scholarly journals Geometric Processing and Accuracy Verification of Zhuhai-1 Hyperspectral Satellites

2019 ◽  
Vol 11 (9) ◽  
pp. 996 ◽  
Author(s):  
Yonghua Jiang ◽  
Jingyin Wang ◽  
Li Zhang ◽  
Guo Zhang ◽  
Xin Li ◽  
...  
Keyword(s):  
Spectral Band ◽  
Regional Network ◽  
Registration Accuracy ◽  
Network Adjustment ◽  
Basic Product ◽  
Geometric Calibration ◽  
Calibration Accuracy ◽  
Geometric Processing ◽  
Single Orientation ◽  
Better Than

The second batch of Zhuhai-1 microsatellites was successfully launched on 26 April 2018. The batch included four Orbita hyperspectral satellites (referred to as OHS-A, OHS-B, OHS-C, and OHS-D) and one video satellite (OVS-2A), which have excellent hyperspectral data acquisition abilities. For the first time in China, a number of hyperspectral satellite networks have been realized. To ensure the application of hyperspectral remote sensing data, a series of on-orbit geometry processing and accuracy verification studies has been carried out on the “Zhuhai-1” hyperspectral camera since the satellite was launched. This paper presents the geometric processing methods involved in the production of Zhuhai-1 hyperspectral satellite basic products, including geometric calibration and basic product production algorithms. The OHS images were used to perform on-orbit geometric calibration, and the calibration accuracy was better than 0.5 pixels. The registration accuracy of the image spectrum of the basic product after calibration, the single orientation accuracy, and the accuracy of the regional network adjustment were evaluated. The spectral registration accuracy of the OHS basic products is 0.3–0.5 pixels, which is equivalent to the spectral band calibration accuracy. The single orientation accuracy is better than 1.5 pixels and the regional network adjustment accuracy is better than 1.2 pixels. The generated area orthoimages meet the seamless edge requirements, which verifies that the OHS basic product image has good regional mapping capabilities and can meet the application requirements.

scholarly journals The Geometric Calibration and Validation for The ZY3-02 Satellite Optical Image

2017 ◽  
Vol XLII-1/W1 ◽  
pp. 587-593 ◽  
Author(s):  
X. Tang ◽  
X. Zhu
Keyword(s):  
Earth Observation ◽  
Ground Control ◽  
Control Points ◽  
Registration Accuracy ◽  
Positioning Accuracy ◽  
Geometric Calibration ◽  
Ground Control Points ◽  
System Errors ◽  
Better Than ◽  
Multispectral Camera

Chinese ZY3-02 satellite, which is the second of ZY3 series satellites, was launched in May 30th 2016 for complementing the mapping and earth observation. In order to eliminate various system errors of the platform and payload, the on-orbit geometric validation and calibration was carried out. Firstly, we introduced the parameters of the three-line stereo camera and multispectral camera bound on ZY3-02 in this paper. There are four optical cameras on ZY3-02: a 4-band nadir-looking multi-spectral camera with 5.8 m resolution, a 2.1m resolution nadir-looking panchromatic band camera, as well as 2.5m resolution forward- and backward-looking panchromatic band cameras. Compared with ZY3-01, the resolution of the forward- and backward-looking cameras on ZY3-02 were upgraded from 3.5 m to 2.5 m. Then we presented the methods and datasets used for calibration in details. After our calibration, the total positioning accuracy of the three-line camera images is better than 10m without ground control points (GCPs). The plane and height accuracy are improved to 3 and 2 m respectively, with few control points. The band-to-band registration accuracy of the multispectral camera is better than 0.15 pixels.

