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7.4.
Step 4: Characterization of the angular profiles
All the profiles are characterized by parameters such as the maximum, width and
integral values.
Parameters given for:
SPECULAR PROFILES
(Luminance*, Red, Green and Blue profiles)
* Luminance is the average of the three RGB (Red/Green/Blue) profiles:
-
Max: maximum of the profiles
-
θ
0
(deg) : half width of the peak at Max/e (note: e~2.72)
-
Integral: mathematical integral (area under the curve)
-
W
visual
(deg): this parameter is computed on the specular image and not on the
specular profile. W
visual
is the averaged width of the specular band along the ROI
width.
When looking at hair, the human eye follows the change of the shine band due to
the shape of the object. By measuring W
visual
on the image rather than on the profile,
the result we obtained is more correlated to human perception.
Max
Width at
Max/2