Is there an analogue in PixInsight to Photoshop's "pinch" filter?
Some very pleasing images, including ones posted in this forum, feature especially bright stars as quite small cores at the centres of much larger and relatively soft halos. This is a result that I only know how to achieve in Photoshop, using its pinch filter. I can do so by selecting one bright star at a time, using an appropriately scaled circular marquee selection, to achieve proportionate "tightening" of stars of different brightness, for an aethestically pleasing consistency across the entire frame. I believe this is a common approach in the Photoshop world of astronomical image processing, though I can't recall where I came across it. I have not actually made use of pinch in any image to date.
Now that I'm a PixInsight devotee, I use Deconvolution for the usual purposes, and near the end of the workflow I use the MorphologicalTransformation's Erosion filter for reducing fainter stars in crowded fields. However, I haven't been able to use Erosion to good ends for very bright stars. For those, I've tried instead to reduce their large halos using StarMask to select the most bloated stars and their halos, and then making use of CurvesTransformation both to bring the halos down in size, whilst tightening up on the star profile. But this leaves me with relatively large bright stars, though their halos are considerably reduced.
But now that I've stared again at several beautiful images - by other PixInsight devotees
- that appear to have used something analogous to pinch, to achieve much smaller cores with large halos for very bright stars, I find that provides a much more pleasing appearance, and I would like to do that too! I'd rather not "break out" of PixInsight to do this using pinch in post-PixInsight processing. So I long for a correct and aesthetically pleasing technique to this end in PixInsight
.
