The Spectralon is commonly used in reflectance spectroscopy for reflectance calibration. Since the laser scanner measurement only occurs in backscatter direction only,
we call the intensity measured with TLS (and calibrated with the intensity of Spectralon reference measured similarly), i.e., the directional portion of the (hemispherical) reflectance,
the backscattered reflectance of the target (cf. Kaasalainen et al., 2009a).