Thursday, November 3, 2016

Hot pixels in DrizzleIntegration

I wanted to use DrizzleIntegration in Pixinsight. I read a lot about it and how it improves the stacked images.

I processed my latest images of the Bubble Nebula and surrounding as I always do plus created Drizzle files. The ImageIntegrated image looks good. But the DrizzleIntegrated image shows some hot pixels:

I tried a number of things:

  • lower the "Linear Fit High" value
  • play with the "Drop Shrink" value in DrizzleIntegration
  • <several other things that I can't remember>
always with the same outcome: left over hot pixels!

I left a message on the Pixinsight Forum asking for help. And received A LOT of feedback and help from Vicent Peris - he seemed to know a lot about this. We tried a lot of things (and I learnt A LOT) but always with the same outcome. Vicent finally tried my data and for him it worked!!! The main difference was that he used an older version of the ImageIntegration process. Apparently the latest version had a problem with rotated images (and some of my frames did of course rotate during registration).

...

Yesterday the new ImageIntegration process came out ... and it is fixed!!! No more hot pixels!!! So, now I can actually go back to processing my Bubble Nebula images.