US Patent 7187452 Lidar system and method

A ground-based method is disclosed which determines the spatial statistics of fragmented and spatially variably dispersed objects in a transmissive medium, by generating a plurality of pulsed beams of laser energy, the beams having selectively variable width and shape; selectively varying the width and shape of the beams; directing the beams toward the dispersed objects; measuring the time and/or phase and intensity of signals returned by the dispersed objects, and calculating the apparent reflectance of the dispersed objects as a function of the range of the dispersed objects for each beam width and beam shape.