If you have ever processed an astrophotographical image, you will have had to non-linearly stretch the image at some point, to make the darker parts with faint signal visible. Whether you used levels & curves, digital development, or some other tool, you will have noticed noise grain becoming visible quickly.
You may have also noticed that the noise grain always seems to be worse in the darker areas than the in brighter areas. The reason is simple; when you stretch the image to bring out the darker signal, you are also stretching the noise component of the signal along with it.
And the former is just a simple global stretch. Now consider that every pixel's noise component goes through many other transformations and changes as you process your image. Once you get into the more esoteric and advanced operations such as local contrast enhancements or wavelet sharpening, noise levels get distorted in all sorts of different ways in all sorts of different places.
The result? In your final image, noise is worse in some areas, less in others. A "one-noise-reduction-pass-fits-all" no longer applies. Yet that's all other software packages - even the big names - offer.
As of StarTools 1.6, you can now control how Sharp enhances detail based on the Signal-to-Noise Ratio (SNR) per-pixel in your image.
As of StarTools 1.6, you get the choice of two noise reduction styles.
The Filter module allows for the modification of features in the image by their colour by simply clicking on them.
Exclusive to the main screen, the buttons that activate the different modules, reside on the left hand side of the main screen.
This is different from other software, which allow you to reduce noise at any stage, since such software does not track signal evolution and its noise component.
You can convert everything you see to a format you find convenient. Give it a try!