238000001228 spectrum Methods 0.000 claims abstract description 30
- 239000000523 sample Substances 0.000 claims abstract description 12
- 238000003384 imaging method Methods 0.000 claims abstract description 11
- 230000010354 integration Effects 0.000 claims description 3
- 238000005316 response function Methods 0.000 claims description 3
- 238000007781 pre-processing Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005855 radiation 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
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/2823—Imaging spectrometer
Abstract
The invention relates to an airborne area array staring type hyperspectral image illumination correction method which comprises the steps of 1) observing descending irradiance at the imaging time of an airborne area array staring type hyperspectral imager by using an ASD (automatic serial display) and a cosine probe to obtain a descending irradiance spectrum curve; 2) calculating the minimum distance between each spectral curve to be detected and the descending irradiance spectral curve at the previous moment, namely the illumination difference; if the illumination difference is larger than a preset threshold value, marking the corresponding moment of the spectral curve to be detected as the moment to be corrected; 3) performing radiometric calibration on the staring type hyperspectral image of the original airborne area array to obtain apparent radiance L (mu)v) (ii) a 4) Positioning a wave band needing to be corrected through time matching; equivalently integrating the downstream irradiance spectral curve at the moment to be corrected to the waveband, and calculating the correction coefficient of the waveband; 5) using correction coefficient to correct the apparent radiance L (mu) of the wave bandv) Correcting to obtain a corrected wave band; 6) and combining the corrected wave band with the uncorrected wave band to obtain a corrected image.
Description
Technical Field
The invention relates to the field of high-spectrum data pre-correction in quantitative remote sensing, in particular to an airborne area array staring type high-spectrum image illumination correction method.
Background
The imaging mode of the hyperspectral imager can be generally divided into a sweep type, a push-sweep type and a staring type, wherein the area array staring type hyperspectral imager can realize space three-dimensional imaging by single exposure without mechanical movement and is less influenced by the stability of a platform. During the staring imaging period of the area array staring type hyperspectral imager, the influence of solar illumination and atmospheric space-time change cannot be ignored. In the staring imaging process, multiple exposures of different wave bands are required to be completed within several seconds, and a final hyperspectral data cube can be obtained. Even under the sunny and cloudless weather condition, the solar illumination still changes along with the time, and the phenomenon of different brightness appears on the remote sensing image. The existing data preprocessing methods ignore the illumination change in the airborne remote sensing acquisition time period, and the acquiescent acquired remote sensing images have better illumination consistency, which brings larger uncertainty to the quality of hyperspectral data.
Disclosure of Invention
The invention aims to solve the problems that in the prior art, due to the fact that the change of illumination in an airborne remote sensing acquisition time period is ignored, the default acquired remote sensing image has better illumination consistency and great uncertainty is brought to the quality of hyperspectral data in a data preprocessing method, and provides an airborne area array staring type hyperspectral image illumination correction method.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
an onboard area array staring type hyperspectral image illumination correction method is characterized by comprising the following steps:
1) observing the downlink irradiance of the airborne area array staring type hyperspectral imager at the imaging time by using a portable ground object spectrometer and a cosine probe, wherein the observation frequency is greater than the number of imaging frames per second of the airborne area array staring type hyperspectral imager, and obtaining a downlink irradiance spectrum curve;
2) the method comprises the steps that the time of an airborne area array staring type hyperspectral imager for obtaining a first waveband is taken as an initial time, a descending irradiance spectrum curve corresponding to the initial time is selected as a reference spectrum curve, the descending irradiance spectrum curve corresponding to each time after the initial time is a spectrum curve to be detected, and the minimum distance between each spectrum curve to be detected and the descending irradiance spectrum curve at the previous time, namely the illumination difference, is calculated; if the illumination difference is larger than a preset threshold value, marking the corresponding moment of the spectral curve to be detected as the moment to be corrected;
3) performing radiometric calibration on the staring type hyperspectral image of the original airborne area array to obtain apparent radiance L (mu)v)；
4) Positioning a wave band needing to be corrected of the original airborne area array staring type hyperspectral image through time matching; equivalently integrating the downstream irradiance spectral curve at the moment to be corrected to the wave band, and calculating the correction coefficient of the wave band by using the downstream irradiance spectral curve after equivalent integration;
5) using correction coefficient to correct the apparent radiance L (mu) of the wave bandv) Correcting to obtain a corrected wave band;
6) and combining the corrected wave band with the uncorrected wave band to obtain a corrected image.
