A very warty M42

[mickw]

That script seems to work well Mark

[RobertM]

Could you send me details of the Iris script as I may have a go at implementing it in PI.

Thanks
Robert

[MarkS]

Could you send me details of the Iris script as I may have a go at implementing it in PI.

Sequence is as follows:

1) First create a mask to wipe out stars and bright bits:
   Convert image to greyscale
   Apply a Gauss smear radius 10
   Divide greyscale image by smeared image
   Anthing values above say 150% are "stars" so set them to 0.0
   Set the rest to 1.0
   Save mask
2) Isolate the streaks
   Load colour image
   Multiply by mask to erase bright bits
   Apply a Gauss smear radius 15
   Subtract smeared version from original
   Multiply by mask again
   The streaks are now getting quite apparent
   Set any other bright areas to zero before the stage 3 smearing
   Save this streaky template
3) Emphasize streaks vertically (or horizontally)
   Pick up the streaky template
   Do some kind of vertical (or horizontal) averaging to isolate streaks
   The idea is to smear the streaks over approx 100 pixels
   I did this by continual vertical (or horixontal) shift and adds
   Save this as the final streaky image
4) Subtract streaky image from original
   But mask off the bright areas of the original image where you don't want subtraction to take place.

Voila!

You may need to do some fine tuning of the size of the gaussians and the length of the vertical smearing

[RobertM]

Thanks, that all looks doable.