An In-Orbit Radiometric Calibration Method of the Geostationary Ocean Color Imager

To calibrate the low signal response of the ocean color (OC) bands and test the stability of the Fengyun-3D (FY-3D)/Medium Resolution Spectral Imager II (MERSI-II), an absolute radiometric calibration field test of FY-3D/MERSI-II at the Lake Qinghai Radiometric Calibration Site (RCS) was carried out in August 2018. The lake surface and atmospheric parameters were mainly measured by advanced observation instruments, and the MODerate spectral resolution atmospheric TRANsmittance algorithm and computer model (MODTRAN4.0) was used to simulate the multiple scattering radiance value at the altitude of the sensor. The results showed that the relative deviations between bands 9 and 12 are within 5.0%, while the relative deviations of bands 8, and 13 are 17.1%, and 12.0%, respectively. The precision of the calibration method was verified by calibrating the Aqua/Moderate-resolution Imaging Spectroradiometer (MODIS) and National Polar-orbiting Partnership (NPP)/Visible Infrared Imaging Radiometer (VIIRS), and the deviation of the calibration results was evaluated with the results of the Dunhuang RCS calibration and lunar calibration. The results showed that the relative deviations of NPP/VIIRS were within 7.0%, and the relative deviations of Aqua/MODIS were within 4.1% from 400 nm to 600 nm. The comparisons of three on-orbit calibration methods indicated that band 8 exhibited a large attenuation after launch and the calibration results had good consistency at the other bands except for band 13. The uncertainty value of the whole calibration system was approximately 6.3%, and the uncertainty brought by the field surface measurement reached 5.4%, which might be the main reason for the relatively large deviation of band 13. This study verifies the feasibility of the vicarious calibration method at the Lake Qinghai RCS and provides the basis and reference for the subsequent on-orbit calibration of FY-3D/MERSI-II.

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A Subband Radiometric Calibration Method for UAV-Based Multispectral Remote Sensing

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing ◽

10.1109/jstars.2018.2842466 ◽

2018 ◽

Vol 11 (8) ◽

pp. 2869-2880 ◽

Cited By ~ 4

Author(s):

Lei Deng ◽

Xianglei Hao ◽

Zhihui Mao ◽

Yanan Yan ◽

Jie Sun ◽

...

Keyword(s):

Remote Sensing ◽

Calibration Method ◽

Radiometric Calibration ◽

Multispectral Remote Sensing

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Radiometric Calibration Method of 2-14 μm Infrared Spectroradiometer

Acta Optica Sinica ◽

10.3788/aos201939.0212003 ◽

2019 ◽

Vol 39 (2) ◽

pp. 0212003

Author(s):

刘加庆 Liu Jiaqing ◽

韩顺利 Han Shunli ◽

孟鑫 Meng Xin ◽

胡德信 Hu Dexin

Keyword(s):

Calibration Method ◽

Radiometric Calibration

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Automated Radiation Calibration Method Based on Dunhuang Radiometric Calibration Site

Acta Optica Sinica ◽

10.3788/aos201737.0801003 ◽

2017 ◽

Vol 37 (8) ◽

pp. 0801003 ◽

Cited By ~ 1

Author(s):

吕佳彦 Lü Jiayan ◽

何明元 He Mingyuan ◽

陈林 Chen Lin ◽

胡秀清 Hu Xiuqing ◽

李新 Li Xin

Keyword(s):

Calibration Method ◽

Radiometric Calibration

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On-Orbit Polarization Calibration for Multichannel Polarimetric Camera

Applied Sciences ◽

10.3390/app9071424 ◽

2019 ◽

Vol 9 (7) ◽

pp. 1424 ◽

Cited By ~ 3

Author(s):

Mingxin Liu ◽

Xin Zhang ◽

Tao Liu ◽

Guangwei Shi ◽

Lingjie Wang ◽

...

