Any secret NR methods? Topaz Denoise? What is your method? [Deep Sky] Processing techniques · Oscar · ... · 142 · 11336 · 42

But I think the techniques Bray uses are integral to this thread. The op started this thread by questioning how Bray specifically gets the results he does. That question has still not been answered, and other questions have been raised. I guess I for one am not comfortable simply ignoring the very significant questions raised and just going on to academic discussions on noise as some posters are suggesting. As for minding our own business - the techniques, ethics and principles used by this community are our business, aren’t they? Especially when it comes to people in positions to pass judgement over our own images. When it comes to the methods used, I am reminded of this cartoon:

Well, heavy noise reduction, and in such cases the sheer amount of noise is ridiculous, is always going to be destructive… and creative, in a negative way.

There's just no way around it- we loose some details and contrasts. This is a heavy handed process and it must be. It will not be repeatable, that is - other kind of software will yield differing results.
There's also another side to that- some structures/details/contrasts that aren't really there will pop up. Again - this is not repeatable. Even changing some settings in denoising software will meaningfully change the result.
And when there's no reference image in existence, things get extremely difficult and it's up to the individual doing the processing to decide how aggressive the processing should be. More aggressive = more aesthetically pleasing image (if one has the skills). Less aggressive = less pleasing image (but still a lot of uncertainty).

Besides, AB is not Astronomy & Astrophysics or even arXiv. It's a social media portal specialized in astrophotography. Pretty pictures of genuine new discoveries published here are not the basis for registering a new discovery. I don't consider it proper to push anyone to reveal their methods or share their data regardless of what I think about the veracity of any particular image.

To put is succinctly: one cannot have his cake and eat it. That is, it's not possible to have an image of such a faint object, that's both aesthetically impeccable and scientifically accurate.

Mauricio Christiano de Souza:
My problem is that once I blend the NB on the BB image, I can’t go back and separate them

My assumption is that they blend NB and BB as late as possible (maybe as a the last step), so they can make different versions like HORGB, HRGB, ORGB and also the layer representation they posted for the Atlas SNR.

To support what you are saying regarding noise reduction and Photoshop/AI tools this is written in Marcel's image description

Mauricio Christiano de Souza:
Noise reduction is something incredibly hard to reverse engineering, there is so many ways of doing the same thing using softwares with slightly different algorithms and different processes inside these applications.

The OP has given an example of Bray’s results, but I personally like Marcel’s results more because they tend to be a little more balanced to me. Anyway, both seem to have similar NR routines since they started collaborating, so getting a hint from any of them would work.

What I can say is that it is obvious that they are using Topaz or some similar AI plugin at some point. I speculate this is applied closer to the end of the flow though.
Below is a print of a revision of Marcel’s image. My experience tells this texture is from some of Topaz plugins used in PS, so it probably is used to both enhance details and denoise.



While the bigger structures are somewhat accurate, it makes fainter and smaller features at maximum plausible (not their existence but their shape) . So it is kind of a guess of how it would look like if it was much brighter than it actually is.

For the background I think Continuum Subtraction technique and different PixInsight processes take a big role to achieve what we see here. If I had to guess what they use in PixInsight (I have no idea of the parameters though and I did not put in order of workflow):
- Multiscale Median Transform (masked)
- Multiscale Linear Transform (masked)
- NoiseXTerminator (low doses and masked)
- TGVDenoise (maybe???)

In Photoshop they could really use anything available, so I won’t even try to guess anything other than the obvious AI work (probably using Topaz). They also use AstroPixelProcessor but I have no idea what they do in that stage.

Another thing I really wanted to know so bad is how they separate Narrowband into layers that are stacked on top of each other. However I don’t think this is the right topic to discuss it though. My problem is that once I blend the NB on the BB image, I can’t go back and separate them. If there’s already a topic on this, please share the link with me, otherwise I will start one. Marcel’s Atlas SNR example:

To be honest, I do not appreciate these types of images at all. They just changed the direction of the astrophotography, which may be good or may not  be good. Adding ~100> narrowband on top of dominant RGB data, is deceiving. Look at APY last year, M31, that amazing O3. After that was published, my friend spent >200 hours to get 'that O3 data'. At the end, he did not get those fine, sharp,  structures, but just a smear of clouds. What ever noise reduction people do, they cannot get the same structure, even from the same person, which means some kind of data manipulation. Then we can see the technique is actually like painting. Do we really need to go this direction? 