Further, the portable surface feature spectrometer is calibrated before observation in the step 1, and an error range is obtained.
Further, in the step 2, the minimum distance between each spectral curve to be detected and the descending irradiance spectral curve at the previous moment is calculated according to the following formula;
in the formula, xiA spectral vector representing a spectral curve to be examined;
yia spectral vector representing a descending irradiance spectral curve at a previous time;
i is the number of the wave band and n is the total number of the wave band.
Further, in the step 3, the apparent radiance L (μ) of the original airborne area array staring type hyperspectral image is calculated according to the following formulav)；
L(μv)＝Gain×DN+Bias
In the formula, Gain is the Gain of the airborne area array staring type hyperspectral imager;
the Bias is a deviation value of the airborne area array staring type hyperspectral imager;
DN is a digital quantized value output by the airborne area array staring type hyperspectral imager.
Further, in the step 4, the downstream irradiance spectrum curve at the moment to be corrected is equivalently integrated to a wave band of the original airborne area array staring type hyperspectral image to be corrected according to the following formula;
in the formula, ρ* iThe equivalent integrated radiance of the corresponding wave band;
Si(λ) is the spectral response function;
rho (lambda) is a spectrum curve of descending irradiance measured by the portable surface feature spectrometer;
λ1、λ2the start and end wavelengths of each band.
Further, the cosine probe in the step 1 is an equiangular cosine probe;
during observation, the cosine probe always faces the zenith position.
Compared with the prior art, the invention has the beneficial effects that:
according to the illumination correction method for the on-board area array staring type hyperspectral image, provided by the invention, a correction coefficient is calculated by utilizing a downlink irradiance spectrum curve obtained by observing the portable ground object spectrometer and the cosine probe, so that the illumination inconsistency of the on-board area array staring type hyperspectral image is corrected, the radiation difference of the front end of data can be reduced, the hyperspectral data quality is improved, and the method is simple and effective.
Drawings
FIG. 1 is a flow chart of an onboard area array staring type hyperspectral image illumination correction method according to the invention;
FIG. 2 is a graph of descending irradiance spectra of a white target under different illumination in an embodiment of the present invention;
FIG. 3 is an image before a certain wave band illumination correction of an airborne area array staring type hyperspectral image in an embodiment of the invention;
FIG. 4 is an image of an airborne area array staring type hyperspectral image after illumination correction at a certain wave band in an embodiment of the invention;
FIG. 5 is a spectral graph of an airborne area array staring type hyperspectral image before and after full-band illumination correction in an embodiment of the invention.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
The invention provides an onboard area array staring type hyperspectral image illumination correction method, the flow of which is shown in figure 1, and the method comprises the following steps:
1) and observing the descending irradiance at the imaging moment of the airborne area array staring type hyperspectral imager by using a portable surface feature spectrometer (ASD) and a cosine probe, wherein the observation frequency is greater than the imaging frame number of the airborne area array staring type hyperspectral imager per second, and obtaining a descending irradiance spectrum curve.
And calibrating the portable ground object spectrometer before observation to obtain an error range.
During testing, the integration time of the portable surface feature spectrometer is as small as possible, and the average times are as small as possible, so that high-frequency observation can be conveniently realized.
The equiangular cosine probe is selected for high-frequency observation, and is placed in an open area and always faces to the zenith position during high-frequency observation, so that errors caused by observation angle changes and stray light are avoided.
In this embodiment, a descending irradiance spectral curve of the white target under different illumination obtained by high-frequency observation is shown in fig. 2.
