Chapter 10: Image Sharpening
6. Visual Effects - Making the screen easier to see
Menu: Visual > Advanced Options > Enhancement
The "Sharpen" check box controls whether SuperNova sharpens magnified images (including photographs) as well as non-True Font text.
If the "Sharpen" check box is enabled SuperNova will sharpen magnified images and non-True Font text by exaggerating the brightness difference along any edges on your screen, thus making those edges appear more pronounced. The sharpening process works by subtracting a slightly blurred version of your screen image from your original screen image in order to detect the presence of edges, creating what's known as a "mask". Using this mask the contrast along the detected edges is then selectively increased leaving behind a sharper image.
The "Contrast" slider controls the minimum brightness difference sharpened. This can be used to sharpen more pronounced edges, while leaving more subtle edges untouched. It's especially useful to avoid sharpening noise.
The "Size" slider controls the size of the edges you wish to enhance, where a smaller size enhances smaller detail. You'll usually want a size setting that's comparable to the size of the smallest detail within your image. The key to effective sharpening is finding the right settings for making edges appear sufficiently pronounced while minimising sharpening "halos".