To follow and inspect a common edge between two sheet metal blanks which are
to
be welded together, a line pattern is projected across the edge by a projector
and is imaged by a camera. The image captured is analyzed in order to derive from
the trace of the lines information on the gap between the blanks, or on the track
of the edge. The pattern projected has several lines with different light intensities.
When the photographed image is processed, it is then possible-even if there is
variation in the reflection characteristics of the sheet metal blanks-to select
a line which is neither too faint nor too bright in the image obtained and which
can therefore be used for meaningful analysis.