DENOISING OF THREE-DIMENSIONAL DATA CUBE USING BIVARIATE WAVELET SHRINKING

2011 ◽  
Vol 25 (03) ◽  
pp. 403-413 ◽  
Author(s):  
GUANGYI CHEN ◽  
TIEN D. BUI ◽  
ADAM KRZYZAK
Keyword(s):  
Spectral Band ◽  
Gaussian White Noise ◽  
Three Dimensional ◽  
Classical Problem ◽  
Data Cube ◽  
Wavelet Thresholding ◽  
3D Data ◽  
Signal Image ◽  
3D Data Cube ◽  
Better Than

The denoising of a natural signal/image corrupted by Gaussian white noise is a classical problem in signal/image processing. However, it is still in its infancy to denoise high dimensional data. In this paper, we extended Sendur and Selesnick's bivariate wavelet thresholding from two-dimensional (2D) image denoising to three-dimensional (3D) data cube denoising. Our study shows that bivariate wavelet thresholding is still valid for 3D data cubes. Experimental results show that bivariate wavelet thresholding on 3D data cube is better than performing 2D bivariate wavelet thresholding on every spectral band separately, VisuShrink, and Chen and Zhu's 3-scale denoising.

HIGH-PRECISION IN-FLIGHT CALIBRATION USING UNKNOWN LANDMARKS

2021 ◽  
Vol 4 ◽  
pp. 117-124
Author(s):  
Alexander Tkachenko ◽  
Keyword(s):  
Good Accuracy ◽  
Star Tracker ◽  
Coordinate Frame ◽  
Geometric Calibration ◽  
The Earth ◽  
Imaging Camera ◽  
Calibration Accuracy ◽  
Combined Algorithm ◽  
Fuzzy State ◽  
Fuzzy State Observer

An in-flight geometric calibration (further — calibration) is interpreted here as a procedure of making more preceise mutual attitude parameters of the onboard imaging camera and the star tracker. The problem of calibration is solved with using of observations of the landmarks from the orbit. In this work, the landmarks are considered as unknown in the sense that they may be identified on the several snapshots, they may be associated with synchronous data of the star tracker and GPS, but their location in the Earth coordinate frame is unknown. While unknown markers are used, it is more complicated to provide high accuracy of calibration than when geo-referenced markers are observed. In such a situation, improvement of the onboard devices and gauges and increasing of their accuracy strenghtens advisability of agreement of attainable accuracy of calculations while in-flight geometric calibration with accessible measurings accuracy. It concerns properly calibration so as geo-referencing of space snaps using results of calibration. In particular, it is important to consider how accuracy of calibration depends on the accuracy of specific measurings and initial data. Actuality of the considered problem is indisputable. Without its solution, attraction of high-accurate measurings is senseless. A main means of investigation is computer simulanion and analysis of its results. The combined algorithm is proposed for the processing of the calibration measuring equations. It consists of two independent parts. The first one belongs to author of this work and is based on photogrammetric condition of collinearity The second part belongs to D.V. Lebedev and is based on photogrammetric condition of coplanarity. The method of state estimation with high convergence characteristics — fuzzy state observer — is used for resolving of measuring equations. The results of above-mentioned calibration are fully fit for the geo-referencing of the unknown ground objects with acceptable accuracy. Computer simulation had demonsrated good accuracy of the proposed method of the in-flight geometric calibration using unknown landmarks in a combination with high-precise characteristics of used technical means. The simulation had shown the calibration accuracy on the level of 5 arc sec and accuracy of the geo-referencing on the level of 10–20 m. It is fully comparable with accuracy when geo-referenced markers are observated.

scholarly journals GEOMETRIC CALIBRATION OF ZIYUAN-3 THREE-LINE CAMERAS COMBINING GROUND CONTROL POINTS AND LINES

2016 ◽  
Vol XLI-B1 ◽  
pp. 163-168
Author(s):  
Jinshan Cao ◽  
Xiuxiao Yuan ◽  
Jianya Gong
Keyword(s):  
Ground Control ◽  
Calibration Model ◽  
Control Points ◽  
Charge Coupled Device ◽  
Geometric Calibration ◽  
Ground Control Points ◽  
The Look ◽  
Ccd Detectors ◽  
True Values ◽  
Better Than