While this is a hobby, people can do whatever they want with the data. People decide what they want to do. For me, I just stay away from it

Min Xie:
I understand where you're coming from, but I have to respectfully disagree. The use of narrowband data in astrophotography, when done ethically and transparently, can be a powerful tool for revealing subtle details in celestial objects. While it's true that adding narrowband data to RGB images can sometimes produce results that look almost too good to be true, this doesn't necessarily mean that the data is being manipulated or that the resulting images are deceptive. In fact, many astrophotographers go to great lengths to ensure that their images are accurate representations of the data they've collected. Rather than viewing the use of narrowband data as "painting" or manipulating the data, I think it's more accurate to see it as a legitimate technique for enhancing and revealing the beauty of the universe.

I think the key part here is “accurate representation of the data”. As long as the final product presented has some correlation with the raw stack - whether NB or LRGB- and we can correlate each structure present in the final image with something in the raw data, it should be permissible. I think what is questionable is when structures are invented that have no obvious correlation to the raw stack and the presented image has significant differences in structure versus other images in areas of commonality. I don’t particularly care to know the specific technique someone uses. I do care that the result of the technique does not appear to be true to the raw data in any obvious way. When such a result is presented, a better explanation than “it is a secret” is asked for. Otherwise, we might as well call this Astro art and be done with it.

Yuexiao Shen:
What ever noise reduction people do, they cannot get the same structure, even from the same person, which means some kind of data manipulation. Then we can see the technique is actually like painting. Do we really need to go this direction?

What I appreciate from their NR routine is how they are able to turn something so dim and noisy into something that can be used to produce a photo. I don’t like these filaments produced by AI, I think it falls more into the interpretation of the author rather than something that is faithful to the real details, but I admit it looks good, although not real.

I think to this point it is very clear that final photos should not be taken so serious, they are artistic in purpose... They are just interpretations of what they would look like if we could just get more signal from them, however that is impossible with our current technology, it doesn’t matter anymore if you put 200 or 5000h on some of these, they won’t have the SNR a photo of M42 has for example. Obviously more exposure helps, but after hundreds of hours, the maths indicate you would need absurd numbers to actually improve the data significantly, which is almost impossible.

What really matters is that one raw photo that goes to the papers (which they sometimes provide as a revision), and not the ones here from AstroBin, those are expressions of what we can closest get of their probable appearance. And this is valid to almost all photos posted here. It is also up to you to decide what you think is true or not, based on your experience and knowledge.

Mauricio Christiano de Souza:

Yuexiao Shen:
What ever noise reduction people do, they cannot get the same structure, even from the same person, which means some kind of data manipulation. Then we can see the technique is actually like painting. Do we really need to go this direction?

What I appreciate from their NR routine is how they are able to turn something so dim and noisy into something that can be used to produce a photo. I don’t like these filaments produced by AI, I think it falls more into the interpretation of the author rather than something that is faithful to the real details, but I admit it looks good, although not real.

I think to this point it is very clear that final photos should not be taken so serious, they are artistic in purpose... They are just interpretations of what they would look like if we could just get more signal from them, however that is impossible with our current technology, it doesn’t matter anymore if you put 200 or 5000h on some of these, they won’t have the SNR a photo of M42 has for example. Obviously more exposure helps, but after hundreds of hours, the maths indicate you would need absurd numbers to actually improve the data significantly, which is almost impossible.

What really matters is that one raw photo that goes to the papers (which they sometimes provide as a revision), and not the ones here from AstroBin, those are expressions of what we can closest get of their probable appearance. And this is valid to almost all photos posted here. It is also up to you to decide what you think is true or not, based on your experience and knowledge.

While there is some good truth here. The problem is that the images that were published in the scientific paper of the O3 arc were heavily manipulated and then inverted. There is a difference in putting an image of a new object out there and saying "This is the best I could do with the data I got, and these are the techniques I used." and saying "this is an image of something no one has imaged before or very few have imaged (in the case of Goblet of Fire there are only two others besides Bray's)". See the difference? One is honest, the other is purveying the data as real. And what is even more suspect here, is that it's a common, consistent, complaint that these structures broadly do not match other images taken (the Goblet of Fire), or new data taken by others ( the O3 arc). We aren't just talking about some small scale structures that got smoothed out because of aggressive noise reduction although that is part of it. We are talking about something like completely changing the way a galaxy's spiral arms are constructed. That is much different. 

And when this is brought up, we are told "go image it yourself" and " it's a secret", or "the other images should match my image because it's the deeper one".

Concerning to say the least. 

Best Regards,
Joe

I've been avoiding this thread for a lot of reasons but it's come to a point where  I can't resist.  There's a lot of talk here about what is acceptable and what isn't. The fact is, the vast majority of posted images are highly manipulated. We can argue about where to draw the line but there's no question that it's true. Even something as basic as star removal could be considered a questionable practice as it can produce effects that are not reality. Noise reduction can do the same thing. How many images of M-42 have an image of the core taken with a shorter exposure  brushed in with a layer based editor.  People slave over the pallet of colors in narrow band recombination to get a pleasing result. I can go on and on but the as stated at the beginning. Our images are highly manipulated and that doesn't offend me. Do I think it's ok to draw in details that don't exist, of course not, but anything short of that is fair game. Like it or not, most of use are producing art to please ourselves, not scientific images. We make many processing choices based on aesthetics, not scientific accuracy. If that weren't the case we would shoot, stack, stretch, color balance (photometric) and call it a day but where would be the fun in that?

