Reflection lines are another first-order interrogation method
used in the automotive industry to assess the fairness of a surface.
Reflection lines simulate the mirror images of a number of parallel
straight fluorescent lights on an automobile surface. In this method,
deviations of the surface from a smooth shape can be detected by
irregularities of the reflection lines. Originally a reflection line
was defined as a reflected image of a linear light source on a surface
by Klass [202]. Kaufmann and Klass [190] modified
the above definition to reduce the computation as follows. A family of
curves
,
on the surface, which are
intersection curves of the surface with a specific family of
planes parallel to a unit vector
, are evaluated. For each
intersection curve
, parameter
that satisfies
(8.3)
is evaluated.
Then points
,
,
are connected to form the reflection line. The procedure
is repeated for different values of
. If iso-parametric lines
are used instead of intersection curves of the surface with a family
of parallel planes, computational efficiency is further improved
as in [3]. Choi and Lee [61] applied the Blinn-Newell
type of reflection mapping [118], which uses simple and
physically acceptable mapping algorithm, to generate reflection lines
on a trimmed NURBS surface. Choi and Lee [61]
also provide a thorough recent review of this topic.
Color Plate A.2 depicts reflection lines on the
bicubic B-spline surface patch shown in Fig.
8.1, where values of
with
are
evaluated along iso-parametirc curves and the equal value points found
by interpolation between mesh points are connected to form the
reflection lines.
Next: 8.1.2.4 Highlight lines
Up: 8.1.2 First-order interrogation methods
Previous: 8.1.2.2 Isophotes
Contents Index
December 2009