| 摘要 |
There is described a hand-held device for recognising markings on a substrate. The hand-held device has a body (101) that has light directing means (209), light detecting means (203), means for analysing the detected light (103), and means (105) for shielding the light detecting means from ambient light. The analysing means is able to determine whether or not the directed light is incident upon the markings on the substrate.
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