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We are delighted to welcome you to this forum

Siril is now in RC1 version ;-)

The forum has been migrated to www.forum.siril.org update your bookmarks!!!

View window vs. Transformation

elladan · 34

Hors ligne elladan

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le: mai 12, 2019, 05:46:15 05
In a previous version of Siril, I remember being able to get an image the way I liked it in the image view window and then right click -> save the image, and I'd get a copy of what the window was showing.

In more recent versions, I have to modify the image using histogram or asin transformation and then save it. When I try saving from the view window, I just get a linear copy.

This is a problem mostly because the user interface in the image view window is actually much nicer, especially for ASIN, than the transformations. In particular:

In the view window, I the scroll bars are very long, and more importantly, the numerical setting to the right is manually editable. This way, if I happen to need to set the ASIN transformation just so, it's very easy. With the transformation interface, I'm stuck with very fiddly mouse dragging.

It would be nice to just be able to save what I see (potentially as a 16 bit or even higher fits so no information is lost!), and also it would be nice if the asin, histogram, and numerous other UI elements like for example the A trous wavelet transformation which consist of sliders also allowed for fine control by editing the numbers on the right.

Is there something I'm missing here?



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Réponse #1 le: mai 12, 2019, 08:54:53 08
Actualy you are saving what you are seeing.
But you need to know what you are doing.
For example check the viewer slider positions and if you are in linear visualisation.



Hors ligne elladan

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Réponse #2 le: mai 12, 2019, 10:07:51 10
Actualy you are saving what you are seeing.
But you need to know what you are doing.
For example check the viewer slider positions and if you are in linear visualisation.

I just tested using Siril 0.9.11rc2, using the following settings on a one channel image:

1. FITS: Linear full 16 bit range.
2. FITS: Linear half - 15 bit range.
3. FITS: Log mode with sliders set to full 16 bit range.
4. FITS: asin mode with sliders set to "pleasing" values.
5. PNG: Log mode
6. PNG: asin mode

1-4 are identical except for different lo/hi values in the fits header.
5-6 are bit-for-bit identical.



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Réponse #3 le: mai 13, 2019, 12:34:50 00
Hello, this is the expected result with the recent versions. As you found out, you need to change the pixel values before saving the file, it's not related any more to the screen transfer function of the view.

Using the asinh or histogram is indeed the way to go now, I'm sorry if you don't find it good. In recent versions previewing is possible. We'll think about adding the values in the GUI.

Regards



Hors ligne elladan

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Réponse #4 le: mai 13, 2019, 09:34:19 09
Hello, this is the expected result with the recent versions. As you found out, you need to change the pixel values before saving the file, it's not related any more to the screen transfer function of the view.

Using the asinh or histogram is indeed the way to go now, I'm sorry if you don't find it good. In recent versions previewing is possible. We'll think about adding the values in the GUI.

Regards

Thanks for the response. Siril is a great tool, and I'm really enjoying using it. :-)

My criticism of the pixel transform approach is primarily just that the GUI for the screen transfer is much nicer in certain ways. In addition to the fine control problem, I guess I should note also that there just doesn't seem to be an option for log, sqrt, or squared transforms in case someone wanted those. I did notice that autostretch was available as a button in the histogram tool.

That said, an "apply this transform to the pixel values" button in the view window would seem quite convenient. Certainly right clicking (on the RGB preview!) didn't seem like a particularly intuitive interface in the past.



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Réponse #5 le: mai 13, 2019, 10:22:25 22
The thing is also that many users use siril results to start the final processing of their images in an image manipulation program. In that case, they need to keep the 16 bits.

But I understand your need. We assume that the histogram tool is more powerful than having the rendering modes and cursors like the display window, maybe we are wrong. We also assumed that the histogram tool was fast enough.

We'll think about it and see how we can integrate the best of both worlds.
Thanks



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Réponse #6 le: mai 14, 2019, 05:43:56 05
The thing is also that many users use siril results to start the final processing of their images in an image manipulation program. In that case, they need to keep the 16 bits.

But I understand your need. We assume that the histogram tool is more powerful than having the rendering modes and cursors like the display window, maybe we are wrong. We also assumed that the histogram tool was fast enough.

We'll think about it and see how we can integrate the best of both worlds.
Thanks

Thanks for the comments! I also like to process my images into an external editing tool, but I find it convenient to do the first pass in Siril.

Just to clarify here, applying the visualization mapping doesn't imply reducing the bit depth. You can just scale whatever transformation is being displayed to map the pixel values into a 16-bit linear space.