be done for several reasons. First, machine vision systems can locate the
position and orientation of a part, compare it to a specified tolerance, and
ensure it’s at the correct angle to verify proper assembly. Next, guidance can
be used to report the location and orientation of a part in 2D or 3D space to a
robot or machine controller, allowing the robot to locate the part or the
machine to align the part. Machine vision guidance achieves far greater speed
and accuracy than manual positioning in tasks such as arranging parts on or off
pallets, packaging parts off a conveyor belt, finding and aligning parts for
assembly with other components, placing parts on a work shelf, or removing
parts from bins.
Guidance can also be used for alignment to other
machine vision tools. This is a very powerful feature of machine vision because
parts may be presented to the camera in unknown orientations during production.
By locating the part and then aligning the other machine vision tools to it,
machine vision enables automatic tool fixturing. This involves locating key
features on a part to enable precise positioning of caliper, blob, edge, or
other vision software tools so that they correctly interact with the part. This
approach enables manufacturers to build multiple products on the same
production line and reduces the need for expensive hard tooling to maintain
part position during inspection.
Sometimes guidance requires geometric pattern matching. Pattern matching tools must tolerate large variations in contrast and lighting, as well as changes in scale, rotation, and other factors while finding the part reliably every time. This is because location information obtained by pattern matching enables the alignment of other machine vision software tools.