| 摘要 |
<p>An infrared emitting surface which is obscured by fume particles is inspected by an imaging appts.. This rejects visible light scattered by the frame particles and infrared radiation emitted by hot gases. The system includes optical filters which limit the sensitivity to wavelengths longer than 1 micrometer and which pref. lie within predetermined bands, esp. that centred on 1.68 microns. The optically filtered image is focussed on a detector which is pref. an infrared vidicon tube or a television camera which is used to operate a display.</p> |
