The first stage of noise reduction involves helping StarTools establish a baseline for visual noise grain and the presence (and direction) of walking noise. To establish this baseline, increase the 'Grain size' parameter until no noise grain of any size can be seen any longer. StarTools will use this baseline as a guide as to what range of details in your image is affected by visible noise.
If walking noise is present, then temporarily set 'Grain Size' parameter to 1.0. Next, use the 'Walking Noise Angle' level setter, or click & drag an imaginary line on the image in the direction of the walking noise to set the 'Walking Noise Angle' that way. Now increase the 'Walking Noise Size' parameter until individual streaks are no longer visible in the direction you detected them in (though other imperfections may still be visible). After that, increase the 'Grain Size' parameter until other noise grain can no longer be seen.
After clicking 'Next', analysis and wavelet scale extraction starts, upon which, after a short while, the second interactive noise reduction stage interface is presented.
In StarTools, your signal is processed (read and written) in a time-fluid way, by means of an ever changing equation for every pixel.
StarTools monitors your signal and its noise component, per-pixel, throughout your processing (time).
StarTools' Deconvolution module allows for recovering detail in seeing-limited and diffraction-limited datasets.
The Unified De-Noise module offers detail-aware, astro-specific noise reduction.
You can convert everything you see to a format you find convenient. Give it a try!