Theoretical Study on Radiative Properties of a Painted Layer Containing Spherical Pigment : Cases of Oblique and Hemispherical Incidences

抄録

The analysis is carried out on the reflective properties of a painted layer of absorbing and anisotropically scattering medium. The cases of oblique and hemispherical incidences are treated together with a special case of axisymmetric incidence. The azimuth-dependent functions in the case of oblique incidence are expressed in a finite Fourier series whose argument is the azimuth difference between the direction of incidence to the layer and the direction of the diffuse radiation inside it. The effects of the optical thickness, the incidence angle, the optical properties of the pigment (TiO₂, Fe₂O₃ and carbon) and the reflection characteristics of the substrate (specular or diffuse) on the bidirectional, directional and hemispherical reflectances are examined in the wavelength range from 0.35 to 20 μm. The results for hemispherical incidence with uniform irradiation show a coincidence with those for axisymmetric incidence at a polar angle of 60°.