PixInsight Forum (historical)
PixInsight => General => Off-topic => Topic started by: Harry page on 2010 September 25 13:06:49
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Hi
After a small conversation with mr newbie dave about star reduction in pixinsight , the usual use of morph transform through a star mask was used and
I do have to agree that stars can become misshaped and do they really reduce in size or do they become just fainter >:D
So how do we improve , better use of the tool ( advice please ) or do we need a better tool as I would hate to say Photoshop >:D
Discussion Please
Harry
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I agree the stars look fainter, not just smaller. Not always desirable but it does reduce the star intensity effectively.
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For a first approach, let's discuss this using the MorphologicalTransform only.
Morphological transformations are common operators on image processing, specially in the field of binary images (black or white). The grayscale/color expansion works in the same basis: define a kernel or structuring element, which tells the algorithm the neighbourhood of pixels that will be included; and of course, we define a morphological operation (maximum, minimum, dilation, etc.), and perform the calculations.
So, what happens if we use a minimum filter, with a square 5x5 kernel? (just an example) For every pixel, it looks for the minimum value surrounding it, in the 5x5 box centered at that each particular pixel. At the end, pixels are replaced with that value. If there is a mask, it acts at the end, "merging" with the original image.
From this behavior, it is completely natural (and expected) that stars are dimmed. The only way to avoid this is to create a goos mask, that protects the inner core of them. Also, it does help a bit using other operator, such as median or any percentile lower then 0.5 and greater than 0. If the star's edges aren't soft, these operator will still reduce the star size (and make it softer) but without changing too much the central peak.
Now, the problem sometimes is with the shape, the kernel or structuring element. I prefer to keep it as small as possible, and if needed, perform several iterations. This will produce softer results, and edges will preserve better the shape. 3x3 cross, or 3x3 square work fine. Also, it is a good idea to create a two ways element, with both the cross and box, one at each side. This will average the particular results, and then, preserving better whose circular shapes.
To summarize: Small kernels, with 2 (or more ways, if needed), several iterations, and play with the percentile. Also, refine the mask, to protect the cores.
Other alternatives:
- DefectMap: Basically, this process implements morphological transformations and convolutions, where the main difference is that the defect map image tells the algorithm which pixels are going to be replaced, and performs the calculations with the surviving pixels. For small star resizing tasks, this may work fine. A suitable "defect map" may be created from the gradient of the image.
- Deconvolutions: If properly used, stars will be reduced and their peaks increased. With a good mask, you can use it to affect only the outer regions of the stars.
- Curves: Decrease the L curve... using a mask, or course.
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I have been using MT to reduce star size and find that stars seem to get both smaller and a little misshapen like little + signs. To deal with this I follow MT with Atrous Wavelets to blur the stars slightly. On Atrous try: "x" the first layer and set second layer to -0.1. Using iterations of MT also helps setting the amount to say 0.5 and doing the process twice. Atrous can be used after each iteration of MT or just after the last iteration. Use trial and error, of course. ;D
Steve
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What we need is a module that forms a new PSF at the centroid location.
Max
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What we need is a module that forms a new PSF at the centroid location
I assume that you mean it 'creates a mask, based on a PSF, at an established centroid'. I don't think we would be wanting to 'paint on artificially created stars' :o
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I have been using MT to reduce star size and find that stars seem to get both smaller and a little misshapen like little + signs.
This is the effect I immediately noticed when I used MT on a 'star mask' the very first time I used it. As I don't see this effect when using 'expand' and 'feather', followed by the application of the 'minimum' filter in Photoshop, it seemed alien to me, and hence my discussing this with Harry.
I should add, that if you apply the minimum filter in PS more than once, then the stars will take on a diamond shape. There is a way around this, which is to rotate the image through 90 degrees, before applying the filter for a second time.
That said, there is enough control over the parameters of the PS minimum filter, to make only a single application ample. The brightness of the stars can always be lifted if desired.
Creating a star layer is much easier in Pixinsight, but star reduction is easier and more effective in Photoshop.
