Solar processing using ImPPG

[Nigella Bryant]

Work flow using ImPPG after stacking. 

1. Launch ImPPG.

2. As per screenshot. At this point check the prevent ringing box and then disk is sharpened using Lucy Richardson Deconvolution set between 1200 and 1500 depending on how this looks. Try not to over cook this as the image will look artificial. 

3. Tick adaptive and place the Sigma setting to around 1.0. Amount Min 1.2 and Amount Max 3.0. You will know if this has gone to far and again looks cooked.

4. Open the Tone Curve Box. Screen shot 6 will open the histogram with the image still having no detail of prominence.  

5. Beging to adjust the curve of the histogram to roughly follow the histogram pattern. This brightens the background and begins to reveals the prominence's around the disk. If your image is sharp then spicules will also be revealed around the disk too.  Adjust the histogram until you get the best background and foreground features.

6. When you are satisfied with the results save using the year, month, day and time ie, 20200430-1400UT followed by your name. The standard for submitting to the British Astronomical Association. 

7. False colour can be added in software such as Photoshop. 

I'm sure the BAA will appreciate your results.

Hope this helps.

[Altocumulus]

Thank you - more mysteries solved.....

[Nigella Bryant]

14 minutes ago, Altocumulus said:

Thank you - more mysteries solved.....

Armed with the info we can produce great image's with modest equipment. Accidentally worked out this new processing technique. Eliminates the need to produce two images, one of disk and one of proms and having to combine them. 

[Freddie]

That’s an interesting tutorial.
Although you use “adaptive” you don’t adjust the settings to control how the sharpening is applied across the image. Any reason for that given that using them would give you better control over how your two settings are being applied?

 

 

 

 

[Nigella Bryant]

1 hour ago, Freddie said:

That’s an interesting tutorial.
Although you use “adaptive” you don’t adjust the settings to control how the sharpening is applied across the image. Any reason for that given that using them would give you better control over how your two settings are being applied?

 

 

 

 

Hi Freddie, I usually alter the settings then press the apply button on the top of the screen. That applies all my settings. Sorry, forgot to mention that detail. 

[Freddie]

Thanks. It was specifically the threshold and trans. width settings I was referring to as you make no mention of those in your process flow and you have left them as default on your screen shots. Without setting them to appropriate levels for your particular image, there is no point in using adaptive.

[GreatAttractor]

Hi Nigella,

Note that the "prevent ringing" function has no effect in an image like above. It's only applied around overexposed=fully white regions, e.g. when shooting prominences with an overexposed disc (there's an example here: link).

[Nigella Bryant]

1 hour ago, GreatAttractor said:

Hi Nigella,

Note that the "prevent ringing" function has no effect in an image like above. It's only applied around overexposed=fully white regions, e.g. when shooting prominences with an overexposed disc (there's an example here: link).

Thanks, appreciate this. I'm just discovering ImPPG's varied processing abilities. I was just publishing my work flow so far as I was asked what it was to produce my solar image's. Still on the learning curve myself.

[Freddie]

Just let us know if you want any thoughts/help with the adaptive settings.

[Nigella Bryant]

1 hour ago, Freddie said:

Just let us know if you want any thoughts/help with the adaptive settings.

Thanks Freddie.

[Altocumulus]

Can you pinpoint which parts of the tone curve affect which parts of the image; other than black/left - white/right.

[Nigella Bryant]

1 hour ago, Altocumulus said:

Can you pinpoint which parts of the tone curve affect which parts of the image; other than black/left - white/right.

Hi, yeah, the left of the high peak and left high peak of the histogram affects the outer part of your image bringing out the prominences, the lower part after the high peak and to the right affects the disk itself. Hope this makes sense.

[Altocumulus]

Thanks Nigella. As I said before , mysteries !

[Freddie]

Just to expand on this a bit, if you think about it, you already know the answer to your question.

As you say, the black part of the histo is on the left and white on the right. If you look at the original image, the sky is dark (left part of histo) and the disk is lighter (right part of histo) The curve that Nigella has applied lifts the left part of the histo to the top i.e. telling it to turn the darkest parts of the image to pure white as seen in the next picture. Care however is needed as the curve is basically turning the darkest ~20% of the image to pure white so if not careful you could turn some very faint part of a prom i.e. a dark part, pure white and therefore lose it in the pure white background.

The same is true for the right part of the histo. Yes, most of it applies to the disk but any very dark parts are in the left side of the histo so again, care is needed when adjusting the curve that you consider this.

So as you know which parts of the histo represent which parts of the image, you can adjust the curve to brighten the dark parts or darken the bright parts to give you the contrast you need to bring out the detail you want.

[Altocumulus]

Thanks Freddie - I often find some settings doing things unexpectedly. I watched a u-tube tutorial earlier this morning in which points were created on the curve and then moved to the left, rather than a straight upward lift.

It's all very clever

[Freddie]

Don’t get confused by points being moved left or right. All that matters is where a point ends up. If the point ends up above the original diagonal line it means all pixels with the particular brightness as defined by the bottom scale have been made brighter. If the point ends up below, they are darker. Height above (or below) the original line indicates by how much the pixels have brightened (or darkened). This is why the line is at the very bottom on the left (represents pure black, so you can only brighten, lift the point, from there) and at the top on the right (represents pure white, so you can only darken, lower the point, from there)

Some histograms show input and output numbers when you select a point. Input being the original brightness value, output being the new brightness value.

[GreatAttractor]

Dont' forget to grab the latest version 0.6.1: https://github.com/GreatAttractor/imppg/releases

It's much faster, all processing (except image alignment) is now performed on the GPU (details can be found here).

Edited May 8, 2020 by GreatAttractor

[Altocumulus]

Double checked - that's the version I'm using.

Great software, by the way, even if it does confuse my old brain cells.....

[richard ashbee]

Thanks Nigella , very helpful when you are just starting

[Nigella Bryant]

1 hour ago, richard ashbee said:

Thanks Nigella , very helpful when you are just starting

No probs, I'm probably going to do a tuning on band for a lunt solar scope tutorial soon as I've seen some images that aren't tuned properly and thus you don't get the best details on the disk. 

[richard ashbee]

Could admin pin this post to the top- thanks

[Altocumulus]

15 hours ago, richard ashbee said:

Could admin pin this post to the top- thanks

Seconded.

[Altocumulus]

I'm going to confess I'm still somewhat baffled.

Left bottom = dark with white to the right - input

Left bottom = dark with white to the top - output.

 

Nigella, did you lift the tone curve at each point in order to achieve the necessary adjustment. I'm asking because a couple of youtube

tutorials show the user moving tone points to the left. What's the underlying rationale behind that? In my limited experiments I end up with

peculiarities creeping in.

[Nigella Bryant]

31 minutes ago, Altocumulus said:

I'm going to confess I'm still somewhat baffled.

Left bottom = dark with white to the right - input

Left bottom = dark with white to the top - output.

 

Nigella, did you lift the tone curve at each point in order to achieve the necessary adjustment. I'm asking because a couple of youtube

tutorials show the user moving tone points to the left. What's the underlying rationale behind that? In my limited experiments I end up with

peculiarities creeping in.

Hi, yes, just follow the histograms highs and lows (apart from the very right hand side of the histogram, leave that as is) and then slightly adjust at each point.

[David Smith]

Thanks for posting this, applied to my Ca-K mosaic from the 9th and I found proms I didn't know I had!