High resolution active laser imaging and range gating at 1.5 μm up to 10 km

摘要

An innovative Active Laser Imaging (ALI) vision system is presented. We report the experimental data of a short range ALI able to achieve range measurements and to recognize people up to 5 km away, according to Johnson's criterion. We also report the simulation data of a long range ALI working in excess of 10 km. The ALI uses a laser to illuminate an area and a telescope to collect the scattered light into an InGaAs camera. The laser has been developed internally; it is an eye safe class I pulsed laser operating at about 1.5 urn; its divergence and direction are changed according to the scene and environmental conditions. The ALI can be used in active mode, with the laser on, or in passive mode using external short wave infrared (SWIR) illumination sources. The data collected by the ALI and a thermal IR camera show the ability of ALI to look across glasses and to read writings and the impossibility of thermal IR camera to do the same. We describe the software models developed to emulate the ALI, the scenes, and the environmental conditions. The models have been validated by experimental data and used to design the ALI.