Author Topic: Star Masks  (Read 6669 times)

Offline sreilly

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Star Masks
« on: 2010 September 06 00:22:53 »
I am working on an image of the Bubble Nebula and tried generating a star mask to use in trying the HDRWavelets tool on just the nebula, in particular the inside area of the bubble itself. In order to get the several really bright stars in the field included in the mask I had to use a setting of 0.05 for the Threshold and 10 for the Scale. Applying the mask seemed to get the stars and then I would invert the mask. This is where I'm a bit confused, if I'm masking the stars, do I invert the mask to work on the nebula only? Seems no matter what I do, the processes effect the stars as well. I've watched Harry's video several times and must be a bit daft. I create the mask, drag the "mask over to the image I'm working on, the mask is applied as the image turns red, and then I use the mask icon on the menu bar with the (i) to invert the mask. In this particular case, the nebula is left clear while the stars are red. Is this the correct procedure? Anyone who wants to try masks settings for this image is welcome to try. The image, 11.9 MBs, can be downloaded from my website using the following url http://www.astral-imaging.com/NGC%207635-Med-20-Luminance_C_HST%20.fit As the title suggests, this is NGC7635 Median combined of 20-20 minute subs, cropped and HST applied. The equipment is a 12.5" RC with a SBIG ST10XME/CFW8/AO8/Pyxis 3" imaging train.

Steve
Steve
www.astral-imaging.com
AP1200
OGS 12.5" RC
Tak FSQ-106ED
ST10XME/CFW8/AO8
STL-11000M/FW8/AO-L
Pyxis 3" Rotator
Baader LRGBHa Filters
PixInsight/MaxIm/ACP/Registar/Mira AP/PS CS5

Offline Niall Saunders

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Re: Star Masks
« Reply #1 on: 2010 September 06 04:35:52 »
Hi Steve,

Can you save, and then send us, the process icon for the HDRW that you used to create the mask. I'll try and have a look at things when I get back to may 'PI' computer tonight.
Cheers,
Niall Saunders
Clinterty Observatories
Aberdeen, UK

Altair Astro GSO 10" f/8 Ritchey Chrétien CF OTA on EQ8 mount with homebrew 3D Balance and Pier
Moonfish ED80 APO & Celestron Omni XLT 120
QHY10 CCD & QHY5L-II Colour
9mm TS-OAG and Meade DSI-IIC

Offline lucchett

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Re: Star Masks
« Reply #2 on: 2010 September 06 13:48:47 »
Hi Steve,

I think I went through the same once. (masking for big stars?)

This is the thread of the discussion at the time: PixInsight Forum > PixInsight > PixInsight > star mask for "biggest stars" and mask for nebulosity.

Hope this helps,
Andrea

Offline sreilly

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Re: Star Masks
« Reply #3 on: 2010 September 06 14:57:05 »
Hello Andrea,

Seems I more of a newbe than I realized. I was simply using the Star Mask tool to create and use the mask. I did not realize that you could actually perform operations on the mask itself to further refine the mask. I think that's what I am seeing suggested.

Steve
Steve
www.astral-imaging.com
AP1200
OGS 12.5" RC
Tak FSQ-106ED
ST10XME/CFW8/AO8
STL-11000M/FW8/AO-L
Pyxis 3" Rotator
Baader LRGBHa Filters
PixInsight/MaxIm/ACP/Registar/Mira AP/PS CS5

Offline lucchett

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Re: Star Masks
« Reply #4 on: 2010 September 07 04:27:24 »
Steve, what I've learned reading this forum is that the Star mask tool is very powerful but it solves the issue of an "average star mask".
if you need to protect very small stars or very bright stars (if you browse the forum you can get many hints on that), you need to play a lot integrating other tools.
actually, today I spend more than 50% of the time on one image striving to get the right mask!
I can have a small star mask, a big star mask, combine the two and playing with the Hystogram transform tool on the mask to adjust the protection.
At least, this helped me to improve my images and leverage more on deconv, noise reduction, etc.

Andrea

Offline sreilly

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Re: Star Masks
« Reply #5 on: 2010 September 07 08:27:33 »
Andrea,

I'll spend more time investigating this process. Most often I want to protect all the stars and most of my images seem to have at least a few very bright stars that don't get included in the Star Mask operation. How are you combining different masks? This would apply to most of my images where I would like to sharpen the object leaving the stars alone. I usually use data that ranges from 1.5 - 2.5' arc seconds seeing discarding the higher data >2.5". This usually keeps the stars reasonable and I don't try to reduce their size. Central Virginia doesn't have the greatest seeing but I try to make the most of what she gives me.

Steve
Steve
www.astral-imaging.com
AP1200
OGS 12.5" RC
Tak FSQ-106ED
ST10XME/CFW8/AO8
STL-11000M/FW8/AO-L
Pyxis 3" Rotator
Baader LRGBHa Filters
PixInsight/MaxIm/ACP/Registar/Mira AP/PS CS5

Offline sreilly

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Re: Star Masks
« Reply #6 on: 2010 September 07 08:35:49 »
Hi Steve,

Can you save, and then send us, the process icon for the HDRW that you used to create the mask. I'll try and have a look at things when I get back to may 'PI' computer tonight.

Hello Niall,

I wasn't ignoring you but got lost in this thread. I'm a bit confused with the request. The mask was made using just the Star Mask Tool but was intended for me to use with the HDRW tool when applied to not include the stars in that process. I simply made the mask using the Star Mask Tool with it's adjustments to include all stars, applied the mask to the image and then ran the HDRW tool. I am trying to dig out the faint subtle details within the Bubble Nebula itself. I posted a link to the combined luminance image I was trying this on at my website http://www.astral-imaging.com/NGC%207635-Med-20-Luminance_C_HST%20.fit It's the detail in the bubble not so much the background nebulosity I'm interested in. I wasn't aware that you could save process icons. I'm really not as familiar with PI as I'd like but I'm getting there slowly.