Tony Gondola:
I've been avoiding this thread for a lot of reasons but it's come to a point where  I can't resist.  There's a lot of talk here about what is acceptable and what isn't. The fact is, the vast majority of posted images are highly manipulated. We can argue about where to draw the line but there's no question that it's true. Even something as basic as star removal could be considered a questionable practice as it can produce effects that are not reality. Noise reduction can do the same thing. How many images of M-42 have an image of the core taken with a shorter exposure  brushed in with a layer based editor.  People slave over the pallet of colors in narrow band recombination to get a pleasing result. I can go on and on but the as stated at the beginning. Our images are highly manipulated and that doesn't offend me. Do I think it's ok to draw in details that don't exist, of course not, but anything short of that is fair game. Like it or not, most of use are producing art to please ourselves, not scientific images. We make many processing choices based on aesthetics, not scientific accuracy. If that weren't the case we would shoot, stack, stretch, color balance (photometric) and call it a day but where would be the fun in that?

I have been silently following this because some commentators here are just showing opposition because of their bad intent and trying to make arguments that look logical to just serve their intent. But for the rest that seeks a real reasonable discussion, I want to share my perspective as I took this issue very seriously in the past years. I took so seriously that I reached out to a world-renowned philosophy professor in this field and had a long discussion. Where do we draw the line between fake and real? And this is a 'criteria problem' in philosophy. In the end, the arrived conclusion was 'unless educationally deceptive'. Now this is for APOD, because APOD is an education/public outreach platform. It is a different story for Astrobin. 

At APOD, we have a single ethics statement: APOD accepts composited or digitally manipulated images, but requires them to be identified as such and to have the techniques used described in a straightforward, honest and complete way.

Now, that doesn't mean that we'll just accept everything, but the photographers are 'free' to do so. It might be their style. But we can't share false information. Therefore, we have to know what has been done. In Astrobin, the same thing is falsely accepted. I'm saying 'falsely' because Astrobin's mission is not education or scientific research. 

In case of a discovery, if this is the real worry, there are scientific papers that are published for this purpose. One shouldn't be checking the Astrobin post for the details, but should read those papers. Everything is transparent there.

I know many images here with very major wrong results yet got awards. Do you know why? Because none of us actually notice or remember those details. The differences between images that are discussed here, I bet no one can draw on a paper from their memory. This isn't even educationally deceptive and when there is a published research paper on it, looking at the Astrobin image and saying that is not a constructive criticism. 

But I'll tell you something educationally deceptive and yet accepted as very normal here: The inverted Sun images. Totally against the physics of limb darkening. I have even had students who got so confused when learned about limb darkening, because what they were seeing for their lifetime was an inverted Sun images. Yet the astrocommunity seems to be not bothered by that non-realistic fact.

We can't just take some tiny detail and make it a big deal, then ignore a major factors such as inverted Sun images. This is not how this problem should be handled. When it handled in this way, it is usually for bad intent only emanating from our biases and personal relations with others. This is not constructive. Let the community be free. If you don't like it, don't like it and move on. Your style is your style, other's style is other's. This is not science. The science is on the papers.

Bob Lockwood:

Kay Ogetay:
Let the community be free. If you don't like it, don't like it and move on. Your style is your style, other's style is other's. This is not science. The science is on the papers.

It took 4 pages for someone to finely say what really matters. If you don't like it or think it's fake, get over it and move on.

I think what would be helpful is a way to know if it was real or fake. That is what this discussion is about. Otherwise, you have people literally spending thousands of dollars and hundreds of hours trying to achieve what someone else has. As stated in some of the comments here. Not to speak of paying for courses that do not even cover some of the methods used to generate some of the more highly regarded images. If we as a community are OK with an “Anything Goes” mentality, let’s just make that explicit and get on with life. Anyone can then post anything captured, drawn, painted, processed using any method they choose with no reason for there to be any connection to reality.  It looks like we are there already, lol.

Bob Lockwood:

Kay Ogetay:
Let the community be free. If you don't like it, don't like it and move on. Your style is your style, other's style is other's. This is not science. The science is on the papers.

It took 4 pages for someone to finely say what really matters. If you don't like it or think it's fake, get over it and move on.

If it was an image of a common target with tons of other references - sure. I don't think anyone would care if people put fake detail in M42, or the dust lanes of M31.