Keyword(s):

Linear Polarization ◽

Calibration Method ◽

Experimental Results ◽

Calibration Model ◽

Radiometric Calibration ◽

Relative Deviation ◽

Transmission Process ◽

Radiation Transmission ◽

Polarimetric Imaging ◽

Imaging Detection

In this paper, a new on-orbit polarization calibration method for the multichannel polarimetric camera is presented. A polarization calibration model for the polarimetric camera is proposed by taking analysis of the polarization radiation transmission process. In order to get the polarization parameters in the calibration model, an on-orbit measurement scheme is reported, which uses a solar diffuser and a built-in rotatable linear analyzer. The advantages of this scheme are sharing the same calibration assembly with the radiometric calibration and acquiring sufficient polarization accuracy. The influence of the diffuser for the measurement is analyzed. By using a verification experiment, the proposed method can achieve on-orbit polarization calibration. The experimental results show that the relative deviation for the measured degree of linear polarization is 0.8% at 670 nm, which provides a foundation for the accurate application of polarimetric imaging detection.

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Radiometric Calibration for Incidence Angle, Range and Sub-Footprint Effects on Hyperspectral LiDAR Backscatter Intensity

Remote Sensing ◽

10.3390/rs12172855 ◽

2020 ◽

Vol 12 (17) ◽

pp. 2855

Author(s):

Changsai Zhang ◽

Shuai Gao ◽

Wang Li ◽

Kaiyi Bi ◽

Ni Huang ◽

...

Keyword(s):

Near Infrared ◽

Spatial Information ◽

Incidence Angle ◽

Incident Angle ◽

Calibration Method ◽

Correction Method ◽

Intensity Data ◽

Radiometric Calibration ◽

Backscatter Intensity ◽

Reference Target

Terrestrial hyperspectral LiDAR (HSL) sensors could provide not only spatial information of the measured targets but also the backscattered spectral intensity signal of the laser pulse. The raw intensity collected by HSL is influenced by several factors, among which the range, incidence angle and sub-footprint play a significant role. Further studies on the influence of the range, incidence angle and sub-footprint are needed to improve the accuracy of backscatter intensity data as it is important for vegetation structural and biochemical information estimation. In this paper, we investigated the effects on the laser backscatter intensity and developed a practical correction method for HSL data. We established a laser ratio calibration method and a reference target-based method for HSL and investigated the calibration procedures for the mixed measurements of the effects of the incident angle, range and sub-footprint. Results showed that the laser ratio at the red-edge and near-infrared laser wavelengths has higher accuracy and simplicity in eliminating range, incident angle and sub-footprint effects and can significantly improve the backscatter intensity discrepancy caused by these effects.

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Autonomous Mobile Ground Control Point Improves Accuracy of Agricultural Remote Sensing through Collaboration with UAV

Inventions ◽

10.3390/inventions5010012 ◽

2020 ◽

Vol 5 (1) ◽

pp. 12

Author(s):

Xiongzhe Han ◽

J. Alex Thomasson ◽

Tianyi Wang ◽

Vaishali Swaminathan

Keyword(s):

Remote Sensing ◽

Control Point ◽

Field Testing ◽

Calibration Method ◽

Large Field ◽

Ground Control ◽

Radiometric Calibration ◽

Look Ahead ◽

Data Collection Process ◽

Actual Field

Ground control points (GCPs) are critical for agricultural remote sensing that require georeferencing and calibration of images collected from an unmanned aerial vehicles (UAV) at different times. However, the conventional stationary GCPs are time-consuming and labor-intensive to measure, distribute, and collect their information in a large field setup. An autonomous mobile GCP and a collaboration strategy to communicate with the UAV were developed to improve the efficiency and accuracy of the UAV-based data collection process. Prior to actual field testing, preliminary tests were conducted using the system to show the capability of automatic path tracking by reducing the root mean square error (RMSE) for lateral deviation from 34.3 cm to 15.6 cm based on the proposed look-ahead tracking method. The tests also indicated the feasibility of moving reflectance reference panels successively along all the waypoints without having detrimental effects on pixel values in the mosaicked images, with the percentage errors in digital number values ranging from −1.1% to 0.1%. In the actual field testing, the autonomous mobile GCP was able to successfully cooperate with the UAV in real-time without any interruption, showing superior performances for georeferencing, radiometric calibration, height calibration, and temperature calibration, compared to the conventional calibration method that has stationary GCPs.

