SPECTRAL RECONSTRUCTION BASED ON SVM FOR CROSS CALIBRATION

Chinese HY-1C/1D satellites will use a 5nm/10nm-resolutional visible-near infrared(VNIR) hyperspectral sensor with the solar calibrator to cross-calibrate with other sensors. The hyperspectral radiance data are composed of average radiance in the sensor’s passbands and bear a spectral smoothing effect, a transform from the hyperspectral radiance data to the 1-nm-resolution apparent spectral radiance by spectral reconstruction need to be implemented. In order to solve the problem of noise cumulation and deterioration after several times of iteration by the iterative algorithm, a novel regression method based on SVM is proposed, which can approach arbitrary complex non-linear relationship closely and provide with better generalization capability by learning. In the opinion of system, the relationship between the apparent radiance and equivalent radiance is nonlinear mapping introduced by spectral response function(SRF), SVM transform the low-dimensional non-linear question into high-dimensional linear question though kernel function, obtaining global optimal solution by virtue of quadratic form. The experiment is performed using 6S-simulated spectrums considering the SRF and SNR of the hyperspectral sensor, measured reflectance spectrums of water body and different atmosphere conditions. The contrastive result shows: firstly, the proposed method is with more reconstructed accuracy especially to the high-frequency signal; secondly, while the spectral resolution of the hyperspectral sensor reduces, the proposed method performs better than the iterative method; finally, the root mean square relative error(RMSRE) which is used to evaluate the difference of the reconstructed spectrum and the real spectrum over the whole spectral range is calculated, it decreses by one time at least by proposed method.

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Active Hyperspectral Sensor Based on MEMS Fabry-Pérot Interferometer

Sensors ◽

10.3390/s19092192 ◽

2019 ◽

Vol 19 (9) ◽

pp. 2192 ◽

Cited By ~ 1

Author(s):

Teemu Kääriäinen ◽

Priit Jaanson ◽

Aigar Vaigu ◽

Rami Mannila ◽

Albert Manninen

Keyword(s):

Near Infrared ◽

Spectral Power ◽

Spectral Response ◽

Field Measurements ◽

Spectral Power Density ◽

Long Term Stability ◽

Spectral Discrimination ◽

Fabry Perot ◽

Cost Efficient ◽

Hyperspectral Sensor

An active hyperspectral sensor (AHS) was developed for target detection and classification applications. AHS measures light scattered from a target, illuminated by a broadband near-infrared supercontinuum (SC) light source. Spectral discrimination is based on a voltage-tunable MEMS Fabry-Pérot Interferometer (FPI). The broadband light is filtered by the FPI prior to transmitting, allowing for a high spectral-power density within the eye-safety limits. The approach also allows for a cost-efficient correction of the SC instability, employing a non-dispersive reference detector. A precision of 0.1% and long-term stability better than 0.5% were demonstrated in laboratory tests. The prototype was mounted on a car for field measurements. Several road types and objects were distinguished based on the spectral response of the sensor targeted in front of the car.

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Integrated near-infrared spectral sensing

Nature Communications ◽

10.1038/s41467-021-27662-1 ◽

2022 ◽

Vol 13 (1) ◽

Author(s):

Kaylee D. Hakkel ◽

Maurangelo Petruzzella ◽

Fang Ou ◽

Anne van Klinken ◽

Francesco Pagliano ◽

...

Keyword(s):

Near Infrared ◽

Prediction Models ◽

Spectral Response ◽

Resonant Cavity ◽

Industrial Process ◽

Chemical Information ◽

Minimal Size ◽

Spectral Reconstruction ◽

Infrared Spectral ◽

Spectral Sensing

AbstractSpectral sensing is increasingly used in applications ranging from industrial process monitoring to agriculture. Sensing is usually performed by measuring reflected or transmitted light with a spectrometer and processing the resulting spectra. However, realizing compact and mass-manufacturable spectrometers is a major challenge, particularly in the infrared spectral region where chemical information is most prominent. Here we propose a different approach to spectral sensing which dramatically simplifies the requirements on the hardware and allows the monolithic integration of the sensors. We use an array of resonant-cavity-enhanced photodetectors, each featuring a distinct spectral response in the 850-1700 nm wavelength range. We show that prediction models can be built directly using the responses of the photodetectors, despite the presence of multiple broad peaks, releasing the need for spectral reconstruction. The large etendue and responsivity allow us to demonstrate the application of an integrated near-infrared spectral sensor in relevant problems, namely milk and plastic sensing. Our results open the way to spectral sensors with minimal size, cost and complexity for industrial and consumer applications.