But for new discoveries or objects that are extremely faint and have little to no other references, it's hard to "move on". Some folk here want to capture these targets for themselves and they will waste hundreds of hours chasing nonexistent structures because someone wasn't honest about their processing. In my opinion, that's unacceptable.

After seeing the GIFs above I couldn't resist commenting. I am a newcomer. I frequently browse here to see what targets I may want to shoot, and what I can hope to get from them. Of course everyone can process how they want. In the case of artistic liberties however, I would really appreciate a before/after just so that I have realistic expectations when it comes to referencing some of these more professional looking images.

I personally would not take artistic liberties and also be associated with scientific papers. Even as a complete noob, I know that is not a great look.

Joseph Biscoe IV:

This topic may have started with good intent to learn, but quickly some haters saw the opportunity to take the discussion to defamation level. When some people here seem to make logical statements but call 'all of us' with insults behind the doors, we can't have a meaningful discussion with them here. They keep diverging the topic for their intent. We know their intention is not to learn, but public bashing. But as you make kind comments and raise some questions, I'm happy to answer them. Hope this further clarifies my points.

First of all, I think there is still confusion here. Switching between Astrobin images and seeing some minor parts that are slightly different on a very faint object has absolutely no impact on any of our lives. Let's admit that. Nobody will say 'oh shoot, that 30px long filament seems to be curved in by 10 degrees more, I'm not shooting it!'. The majority of the structure remains the same. It is not deceptive to me, because what I'll remember from this object does not change from one image to another. A very faint detail seems diffused, so what? That data difference is maybe on linear data only 1-2 value difference. That is a very natural and expected outcome. 

Now this might matter to you of course! But in such case, you should be aware that this is a very faint object with heavy noise reduction. So you should expect such difference anyway.

One can always make a better version and we'll appreciate their work. It is as simple as that. I personally know how Bray process those images and there is absolutely no 'human interference' (like brushing etc) that can cause an intentional change. Every difference is solely due to very low signal noise reduction. 

Note that if two different people with two different eyesight would look at the raw image, they'd see such differences too! So it's not even about the noise reduction. It is the lack of data, the contrast. We are just not realizing this since we can't compare what our eyes see. And discussing over these tiny details, has no merit to me --especially when it doesn't even scientifically matter, let alone for aesthetic purposes.

If you are taking these as a reference for your future work, one can always figure out a solution for this: If the target is too faint and has a heavy noise reduction for aesthetic reasons, then I know what I'll face if I shoot this image. There might be slight differences. If you perceive this as 'not slight', then you act accordingly. 

There is a good deal of "us" that like to reveal structure detail in our images and look to astrobin not as a scientific release, but as a planning software. You miss the mark here.

The quite opposite actually. Not pointing anyone here, but there was an IOTD I took as a reference, because of a simple aspect in the image -a blue brightness between the dark nebulosity-- and I took image of that region for 20+ hours. Turns out there is no such blue there! And no other image shows such blue whatsoever. I ended up with something that I did not want. But I did not get mad. I learned something, still got a nice picture. And I also know we take a risk when we are on the edge of discovery. Sometimes we work on a theory over years and at the end we realize it doesn't work. If you start the journey with the assumption of a good result, then you are not the right adventurer for this kind of journey. Many become experimentalists because of this and avoid theoretical works for example.

Maybe I'll post these findings when I post the image. Even in science --intentional or unintentional-- such cases occur. We figure it out in the community by replicating and posting our results. Pages-long discussions are not the solution.

If the concern is scientific. Then you don't compare the scientific paper to the Astrobin post (as the Astrobin post is intended for aesthetic purposes, not scientific purposes). If there is actually a 'significant difference' on the raw data on the scientific paper then you leave a comment to the paper. But to my expertise in this field, even these differences do not matter. I know that no one will take you seriously if you try to do that. Simply because it doesn't matter. Pixel-by-pixel structure doesn't have a significance --unless you derive information from that structure-- say the magnetic field around the object is constructed in such way because the filaments show the field lines --which is not the case here whatsoever. And you always know that there is a 'margin of error' in every measurement. If you don't acknowledge that and conclude with 'significant difference' then the issue isn't the OP's data.

So we can discuss this forever, where to draw the red line between fake and real. To me, these discussions usually restrict this community from being more creative which is very sad to me because we all like experimenting with our data. I'm pretty sure many of you who read this thread had the hesitation to share something really interesting because of the worry of such criticisms. I did and I still do. Such harsh comments only harm the diversity we could possibly have. We don't have to like it at all. Different styles can just have a small audience. Why neglect them? Why suppress them? So in terms of styles, yes we can simply move on. They will naturally fail anyway. If it doesn't fail but gets more attention, maybe it is just because we are not the audience anymore. 

Jazz music is great, but it doesn't have the same audience anymore. But it doesn't make Rock more valuable or Jazz. It is great to have both.