| 摘要 |
Scanning apparatus for scanning electromagnetic radiation emitted or reflected from a moving object (11) e.g. ore. A lens (17) receives the radiation and forms it into a beam directed toward one or more photoelectric cells (28, 29). A movable member, such as a rotary disc 22 or a travelling belt, intercepts the beam and is provided with apertures which periodically sweep transversely across the path of the beam. There may also be a fixed member (18) provided with an aperture e.g. a slit (19) in the path of the beam such that the apertures in the moving member sweep across the aperture in the fixed member. U.V. from sources 13 is reflected by the ore to detector 29 to indicate the size of the rock. Fluorescence from the ore is sensed by detector 28. Fluorescence from reference material 32 on the ends of optical fibres 31 is chopped by apertures 21 to give a reference signal to detector 28 before each scan. <IMAGE> |
