This is a bit old taken from February 2007’s New Horizons encounter at Jupiter. A very noisy image was released of Io on the dark side of Jupiter that illustrated the glowing lights of lava flows and auroral displays in Io’s tenuous atmosphere interacting with Jupiter’s magnetosphere. Noise always bothers me and there has been a desire to somehow clean up the presentation of this fantastic image.
The process was simply to blur the image, layer highlight information a few times with varying degrees of sharpness or blur and to simply hand remove what would seem to be simply noise artifacts. The problem is that some of this information wasn’t just noise, but is actually auroral glow (especially at the disk edge). So after some of the noise was removed it was softened and re-introduced selectively around active areas where the assumption is that the glow near these spots is more intense. The final step was to simply reduce the file size so that it became sharper.
This presentation is purely artistic although it does come from real image data… I just wouldn’t use it to support any scientific papers. The items marked simply as “volcano” were newly discovered by New Horizons.