Real-Time Motion Desmearing of Airborne Imagery

This paper considers the real-time "desmearing" of motion- "smeared" imagery telemetered from an airborne platform. The specific configuration considered is the direct raster scan readout of a satellite-mounted vidicon. Three types of smearing are considered: 1) linear uniform smearing, 2) linear nonuniform smearing, and 3) nonlinear smearing. The simplest type of smearing, linear uniform, has as its desmearing or inverse filter a circulating delay line (CDL) cascaded with a differentiator. An error analysis of this filter is presented along with an experimental simulation. Linear, non-uniform smearing characterized by the operator \begin{equation*}\int^{t}_{t-\delta(t)}I(\tau){ }{d\tau}\end{equation*} is considered next. Two possible realizations for the inverse filter are discussed as to accuracy and practicality. Finally, an error analysis is performed for the nonlinear smearing that results from a skewing of the raster scan.