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Modeling the night-sky radiances and inversion of multi-angle and multi-spectral radiance data

Journal of Quantitative Spectroscopy and Radiative Transfer ◽

10.1016/j.jqsrt.2013.12.002 ◽

2014 ◽

Vol 139 ◽

pp. 35-42 ◽

Cited By ~ 9

Author(s):

Miroslav Kocifaj

Keyword(s):

Spectral Radiance ◽

Night Sky ◽

Radiance Data ◽

And Inversion

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Near Infrared Spectroscopic Determination of Alcohols—Solving Non-Linearity with Linear and Non-Linear Methods

Journal of Near Infrared Spectroscopy ◽

10.1255/jnirs.235 ◽

1999 ◽

Vol 7 (1) ◽

pp. 55-62 ◽

Cited By ~ 18

Author(s):

Yue Li ◽

Chris W. Brown ◽

Su-Chin Lo

Keyword(s):

Near Infrared ◽

Spectroscopic Determination ◽

Non Linear ◽

Infrared Spectroscopic

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Influence of local surface albedo variability and ice crystal shape on passive remote sensing of thin cirrus

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-1943-2014 ◽

2014 ◽

Vol 14 (4) ◽

pp. 1943-1958 ◽

Cited By ~ 12

Author(s):

C. Fricke ◽

A. Ehrlich ◽

E. Jäkel ◽

B. Bohn ◽

M. Wirth ◽

...

Keyword(s):

Optical Thickness ◽

Surface Albedo ◽

Near Infrared ◽

Effective Radius ◽

High Spectral Resolution ◽

Spectral Radiance ◽

Crystal Shape ◽

Frequency Distributions ◽

Airborne Measurements ◽

Moderate Resolution Imaging Spectroradiometer

Abstract. Airborne measurements of solar spectral radiance reflected by cirrus are performed with the HALO-Solar Radiation (HALO-SR) instrument onboard the High Altitude and Long Range Research Aircraft (HALO) in November 2010. The data are used to quantify the influence of surface albedo variability on the retrieval of cirrus optical thickness and crystal effective radius. The applied retrieval of cirrus optical properties is based on a standard two-wavelength approach utilizing measured and simulated reflected radiance in the visible and near-infrared spectral region. Frequency distributions of the surface albedos from Moderate resolution Imaging Spectroradiometer (MODIS) satellite observations are used to compile surface-albedo-dependent lookup tables of reflected radiance. For each assumed surface albedo the cirrus optical thickness and effective crystal radius are retrieved as a function of the assumed surface albedo. The results for the cirrus optical thickness are compared to measurements from the High Spectral Resolution Lidar (HSRL). The uncertainty in cirrus optical thickness due to local variability of surface albedo in the specific case study investigated here is below 0.1 and thus less than that caused by the measurement uncertainty of both instruments. It is concluded that for the retrieval of cirrus optical thickness the surface albedo variability is negligible. However, for the retrieval of crystal effective radius, the surface albedo variability is of major importance, introducing uncertainties up to 50%. Furthermore, the influence of the bidirectional reflectance distribution function (BRDF) on the retrieval of crystal effective radius was investigated and quantified with uncertainties below 10%, which ranges below the uncertainty caused by the surface albedo variability. The comparison with the independent lidar data allowed for investigation of the role of the crystal shape in the retrieval. It is found that if assuming aggregate ice crystals, the HSRL observations fit best with the retrieved optical thickness from HALO-SR.

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Effects of Metal Stress on Visible/Near-Infrared Reflectance Spectra of Vegetation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.347-353.2735 ◽

2011 ◽

Vol 347-353 ◽

pp. 2735-2738 ◽

Cited By ~ 3

Author(s):

Guang Yu Chi ◽

Yi Shi ◽

Xin Chen ◽

Jian Ma ◽

Tai Hui Zheng

Keyword(s):

Heavy Metal ◽

Structural Changes ◽

Near Infrared ◽

Leaf Surface ◽

Spectral Response ◽

Spectral Characteristics ◽

Surface Characteristics ◽

Heavy Metal Stress ◽

Metal Stress ◽

Near Infrared Reflectance

Vegetation which suffers from heavy metal stresses can cause changes of leaf color, shape and structural changes. The spectral characteristics of vegetation leaves is related to leaf thickness, leaf surface characteristics, the content of water, chlorophyll and other pigments. So the eco-physiology changes of plants can be reflected by spectral reflectance. Studies on the spectral response of vegetation to heavy metal stress can provide a theoretical basis for remote sensing monitoring of metal pollution in soils. In recent decades, there are substantial amounts of literature exploring the effects of heavy metals on vegetation spectra.