2) The method comprises the steps of taking the time of an airborne area array staring type hyperspectral imager for obtaining a first waveband as an initial moment, selecting a downlink irradiance spectrum curve corresponding to the initial moment as a reference spectrum curve, selecting downlink irradiance spectrum curves corresponding to moments after the initial moment as to-be-detected spectrum curves, and calculating the minimum distance between each to-be-detected spectrum curve and the downlink irradiance spectrum curve at the previous moment, namely the illumination difference.
Specifically, the minimum distance between each spectral curve to be detected and the descending irradiance spectral curve at the previous moment is calculated according to the following formula;
in the formula, xiA spectral vector representing a spectral curve to be examined;
yia spectral vector representing a descending irradiance spectral curve at a previous time;
i is the number of the wave band and n is the total number of the wave band.
Comparing the calculated illumination difference with a preset threshold, and marking the corresponding moment of the spectral curve to be detected as the moment to be corrected if the illumination difference is greater than the preset threshold; if the illumination difference is smaller than the threshold value, the illumination fluctuation is not obvious, and the wave band at the moment is not changed.
3) Performing radiometric calibration on the staring type hyperspectral image of the original airborne area array to obtain apparent radiance L (mu)v)。
Specifically, the apparent radiance L (mu) of the staring type hyperspectral image of the original airborne area array is calculated according to the following formulav)；
L(μv)＝Gain×DN+Bias
In the formula, Gain is the Gain of the airborne area array staring type hyperspectral imager;
the Bias is a deviation value of the airborne area array staring type hyperspectral imager;
DN is a digital quantized value output by the airborne area array staring type hyperspectral imager.
4) Positioning a wave band needing to be corrected of the original airborne area array staring type hyperspectral image through time matching; and equivalently integrating the downstream irradiance spectral curve at the moment to be corrected to the waveband, so that the spectral resolution of the downstream irradiance spectral curve is consistent with the waveband to be corrected.
Specifically, equivalently integrating a descending irradiance spectral curve at a moment to be corrected to a wave band required to be corrected of the original airborne area array staring type hyperspectral image according to the following formula;
in the formula, ρ* iThe equivalent integrated radiance of the corresponding wave band;
Si(λ) is the spectral response function;
rho (lambda) is a spectrum curve of descending irradiance measured by the portable surface feature spectrometer;
λ1、λ2the start and end wavelengths of each band.
And calculating a correction coefficient of a corresponding wave band by using the equivalent integrated downstream irradiance spectral curve.
5) Using correction coefficient to correct the apparent radiance L (mu) of the wave bandv) And correcting to obtain a corrected waveband.
In this embodiment, an image of the airborne area array staring type hyperspectral image before illumination correction at a certain wave band is shown in fig. 3, and an image after correction is shown in fig. 4. After correction, the radiance of the wave band image is obviously changed, and observation errors caused by solar illumination changes are effectively removed.
6) And combining the corrected wave band with the uncorrected wave band to obtain a corrected image.
In this embodiment, the spectral curves before and after the full-waveband illumination correction of the airborne area array staring type hyperspectral image are shown in fig. 5, in the graph, the solid line is the spectral curve before the correction, and the dotted line is the spectral curve after the correction.
Claims (6)
1. An onboard area array staring type hyperspectral image illumination correction method is characterized by comprising the following steps:
1) observing the downlink irradiance of the airborne area array staring type hyperspectral imager at the imaging time by using a portable ground object spectrometer and a cosine probe, wherein the observation frequency is greater than the number of imaging frames per second of the airborne area array staring type hyperspectral imager, and obtaining a downlink irradiance spectrum curve;
2) the method comprises the steps that the time of an airborne area array staring type hyperspectral imager for obtaining a first waveband is taken as an initial time, a descending irradiance spectrum curve corresponding to the initial time is selected as a reference spectrum curve, the descending irradiance spectrum curve corresponding to each time after the initial time is a spectrum curve to be detected, and the minimum distance between each spectrum curve to be detected and the descending irradiance spectrum curve at the previous time, namely the illumination difference, is calculated; if the illumination difference is larger than a preset threshold value, marking the corresponding moment of the spectral curve to be detected as the moment to be corrected;
3) performing radiometric calibration on the staring type hyperspectral image of the original airborne area array to obtain apparent radiance L (mu)v)；
4) Positioning a wave band needing to be corrected of the original airborne area array staring type hyperspectral image through time matching; equivalently integrating the downstream irradiance spectral curve at the moment to be corrected to the wave band, and calculating the correction coefficient of the wave band by using the downstream irradiance spectral curve after equivalent integration;
5) using correction coefficient to correct the apparent radiance L (mu) of the wave bandv) Correcting to obtain a corrected wave band;
6) and combining the corrected wave band with the uncorrected wave band to obtain a corrected image.
