The cross-calibration method for “Sich-2” data

2014 ◽  
Vol 20 (1(86)) ◽  
pp. 44-50
Author(s):  
R.M. Basarab ◽  
Keyword(s):  
Calibration Method ◽  
The Cross ◽  
Cross Calibration

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

2019 ◽  
Vol 11 (6) ◽  
pp. 707 ◽  
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%.

The cross-calibration method for “Sich-2” data

2014 ◽  
Vol 20 (2(87)) ◽  
pp. 67-72
Author(s):  
S.A. Zasuha ◽  
◽  
N.I. Lykholit ◽  
A.L. Makarov ◽  
Y.A. Melenevskiy ◽  
...  
Keyword(s):  
Calibration Method ◽  
The Cross ◽  
Cross Calibration

scholarly journals Radiometric Cross-Calibration of the Wide Field View Camera Onboard GaoFen-6 in Multispectral Bands

2020 ◽  
Vol 12 (6) ◽  
pp. 1037
Author(s):  
Aixia Yang ◽  
Bo Zhong ◽  
Longfei Hu ◽  
Shanlong Wu ◽  
Zhaopeng Xu ◽  
...  
Keyword(s):  
Test Site ◽  
Calibration Method ◽  
Observation System ◽  
Landsat 8 ◽  
Wide Field ◽  
Badain Jaran Desert ◽  
Radiometric Calibration ◽  
High Definition ◽  
The Cross ◽  
Cross Calibration

GaoFen6 (GF-6), successfully launched on June 2, 2018, is the sixth satellite of the High-Definition Earth observation system (HDEOS). Although GF-6 is the first high-resolution satellite in China to achieve precise agricultural observation, it will be widely used in many other domains, such as land survey, natural resources management, emergency management, ecological environment and so on. The GF-6 was not equipped with an onboard calibration instrument, so on-orbit radiometric calibration is essential. This paper aimed at the on-orbit radiometric calibration of the wide field of view camera (WFV) onboard GF-6 (GF-6/WFV) in multispectral bands. Firstly, the radiometric capability of GF-6/WFV is evaluated compared with the Operational Land Imager (OLI) onboard Landsat-8, Multi Spectral Instrument (MSI) onboard Sentinel-2 and Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra, which shows that GF-6/WFV has an obvious attenuation. Consequently, instead of vicarious calibration once a year, more frequent calibration is required to guarantee its radiometric consistency. The cross-calibration method based on the Badain Jaran Desert site using the bi-directional reflectance distribution function (BRDF) model calculated by Landsat-8/OLI and ZY-3/Three-Line Camera (TLC) data is subsequently applied to GF-6/WFV and much higher frequencies of calibration are achieved. Finally, the cross-calibration results are validated using the synchronized ground measurements at Dunhuang test site and the uncertainty of the proposed method is analyzed. The validation shows that the relative difference of cross-calibration is less than 5% and it is satisfied with the requirements of cross-calibration.

Cross Calibration by FFT Equalization

1997 ◽  
Vol 119 (2) ◽  
pp. 236-242 ◽  
Author(s):  
K. Peleg
Keyword(s):  
Measurement Method ◽  
Functional Relationship ◽  
Measurement Methods ◽  
New Method ◽  
Measurement Systems ◽  
True Value ◽  
Calibration Problem ◽  
Regression Techniques ◽  
The Cross ◽  
Cross Calibration

The classical calibration problem is primarily concerned with comparing an approximate measurement method with a very precise one. Frequently, both measurement methods are very noisy, so we cannot regard either method as giving the true value of the quantity being measured. Sometimes, it is desired to replace a destructive or slow measurement method, by a noninvasive, faster or less expensive one. The simplest solution is to cross calibrate one measurement method in terms of the other. The common practice is to use regression models, as cross calibration formulas. However, such models do not attempt to discriminate between the clutter and the true functional relationship between the cross calibrated measurement methods. A new approach is proposed, based on minimizing the sum of squares of the differences between the absolute values of the Fast Fourier Transform (FFT) series, derived from the readings of the cross calibrated measurement methods. The line taken is illustrated by cross calibration examples of simulated linear and nonlinear measurement systems, with various levels of additive noise, wherein the new method is compared to the classical regression techniques. It is shown, that the new method can discover better the true functional relationship between two measurement systems, which is occluded by the noise.

