Histogram Features

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CityObserver
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Histogram Features

Post by CityObserver » Mon Nov 13, 2017 5:01 pm

Hi Robin,

First -- thanks for the fantastic updates on 3.1. There's loads of new features I'd never even thought of that are amazingly useful.

I also really like the new histogram setup in the latest 3.1 beta. It gives you a lot more general control.

However...

There are a few things that would be really great... I don't know how easy or difficult these would be.

--I'd love to be able to zoom into the histogram, to provide more fine controls over the level lines.

When I was working with it last night, I ended up needing to tweak the Black level and the Mid level lines so close to each other that the slightest movement made a huge difference and it was very difficult to control.

If there was a zoom in/out button that would be super useful, I would imagine if you zoomed in then a standard window slider bar would need to appear so you could scroll along the histogram.

In addition to the zoom in/out there could also be a click to section button -- where the histogram display zooms into the area between the Black and the White level lines. So that the level lines are at the at the edges of the histogram display.

Alternately, perhaps a just fine tune slider as you have had in previous versions, so a long drag of the mouse only moves the level line a little bit.

Would this be an easy tweak?


-- I'd love to have curves control on the Live Stacking image.


I've just started with an OSC camera when previously I'd been mono. Something I would love is to have curve control over all the levels as in photoshop (for instance: http://www.cambridgeincolour.com/tutori ... curves.htm).

Previously I'd in a feature suggestion post I suggested a multi-special UI layout with mockup. You could use almost exactly the same layout for this.

At the moment, I'm taking a screenshot on my iPad and doing a quick colour grade in Lightroom to seek out some more details, then switching back to SharpCap. Lightroom on iOS has curve control so you can tweak things to see things otherwise hidden -- even just from the screenshot you can make detail easier to see, so I would imagine with proper access to the data you could actually discover more detail hidden in there.


-- Something very minor, and probably only effects me... slightly larger target zones on some lines, for people who use touch

I know this is probably a niche request... but it would help all those who use SharpCap on a touch PC, Surface Pro or on iPad.

I use RDP to access a compute stick from an iPad, essentially turning my iPad into a Surface Pro. This means that a lot of the time I'm using my fingers to move sliders and windows. I use the Pencil, and the precision makes things much like mouse control, however, frequently it's packed and using fingers can become frustrating. In particular...

Resizing the right hand panel where the camera controls and other panels are docked is very tricky. Using using your finger sometimes takes six or seven attempts before you grab the edge to resize. It can occasionally even be fiddly with the Pencil.

If there was a few more pixels of width to activate the edge bar so you can grab, drag, and change the width of the panel things would be massively easier to control.

This became clear to me when I was using the new histogram, because I discovered after a while that the lines are not click-and-dragable on touch -- but the text is. It is a little fiddly with fingers, but it does work -- and it's is fine with the pencil.


Thanks again for the great features update on 3.1. In particular, the plate solving is amazingly useful, and has relegated my xbox gamepad mount control to very occasional use (and the sensor analysis stuff is great too).

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Re: Histogram Features

Post by admin » Mon Nov 13, 2017 7:50 pm

So, quick question first so that I can get my bearings... Are you talking about the new black/mid/white level lines in the live stacking or the display control sliders for the levels in the right hand panel?

If it's the latter then they have been replaced already with a mini-histogram with lines on it like the live stack histogram and that will be in the next build. I have also updated the live stack histogram to look more like the normal histogram (and to have separate LRGB lines if you are imaging in colour).

Further improvements I'm planning (which should be in for 3.1) include

* Colour adjustment in Live stack, although probably just simple sliders for the R and B multipliers I'm afraid, nothing near as good looking as your mockup :(

I also have considered that there might be a need for finer adjustments but haven't had time to implement anything yet. Zoom is not impossible, but awkward to keep all the different parts in sync, so more likely will be some 'fine adjust' buttons that appear when you hover over the lines I will also see what can be done about the width of the drag handles, although making them too wide makes it harder to adjust when the levels are close to each other.

cheers,

Robin

CityObserver
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Re: Histogram Features

Post by CityObserver » Tue Nov 14, 2017 9:35 am

I’m mainly talking about the black/mid/white level lines on the new histogram. Though I do like the sound of the new addition!

Fine tuning the lines in the Live Stack main histogram I found quite tricky — not really related to using touch though I’m sure it made it marginally harder. I was imaging Orion and to get the most detail and a fractional move on the black line had a huge impact on the image because the black and mid lines were so close. Additional “fine tune” sliders like there was before for black would indeed probably solve this.

