Re: [APML] Announcement: New PixInsight LE Version 1.0.2.143 Available

["Carlos Milovic F." <cmilovic@yahoo.es>]

Hi Greg!

> Sorry about that. I'm not sure what I did to send
> out that fragment but it
> was something goofy. Also worth mentioning: I had to
> reformat this from
> "Rich Text" to "Plain Text" to get under the APML 10
> kB message size limit.
> Maybe the limit is a little too restrictive?
> 

I agree with you... today's number of messages are not
as many as to slow down things too much. =)

> When I did the DBE, I allowed the program to
> generate the sampling. I used
> 24 horizontal samples of size 16. As your
> documentation suggested, I zoomed
> in and moved sample boxes as required to avoid
> stars. That didn't take as
> long as you might think. 

Yes. This procedure is quite straightforward and can
be done fast. The rejection algorithm (threshold)
isolates very well those faint/little star. You just
have to take care of the larger ones.

> Your comment about the
> order is interesting. I
> confess to having done the DBE several times because
> I inadvertently
> destroyed my work a couple of times. Clever boy.

A suggestion... before pressing "Done" or "Generate",
create a new Process Icon with DBE. There will be
stored all your setup.

> Anyway, I thought the
> results generated using the 2nd order fit had a
> little more secular
> variation than I might have expected based on what
> I've seen when I removed
> uneven field illumination in PS. For that reason, I
> tried the 4th order fit
> which seemed to result in a smoother background.
> 

First of all, PI's interpolation order isn't refered
to a polynomial two-dimensional fit. This means,
second order are not just conic sections. PixInsight
uses Splines, and the order is refered to the
continuity order (differenciation degree) of all of
those local interpolations.

Just a "ruler of thumb", if you have exotic vigneting
patterns, use higher orders... while if you want to
smooth things, use the "Smooth" parameter at 2nd or
3rd order. Usually the defaults parameters work well
for most images. 

> BTW, after I thought about it last night I decided
> the reason there was less
> noise in the result might have been because the
> program was working at a
> high level of precision. I'll do some more
> experimentation, of course, but I
> really liked the result a lot.
> 

Well, surelly you'll see no posterization or steps in
the background generated throught DBE. Unlike PS, PI
works always with 32bits. Then, the interpolation
gives you a very smooth gradient. If you can see any
step or abrupt change of tone, most likelly it is a
problem with the visualization, and the limitations of
the 8bits per channel display. In those cases, try
this: explore the image with the mouse cursor,
verifying the continuity of the gradient. You'll see
no jump at all.

> In PS I like layers for the ability to do one step
> at a time and to do the
> same thing multiple times with easy comparison of
> results. 

Do you make use of Previews? With the combination of a
Process Container you can try any combination or
sequence of processes. All right, it is much more
slower, but the benefits of a real preview instead of
an aproximation worths it.

> It's also easy in
> PS to undo anything you've done. That's important to
> someone like me who is
> hardly a star image processor like some of the folks
> who hang out here.

I bet that everyone here works in a trial and error
basis. That's the main reason to make a good use of
previews, real time previews and process containers. I
apply a process only if I'm sure that it works well.

> That's not to say I can't work out a way to do these
> things in PixInsight,
> I'm just not that familiar with it so naturally I
> prefer PS for some
> procedures. I did indeed have the Real Time Preview
> enabled but I'm still an
> extreme neophyte.

Don't worry. The same happened to me the first weeks.
But, believe me, once you get used to it, you are
gonna  do things much more complex that you used to
do, and get better results.

> I'm not saying PS is better than PI at these tasks.
> I'm simply used to the
> procedures in PS. In fact, I'm going back to redo
> the image in PI yet again
> (I saved the image after fixing the background) to
> gain more experience with
> the tools available. I suspect the handwriting is on
> the wall and PI will
> become an important tool for astrophotography
> processing so it seems to me
> as if it would be a good idea for me to get in on
> the ground floor before
> the real version of PI becomes available.

Your words are very encouraging. Juan is going to be
very happy if that becomes true. =)
Seriusly, there is a lot of power lying in the
standard edition. And the most important thing, that
we think will make the difference over other
softwares, is the object oriented scheme. You will be
able not only to choose wich processes to install. The
main core of the application will be kept intact, and
you just have to install modules to add other file
formats support, new processes, and who knows what
more. Also, users with basic C++ knowledge will be
able to create theyr own processes as modules or
command line standalone executables. Once other people
begin to create such modules, amateurs and
professionals (yes, I'm sure PI can be used with
scientifical purposes), the revolution  will begin.

> Obviously there's a lot of cool functionality in PI.
> Like anything else of
> that complexity, it takes time to learn how to use
> it.
> 


Precisily this is our gratest concern. We want to have
total contron over what the processes do, and that
requires a lot f paramethers and a complex interfase.
Also the user interfase, the preview system, etc. are
quite different from other precedents, so it requires
a new way of seeing and thinking about image
processing. We have heard that many new users got so
lost in there that gave up and went back to more
"user-friendly" programs. That's the main reason why
we ask for critics ans suggestions so often... PI is
just different, and we know that it requires a very
good documentation and lots of examples to get used to
it, and see how things work.

Sorry folks for the long and barely off-topic message.
<g>




Regards,

Carlos Milovic F.
-------------------------
Astro & Photo - CMF
http://www.astrophoto.vze.com
-------------------------
Visita "AstroFoto", el foro de astrofotografía en español
http://espanol.groups.yahoo.com/group/astrofoto


		
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