Quantification of the atmospheric scintillation for laser illumination in active imaging.

Most of the analytical scintillation models used by experts to simulate the illumination performances of active imaging systems are based on the use of monochromatic, punctual, and coherent sources. These analytical models seem pessimistic regarding lightpipe-based illumination techniques. Outdoor trials have been made with 1.57 µm laser illuminators with and without lightpipe to record illumination maps and associated refractive index structure parameter C(n)2 with a propagation distance of 1 km. Analysis shows a reduction of the scintillation by a factor of 2.5 comparing analytical models and laser illumination with lightpipe.