If colour adjustment curves are not easy, is a master RGB curve possible? When I’m trying to reveal structure with the curve I’m trying to hold the highlights from blowing out, while revealing more in the blacks, then cutting thought glow or putting more black in the darker shadows, stretching the histogram is sometimes not enough. Or is this something I can already do in the software using another method than I’m not aware of?

In terms of the drag handles, the new histogram is actually okay to drag because the text is a good target, though a little more is always welcome. The frustrating one on touch is the right hand panel resizing, not the controls themselves.

Just to note that in the right hand panel, when using touch the drag sliders don’t work. For whatever reason you can’t grab the slider, you have to click on the bar itself and move in increments. This may be to do with the size of the activation area on the button.

This isn’t something I’d mention as a particular issue this since it doesn’t effect functionality or practical use, but that’s how it seems to run. The main Live Stack histogram lines slide quite nicely if you grab he black/mid/white text labels.

Thanks!

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Re: Histogram Features

Post by admin » Tue Nov 14, 2017 5:05 pm

Try the very latest build when you have a chance (new one last night). I have added

* R/G/B sliders to the right of the histogram to adjust the relative colour balance of the three channels in the display and when saved 'as seen'
* Finer adjustment of the level positions if you hold down shift while dragging them

Hope this moves in the right direction.

cheers,

Robin

CityObserver
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Re: Histogram Features

Post by CityObserver » Tue Nov 14, 2017 6:34 pm

That's fantastic. I will check that out this evening. Alas, I think the clouds will prevent me from using it on the sky though.

Thanks again -- I really appreciate the work that goes into the software -- the good user experience in SharpCap -- especially with live stacking has totally changed the astronomy experience for me, allowing me to explore stuff I never thought I'd be able to see.

CityObserver
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Re: Histogram Features

Post by CityObserver » Wed Nov 15, 2017 2:13 pm

I think the new colour sliders are very good addition.

The additional colour information in the histogram panel looks good too and I like the auto adjustment for a quick solution to get started. For what I was trying to do, this does 85% — it’s definitely in the right direction.

A few thoughts:

— Touch

I realised when I loaded it up that using touch, I couldn’t hold down shift since I only have a virtual keyboard. Maybe I can find a workaround to this. I will test again tonight.


— Colour bar adjustments

I did find that most of the colour adjustments that you make are going to be on all a the lower area of the bar. I would expect that it will be very rare when you slide one colour multiplier all the way to the top while keeping the others lower down.

So, in terms of UI, there is a large section of the bars (toward the top) that is not likely to be used, and most of the adjustments are in the lower end of the scale, tweaking small amounts.

I’m not sure what the best solution is. Possibly a scale the same as the exposure slider in the panel that has two levels of view? Maybe a logarithmic scale? Perhaps the holding shift to change sensitivity will help when I figure out how to do that.


— Specificity and repeatability of colour balance

It would also be very good to be able to put a number to the colour balance. That way it is repeatable to go and set a specific r,g,b balance.

Another thought is that it would be good to be able to reset the display balance without resetting the histogram too.


— Performance

I got home from work late last night, so I only had a chance to test the build using the simulation, rater than a real camera. However, my core M3 powered Compute Stick was struggling a little. Dragging the histogram level lines now only refreshes once every 0.5 of a second or so which is notably slower than in the previous build where it was smooth. This adds to the difficult of precise control. What is causing this I don’t know.

While I like the visual information from interest, I don’t think the colour histogram would be key to the workflow of eeking out detail since I’m usually just watching the image.

If rendering the extra information in the histogram is expensive, it would be good to have the option to turn it off. I suspect people with an Atom based PCs such as the Compute Stick are going to struggle.

However -- as I said, this was only using the simulator, so it may be different when a real camera is plugged in.

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Re: Histogram Features

Post by admin » Wed Nov 15, 2017 7:03 pm

Thanks for the feedback - I had thought I had added the code to show the slider values while they were being moved which would make repeatable adjustment easier, but looks like I forgot :(

There is a difference in behaviour in how the screen updates when using shorter exposures

- firstly the bigger fraction of the time that is spent actually stacking the images, the less the fraction available to update the display when dragging the sliders

- secondly, if the exposure time is less than one second then I think it always waits for the next frame to arrive before updating

- thirdly, there was an issue in a previous build with the update messages caused by slider dragging stacking up in a queue which would cause all sorts of problems with complete lockups or out-of-memory issues, so now the update rate is limited. I will have to check whether I have gone too far in that area though!

I do see the issue with not being able to drag and press shift at the same time - can you simulate the right button with your touch screen? Maybe I could make right button dragging slow?

cheers,

Robin

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