scholarly journals A Hyperspectral Bidirectional Reflectance Model for Land Surface

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4456
Author(s):  
Qiguang Yang ◽  
Xu Liu ◽  
Wan Wu
Keyword(s):  
Land Surface ◽  
Solar Observation ◽  
Bidirectional Reflectance Distribution Function ◽  
Satellite Measurements ◽  
Bidirectional Reflectance ◽  
Reflective Spectrum ◽  
Vegetation Database ◽  
Airborne Sensors ◽  
Bidirectional Reflectance Distribution

A hyperspectral bidirectional reflectance (HSBR) model for land surface has been developed in this work. The HSBR model includes a very diverse land surface bidirectional reflectance distribution function (BRDF) database with ~40,000 spectra. The BRDF database is saved as Ross-Li parameters, which can generate hyperspectral reflectance spectra at different sensor and solar observation geometries. The HSBR model also provides an improved method for generating hyperspectral surface reflectance using multiband satellite measurements. It is shown that the land surface reflective spectrum can be easily simulated using BRDF parameters or reflectance at few preselected wavelengths. The HSBR model is validated using the U.S. Geological Survey (USGS) vegetation database and the AVIRIS reflectance product. The simulated reflective spectra fit the measurements very well with standard deviations normally smaller than 0.01 in the unit of reflectivity. The HSBR model could be used to significantly improve the quality of the reflectance products of satellite and airborne sensors. It also plays important role for intercalibration among space-based instruments and other land surface related applications.

Evapotranspiration estimation with MODIS land surface temperature after correction of the angle effect with two MODIS BRDF related products

2020 ◽  
Author(s):  
Yazhen Jiang ◽  
Ronglin Tang ◽  
Xiaoguang Jiang ◽  
Zhao_Liang Li
Keyword(s):  
Distribution Function ◽  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Three Dimensional ◽  
Bidirectional Reflectance Distribution Function ◽  
Bidirectional Reflectance ◽  
Angle Effect ◽  
Bidirectional Reflectance Distribution ◽  
Satellite Sensor

<p>Land surface temperature (LST) from remote sensing has been widely used to estimate regional and local scale evapotranspiration (ET). However, remotely sensed LST viewed by the same sensor from different angles would lead to different LST retrievals and this would lead to the deviation in ET estimations with LST as input. The terrestrial surface bidirectional reflectance distribution function (BRDF) are commonly inverted against multiple cloud-free, atmospherically-corrected directional reflectance values that sufficiently sample the anisotropy caused by different view angles. The MODerate-resolution Imaging Spectroradiometer (MODIS) product MCD43A1 contains three-dimensional (3D) data sets and can provide weighting parameters for the models used to derive the Albedo. The MODIS MCD43A4 is reflectance product providing reflectance data adjusted using a bidirectional reflectance distribution function (BRDF) to model the values as if they were taken from nadir view and solar zenith. Here we intend to operate the correction of the angle effect in LST with these two MODIS BRDF related products in ET estimation. The two products are used to provide reflectance with consistent view angle and with solar zenith of satellite sensor and 0° solar zenith, respectively, and then corresponding fractional vegetation cover (FVC) are calculated with two kinds of corrected reflectance, respectively. Combining the soil temperature (T<sub>s</sub>) and vegetation temperature (T<sub>v</sub>) components which are separated from MODIS LST and have no directional effects with the corrected FVC, the nadir LST (with solar zenith of satellite sensor and 0°solar zenith, respectively) were obtained. Finally, ET were estimated with the surface energy balance system (SEBS) model using the remote sensed LST and the two kinds of corrected LST as input, respectively. The results showed that compared to ET measurements, the ET estimations with two kinds of corrected LST as input performed much better than that with uncorrected LST as input, and ET estimation with corrected LST in which FVC are calculated from MCD43A1 had highest accuracy.</p>

scholarly journals The effect of molding conditions on the quality of geopolymer surfaces

2020 ◽  
Vol 50 (1) ◽  
Author(s):  
Janusz Jaglarz ◽  
Dominik Wyszyński ◽  
Michał Lach ◽  
Janusz Mikuła ◽  
Ryszard Duraj
Keyword(s):  
Point Of View ◽  
Contact Method ◽  
Bidirectional Reflectance Distribution Function ◽  
Qualitative Properties ◽  
Large Area ◽  
Bidirectional Reflectance ◽  
Measuring Surface ◽  
Measurement And Analysis ◽  
Bidirectional Reflectance Distribution

The presented work describes the method of measuring surface topography with application of BRDF (bidirectional reflectance distribution function), ellipsometry and spectrophotometry. This non-contact method enables measurement and analysis of large area surfaces, such as plasters and facades. A standard method of topography analysis does not describe sufficiently all of the interesting features. The visual aspect of the surface evaluation is very important from the functional and utilitarian point of view. The proposed methods of surface analysis enable not only the quantitative evaluation but also indirectly the qualitative properties (visual aspects).

scholarly journals One-shot BRDF imaging system to obtain surface properties

2021 ◽  
Author(s):  
Hiroshi Ohno ◽  
Takahiro Kamikawa
Keyword(s):  
Surface Properties ◽  
Imaging System ◽  
Reconstruction Method ◽  
Surface Reflectance ◽  
Bidirectional Reflectance Distribution Function ◽  
Bidirectional Reflectance ◽  
Color Mapping ◽  
System A ◽  
Cone Surface ◽  
Bidirectional Reflectance Distribution

AbstractThe bidirectional reflectance distribution function (BRDF) that describes an angle-resolved distribution of surface reflectance is available for characterizing surface properties of a material. A one-shot BRDF imaging system can capture an in-plane color mapping of light direction extracted from a surface BRDF distribution. A surface roughness identification method is then proposed here using the imaging system. A difference between surface properties of a matt paper and a glossy paper is experimentally shown to be detected using the method. A surface reconstruction method of an axisymmetric micro-object using the imaging system is also proposed here. The imaging system experimentally shows that it can reconstruct an axisymmetric aluminium cone surface with a height of 37 μm.

Comparison of Experiment With Monte Carlo Simulations on a Reflective Gap Using a Detailed Surface Properties Model

1996 ◽  
Vol 118 (2) ◽  
pp. 388-393 ◽  
Author(s):  
J. Zaworski ◽  
J. R. Welty ◽  
B. J. Palmer ◽  
M. K. Drost
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Grazing Angle ◽  
Incident Radiation ◽  
Monte Carlo Code ◽  
Bidirectional Reflectance Distribution Function ◽  
Bidirectional Reflectance ◽  
Detailed Surface ◽  
Bidirectional Reflectance Distribution

The spatial distribution of light through a rectangular gap bounded by highly reflective, diffuse surfaces was measured and compared with the results of Monte Carlo simulations. Incorporating radiant properties for real surfaces into a Monte Carlo code was seen to be a significant problem; a number of techniques for accomplishing this are discussed. Independent results are reported for measured values of the bidirectional reflectance distribution function over incident polar angles from 0 to 90 deg for a semidiffuse surface treatment (Krylon™ flat white spray paint). The inclusion of this information into a Monte Carlo simulation yielded various levels of agreement with experimental results. The poorest agreement occurred when the incident radiation was at a grazing angle with respect to the surface and the reflectance was nearly specular.

Sign in / Sign up

Export Citation Format

Share Document