| 摘要 |
<p>A monitoring device for security surveillance application, the device comprising: an electromagnetic wave sensor (120) for sensing an external electromagnetic wave source; a detection window (140) for forming a partition between the external electromagnetic wave source and the electromagnetic wave sensor; and an anti-tampering arrangement (160) comprising an optical arrangement (170) for deploying an optical surveillance beam and control circuitry (180), wherein (i) the optical surveillance beam comprises a first beam portion (172) and a second beam portion (174), the first beam portion being a beam emitted by the optical arrangement towards the detection window, and the second beam portion being due to reflection of the first beam portion by said detection window; and (ii) the control circuitry is for detection of a variation of the second beam portion, wherein the variation is indicative of tampering of the detection window.</p> |
