  Directed energy applications require the estimation of digital-holographic
(DH) phase errors due to atmospheric turbulence in order to accurately focus
the outgoing beam. These phase error estimates must be computed with very low
latency to keep pace with changing atmospheric parameters, which requires that
phase errors be estimated in a single shot of DH data. The digital holography
model-based iterative reconstruction (DH-MBIR) algorithm is capable of
accurately estimating phase errors in a single shot using the expectation
maximization (EM) algorithm. However, existing implementations of DH-MBIR
require hundreds of iterations, which is not practical for real-time
applications. In this paper, we present the Dynamic DH-MBIR (DDH-MBIR)
algorithm for estimating isoplanatic phase errors from streaming single-shot
data with extremely low latency. The Dynamic DH-MBIR algorithm reduces the
computation and latency by orders of magnitude relative to conventional
DH-MBIR, making real-time throughput and latency feasible in applications.
Using simulated data that models frozen flow of atmospheric turbulence, we show
that our algorithm can achieve a consistently high Strehl ratio with realistic
simulation parameters using only 1 iteration per timestep.
