Range-gated active-imaging system for search-and-rescue and surveillance operations

摘要

Search and rescue (SAR) and general surveillance missions pose a number of challenges to imaging system. These systems must work often in low-light level, low-visibility conditions to find and identify targets. A new airborne payload has been developed to overcome several deficiencies encountered with conventional or low-light level cameras as well as thermal imaging sensors. The recent developments in laser diode arrays, laser diode beam collimation and gatable micro-channel plate intensifier have made it possible to build a compact active imaging system. This Airborne Laser Based Enhanced Detection and Observation System (ALBEDOS) is particularly efficient at night and in degraded weather conditions. ALBEDOS is based on a powerful laser diode array illuminator and a range-gated low-light-level TV camera. Therefore, it is immune to the blooming effect specific to highly sensitive cameras and eliminates most of the light backscatter caused by the presence of aerosols. It was proven to detect small retroreflective tapes over many kilometers. In October 1995, the system was installed on a Bell 412 helicopter and tested in various scenarios.