Astronomy work with Krita

[Cyrille Berger]

Hi,

First I will mention that Krita itself is aiming at being a painting 
application, but we don't have objections on other people working to adapt or 
write plug-ins for Krita for other purposes. We have some kind of in-progress 
infrastructure to help with that situation (http://extensions.krita.org/).

On Monday 30 August 2010, Stephen Williams wrote:
> The images I work with are RGB48 from a Nikon D80 camera, so they
> are fairly large.

The question is how large should be the result, I often do 4000x2000 drawings 
with Krita, with dozen of layers, so a bit more than the D80 resolution, but I 
suspect that you would want a significantly larger image as a result. That 
said, usually the bottleneck is memory, since you are ready to invest some 
money, I guess, investing in memory might not be a problem ;) Otherwise if the 
resulting image is really too big, an alternative would be to use VIPS [1], 
which is a library design for processing of very large image.

> Then I will want to build up a stack of them,
> typically a half dozen or dozen images, and also combine a few
> dark field shots. The processing would amount to aligning each
> image, adding them to a stack, subtracting out the dark-field
> images, then tone-mapping the results.
There is already a tone mapping plugin, but currently it is implemented 
separately of the filter API, as a special color conversion plugin. But it 
would be possible to make it a filter and then use it as a filter layer/mask. 
For the combination itself, right now it is implemented as a "cascade", layers 
are combined two-by-two, so if you have four layers in a group: "layer1", 
"layer2", "layer3" and "layer4", then first "layer1" is combined with "layer2" 
to give "layer12" which is combined with "layer3" to give "layer123" which is 
combined with "layer4" to give the result on the screen. I suspect that for 
your use case, you would need to write an algorithm that is combining all four 
layers at the same time. If this is the case, the good thing is that it is 
actually a todo of mine (for a future release, and I would not mind anyone 
else implementing that for me ;) ) to make it possible to replace the 
combination algorithm of a group.

> I have been thinking along the lines of importing the images into
> an image stack layer group, and the dark fields into another layer
> group. Within each layer group, it would be nice to be able to turn
> individual frames on/off.
That would be already doable.

[1] http://www.vips.ecs.soton.ac.uk/index.php?title=VIPS

-- 
Cyrille Berger