Arrest/masking specific color/size features

[puckja]

In some ST tutorial, it mentioned about masking certain stars with blue/red/green colors (mostly due to noise). I have tried to use auto mask to arrest some small blob (about star size) color artifact using EXCLUDE certain colors. However, the criteria were still too general and many good stars were also selected. In my case, the color artifact has quite specific color (blue, red, green or dark purple). So I wonder if there is a way to auto mask with color sampling (from a group of pixels) capability to provide more spectroscopically specific condition. And threshold may be used as intensity criterion.

This may be already possible with current version, but I cannot figure it out yet.

Thanks!

[admin]

Yes, your best bet is currently the 'Exclude color parameter'. There is also a 'select similar color' brush in the manual mask editor (though I'd like to work some more on its effectiveness). I'll have to think about this one on how exactly we could automate this...

[puckja]

Ivo:

I have never used the FILTER module successfully. I imagine using it to auto mask out features for later HEAL module (but it was not intended for that purpose in the current version). That was the reason why I propose such feature with the addition of size (or even morphology) information for auto masking.

I would appreciate it if it was feasible since it could be very useful for the large pixel OSC camera especially using CGYM bayer pattern for high photon efficiency (such as Lodestar). Or other type of systematic noise features with color & shape correlation.

Thanks!

[puckja]

I did not use Photoshop much before. Recently I went through some tutorial about masking. And quickly one can realize the power of advanced mask. It seems to me ST has been great in providing similar capability and I was using it before even realized it.

It also seems to me additional mask capability such as using intensity and colormatric(spectroscopic) thresholds to define advanced mask will further enhance the power of ST.

The truth is that ST is already very powerful. I have process some images that owners considered difficult. ST have not yet disappointed me at all. Every time it pulls its trick and shows the amazing details with minimized noise.

[admin]

Awesome to hear Puck!
Will have to give color-based masking some thought. Defining 'color' itself is a tricky one to begin with (color as visible, color as recorded, color as balanced, etc.), so I'd have to come up with something at least slightly intuitive. The FIlter module uses color 'as visible', which is probably the way to go...

[puckja]

Yes, maybe using sample from a selected region (mouse drag) to define the color component.