Fast approximate calculation of multiply scattered lidar returns

Robin J. Hogan
2006 Applied Optics  
An efficient method is described for the approximate calculation of the intensity of multiply scattered lidar returns. It divides the outgoing photons into three populations, representing those that have experienced zero, one, and more than one forward-scattering event. Each population is parameterized at each range gate by its total energy, its spatial variance, the variance of photon direction, and the covariance of photon direction and position. The result is that for an N-point profile the
more » ... -point profile the calculation is O͑N 2 ͒ efficient and implicitly includes up to N-order scattering, making it ideal for use in iterative retrieval algorithms for which speed is crucial. In contrast, models that explicitly consider each scattering order separately are at best O͑N m ͞m!͒ efficient for m-order scattering and often cannot be performed to more than the third or fourth order in retrieval algorithms. For typical cloud profiles and a wide range of lidar fields of view, the new algorithm is as accurate as an explicit calculation truncated at the fifth or sixth order but faster by several orders of magnitude.
doi:10.1364/ao.45.005984 pmid:16926887 fatcat:cn2ippewr5cldjyqyibyju6joy