| 摘要 |
<p>A system for simultaneously detecting imperfections of both sides of a dual sided compact disc (1) includes a self-centering chuck (7) for retaining the compact disc (1) and rotating it beneath two illumination sources (9) and dual video cameras (15) or other devices for receiving light from the illumination source (9) that reflects from the surface (17) under study. The cameras (15) are oriented to receive illumination reflected only from an imperfectly flat portion of the surfaces (17) being inspected. A stepping motor (19) is used to turn the compact disc (1) through a number of positions during at least one complete revolution while it is exposed to the light sources (9). The signals received in the video cameras (15) are then processed by a template algorithm to compare the light level received with that from an assumed flat portion of the disc.</p> |
