Abstract: Optical inspection apparatus includes an illumination system illuminating an area of the workpiece surface with a sky of illumination which is, with respect to each point in the illuminated area, substantially circularly symmetric over a solid angle around the optical axis passing perpendicularly through the electro-optical sensor and the workpiece surface.

Abstract: An illumination system particularly useful for inspecting a workpiece by an optic scanner includes darkfield illumination produced mainly by two elongate light sources each having a reflector focussing member and a lenticular lens sheet spreading the light from its light source over its reflector focussing member to produce an approximate image of its light source on the line to be scanned. The illumination system further includes brightfield illumination produced mainly by a third elongate light source mounted laterally of the scanner optic axis, a refractive focussing member, and a further lenticular lens sheet producing an approximate image of the third light source on the line to be scanned. A beamsplitter aligned with the scanner optic axis reflects the light from the refractive focussing member towards the workpiece, and conducts therethrough both the darkfield and brightfield illumination reflected from the workpiece to the optic scanner.

Abstract: An immobilizing device particularly useful during processing or testing flat workpieces includes an air-cushion unit carried at the lower end of a carrier member and having an annular skirt defining with the workpiece, an air-cushion chamber effective, when pressurized, to cause the air-cushion unit to hover over the workpiece to permit relative movement between the air-cushion unit and the workpiece and table, while immobilizing and flattening the board with respect to the table.

Abstract: A telecentric imaging system includes a Fresnel lens mountable in proximity to an object to be imaged, a source of light for illuminating the object, and an aperture stop located at least in the telecentric imaging system is incorporated into an optical inspection machine which permits optical distortion produced by the telecentric imaging system to be corrected using a look-up table.

Abstract: Inspection of workpieces traveling along a production line includes on-line inspection of the workpieces at an upstream inspection station to detect possible flaws without interrupting the progression of workpieces along the production line. Possible flaws in the inspected workpieces are imaged, and images of possible flaws are stored in a memory in a way that associates a stored image with the workpiece containing the possible flaw. Off-line, a stored image is retrieved from the memory before the workpiece with which the image is associated reaches a downstream sorting station. The retrieved image is displayed on a monitor for verifying, by visual inspection, whether the possible flaw in the workpiece with which the retrieved image is associated, is valid. Workpieces are diverted at the downstream sorting station in response to vertification of flaws.