Portable bi-λ SWIR/NIR GV gated viewing system for surveillance and security applications

Abstract

Active imaging is an emerging technology in the field of surveillance for security and military applications. Numerous works have demonstrated the value of active imaging in target recognition and identification, vision through fog, underwater vision or three-dimensional (3D) imaging. However, surveillance applications in civilian and military fields need the use of an eye-safe illumination. Unfortunately in this spectral region, there is still a lack of ITAR-free, commercially available and efficient intensified cameras or laser sources which are the two main components of an active imaging system. Though, a few years ago, ISL showed the feasibility of a portable SWIR night-vision goggle with the PELIS system. This goggle was based on a continuous illumination associated with an InGaAs camera, but with this technique, the fundamental properties of range-gating were not exploited. In this paper, we report on a new portable and range-gated night-vision goggle in the SWIR spectral region. This goggle will be a useful eye-safe device for surveillance and imaging under all weather conditions. At 1.5 μm, it is well known that human skin appears black making face recognition ineffective. For applications which need facial identification as a legal proof, we implemented a bi-wavelength laser where it is also possible to extract one pulse of light at a second wavelength, where the skin appears with the same reflectance as in the visible spectrum (1.06 μm). After a theoretical analysis, we will describe the goggle technology and show some lab and outdoor recordings.