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7.2.
Step 2: Extraction of the angular profiles
Vertical crossed sections of the ROI are averaged (rectangles of ten pixels by 778) to give
the angular distributions.
The profiles are then normalized by the average level in the reference target. The
normalization target consists of a gray gloss tile. This allows to compensate for any drift
of the light power. Therefore, the measurements are highly reproducible and stable in
time.
The profiles are unitless. They can be seen as the reflectance of hair.
Averaging of the
crossed sections
along the ROI width
Specular (3)
Region Of
Interest
(ROI)
Reference
Target
(Glossy gray
tile)
778 pixels = 90deg