Due to the large biases between the laboratory-calibrated values of the orientation parameters and their in-orbit true values, the initial direct georeferencing accuracy of the Ziyuan-3 (ZY-3) three-line camera (TLC) images can only reach the kilometre level. In this paper, a point-based geometric calibration model of the ZY-3 TLCs is firstly established by using the collinearity constraint, and then a line-based geometric calibration model is established by using the coplanarity constraint. With the help of both the point-based and the line-based models, a feasible in-orbit geometric calibration approach for the ZY-3 TLCs combining ground control points (GCPs) and ground control lines (GCLs) is presented. Experimental results show that like GCPs, GCLs can also provide effective ground control information for the geometric calibration of the ZY-3 TLCs. The calibration accuracy of the look angles of charge-coupled device (CCD) detectors achieved by using the presented approach reached up to about 1.0''. After the geometric calibration, the direct georeferencing accuracy of the ZY-3 TLC images without ground controls was significantly improved from the kilometre level to better than 11 m in planimetry and 9 m in height. A more satisfactory georeferencing accuracy of better than 3.5 m in planimetry and 3.0 m in height was achieved after the block adjustment with four GCPs.

scholarly journals Block Adjustment without GCPs for Chinese Spaceborne SAR GF-3 Imagery

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 4023 ◽  
Author(s):  
Guo Zhang ◽  
Qingwei Wu ◽  
Taoyang Wang ◽  
Ruishan Zhao ◽  
Mingjun Deng ◽  
...  
Keyword(s):  
High Accuracy ◽  
Control Points ◽  
Wuhan City ◽  
Error Sources ◽  
Geometric Calibration ◽  
Ground Control Points ◽  
Rational Polynomial ◽  
Sar Imagery ◽  
Orientation Parameters ◽  
Better Than

The Gaofen-3 (GF-3) satellite is the first C-band multi-polarization synthetic aperture radar (SAR) with the ability of high-accuracy mapping in China. However, the Ground Control Points (GCPs) are essential to ensure the accuracy of mapping for GF-3 SAR imagery at present. In this paper, we analyze the error sources that affect the geometric processing and propose a new block adjustment method without GCPs for GF-3 SAR imagery. Firstly, the geometric calibration of GF-3 image is carried out. Secondly, the rational polynomial coefficient (RPC) model is directly generated after the geometric calibration parameters compensation of each image. Finally, we solve the orientation parameters of the GF-3 images through DEM assisted planar block adjustment and conduct ortho-rectification. With two different imaging modes of GF-3 satellite, which include the QPSI and FS2, we carry out the block adjustment without GCPs. Experimental results of testing areas including Wuhan city and Hubei province in China show that the geometric mosaic accuracy and the absolute positioning accuracy of the orthophoto are better than one pixel, which has laid a good foundation for the application of GF-3 image in global high-accuracy mapping.

scholarly journals GEOMETRIC CALIBRATION OF ZIYUAN-3 THREE-LINE CAMERAS COMBINING GROUND CONTROL POINTS AND LINES

2016 ◽  
Vol XLI-B1 ◽  
pp. 163-168
Author(s):  
Jinshan Cao ◽  
Xiuxiao Yuan ◽  
Jianya Gong
Keyword(s):  
Ground Control ◽  
Calibration Model ◽  
Control Points ◽  
Charge Coupled Device ◽  
Geometric Calibration ◽  
Ground Control Points ◽  
The Look ◽  
Ccd Detectors ◽  
True Values ◽  
Better Than