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Radiometric Cross-Calibration of GF-1 PMS Sensor with a New BRDF Model

Remote Sensing ◽

10.3390/rs11060707 ◽

2019 ◽

Vol 11 (6) ◽

pp. 707 ◽

Cited By ~ 1

Author(s):

Qiyue Liu ◽

Tao Yu ◽

Hailiang Gao

Keyword(s):

Calibration Method ◽

Reference Image ◽

Landsat 8 ◽

Radiometric Calibration ◽

Sensing Applications ◽

Quantitative Remote Sensing ◽

Calibration Accuracy ◽

The Cross ◽

One Year ◽

Cross Calibration

On-orbit radiometric calibration of a space-borne sensor is of great importance for quantitative remote sensing applications. Cross-calibration is a common method with high calibration accuracy, and the core and emphasis of this method is to select the appropriate reference satellite sensor. As for the cross-calibration of high-spatial resolution and narrow-swath sensor, however, there are some scientific issues, such as large observation angles of reference image, and non-synchronization (or quasi-synchronization) between the imaging date of reference image and the date of sensor to be calibrated, which affects the accuracy of cross-calibration to a certain degree. Therefore, taking the GaoFen-1 (GF-1) Panchromatic and Multi-Spectral (PMS) sensor as an example in this research, an innovative radiometric cross-calibration method is proposed to overcome this bottleneck. Firstly, according a set of criteria, valid MODIS (Moderate Resolution Imagine Spectroradiometer) images of sunny day in one year over the Dunhuang radiometric calibration site in China are extracted, and a new and distinctive bidirectional reflectance distribution function (BRDF) model based on top-of-atmosphere (TOA) reflectance and imaging angles of the sunny day MODIS images is constructed. Subsequently, the cross-calibration of PMS sensor at Dunhuang and Golmud radiation calibration test sites is carried out by using the method presented in this paper, taking the MODIS image with large solar and observation angles and Landsat 8 Operational Land Imager (OLI) with different dates from PMS as reference. The validation results of the calibration coefficients indicate that our proposed method can acquire high calibration accuracy, and the total calibration uncertainties of PMS using MODIS as reference sensor are less than 6%.

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Field Intercomparison of Radiometers Used for Satellite Validation in the 400–900 nm Range

Remote Sensing ◽

10.3390/rs11091129 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1129 ◽

Cited By ~ 9

Author(s):

Viktor Vabson ◽

Joel Kuusk ◽

Ilmar Ansko ◽

Riho Vendt ◽

Krista Alikas ◽

...

Keyword(s):

Ocean Color ◽

European Space Agency ◽

Field Measurements ◽

Stray Light ◽

Radiometric Calibration ◽

Space Agency ◽

Systematic Effects ◽

Funded Project ◽

Field Intercomparison ◽

Reference Measurements

An intercomparison of radiance and irradiance ocean color radiometers (the second laboratory comparison exercise—LCE-2) was organized within the frame of the European Space Agency funded project Fiducial Reference Measurements for Satellite Ocean Color (FRM4SOC) May 8–13, 2017 at Tartu Observatory, Estonia. LCE-2 consisted of three sub-tasks: (1) SI-traceable radiometric calibration of all the participating radiance and irradiance radiometers at the Tartu Observatory just before the comparisons; (2) indoor, laboratory intercomparison using stable radiance and irradiance sources in a controlled environment; (3) outdoor, field intercomparison of natural radiation sources over a natural water surface. The aim of the experiment was to provide a link in the chain of traceability from field measurements of water reflectance to the uniform SI-traceable calibration, and after calibration to verify whether different instruments measuring the same object provide results consistent within the expected uncertainty limits. This paper describes the third phase of LCE-2: The results of the field experiment. The calibration of radiometers and laboratory comparison experiment are presented in a related paper of the same journal issue. Compared to the laboratory comparison, the field intercomparison has demonstrated substantially larger variability between freshly calibrated sensors, because the targets and environmental conditions during radiometric calibration were different, both spectrally and spatially. Major differences were found for radiance sensors measuring a sunlit water target at viewing zenith angle of 139° because of the different fields of view. Major differences were found for irradiance sensors because of imperfect cosine response of diffusers. Variability between individual radiometers did depend significantly also on the type of the sensor and on the specific measurement target. Uniform SI traceable radiometric calibration ensuring fairly good consistency for indoor, laboratory measurements is insufficient for outdoor, field measurements, mainly due to the different angular variability of illumination. More stringent specifications and individual testing of radiometers for all relevant systematic effects (temperature, nonlinearity, spectral stray light, etc.) are needed to reduce biases between instruments and better quantify measurement uncertainties.

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