GERAET ZUM AUTOMATISCHEN PRUEFEN VON ACHSSYMMETRISCHEN WERKSTUECKPROFILEN

1504537 Automatic inspection of machined parts INDUSTRY SECRETARY OF STATE FOR 4 June 1976 [12 June 1975] 25273/75 Heading G1A In an apparatus for the automatic inspection of an axially symmetric conponent 18 in a groove 9 of a rotating annular transparent plate 5, radiation from a quartz halogen light source 15 is directed as shown in Figs. 1 and 2. Thus a "shadow-image" is projected by lenses 31, 32 on to a vidicon tube or a line of photo-diodes 34. The resulting electrical signals are fed via timing logic TL, control logic CL and a threshold detector to an interface unit IU in a computer processor CP. The annular plate 5 is supported on a turntable 1 whose spindle 2 supports a radial diffractor grating 35. At the periphery a light source 39 an index grating 36 and a photodiode are arranged. Each time that the diode 40 detects a null-intensity of the beam from the source 39, a pulse P is sent to the interface unit IU which relays a "START SCAN" signal to the vidicon tube or the array 34. The resulting data is processed by a processing module PH according to flow diagrams Figs. 3 and 8 (not shown). The module PM is connected to a keyboard K and may supply a visual display unit VDU, an accept/reject facility AR, and an alarm unit AU. The description discloses formula and methods concerned with overcoming the effects of distortion of the video image. The distortion is caused by the component 18 moving in a circular path so that successive "scans" are at an angle relative to one another.