Due to the large biases between the laboratory-calibrated values of the orientation parameters and their in-orbit true values, the initial direct georeferencing accuracy of the Ziyuan-3 (ZY-3) three-line camera (TLC) images can only reach the kilometre level. In this paper, a point-based geometric calibration model of the ZY-3 TLCs is firstly established by using the collinearity constraint, and then a line-based geometric calibration model is established by using the coplanarity constraint. With the help of both the point-based and the line-based models, a feasible in-orbit geometric calibration approach for the ZY-3 TLCs combining ground control points (GCPs) and ground control lines (GCLs) is presented. Experimental results show that like GCPs, GCLs can also provide effective ground control information for the geometric calibration of the ZY-3 TLCs. The calibration accuracy of the look angles of charge-coupled device (CCD) detectors achieved by using the presented approach reached up to about 1.0''. After the geometric calibration, the direct georeferencing accuracy of the ZY-3 TLC images without ground controls was significantly improved from the kilometre level to better than 11 m in planimetry and 9 m in height. A more satisfactory georeferencing accuracy of better than 3.5 m in planimetry and 3.0 m in height was achieved after the block adjustment with four GCPs.

scholarly journals On Study of Two-Dimensional Lunar Scan for Advanced Technology Microwave Sounder Geometric Calibration

2019 ◽  
Author(s):  
Jun Zhou ◽  
Hu Yang
Keyword(s):  
Inflection Point ◽  
Gaussian Function ◽  
Euler Angle ◽  
Advanced Technology ◽  
Two Dimensional ◽  
Geometric Calibration ◽  
Pointing Error ◽  
V Band ◽  
W Band ◽  
Calibration Accuracy

Abstract. The NOAA-20 satellite was successfully launched on 18 November 2017. It carries five key instruments including Advanced Technology Microwave Sounder (ATMS). On January 31, 2018, the spacecraft performed a pitch-over maneuver operation, during which the two-dimensional lunar scan observations were collected. In this study, a technique has been developed by which the ATMS on-orbit geometric calibration accuracy can be validated based on this lunar scan dataset. The fully calibrated data are fitted in the antenna pattern coordinate by Gaussian function. The deviation of the center of the fit function from the origin of the frame is taken to be the boresight pointing error of the instrument. This deviation is further transformed to the Euler angle roll and pitch defined in spacecraft coordinate system. The estimated ATMS boresight pointing Euler angle roll (pitch) is 0.05°, (0.22°) at K-band, −0.07°, (0.25°) at Ka-band, 0.02°, (0.24°) at V-band, −0.07°, (−0.08°) at W-band, and −0.04°, (0.02°) at G-band. The results are validated by comparing with those derived from the coastline inflection point method. It shows that the Euler angles derived from these two independent methods are consistent very well. For the sounding channels where the coastline method is inapplicable, the lunar scan method is still capable of delivering reasonable estimations of their geometric calibration errors.

scholarly journals Intercalibration of GOES-11 and GOES-12 Water Vapor Channels with MetOp IASI Hyperspectral Measurements

2009 ◽  
Vol 26 (9) ◽  
pp. 1843-1855 ◽  
Author(s):  
Likun Wang ◽  
Changyong Cao ◽  
Mitch Goldberg
Keyword(s):  
Water Vapor ◽  
Weather Forecasting ◽  
Spectral Response ◽  
Sensor Performance ◽  
Calibration Accuracy ◽  
Polar Orbiting Satellite ◽  
One Year ◽  
Climate Studies ◽  
Better Than