2. The method for correcting illumination of the vehicle-mounted area array staring type hyperspectral image according to claim 1, which is characterized in that:
and calibrating the portable surface feature spectrometer before observation in the step 1 to obtain an error range.
3. The method for correcting illumination of the vehicle-mounted area array staring type hyperspectral image according to claim 1, which is characterized in that:
in the step 2, the minimum distance between each spectral curve to be detected and the descending irradiance spectral curve at the previous moment is calculated according to the following formula;
in the formula, xiA spectral vector representing a spectral curve to be examined;
yia spectral vector representing a descending irradiance spectral curve at a previous time;
i is the number of the wave band and n is the total number of the wave band.
4. The method for correcting illumination of the vehicle-mounted area array staring type hyperspectral image according to claim 1, which is characterized in that:
in the step 3, the apparent radiance L (mu) of the staring type hyperspectral image of the original airborne area array is calculated according to the following formulav)；
L(μv)＝Gain×DN+Bias
In the formula, Gain is the Gain of the airborne area array staring type hyperspectral imager;
the Bias is a deviation value of the airborne area array staring type hyperspectral imager;
DN is a digital quantized value output by the airborne area array staring type hyperspectral imager.
5. The method for correcting illumination of the vehicle-mounted area array staring type hyperspectral image according to claim 1, which is characterized in that:
in the step 4, the downlink irradiance spectral curve at the moment to be corrected is equivalently integrated to a wave band which needs to be corrected of the original airborne area array staring type hyperspectral image according to the following formula;
in the formula, ρ* iThe equivalent integrated radiance of the corresponding wave band;
Si(λ) is the spectral response function;
rho (lambda) is a spectrum curve of descending irradiance measured by the portable surface feature spectrometer;
λ1、λ2the start and end wavelengths of each band.
6. The method for correcting illumination of the vehicle-mounted area array staring type hyperspectral image according to any one of claims 1 to 5, wherein:
the cosine probe in the step 1 is an equiangular cosine probe;
during observation, the cosine probe always faces the zenith position.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010499645.XA CN111735538B (en) | 2020-06-04 | 2020-06-04 | Airborne area array staring type hyperspectral image illumination correction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010499645.XA CN111735538B (en) | 2020-06-04 | 2020-06-04 | Airborne area array staring type hyperspectral image illumination correction method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111735538A true CN111735538A (en) | 2020-10-02 |
| CN111735538B CN111735538B (en) | 2021-05-18 |
Family
ID=72649273
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010499645.XA Active CN111735538B (en) | 2020-06-04 | 2020-06-04 | Airborne area array staring type hyperspectral image illumination correction method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111735538B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113280919A (en) * | 2021-05-08 | 2021-08-20 | 中国科学院长春光学精密机械与物理研究所 | Target object spectrum detection method, spectrum detection device and storage medium |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004191244A (en) * | 2002-12-12 | 2004-07-08 | Minolta Co Ltd | Spectrograph and correction method |
| US6801309B1 (en) * | 2001-10-16 | 2004-10-05 | Therma-Wave, Inc. | Detector array with scattered light correction |
| CN103344329A (en) * | 2013-07-26 | 2013-10-09 | 杭州远方光电信息股份有限公司 | Handheld optical irradiance meter and correction method thereof |
| CN106500840A (en) * | 2016-10-20 | 2017-03-15 | 无锡创想分析仪器有限公司 | A kind of exceptional spectrum elimination method of full spectrum formula direct-reading spectrometer |
