QUANTITATIVE MEASURE OF THE EFFECTS OF ALIASING ON RASTER SCANNED IMAGERY.

Aliasing in raster scanned imagery limits the ability of an observer to make decisions on image content. A quantitative measure of aliasing for raster scanned imagery which includes the effects of the spectral content of the signal and of the scanning spot function is developed. The aliasing measure is a dimensionless quantity between one and two. Aliasing effects can be reduced by modifying the signal spectrum or the scanning spot function; however, the two effects are not independent. Although the results were developed for raster imagery, the method can be extended to two-dimensional sampled imagery. Relation of the aliasing measure to observer performance through psychophysical experimentation should provide a useful quantitative measure of the ability to detect targets in the presence of aliasing.