The full hemispherical BRDF of spraypainted latex blue paint, Pratt &
Lambert, Vapex Interior Wall Base 1, Color #1243, Cal.III.
The incidence angles are 0°, 20°, 35°, 55°, 65°, 75°,
and 85°. For each of these, there are 19x73 measurement angles across the
hemisphere. Wavelengths span the visible range. Data are in MATLAB binary files.
 paint.raw.mat contains the raw
measurement data:
 e.g. brdf00: BRDF values at 0 degrees incidence angle, for 65
wavelengths and 16 (or more) outgoing directions.
 e.g. phi00: the 16 corresponding outgoing azimuthal angles.
 e.g. theta00: the 16 corresponding outgoing polar angles.
 wavelengths: the 65 corresponding wavelengths (note that data
below 450nm are very noisy).
 paint.clean.mat contains the data
after reorganisation, with interpolation of missing values:
 e.g. brdf00_450: 19x73 BRDF values at 0 degrees incidence angle
and a wavelength of 450nm.
 phi: the 19x73 corresponding outgoing azimuthal angles.
 theta: the 19x73 corresponding outgoing polar angles.
 paint.reformat.mat
contains the same data as paint.raw.mat, but reorganized
to match the format of all our other MATLAB files:
 dir_in: the 1255 incoming direction vectors (with the
zaxis of the coordinate system aligned along the normal).
 dir_out: the 1255 outgoing direction vectors.
 fr: the 1255 BRDF values at 65.
 wavelength: 65 wavelengths corresponding to fr
The following plots give an impression of the behavior for a few incidence
angles at a few wavelengths between 450 and 650nm, in the plane of incidence
only:
0°  largely diffuse, with a
small retroreflective bump. The lobes are larger for short wavelengths (blue,
cyan,... curves), because the paint is blue.
35°  the bump on the left is a
retroreflective bump.
55°  again, the bump is a
retroreflective bump. The forward scattering on the right becomes apparent,
especially for long wavelengths, for which there is less subsurface scattering.
75°
75° zoomed out.
Note the strong forward scattering. The directionaldiffuse lobes are
approximately equally sized for different wavelengths, yielding colorless
highlights.
Bristol Data
We measured a set of five samples provided by Ann McNamara of Bristol
University. These were flat interior house paint in neutral colors
ranging from black to white. The BRDF of each sample was measured at
1502 combinations of incident and exitant angles. The incident angles
were 10°, 20°, ... 80°. The exitant directions are
distributed uniformly over the hemisphere. The BRDF measurements were
made at 550nm; we also include the directionalhemispherical
(diffuse) reflectance as a function of wavelength, as measured by
our Optronics OL750 instrument from 300 to 700nm.
The MATLAB file for each sample contains the following variables:
 dir_in: the 1502 incoming direction vectors (with the
zaxis of the coordinate system aligned along the normal).
 dir_out: the 1502 outgoing direction vectors.
 fr: the 1502 BRDF values at 550nm.
 data: the diffuse reflectance at 41 wavelengths.
 wavelength: 41 wavelengths corresponding to data
Added paint.reformat.mat: data reorganized into format similar
to other datasets April 2, 2001
Added Bristol data January 11, 2001
Separated into its own directory January 11, 2001
