| 摘要 |
<p>The device comprises a darkened housing (2) into which is fed the metallic strip (3) on rollers (4,5). The printed side of the strip is illuminated directly by flash lights (13,14) and indirectly a further flash lights (11,12) using a reflective diffusing surface (25). The objective lens of a video camera is located in a central opening in the diffuser to enable a section (7) of the strip to be examined. The objective lens is fitted with a semi-transparent filter (57) obliquely angled to reflect light received directly from the lower exterior lamp, which itself is fitted with a translucent diffuser. The lights and camera are located on a mounting assembly which can be moved within the housing to scan the full width of the strip. The camera is linked to a computer and monitor, to view and record reference and actual images, at pixel level, to detect print defects.</p> |