Abstract The calibrated radiances from geostationary water vapor channels play an important role for weather forecasting, data assimilation, and climate studies. Therefore, better understanding the data quality for radiance measurements and independently assessing their onboard calibrations become increasingly more important. In this study, the Infrared Atmospheric Sounding Interferometer (IASI) hyperspectral measurements on the polar-orbiting Meteorological Operation-A (MetOp-A) satellite are used to assess the calibration accuracy of water vapor channels on the Geostationary Operational Environmental Satellite-11 (GOES-11) and GOES-12 imagers with one year of data. The near-simultaneous nadir observations with homogeneous scenes from IASI and GOES imagers are spatially collocated. The IASI spectra are convolved with the GOES imager spectral response functions (SRFs) to compare with GOES imager observations. Assuming that IASI is well calibrated and can be used as an on-orbit radiometric reference standard, then the GOES imager water vapor channels have an overall relative calibration bias to IASI of better than 0.3 K (with a standard deviation of ∼0.2 K) at the brightness temperature (BT) range of 240–260 K, which meets the design specification (1.0-K calibration accuracy for infrared channels). This study further demonstrates the technique of using hyperspectral radiance measurements in a polar-orbiting satellite to accurately assess broadband radiometer calibration of the GOES imager, which also provides an effective way for monitoring sensor performance over time. In addition, the potential of using the intercalibration results to integrate and merge data from different observing systems involving both IASI and different GOES imagers to create consistent, seamless global products is explored. The method presented here can potentially be applied to other instruments on both polar-orbiting and geostationary satellites for generating long-term time series.

scholarly journals A study of a two-dimensional scanned lunar image for Advanced Technology Microwave Sounder (ATMS) geometric calibration

2019 ◽  
Vol 12 (9) ◽  
pp. 4983-4992
Author(s):  
Jun Zhou ◽  
Hu Yang
Keyword(s):  
Inflection Point ◽  
Gaussian Function ◽  
Euler Angle ◽  
Advanced Technology ◽  
Two Dimensional ◽  
Geometric Calibration ◽  
Pointing Error ◽  
V Band ◽  
W Band ◽  
Calibration Accuracy

Abstract. The NOAA-20 satellite was successfully launched on 18 November 2017. It carries five key instruments, including the Advanced Technology Microwave Sounder (ATMS). On 31 January 2018, the spacecraft performed a pitch-over maneuver operation, during which two-dimensional lunar scan observations were collected. In this study, a technique has been developed by which the ATMS on-orbit geometric calibration accuracy can be validated based on this lunar scan dataset. The fully calibrated data are fitted to the antenna pattern coordinates via a Gaussian function. The deviation in the center of the fit function from the origin of the frame is taken to be the boresight pointing error of the instrument. This deviation is further transformed to the Euler angle roll and pitch defined in the spacecraft coordinate system. The estimated ATMS boresight pointing Euler angle roll (pitch) is 0.05∘ (0.22∘) at K band, −0.07∘ (0.25∘) at Ka band, 0.02∘ (0.24∘) at V band, -0.07∘ (-0.08∘) at W band, and -0.04∘ (0.02∘) at G band. The results are validated by comparing them with those derived from the coastline inflection point method, showing a good correlation. For the sounding channels where the coastline method is inapplicable, the lunar scan method is still capable of delivering reasonable estimations of their geometric calibration errors.

scholarly journals QUALITY INSPECTION FOR BLOCK ADJUSTMENT OF THE ZY3 STEREO SATELLITE IMAGERY

2021 ◽  
Vol XLIII-B3-2021 ◽  
pp. 775-781
Author(s):  
H. J. Tu ◽  
Y. Zhao ◽  
J. Guo ◽  
J. Zhou ◽  
S. B. Dou ◽  
...  
Keyword(s):  
3D Modeling ◽  
Satellite Image ◽  
Test Method ◽  
National Defense ◽  
Regional Network ◽  
Network Adjustment ◽  
Ecological Protection ◽  
Basic Work ◽  
Economic Construction

Abstract. 3D modeling and DEM results have played an important role in economic construction, national defense construction, social development, and ecological protection. And the regional network adjustment is the basic work of DEM, and 3D modeling. In order to ensure the quality of the following results, this paper selects the regional network adjustment results of the ZY3 stereo satellite image and puts forward the test method of the regional network adjustment results from the inspection content. Meanwhile, the northwest of Africa is selected as the test area, and the inspection contents and methods proposed in this paper are verified. The inspection results show that the quality problems existing in the adjustment results of the regional network can be effectively checked. It has a certain reference function to the quality problem of the production process.

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