| CN109974854A (en) * | 2019-03-18 | 2019-07-05 | 石河子大学 | A kind of radiation correction method of frame width formula FPI high spectrum image |
-
2020
- 2020-06-04 CN CN202010499645.XA patent/CN111735538B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6801309B1 (en) * | 2001-10-16 | 2004-10-05 | Therma-Wave, Inc. | Detector array with scattered light correction |
| JP2004191244A (en) * | 2002-12-12 | 2004-07-08 | Minolta Co Ltd | Spectrograph and correction method |
| CN103344329A (en) * | 2013-07-26 | 2013-10-09 | 杭州远方光电信息股份有限公司 | Handheld optical irradiance meter and correction method thereof |
| CN106500840A (en) * | 2016-10-20 | 2017-03-15 | 无锡创想分析仪器有限公司 | A kind of exceptional spectrum elimination method of full spectrum formula direct-reading spectrometer |
| CN109974854A (en) * | 2019-03-18 | 2019-07-05 | 石河子大学 | A kind of radiation correction method of frame width formula FPI high spectrum image |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113280919A (en) * | 2021-05-08 | 2021-08-20 | 中国科学院长春光学精密机械与物理研究所 | Target object spectrum detection method, spectrum detection device and storage medium |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111735538B (en) | 2021-05-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11448586B2 (en) | Inspection apparatus, sensing apparatus, sensitivity control apparatus, inspection method, and program with pixel sensitivity control | |
| KR101702187B1 (en) | Device and method for calibration of high resolution electro optical satellite | |
| CN109974854B (en) | Radiation correction method for frame-type FPI (field programmable Gate array) hyperspectral image | |
| CN110987821A (en) | Hyperspectral rapid atmospheric correction parameterization method | |
| Gao et al. | Cross-calibration of GF-1 PMS sensor with Landsat 8 OLI and Terra MODIS | |
| Nocerino et al. | Geometric calibration and radiometric correction of the maia multispectral camera | |
| CN111735538B (en) | Airborne area array staring type hyperspectral image illumination correction method | |
| CN115265783B (en) | Multi-platform understar instantaneous cross calibration method based on hyperspectral data | |
| CN111044153B (en) | Nonlinear calibration method and device for infrared spectrum of spectrum correlation system | |
| CN112834051B (en) | Radiation temperature measurement method based on multispectral camera | |
| CN104237869A (en) | Multi-spectral load site-free cross calibration method based on hyperspectral loads | |
| Chakhvashvili et al. | Comparison of reflectance calibration workflows for a uav-mounted multi-camera array system | |
| CN112665829A (en) | Inter-band calibration method for optical remote sensing satellite | |
| Minařík et al. | Rapid radiometric calibration of multiple camera array using in-situ data for uav multispectral photogrammetry | |
| CN110702228B (en) | Edge radiation correction method for aviation hyperspectral image | |
| CN111609937A (en) | Thermal infrared imager external field calibration method and device | |
| JP4904377B2 (en) | Hyperspectral image processing apparatus and hyperspectral image processing method | |
| Simi et al. | Night vision imaging spectrometer (NVIS) performance parameters and their impact on various detection algorithms | |
| CN113029977B (en) | Automatic cross radiometric calibration method for wide-field-angle multispectral sensor | |
| CN109900361B (en) | Atmospheric radiation correction method suitable for aviation hyperspectral image | |
| Pandya et al. | Spectral characteristics of sensors onboard IRS-1D and P6 satellites: Estimation and their influence on surface reflectance and NDVI | |
| CN116109491A (en) | Method for correcting image non-uniformity of imaging spectrometer by using bright-dark uniform region | |
| Ribés et al. | Color and multispectral imaging with the CRISATEL multispectral system | |
| Martínez et al. | ICC experiences on DMC radiometric calibration | |
| Porto et al. | Radiometric Calibration Performance of a Multispectral Camera with a Single Sensor and Multiple Heads |
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 |