In order to obtain a wide-field of view, undersampled detectors are
frequently placed on telescopes. The Hubble Space Telescope (HST) is
no exception. Here we describe a technique properly called Variable
Pixel Linear Reconstruction, but more widely know as Drizzle, that was
developed to handle undersampled dithered data produced by the HST.
The algorithm preserves photometry and resolution, can weight input
images according to the statistical significance of each pixel, and
removes the effects of geometric distortion both on image shape and
photometry. Additionally Drizzle is able to easily handle missing
data, which is common in HST images affected by cosmic rays. The
method and its implementation are presented and the photometric and
astrometric accuracy and image fidelity of the algorithm are discussed.
Further algorithmic developments that are being investigated to
improve upon drizzling will also be presented.
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