I hope that my comments will be viewed in the constructive manner that they are intended.
I am trying PI as a prospective new customer, and as such will speak openly and honestly of my findings during the trial period.
Dave
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I hope that my comments will be viewed in the constructive manner that they are intended.
Of course! That's the spirit here ;)
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will speak openly and honestly
Bummer! We're all devious and dishonest here!
>:D
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Bummer! We're all devious and dishonest here!
:laugh: :laugh: :laugh:
Dave
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Try this on your masked stars
1. MT
2. Blur wit Atrous Wavelets
3. Use L curves to enhance luminosity
4. Add some Color Saturation
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Today I played a bit with the star size reduction again... The gradient of the image worked as a very good mask. Both a combinations of the MT and a very mild sharpen improved a lot the star profiles.
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Part of my MWAIC presentation I didn't get to show was something like this:
- star mask
- MT with star mask applied
- remove star mask
- gentle HT to brighten things back up
I then show that the stars look similar to before but the target (M101 in this case) was more pronounced. In effect you've brightened the target without blowing out the stars. This is similar to what Jack is talking about.
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Yes, but you are changing everything :) It is better to apply a sharpen procedure to recover the central peaks ;) USM with sigma around 1.2 usually works fine.
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Hi
Thanks for the ideas , but as this is a very common problem to deal with I do think we need a more straight forward approach to this as even though I do not have a problem with a mask , I then want to use a module / script that reduces stars in size without me taking a degree :yell:
Sounds like a challenge for someone please
Harry
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I then want to use a module / script that reduces stars in size without me taking a degree
That would be a significant addition to PI, and something that I very quickly found to be a negative aspect, when I started using the software just a few days ago.
Although I have written a few small astro programs in Visual Basic, for my own use, I am by no stretch of the imagination a programmer, and I greatly admire the programming skills of the people that have produced and contributed to PI.
The 'expand', 'feather' and 'minimum filter' approach that I and a great many other astro imagers have used very effectively in PS for a long time, must surely be based upon a set of basic mathematical algorithms, that are not necessarily 'copyright'.
Is it not possible for the programming expertise that resides on this forum, to code a module based on this approach, or similar, that would be make star reduction as easy and effective as it is in PS?
I know this is easy for me to say, as these things take up peoples valuable time, and clearly much of the development and growth of PI, is based upon the goodwill of the ‘team’.
Dave
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Today I spent the most part of my day playing with the Star Mask proces on one of my test images: NGC6992, taken with a BabyQ.
The FOV is filled with stars, and building a perfect star mask is almost impossible, or at least it is impossible to me.
If there are small stars in the mask, then the bigger one are missing.
I wish as well the Star Mask process would be simpler to use, and that it would also contain a "feather" and "expand" tool.
That would surely be awesome.
Emanuele
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Emanuele,
I can send you my "star reduction" process icon that makes it pretty easy (about four or five steps). It's not perfect, but it's a lot easier than using StarMask. All I need is your E-mail address.
Wade
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Wade, that'd be wonderful!
My email is: backyardskies@gmail.com
:) I really appreciate it!
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Different situations are going to require a different approach...
1.- Do you simply have a "normal" star field but wish the stars overall were a bit less prominent? (ie, smaller??)
2.- Do you have one of these shots of areas that are brutally packed with stars and don't want them to eat the features you're most interested in showing?
3.- Do you want to get rid of just the tiny ones? (but, they're so pretty!)
4.- Or make those tennis balls to look more like stars?
