Vision sensors using optical triangulation have been widely used for a
utomatic welding systems in various ways. Their reliability is, howeve
r, seriously influenced by the are light reflected from the base metal
surface. In this study, the reliability of vision sensors was analyze
d for the variation of the are noise by considering the reflectance of
the base metal surfacer The property of the surface reflection of the
base metal was modeled using the bidirectional reflectance-distributi
on function (BRDF), and then the intensity variation of the reflected
are was formulated or various configurations of the torch, base metal
and sensor. The experimental data of the are light reflection were obt
ained for two materials, mild steel and stainless steel, each having d
ifferent surface reflection characteristics. It was found that the res
ults calculated from the proposed model were in good agreement with th
e experimental data.