Deflectometry uses a surface as a light source whose direct reflection is analyzed. In principle, only this approach allows inspection of objects with high-gloss surfaces, such as a vehicle’s painted parts, where alternative approaches that analyze diffuse reflection fail. Furthermore, the system reacts very sensitively to changes in surface curvature, which is exactly why precise error identification in the range of a few micrometers is possible.
The core of defect identification is the use of multi-image shots. For this purpose, the monitor creates a sinusoidal striped pattern, which is shifted in several phased steps; each time, the cameras take a shot of the surface. Next, the pattern is turned by 90° and the process is repeated. This data recording process permits perfectly uniform high resolution across the entire surface.
Any error, independent of its position on the surface and its orientation, is therefore identified. Furthermore, the images’ unavoidable static error effects are not classified as pseudo errors because they automatically cancel each other out when the images are calculated. Together with complex image processing algorithms, all defects that are typically found on vehicle bodies, such as contacts, inclusions/bulges, lint/hairs in the paint, glue residues, mottling, craters, paint separations, paint drops, running paint, pinpricks, overspray, molding defects, marks, shell defects, slider marks, sanding defects, welding beads, spitting, specks, partial/thin paint, contamination and water drops, are identified.
Source: MICRO-Epsilon Messtechnik media clippingsl