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Snow dunes and glazed surfaces in Antarctica: new field and remote-sensing data

Annals of Glaciology ◽

10.3189/172756402781817851 ◽

2002 ◽

Vol 34 ◽

pp. 81-88 ◽

Cited By ~ 57

Author(s):

Massimo Frezzotti ◽

Stefano Gandolfi ◽

Floriana La Marca ◽

Stefano Urbini

Keyword(s):

Remote Sensing ◽

Near Infrared ◽

Accumulation Rate ◽

Spectral Response ◽

Remote Sensing Data ◽

Snow Accumulation ◽

Remotely Sensed Data ◽

Surface Mass ◽

Glazed Surface ◽

Transverse Dunes

AbstractAs part of the International Trans-Antarctic Scientific Expedition project, the Italian Antarctic Programme undertook two traverses from the Terra Nova station to Talos Dome and to Dome C. Along the traverses, the party carried out several tasks (drilling, glaciological and geophysical exploration). The difference in spectral response between glazed surfaces and snow makes it simple to identify these areas on visible/near-infrared satellite images. Integration of field observation and remotely sensed data allows the description of different mega-morphologic features: wide glazed surfaces, sastrugi glazed surface fields, transverse dunes and megadunes. Topography global positioning system, ground penetrating radar and detailed snow-surface surveys have been carried out, providing new information about the formation and evolution of mega-morphologic features. The extensive presence, (up to 30%) of glazed surface caused by a long hiatus in accumulation, with an accumulation rate of nil or slightly negative, has a significant impact on the surface mass balance of a wide area of the interior part of East Antarctica. The aeolian processes creating these features have important implications for the selection of optimum sites for ice coring, because orographic variations of even a few metres per kilometre have a significant impact on the snow-accumulation process. Remote-sensing surveys of aeolian macro-morphology provide a proven, high-quality method for detailed mapping of the interior of the ice sheet’s prevalent wind direction and could provide a relative indication of wind intensity.

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Radiometric Performance Evaluation of FY-4A/AGRI Based on Aqua/MODIS

Sensors ◽

10.3390/s21051859 ◽

2021 ◽

Vol 21 (5) ◽

pp. 1859

Author(s):

Bo Zhong ◽

Yingbo Ma ◽

Aixia Yang ◽

Junjun Wu

Keyword(s):

Near Infrared ◽

Spectral Response ◽

Convective Cloud ◽

Radiation Level ◽

High Attenuation ◽

Total Attenuation ◽

Attenuation Rate ◽

Calibration Facility ◽

Deep Convective Cloud ◽

Directional Reflectance

Fengyun-4A (FY-4A) is the first satellite of the Chinese second-generation geostationary orbit meteorological satellites (FY-4). The Advanced Geostationary Radiation Imager (AGRI), onboard FY-4A does not load with high-precision calibration facility in visible and near infrared (VNIR) channel. As a consequence, it is necessary to comprehensively evaluate its radiometric performance and quantitatively describe the attenuation while using its VNIR data. In this paper, the radiometric performance at VNIR channels of FY-4A/AGRI is evaluated based on Aqua/MODIS data using the deep convective cloud (DCC) target. In order to reduce the influence of view angle and spectral response difference, the bi-directional reflectance distribution function (BRDF) correction and spectral matching have been performed. The evaluation result shows the radiometric performance of FY-4A/AGRI: (1) is less stable and with obvious fluctuations; (2) has a lower radiation level because of 24.99% lower compared with Aqua/MODIS; 3) has a high attenuation with 9.11% total attenuation over 2 years and 4.0% average annual attenuation rate. After the evaluation, relative radiometric normalization between AGRI and MODIS in VNIR channel is performed and the procedure is proved effective. This paper proposed a more reliable reference for the quantitative applications of FY-4A data.

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