I'm curious too about what that script does because I certainly use different techniques depending on the case. In fact, I often consider to try something "else" (this is where the fun begins). I have used Photoshop techniques in the past, and ever since I started to get better results with the MT/wavelets/etc, I have never gone back to solve this problem with PS again. Oh and I'm not the religious type here, I use whatever works better for me, I don't care who sells it >:D
The minimum filter in PS is like using the erosion operator with a structuring element where all the values in the mask are "1". As such, the minimum filter in PS can never produce better results than the MT tool in PI because the minimum filter can be perfectly mimicked with MT (now, with the added features of MT this wouldn't make sense and that's why the MT tool is a much better choice). The only differential factor in whatever technique Dave is using then is in the mask (in PS, the expanded/feathered selection). My take is that via wavelets and/or StarMask one should be able to build a mask that'd work as good or better than the feathered selection in PS. BTW I may be the weird type but I never use the erosion operator, I usually pick the Morphological selection operator and slide the selection slider to the left a certain amount to give more erosion than dilation. No scientific reason, it just fancies me doing it that way :angel:
If the problem is that a MT (with a good mask and all) dims the core of the stars, you can either give them a bit of the punch back with a slight bias over the small scales using wavelets, or simply "save" such cores (again, using wavelets) and add them later to the MT'ed image with PixelMath. This requires no degree and it's rather intuitive IMHO.
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Rogelio,
thanks for your impressions and thoughts on this.
For my images, I usually want to reducer the stars - make the smaller - so that the nebulosity of galactic cirrus is more visible. That's all.
Focus is usually great on my images so all I want is to reduce them of intensity and reduce their size.
I will post an image of NGC6992 tonight, when I get home so that we have something to work it, to keep it practical.
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That's an interesting response RBA, and I fully agree that different images require a different approach, and there is no 'one size fits all' answer.
For me, options 1,2 and 4 from your list apply, and never option 3.
I have only been using PI for just over a week, so am very much a novice when it comes any in-depth knowledge of the software. However, I'm not new to astro image processing, and the difference between PI's MT and PS's 'expand', 'feather' and 'minimum' process, was very quickly apparent, and despite experimentation I cannot achieve as good a star reduction result, as I do with PS.
However, I am very willing to accept that this is very much down to my inexperience with PI. Then again, learning to use the processes in PS, was very easy and logical. To me at least.
As with most software, it is very easy for the skilled developer to forget that the product will be used by people who have no understanding of software development, or the underlying complex mathematical algorithms that make it work.
Having spent the last 20 years of my working career in a research and development environment, I am comfortable with this. To the non-technical end user, the terms ‘expand’, ‘feather’, and minimum are meaningful, whereas Morphological Transformation sounds like something out of a science fiction novel.
I know that this is somewhat going off at a tangent, with respect to the subject matter of this thread, but it does relate to making process easy to use by users at al levels, as well as giving an effective result.
Dave
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I think that I'm beginning to see some correlation between the effects of PI's erosion filter, and PS's minimum filter.
Earlier on I said that if you apply the PS minimum filter more that once to an image, the stars will take on a diamond shape, and that this could be corrected by rotating the image through 90 degrees before applying the minimum filter again.
With PI, as you apply another iteration of the erosion filter, the stars start to take on a diamond shape by about the 5th or 6th iteration. This is with the Interlacing and amount set to 1. I am assuming that the default 1 in the amount 'box' relates to 1 pixel?
So, it would seem that the erosion algorithm used in both PS and PI are much the same, but that a single iteration of the minimum filter in PS produces a greater reduction in star size, without having to resort to multiple iterations.
From this, I deduce that the minimum filter in PS, more aggressive than that in PI, and as such is able to produce effective star reduction without multiple iterations, and the subsequent deformation of the star shape.
If this is the case, then could not the aggressiveness of the erosion filter in PI, be increased so that less iterations are required to reduce the stars to a suitable level?
As I have said before I am no technical expert in these matters, but am just trying to think within the bounds of my limited knowledge. You may tell me that this not a practical solution, and will respect your expert knowledge.
Dave
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Hi Dave
It is possible that this filter in PS uses larger structuring elements. With morphological filters you cannot increase aggressiveness beyond the current maximum setting. As I said before, what this filters do is to calculate statistical data in a neighbourhood you define by the structuring element. You choose either you want the minimum, maximum, median or any other value in the series.
As you saw, PI interface for this process is quite complex. This is for a very good reason: control. Here you control everything that is related to the calculation, and a few extra parameters were added to allow a "selective execution", to protect sharp edges, or low contrast data. Sincerely, I don't think PS implementation is better in any way.
Oh, by the way, the name "Morphological Transformation" is used because this is the "technical" name by all these kind of filters are grouped, and is based on its properties on binary image, where they are used to modify the shape of objects.
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Hi Carlos
Thank you for that explanation, I follow the logic of what you are saying, and I'm learning more about the workings of PI every day :)
You could call it an unfortunate characteristic of mine, but coming from an R&D background, I always find the need to know why something is happening, as opposed to just accepting it, because it does. :)
Accepting now that it is not possible the increase the agressiveness beyond the current maximum setting, and knowing that in PS there is a way around the deformed stars (90 deg rotation), albeit a bit of a crude 'fix', is there a process by which the deformed (diamond shaped) stars can be corrected after MT?. Perhaps not the correct word, but a form of "de-convolution" on the star layer maybe.
I understand that Morphological Transformation is the correct generic technical term. Technical terminolgy was part of my everyday working life, but the point I was making was, that I and the people that I worked with knew the terminology, but to those outside of our area of expertise, it was a foreign language ???.
When giving presenations, it was often necessary to speak in terms that everybody would understand. My point being that the newcomer to astro image processing and PI, could be frightened off by the technical terminolgy used to describe what they were looking to do. e.g. star reduction.
Again, I'm speaking constructively, not destructively.
Dave
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I have only been using PI for just over a week, so am very much a novice when it comes any in-depth knowledge of the software. However, I'm not new to astro image processing, and the difference between PI's MT and PS's 'expand', 'feather' and 'minimum' process, was very quickly apparent, and despite experimentation I cannot achieve as good a star reduction result, as I do with PS.
I understand. that's why I went through this comparison and pointed out that the difference in this case may very well be in the masking process, although I can see that with the many options the MT tool offers, it too is possible to have things go wrong, versus the single slider in PS's Minimum filter.
However, I am very willing to accept that this is very much down to my inexperience with PI. Then again, learning to use the processes in PS, was very easy and logical. To me at least.
I would say that PS's goal is to be a powerful but generic software. As such, they for example, give fancy names to simple pixelmath operations - everyone who uses Photoshop "knows" what the Screen blending mode is, but not many know, nor care, that the Screen mode is simply this PixelMath operation: R = 1 - (1-Target) x (1-Blend). In short, Photoshop probably tries to take away some of the thinking process that goes with doing this or that thing. PixInsight on the other hand tries to give you as many options as you can tweak, and while many of the defaults are often better left alone, this sometimes forces you to know how things are done. In the end, you gain knowledge and experience, but some people just rather get things done (hence the popularity of action tool packages for PS such as this one from Noel Carboni - forgot the name)...
This is not to say that in PI you must do everything manually. Many many things do happen behind the curtain as well, but overall you have more control over what you're doing.
Having spent the last 20 years of my working career in a research and development environment, I am comfortable with this. To the non-technical end user, the terms ‘expand’, ‘feather’, and minimum are meaningful, whereas Morphological Transformation sounds like something out of a science fiction novel.
You and Carlos have already commented on this, but here's my take...
Astrophotography as a whole is a complex discipline that deals with many "obfuscated" terms. During image capture we don't mind using terms such as FWHM, dithering, bias, binning, ADU, and a very very VERY long etc. Why should we feel that ornamenting the terms we use when we reach the post-processing steps is the right thing, and calling things by their real name is obfuscated? (not saying you said this, but some people do)... By calling things by their names we are in fact learning and using the right universal language of image processing. I think that's a GOOD thing. Terms such as dust'n'scratches, levels, lighten blending mode, etc. is not part of the discipline of image processing, but Photoshop-slang. BTW I don't mind learning "slang" about any given software, doesn't bother me, but I am happy that PI, for the most part, doesn't invent new words for well-known and defined processes nor follows someone else's "slang" when there's a universal name for it. We just need to learn it. Just like one day we learned what the heck does FWHM mean and no one complained ;)
One last thing.. You talked about rotating the image (45 degrees I presume) to work around the diamond-effect of PS's minimum filter. You do understand that every time you do a rotation that involves pixel interpolation (any rotation that isn't 90, 180 or 270 degrees), you're in fact losing details and resolution. It may do for your stars what you want, but I think the price to pay isn't worth it. My opinion (also speaking constructively ;) )
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Thank you for that explanation, I follow the logic of what you are saying, and I'm learning more about the workings of PI every day smile
You could call it an unfortunate characteristic of mine, but coming from an R&D background, I always find the need to know why something is happening, as opposed to just accepting it, because it does. smile
That is precisesly the spirit we have here. It is not to learn more about PI ways to do things. It is about learning "Digital Image Processing". We want to know what is happening, and why, and we want you to know. :)
Accepting now that it is not possible the increase the agressiveness beyond the current maximum setting, and knowing that in PS there is a way around the deformed stars (90 deg rotation), albeit a bit of a crude 'fix', is there a process by which the deformed (diamond shaped) stars can be corrected after MT?. Perhaps not the correct word, but a form of "de-convolution" on the star layer maybe.
I don't get why rotating the image 90° should fix that. As far as you use symmetrical structuring elements, I don't see any reason why anything should change. Anyway, what do work fine is rotating the structuring element 45°. For example, applying a 5x5 box, and then a 7x7 diamond generates less artefacts (in terms of modifying the shape of the stars... shape, morphology... :D got it? ) In fact, this procedure was suggested a long time ago by Vicent, to create a "large scale" image, deleting the stars with MT filters (and then smooth the result with layer deletion in ATWT). I use that method to create a sort of sepparation between stars and other small scale elements from the medium and large scale ones, and process them appart. This works well on large field pictures.
BTW, another method to create a star mask is to use the ATWT. Just disable every scale layer greater than 8px (for example) and apply it. Then, use curves or the HT to leave out non stellar features (assuming the their edges were not as sharp as the stars, this works fine). Then MT lets you fine tune the size of the star mask (in this case, MT works as the expand/feather feature, while the mask is the selection).
BWT2, there are no layers in PI ;) (well, wavelet layers are the exception, but they are another beasts). Masks are just other images, that act as such when you create the link, but they still have their own life. You are not putting them on top of the caller image, in the sence of layers.
Again, I'm speaking constructively, not destructively.
Don't worry!!! Critics make us grow. Keep them comming.
I understand your point about the technical name. At the end, this is (will be) Juan's choise, but IMO, if using the technical name gives you a better idea of what is happening, or encourages to to learn more about it, then it should stay. And, in the very specific case of the MT, I simply cannot think on a better name. They are not used just to shrink the stars... you may modify the size of features in a mask, fill gasps, "open bridges"...
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Another well though out response RBA, thanks you.
Perhaps I'm trying to play 'devils advocate' here, and see things from both 'sides of the fence'. In that although I have a technically inquisitive mind, other people don't, and become discouraged by 'tech speak' used to describe a process that could be phrased in layman’s language.
Although technically correct, I wouldn't ask someone to pass me the Sodium Chloride, when I wanted the Salt ;)
I do know that people have been 'frightened off' by PI's less than conventional GUI, technical terms, and lack of documentation (albeit that is now being addressed), which is sad because the software has a lot offer the astro imager. In business terms it represents a lot of lost revenue that could have been 'ploughed back' into the ongoing development of the product.
I note what you say about detail being lost by 45 deg image rotation (sorry that I incorrectly said 90 deg), but as I also said, I find that a single application of the PS minimum filter (preceded by expand and feather), gives me all the star reduction need without distorting the stars. So I don't use the 45 deg rotation technique, as I don't need to.
I have used Noel Carboni’s ‘actions’ for star reduction, and although it works well, I much prefer to do the job myself.
I can only assume that Noel sequences the already in-place PS ‘tools’ into an automated routine, but I could be wrong.
For me at least, I have learnt much about the working structure of PI, mainly thanks to Carlos, and hopefully other members will also have done so.
The more I learn about PI, and the more I experiment with it, the more I’m getting to like it.
Dave
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BTW, another method to create a star mask is to use the ATWT. Just disable every scale layer greater than 8px (for example) and apply it. Then, use curves or the HT to leave out non stellar features (assuming the their edges were not as sharp as the stars, this works fine). Then MT lets you fine tune the size of the star mask (in this case, MT works as the expand/feather feature, while the mask is the selection).
There you go, another option within PI has 'surfaced' 8), thanks Carlos, you are indeed very helpful :)
Dave
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Hi
Some interesting answers , will need to read hard to get into the old brain
don't stop the talking
Harry
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Emanuele,
I can send you my "star reduction" process icon that makes it pretty easy (about four or five steps). It's not perfect, but it's a lot easier than using StarMask. All I need is your E-mail address.
Wade
could I try please Harry@harrysastrosheddotcom
Harry
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One other salient point is when you use erosion on MT I select Size 9 (81 elements) or greater, way of 1 and then importantly select the Circular Icon button below the Way dropdown.
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I do know that people have been 'frightened off' by PI's less than conventional GUI
Deep down, the biggest difference in the UI is that PI uses an object-oriented user interface (OOUI) while most applications use a "modal oriented" user interface. In a modal interface, usually when you pull a dialog box to do something, the entire application waits until you're done with it and click one of the famous OK, CANCEL and sometimes APPLY buttons. No such thing on an OOUI. People used to modal interfaces may find this confusing, but once you get used to it, at least in my experience, you become a lot more productive (and for some odd reason I also find it more fun to use).
Anyway, back to the problem at hand, like I said, if the problem is that a MT dims the core of the stars, you can try this - which I mentioned earlier but I'll break it down a bit:
1) After your MT, use the ATWT tool, select only layer 1, 2 or both, deselecting all others, increase bias to 0.100 or maybe 0.200 for the active layers, and apply. You may also want to check Noise reduction. Just play with all these parameters (bias, NR) on a magnified preview to see the effect of using different values. You could do this while a star mask is being applied to the image, to isolate the effect on stars as opposed to, maybe, noise.
OR...
2) Before your MT, create a dup of the image, use the ATWT tool, select only layer 1, 2 or both, and apply over this duplicate image. Do your MT on the original image, and when you're done, add both images together using PixelMath with something like Max(image,dup)...
Just two ways out of many to deal with this issue. It's a start, one can certainly get fancier than that, but this might get you a bit more familiar with these tools and situations in which you can use them... Before you know it, you might even start to come up with your own way of doing things...
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Hi Jack, I will indeed give that a try, thanks.
BTW, I had been using the circular icon.
RBA, yet more useful info, and options to try :)
This 'thread' has produced a wealth of information, and all of it very helpful :)
Thanks for starting this one off Harry :).
I started out in this 'thead' as 'Mr Newbie', and while I've been here, I got promoted to 'journeyman' :laugh:
Dave
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Loving this thread. Lots of new things I didnt know are coming up!
Ok, so here is the image that I was talking about: look at the amount of stars. I just used Wade StarMask and Reduction algorithm and I really like the results. It generates a perfect mask! I have never been able to obtain a perfect mask. :)
This is a HIGHLY underexposed image: just 10x3 minutes of Luminance, from a 5 mag skies. :) I think it's an ok result for this integration time.
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Nice 'tight' stars in that image Emanuele. :)
What's a Wade Star Mask ???
Dave
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Thanks Dave.
It's not a good image by any means, but it was just a test.
The Wade StarMask is a mask that has been built by Wade, of these forums. Read a few posts earlier and you'll see him mentioning the mask that he uses.
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Hi Emanuele
Well its looks like I need a 'Wade Mask' too, because the star mask in PI is driving me 'nuts' >:(
I open an image, create a star mask, apply it to the main image but do not invert it, apply MT to the stars, see them reduce in the mask.
Remove the mask and nothing in the underlying image has changed. :o
Apparently, I'm following the correct procedure, but it doesn't work for me :yell:
Dave
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Just made an interesting discovery related to the issue raised above.
The image (IC5070) that I was trying to applying star reduction to, using the star mask and MT, was of very low contrast, in that the Pelican nebula filled most all of the image frame, leaving very little dark sky background showing.
Have just tried using exactly the same procedure on an image (M27 wide field) with high contrast (stars against a dark sky background), and the star mask plus MT star reduction worked perfectly.
So, can someone answer why the procedure works on a high contrast image, but not one of low contrast?
Albeit the star mask correctly 'pulled out' the stars from the low contrast image, but would not apply the MT reduction to the underlying image.
Dave
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Hi
Most star masks are not black and white ;D so perhapes one mask is still giving some protection to the stars , try adjusting it with curves :surprised:
Harry
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Most star masks are not black and white ;D so perhapes one mask is still giving some protection to the stars , try adjusting it with curves :surprised:
Ok, I can try that, but it works fine on the same image in PS without any fiddling about with curves or levels ;)
Dave
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Ok, tried that, and it makes no difference!!
Dave
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Hi Dave
Could you upload the mask and the image (at least, two matching crops)?
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Hi Carlos
Yep, I can do that.
Will have to be well 'cropped' as the full FITs is 5.52Mb.
Dave
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You may also downsample the bitdepth, change it to 8bits to save space. Anyway, a jpeg at 95% quality would be good enough.
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Hmm!, even a small crop is well over 1Mb, and the 'board' has a 192kb max image upload.
This means it would have to be a 'micro-crop' and as such would contain very little of the nebula, and few stars.
I can e-mail you the full image if you so desire.
Dave
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You may also downsample the bitdepth, change it to 8bits to save space. Anyway, a jpeg at 95% quality would be good enough.
Ah, crossed 'posts' :laugh:
Ok, a jpeg it will be then :)
Dave
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Sorry Carlos, the 16Bit image just doesn't like being saved as 8Bit. I can save it as a 16Bit TIFF, but that's still way to large.
E-mail seems the best option.
Dave
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It doesn't like it, but it does anyway. ;) PI saves the file as 8bits, and comprises it with the JPEG algorithm, but the working image remains unchanged (no compression, no bit downsample). Just ignore the warnings.
You may get my corporate mail from my forum profile ;)
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Hi Carlos
The full res image (FIT) of IC5070 and it's associated star mask, have been e-mailed to your 'Hotmail' account.
Have sent them in two separate e-mails, in case your mail-box has a size limit. The main image is 5.52Mb and the star mask 2.76Mb.
Dave
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Well there seems to be some mysterious forces at work here :o
Despite all of my efforts I could not get the MT reduced stars in the star mask of my IC5070 image (as sent to Harry and Carlos), to remain reduced in the underlying image, when the mask was removed. ???
Yesterday I uninstalled PI and re-installed it, but no change.
Tonight, Harry successfully managed to make it all work on my image, and 'posted' a video of it on his website. So I followed Harry's move's one-by-one, and still it wouldn't work for me.
In desperation, I again uninstalled and re-installed PI, tried it yet again, and it all worked 8) :)
Now, it has often been said that astro image processing is a 'black art', maybe now I'm starting to believe it :o
Dave
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Did you receive my email with the result today? Everything worked fine, straight using your mask.
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Strange behavior :D I hope Juan jumps in, because this should not happen.
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Did you receive my email with the result today? Everything worked fine, straight using your mask.
No Carlos, it never arrived ???
However, not to worry as it seems to be sorted now, but thanks for taking the time to try it out on my image.
Have just tried it again and its still working fine, and at least as I said to Harry, I can now move on with my assessment of PI :)
Dave
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Strange behavior :D I hope Juan jumps in, because this should not happen.
Maybe something was corrupted in the 'download', but then I haven't downloaded it again, yet the problem cleared itself on the second re-install.
Dave
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Did you receive my email with the result today? Everything worked fine, straight using your mask.
Hi again Carlos
I found the missing e-mails, they had been filtered into the 'Spam Folder' ::)
Thanks again for trying PI on the image, and your comments.
Dave