Cross-Calibration Method Based on Hyperspectral Imager Hyperion

2013 ◽  
Vol 33 (5) ◽  
pp. 0528002 ◽  
Author(s):  
徐文斌 Xu Wenbin ◽  
郑小兵 Zheng Xiaobing ◽  
易维宁 Yi Weining
Keyword(s):  
Calibration Method ◽  
Cross Calibration

Development of a Novel Micro-Gripper Integrating Tri-Axial Force Sensor

2007 ◽  
Author(s):  
Jiachou Wang ◽  
Weibin Rong ◽  
Lining Sun ◽  
Hui Xie ◽  
Wei Chen
Keyword(s):  
Axial Force ◽  
Crystalline Silicon ◽  
Force Sensor ◽  
Calibration Method ◽  
Deep Reactive Ion Etching ◽  
Micro Gripper ◽  
The Cross ◽  
Silicon Frame ◽  
High Level ◽  
Cross Structure

A novel micro gripper integrating tri-axial force sensor and two grades displacement amplifier is presented in this paper, which bases on the technology of Piezoresistive detection and use PZT as its micro driving component. The micro tri-axial force sensor is fabricated on a single-crystalline-silicon by the technology of MEMS and consists of a flexible cross-structure realized by deep reactive ion etching (DRIE). The arms of the cross-structure are connected to a silicon frame and to the central part of the cross-structure. After modeling the amplifier structure of micro gripper and the sensor, finite element method (FEM) is used to analyze the displacement of the micro gripper and the deformation of the cross-structure elastic cantilever. A calibration method of tri-axial sensor based on the technology of microscopic vision and the principle of bending deflection cantilever is proposed. The experimental verified that the sensor are high level of intrinsic decoupling of the signals from strain gauge, high resolutions in all three axes, high linearity and repeatability and simple produce of calculation. And also show the micro gripper is reasonable and practical. The sensor is capable of resolving forces up to 10mN with resolution of 2.4μN in x axis and y axis and up to 10mN with resolution of 4.2μN in z axis; the gripping displacement of the micro gripper is from 20μm to 300μm.

scholarly journals OLCI A/B Tandem Phase Analysis, Part 3: Post-Tandem Monitoring of Cross-Calibration from Statistics of Deep Convective Clouds Observations

2020 ◽  
Vol 12 (18) ◽  
pp. 3105
Author(s):  
Nicolas Lamquin ◽  
Ludovic Bourg ◽  
Sébastien Clerc ◽  
Craig Donlon
Keyword(s):  
Phase Analysis ◽  
Absolute Calibration ◽  
Inflexion Point ◽  
Convective Clouds ◽  
Deep Convective Clouds ◽  
Long Term Monitoring ◽  
The Cross ◽  
Cross Calibration ◽  
Term Monitoring

This study is a follow-up of a full methodology for the homogenisation and harmonisation of the two Ocean and Land Colour Instrument (OLCI) payloads based on the OLCI-A/OLCI-B tandem phase analysis. This analysis provided cross-calibration factors between the two instruments with a very high precision, providing a ‘truth’ from the direct comparison of simultaneous and collocated acquisitions. The long-term monitoring of such cross-calibration is a prerequisite for an operational application of sensors harmonisation along the mission lifetime, no other tandem phase between OLCI-A and OLCI-B being foreseen due to the cost of such operation. This article presents a novel approach for the monitoring of the OLCI radiometry based on statistics of Deep Convective Clouds (DCC) observations, especially dedicated to accurately monitor the full across-track dependency of the cross-calibration of OLCI-A and OLCI-B. Specifically, the inflexion point of DCC reflectance distributions is used as an indicator of the absolute calibration for each subdivision of the OLCI Field-of-View. This inflexion point is shown to provide better precision than the mode of the distributions which is commonly used in the community. Excess of saturation in OLCI-A high radiances is handled through the analysis of interband relationships between impacted channels and reference channels that are not impacted by saturation. Such analysis also provides efficient insights on the variability of the target’s response as well as on the evolution of the interband calibration of each payload. First, cross-calibration factors obtained over the tandem period allows to develop and validate the approach, notably for the handling of the saturated pixels, based on the comparison with the ‘truth’ obtained from the tandem analysis. Factors obtained out of (and far from) the tandem period then provides evidence that the cross-calibration reported over the tandem period (1–2% bias between the instruments) as well as inter-camera calibration residuals persist with very similar proportions, to the exception of the 400 nm channel and with slightly less precision for the 1020 nm channel. For all OLCI channels, relative differences between the cross-calibration factors obtained from the tandem analysis and the factors obtained over the other period are below 1% from a monthly analysis, even below 0.5% from a multi-monthly analysis). This opens the way not only to an accurate long-term monitoring of the OLCI radiometry but also, and precisely targeted for this study, to the monitoring of the cross-calibration of the two sensors over the mission lifetime. It also provides complementary information to the tandem analysis as the calibration indicators are traced individually for each sensor across-track, confirming and quantifying inter-camera radiometric biases, independently for both sensors. Assumptions used in this study are discussed and validated, also providing a framework for the adaptation of the presented methodology to other optical sensors.

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