A new method to determine multi-angular reflectance factor from lightweight multispectral cameras with sky sensor in a target-less workflow applicable to UAV
| Autor: | Manuel Cubero-Castan, Christoph Strecha, Klaus Schneider-Zapp, Dai Shi |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
reflectance
010504 meteorology & atmospheric sciences Computer science media_common.quotation_subject 0208 environmental biotechnology Multispectral image FOS: Physical sciences Soil Science 02 engineering and technology 01 natural sciences multi-angular Physics - Geophysics hemispheric-directional reflectance factor (hdrf) Calibration Computers in Earth Sciences 0105 earth and related environmental sciences Remote sensing media_common Spectralon Orientation (computer vision) Geology multispectral camera downwelling irradiance sensor calibration remote Geophysics (physics.geo-ph) 020801 environmental engineering Photogrammetry Overcast Sky Physics - Data Analysis Statistics and Probability crop surface models systems Radiometry aircraft Data Analysis Statistics and Probability (physics.data-an) |
| Zdroj: | Remote Sensing of Environment. 229:60-68 |
| ISSN: | 0034-4257 |
| Popis: | A new physically based method to estimate hemispheric-directional reflectance factor (HDRF) from lightweight multispectral cameras that have a downwelling irradiance sensor is presented. It combines radiometry with photogrammetric computer vision to derive geometrically and radiometrically accurate data purely from the images, without requiring reflectance targets or any other additional information apart from the imagery. The sky sensor orientation is initially computed using photogrammetric computer vision and revised with a non-linear regression comprising radiometric and photogrammetry-derived information. It works for both clear sky and overcast conditions. A ground-based test acquisition of a Spectralon target observed from different viewing directions and with different sun positions using a typical multispectral sensor configuration for clear sky and overcast showed that both the overall value and the directionality of the reflectance factor as reported in the literature were well retrieved. An RMSE of 3% for clear sky and up to 5 for overcast sky was observed. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect