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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

Image HFR History

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Image HFR History was created by Andrew

I found that Sequence Generator Pro has an interesting feature that I would love to see added to KStars/EKos, an HFR History graph. To me this seems like a very useful way to monitor changes in the focus over time to make better judgement on when to refocus if not automated.
I know the capture module can already identify an image's HFR to trigger an auto-focus during the session, thus the information is already available for a graph.
Here is a screenshot of SGP's feature.


There is probably other information that could be graphed as well. For example the average sky background brightness/contrast that might indicate clouds or end of astro-night.
The following user(s) said Thank You: Alfred, Jose Corazon
4 years 6 months ago #43914
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Replied by Rob Lancaster on topic Image HFR History

Neat ideas!!
4 years 6 months ago #43947

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Replied by Alfred on topic Image HFR History

Many thanks for bringing this up! After acquiring a number of photographs I usually stack them in Regim. The software tells me FWHM and quite often I wish I had known the quality before. If had had, I would have re-focused much earlier. I do not use auto-refocus since I deem autofocus unreliable. I let the auto-focus acquire the V-shaped graph and then set the focus manually. Unfortunately Ekos happens to set the focus not at the graph's minimum so I have to take care of that by myself. A HFR (or even better HFD, FWHM) graph would make me aware of a deteriorating focus beforehand.
4 years 6 months ago #43952

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Replied by Peter Sütterlin on topic Image HFR History

Yes, such a plot would be quite nice.

For a start I wonder what the HFR entry in the FITS Viewer statistics tab is supposed to do (or rather, how to use it). For me, it always only displays '-1' no matter what I do, and I didn't find more info in the help document :(
4 years 6 months ago #43969

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Replied by Andrew on topic Image HFR History

I have been thinking about where such a graph could logically be placed. I believe the best location is in the summary tab sharing space that currently displayed the focus star profile and HFR by adding a History button to toggle the panel to a graph of the measured HFR's of all previous images captured in the sequence.
Also if continuing an incomplete capture sequence from another night, it would be great if the graph maintained that information to easily compare the quality of focus across the entire project over the course of multiple nights.
Last edit: 4 years 5 months ago by Andrew.
4 years 5 months ago #44208

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Replied by Rob Lancaster on topic Image HFR History

I agree 100% with this. It is similar to something I have been thinking about for awhile.

So my thoughts are that we should enable the tracking box in the view in the Summary Tab so that you can choose a star in the photo. Then we should put a closeup image of the star in the Focus area to the right that updates with every image just like the guide star image does. This can serve the purpose of monitoring a star in the actual image for focus, issues, guide issues, and other issues. And then where the focus profile graph is shown, instead it could be your HFR history graph which could be similar to the guide graph.
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4 years 5 months ago #44209

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Replied by Andrew on topic Image HFR History

I love that idea! If it is going to track a single star and not an average across the field, it will somehow have to be capable of identifying the same star after dithering and meridian flips. Perhaps we can leverage the power of a solved field to pinpoint the star's true coordinates. That would make it more robust when the image is dithered, flipped, or somewhat rotated. Perhaps I'm over thinking though, or an average of stars is better.

Another idea that came to mind with yours is monitoring a star's obliqueness. That can be used to monitor guiding performance and possibly cull unacceptable frames preemptively.
For example a sub completes and has oval stars from bad guiding, cable snag, bumped mount, etc. Then automatically delete/move it to an alternate subfolder for later review, and do not count it towards the total captured images.
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4 years 5 months ago #44213

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Replied by Rob Lancaster on topic Image HFR History

So yes, as I said, I had been thinking about it for awhile, but it wasn't the HFR graph I was thinking of. You see, I always use both the fits viewer and the summary screen fits view at the same time. I use one to monitor the whole field, and one to see the closeup details. That way I can detect issues in guiding, etc. So I have been eyeing up the section of the summary screen that displays the focus because that isn't typically doing very much. If we could make that monitor the closeup details, like continuously monitoring one select star, then I wouldn't need to keep zooming in all the time. But your idea with the HFR graph makes that original idea a little more possible, because I couldn't justify changing that part of the summary screen, and leaving the star profile graph the way it was. It just wouldn't make sense since the updating star image would be from every frame, and the star profile graph would be from the last focus.
4 years 5 months ago #44215

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Replied by Rob Lancaster on topic Image HFR History

To be honest I hadn't considered significant movement of a meridian flip. I was thinking that it would be just fine after dithers since it doesn't move too far and it should be able to just use the same star, so I figured we could just keep monitoring the same spot until the user decides to monitor another. And now that I think about it, I don't think it is really a problem to start a new graph once a meridian flip is done?
4 years 5 months ago #44217

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Replied by Andrew on topic Image HFR History

I don't think it would be a problem per-se , but it would interrupt following the long term trend that would tell the tale at a glance of changing focus over time.
Last edit: 4 years 5 months ago by Andrew.
4 years 5 months ago #44219

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Replied by Alfred on topic Image HFR History

Excellent ideas, Gentlemen! All these things would be important improvements IMO, very helpful features!
4 years 5 months ago #44220

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Replied by Andrew on topic Image HFR History

The existing focus star profile should find a new home in the focus module while at it. As there isn't much need to have it in the summary page sitting idle most of the time. It might even be of more use there during a computer assisted manual focus.
4 years 5 months ago #44221

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