Stefan Dangel

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In spectrodirectional Remote Sensing (RS) the Earth's surface reflectance characteristics are studied by means of their angular dimensions. Almost all natural surfaces exhibit an individual anisotropic reflectance behaviour due to the contrast between the optical properties of surface elements and background and the geometric surface properties of the(More)
Field and laboratory goniometers are widely used in the remote sensing community to assess spectrodirectional reflection properties of selected targets. Even when the same target and goniometer system are used, field and laboratory results cannot directly be compared due to inherent differences, mainly in the illumination conditions since actual goniometers(More)
In the remote sensing user community there is a lack of consistency in definitions and properties of reflectance quantities. On one hand, more recent satellite programs such as NASA's MODIS and MISR sensors take into account the directional dimension of the different reflectance products. On the other hand, many published studies still remain unspecific on(More)
Spectrodirectional experiments with goniometer systems are only able to observe approximations of truly directional surface reflectance properties (BRDF). The directly observed quantity in field experiments is called hemispherical directional reflectance factor (HDRF), corresponding to hemispherical illumination, which depends on the atmospheric conditions,(More)
Field and laboratory goniometers are widely used in the remote sensing community to assess spectrodirectional reflectance properties of selected targets. Even when the same target and goniometer system are used, field and laboratory results cannot directly be compared due to inherent differences, mainly in the illumination conditions: typically goniometers(More)
Spectro-directional surface measurements can either be performed in the field or within a laboratory setup. Laboratory measurements have the advantage of constant illumination and neglectable atmospheric disturbances. On the other hand, artificial light sources are usually less parallel and less homogeneous than the clear sky solar illumination. To account(More)
Laser Dynamics 12 Laser Dynamics S. Dangel, A. Schneider, R. Holzner A main part of our research activities, besides the laser related projects described in the section on surface physics, is the investigation of nonlinear spatio-temporal e ects caused by the interaction of resonant laser beams with sodium atoms in the gas phase. A circularly polarized(More)