Apodization Mask

The SVDecon module requires a mask that marks the boundaries of stellar profiles. Pixels that fall inside the masked areas (designated "green" in the mask editor), are used during local PSF model construction. Pixels that fall outside the masked area are disregarded during local PSF model construction.

It is highly recommended to to include as much of a star's stellar profile in the mask as possible. Failure to do so may lead to increased ringing artifacts around deconvolved stars. Sometimes a simple manual "Grow" operation in the mask editor suffices, in order to include more of the stellar profiles.

Compared to most other deconvolution implementations, the SVDecon module is robust in the face of singularities (for example over-exposing star cores). In fact, it is able to coalesce such singularities further. As such, the mask is no longer primarily used for designating singularities in the image, like it was in versions of StarTools before version 1.8.

The mask does however double as a rough guide for the de-ringing algorithm, indicating areas where of ringing may develop. Clearing the mask (all pixels off/not green in the mask editor) is generally recommended for non-stellar objects, including lunar, planetary or solar data. As a courtesy, this clearing is performed automatically when selecting the Planetary/Lunar preset.