I am probably not the first to appreciate the wonders of Starnet and other star-removal tools in astrophotography. However being a great tool for identifying and removing stars, the replacement job is often poor, especially for very bright stars. The resulting image is left with "scars" where the stars have been removed.
As I have not found any good solutions for improved star replacement, I have made my own plastic surgery procedure using Photoshop. It seems to be working quite ok, so I would like to share it with the community. The procedure is using the AI based content-aware fill and goes like this:
1. Run Starnet and produce both a STAR_FREE image and a STAR_MASK image.
2. Load both the STAR_FREE and the STAR_MASK images into Photoshop.
3. Use the magic wand selction tool and select the black area in the STAR_MASK. Then invert selection (so that the stars become selected), and adjust by either marking similar areas (Select > Similar) or simply expand (Select > Modify > Expand) the selection by 1-3 pixel(s) depending on how well the magic wand was able to select all the stars.
4. Transfer the selection from the STAR_MASK over to the STAR_FREE image. There are several ways of doing this in Photoshop, but I found it safest to save the selection, preferably as a part of the STAR_FREE image, then load the selection in the STAR_FREE image.
5. With the star_selection loaded on top of the STAR_FREE image, run Edit > Fill and select Content-Aware in the Contents menu. Make sure also to check for "Color Adaptation". Click Ok, and you have a much smoother image with much less prominent scars.
Example image below shows left to right: 1. Starnet processed. 2. Content aware filled. 3. Original image.
-Martin
As I have not found any good solutions for improved star replacement, I have made my own plastic surgery procedure using Photoshop. It seems to be working quite ok, so I would like to share it with the community. The procedure is using the AI based content-aware fill and goes like this:
1. Run Starnet and produce both a STAR_FREE image and a STAR_MASK image.
2. Load both the STAR_FREE and the STAR_MASK images into Photoshop.
3. Use the magic wand selction tool and select the black area in the STAR_MASK. Then invert selection (so that the stars become selected), and adjust by either marking similar areas (Select > Similar) or simply expand (Select > Modify > Expand) the selection by 1-3 pixel(s) depending on how well the magic wand was able to select all the stars.
4. Transfer the selection from the STAR_MASK over to the STAR_FREE image. There are several ways of doing this in Photoshop, but I found it safest to save the selection, preferably as a part of the STAR_FREE image, then load the selection in the STAR_FREE image.
5. With the star_selection loaded on top of the STAR_FREE image, run Edit > Fill and select Content-Aware in the Contents menu. Make sure also to check for "Color Adaptation". Click Ok, and you have a much smoother image with much less prominent scars.
Example image below shows left to right: 1. Starnet processed. 2. Content aware filled. 3. Original image.
-Martin
