| 摘要 |
1,171,142. Photo-electric inspection of sheet material; determining surface roughness; testing for surface flaws. G.L. WATSON and D. L, STRADLEY. Dec. 1, 1966 [Dec. 10, 1965], No. 53752/66. Headings G1A, G1M and G1S. Sheets of wood are automatically graded after passage through an inspection station containing a television camera whose raster scan is across the direction of movement of the sheets. A sheet of wood is appraised for flaws by counting the times the television camera signal exceeds a selected threshold, indicating a flaw of a particular severity, and the times when a camera signal exceeding the level lasts for at least two non-consecutive scans, indicating a flaw of a particular length. In the embodiment shown in Fig.3 a television camera 10 receives via mirror 58 and polarizer 60 polarized light reflected off the surface of a sheet of wood 14 carried on a moving belt 16 and scans in raster fashion the wood in a direction perpendicular to its direction of movement. The vertical and horizontal synchronization pulses of the raster respectively reset and step on a counter 64 which via pulse generator 24 opens AND gate 62 only during the 15th line of the raster permitting the camera output to pass to a selected one of level detectors A, B or C. The output of a level detector steps a counter 84, particular counts of which set actuators to classify the quality of the wood. If a flaw was detected on the 15th scan a gate 110 receives an input from a level detector and, upon the third line scan of the next raster, operates the AND gate 62 so passing the camera output to the level detector. If the flaw is still present the appropriate counter is stepped on to further downgrade the wood. An array of mechanical sensors spaced across the moving sheet may be used to gauge roughness. Two kinds of mechanical transducer are shown in Figs. 3 and 4, each comprising a serrated wheel 116 upon an arm 114 which swings over to close switch 120 upon scanning a rough patch and operates all level detectors in Fig. 3. |
