| 摘要 |
The re-emitted light or the amount of light, reduced after absorption, of a test object (3) and a reference object (2) which are exposed to a single light source (1) is passed to one optical sensor (10, 11, 12) each with the aid of light guides (4, 5, 6). Arranged in the beam path to the optical sensors there are replaceable optical filters (7, 8, 9) having a narrow pass bandwidth. An analysis unit transforms the signals of the reference object (2) and the test object (3) for various working wavelengths by mathematical transforms, standardises these and converts them into a single variable which can be used for a highly significant Good/Bad decision. The analysis unit with its test program is used both to determine the most advantageous filters (7, 8, 9) and, after these have been defined, for distinguishing test objects. <IMAGE>
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