| 摘要 |
<p>1. Videofrequency image detector apparatus comprising an optical receiver system (1) for forming an image of the observed scene in the photosensitive plane of an image detector (2), and electronically controlled variable optical attenuation means (4) connected to the video output through a control loop (3) for controlling the video signal (SV) in function of the scene illumination and for increasing the operating dynamic ratio of the apparatus, characterized in that the optical attenuation means (4) are formed by the interposition on the optical path of at least one cell having an electrolyte (10) containing metallic ions, the electrolyte being interposed between two walls (11, 13) coated with electrodes (12, 14) connected to electric feeding means for producing, by electro-chemical reaction, according to the direction of current flow the deposition or the dissolution of a metallic layer (15) the optical reflection and transmission properties of which vary in function of the thickness of the deposit, these optical properties being used to produce said variable attenuation, the electric feeding means being formed by the control loop (3), and in that the optical receiver system (1), the optical attenuation means (4) and the detector (2) are carried by a gyroscopic mount (41 to 45) to stabilize the optical receiving axis (Z).</p> |
