  Distinguishing between the instantaneous and delayed scatterers in synthetic
aperture radar (SAR) images is important for target identification and
characterization. To perform this task, one can use the autocorrelation
analysis of coordinate-delay images. However, due to the range-delay ambiguity
the difference in the correlation properties between the instantaneous and
delayed targets may be small. Moreover, the reliability of discrimination is
affected by speckle, which is ubiquitous in SAR images, and requires
statistical treatment.
  Previously, we have developed a maximum likelihood based approach for
discriminating between the instantaneous and delayed targets in SAR images. To
test it, we employed simple statistical models. They allowed us to simulate
ensembles of images that depend on various parameters, including aperture width
and target contrast.
  In the current paper, we enhance our previously developed methodology by
establishing confidence levels for the discrimination between the instantaneous
and delayed scatterers. Our procedure takes into account the difference in
thresholds for different target contrasts without making any assumptions about
the statistics of those contrasts.
