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@ARTICLE{Aasen:830014,
      author       = {Aasen, Helge and Burkart, Andreas and Bolten, Andreas and
                      Bareth, Georg},
      title        = {{G}enerating 3{D} hyperspectral information with
                      lightweight {UAV} snapshot cameras for vegetation
                      monitoring: {F}rom camera calibration to quality assurance},
      journal      = {ISPRS journal of photogrammetry and remote sensing},
      volume       = {108},
      issn         = {0924-2716},
      address      = {Amsterdam [u.a.]},
      publisher    = {Elsevier},
      reportid     = {FZJ-2017-03616},
      pages        = {245 - 259},
      year         = {2015},
      abstract     = {This paper describes a novel method to derive 3D
                      hyperspectral information from lightweight snapshot cameras
                      for unmanned aerial vehicles for vegetation monitoring.
                      Snapshot cameras record an image cube with one spectral and
                      two spatial dimensions with every exposure. First, we
                      describe and apply methods to radiometrically characterize
                      and calibrate these cameras. Then, we introduce our
                      processing chain to derive 3D hyperspectral information from
                      the calibrated image cubes based on structure from motion.
                      The approach includes a novel way for quality assurance of
                      the data which is used to assess the quality of the
                      hyperspectral data for every single pixel in the final data
                      product. The result is a hyperspectral digital surface model
                      as a representation of the surface in 3D space linked with
                      the hyperspectral information emitted and reflected by the
                      objects covered by the surface. In this study we use the
                      hyperspectral camera Cubert UHD 185-Firefly, which collects
                      125 bands from 450 to 950 nm. The obtained data product has
                      a spatial resolution of approximately 1 cm for the spatial
                      and 21 cm for the hyperspectral information. The radiometric
                      calibration yields good results with less than $1\%$ offset
                      in reflectance compared to an ASD FieldSpec 3 for most of
                      the spectral range. The quality assurance information shows
                      that the radiometric precision is better than $0.13\%$ for
                      the derived data product. We apply the approach to data from
                      a flight campaign in a barley experiment with different
                      varieties during the growth stage heading (BBCH 52 – 59)
                      to demonstrate the feasibility for vegetation monitoring in
                      the context of precision agriculture. The plant parameters
                      retrieved from the data product correspond to in-field
                      measurements of a single date field campaign for plant
                      height (R2 = 0.7), chlorophyll (BGI2, R2 = 0.52), LAI (RDVI,
                      R2 = 0.32) and biomass (RDVI, R2 = 0.29). Our approach can
                      also be applied for other image-frame cameras as long as the
                      individual bands of the image cube are spatially
                      co-registered beforehand.},
      cin          = {IBG-2},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IBG-2-20101118},
      pnm          = {582 - Plant Science (POF3-582)},
      pid          = {G:(DE-HGF)POF3-582},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000363075300020},
      doi          = {10.1016/j.isprsjprs.2015.08.002},
      url          = {https://juser.fz-juelich.de/record/830014},
}