Nonlinear filtering of backpropagated fields

As a result of interest in imaging strongly scattering targets, the Air For ce Research Laboratory is making available to the community sets of data fr om various targets; We describe a nonlinear filtering technique, namely, ho momorphic filtering, which we have applied to recover an image of the targe t from the backpropagated field calculated from the scattering data. We sho w new results for targets that other methods, especially linearized methods , are unable to image. While we obtain good images with real data, convolut ional effects arising from limited data can sometimes degrade performance. (C) 1999 Optical Society of America [S0740-3232(99)01907-9].