Removing StarXT artefacts

Gordon Aspin

Hi Adam

Watching your Helix processing video I saw that you use the GAME script to create a mask over the areas where StarXT has removed parts of the nebula. In the past when I used to use StarNet for star removal, if I saw those sorts of artefacts in the Stars-only image then I would paint over them with a black background and then subtract this modified Stars-only image from the original image to create a new Starless image without the artefacts. Does this subtraction method work properly with StarXT or is it the case that Stars+Starless does not equal the original image eg if there is a screen blending operation happening?

Thanks

Gordon

BlockHead

True, you cannot use the subtraction method in the case of screening. 

Applying a mask is probably the most direct and safest way to manage which of the two images the pixel data goes to.

-the Blockhead

Mike Cranfield

Your paint over method on the stars image will work fine but when you are done you will need to "unscreen" the stars from the original image using PixelMath as follows: rescale(original, stars, 1). (This is assuming you are working on non-linear data and have unscreened the stars in the first place - if you are working on linear data don't unscreen, just subtract).