摘要 |
<p>The conformance of an unknown object (12) to predetermined characteristics is evaluated through a characteristic signature, using its transform image. The presence at an inspection station (16) of each successive one of the objects (12) to be inspected is detected. The inspection system includes a rotatable disk (36) having mask apertures (42) that move into the line of sight of a light detector (38). Signals produced by scanning of timing marks (41) upon the disk (36) reflect which one of the plurality of masks (42) is present in the optical path, and the photodetector (38) determines the intensity of the transform image sampled by said mask means (42). The signals representing these intensities, correlated to the domain from which they emanate, are collected to form a signature for the object. This signature is compared to a known signature.</p> |