Steve
Steve
www.astral-imaging.com
AP1200
OGS 12.5" RC
Tak FSQ-106ED
ST10XME/CFW8/AO8
STL-11000M/FW8/AO-L
Pyxis 3" Rotator
Baader LRGBHa Filters
PixInsight/MaxIm/ACP/Registar/Mira AP/PS CS5

Offline Niall Saunders

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Re: Star Masks
« Reply #7 on: 2010 September 07 12:14:15 »
Quote
I wasn't aware that you could save process icons

Whenever you have a process dialogue open, instead of dragging the little blue <New Instance> triangle (the one next to the little blue <Apply (F5)> square) over to your 'target image', drag it to a clear area on your Workspace.

What you will see is a 'ProcessIcon' appearing on the Workspace - and the actual 'graphic icon' will be unique for the process that you have been working with. Look closely at the icon, and on the right-hand side of the automatically-generated 'process name', you will see a tiny letter 'N' and what looks like a 'D' (but which is, in fact, a small square with the top-right corner 'folded over'). Hover over each of these tiny icon 'targets' and you will see tooltips that state "Rename" and "View Info" respectively

Click the <Rename> 'button' and you can change the automatically created name into something more useful - but you MUST start with a non-numeric 'letter', and the name cannot contain spaces or punctuation. This means that you will, inevitably, end up using the oft-despised (for no real reason :sad:) CamelCase_and_UnderScore_123 system of naming the ProcessIcon. And, just before you click <OK> for the New Identifier, perform a quick <Ctrl-A> and <Ctrl-C> to copy and paste your newly created name into the clipboard. You'll see why I do this in a moment.

Now click the <View Info> button, and use the free-form text box to enter any details about, for example, 'why' you have used this process at this stage, and maybe even 'why' you have set the parameters the way that you did. You can even record on what image the process was intended to be used. Or, you can just miss this step out entirely - the space is there for you to use, if you need to. And there aren't the CamelCase restrictions imposed earlier.

Now, having quickly single-clicked on a clear area of Workspace (to actually 'deselect' ALL items), you can then right-click on the main body of the process icon once more, and - if you feel that you need to - you can choose to <Save Selected Icons...>. This will allow you to save that particular icon to an HDD destination of your choice and, when prompted for a filename, you can just use <Ctrl-V> to 'paste' in the actual name that you gave to the process icon earlier (remember, you copied it to the clipbard, above).

One thing to be aware of, if you ever choose to reload the icon from the HDD, it will be returned to the Workspace that it came from, and will be placed at the (x,y) coordinate that you had 'parked it at'. This is a good reason to make use of the 'protected column' that is normally available on the PI Workspaces - as a little 'storage bin' if you like. You also have to remember to 'merge' icons when reloading from HDD - otherwise the new process icon (or group of icons) will REPLACE all existing icons - which is a bit  >:( and sometimes even  :yell: and often  :'(

You can also create a Workspace ProcessIcon by opening the History Explorer, selecting an image to inspect, and - if there is a process history associated with that image - you can drag ANY of the listed steps over to the Workspace, where a new icon will automagically appear!

And, from the History Explorer window, if you drag the little blue cube (shown at 'Stage 0' in the History) over to the Workspace, you will create a ProcessContainer icon - which can be handled just like any other ProcessIcon, except that this 'contains' (or, at least, it 'can' contain) a whole suite of individual process steps, as extracted from the processing history associated with that image, in the order that they were applied to that image. And all the steps described above are equally as applicable to this icon as well (renaming, saving, loading, etc.)

And, very briefly, whilst on the subject of the ProcessContainer - it can be thought of just like a 'bucket'. You can put new processes in, and take existing processes out. It can be filled from the History Explorer, it can be added to by dragging over a Workspace ProcessIcon, or it can be added to by dragging over the little blue <Apply> triangle from an open Process GUI. You can even use the Process Container to help 'create' some basic (in fact, quite sophisticated) PixInsight Java Script (PJSR) code - but that is a whole new topic ;)

One thing though - you only actually have one 'bucket' that you can 'carry' at any one time. If you, for example, relaunch a stored ProcessContainer icon (say, from the Workspace) then you will receive a warning that "You are about to replace the Process Container contents", and that this cannot be undone. Don't worry. Click <NO> and then just save a copy of the existing ProcessContainer contents - as a Workspace ProcessIcon, of course ;D. But, this is where you have to start getting 'clever' with your 'icon renaming', otherwise you might have a bunch of similar-looking icons all over the Workspace, and you might not really have any idea what they were all about.

I think that the whole concept of ProcessIcons is one of the STRONGEST features of PixInsight - and it is unique in this field (as far as I am aware).

Once Juan develops the notion of a PixInsight saveable and reloadable 'ProjectSpace' as well, then a well-organised approach to creating, using, naming and storing Process Icons will become essential.
Cheers,
Niall Saunders
Clinterty Observatories
Aberdeen, UK

Altair Astro GSO 10" f/8 Ritchey Chrétien CF OTA on EQ8 mount with homebrew 3D Balance and Pier
Moonfish ED80 APO & Celestron Omni XLT 120
QHY10 CCD & QHY5L-II Colour
9mm TS-OAG and Meade DSI-IIC