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

Hi, Carlos,

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 Your comment about the order is interesting.

----- Original Message -----

From: Carlos Milovic F.

To: Discussion of Film Astrophotography

Sent: Wednesday, March 09, 2005 11:18 PM

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

>Even I tried the new DBE tool in PixInsight. I found it to work pretty well on a >fairly straightforward image (h and chi Persei), though I did it at 4th order with >no assumed symmetry on a 35 mm negative originally scanned at 4000 dpi.

Hi Greg

I don't recommend you to use higher orders than the default one... If you put several samples this can yield to a wild behavior in the interpolation, or in other words, just too many oscilations in the function. In most cases, vigneting is very soft and smooth.

In such star fields, without large nebulosities, working with automatic generated samples is a good choise... becouse you don't have limitations to where to put them, using the symetries isn't required. In fact, I would say that if you have the oportunity to use real samples instead of "virtual" ones, just take it.

>(It might take a while to do these computations on some platforms and it >even took several minutes on my computer.)

A good idea is to subsample the output. Since PixelMath rescales automaticaly any image in the list to fit the target one, and becouse the background is very smooth, there is no problem with working with 1/2, 1/4 or even 1/8 (at 4000dpi) downsamples. This speeds a lot the interpolation function calculation in DBE, wich is by far slower than upsampling.

>I still find myself going back to PS for curves and levels. I couldn't get use to >the curves tool in PixInsight

Why? Do you miss something? Have you tried the Real Time Preview?

>and I hated giving up the ability to do layers.

For most of the processing steps you don't need the use of layers. PixInsight works with a 32bits inner accuracy, so it doens't matter how many curves, or histogram's adjustements you apply... there are so many avalaible levels that there are almost no rounding errors.

If you used layers to mask process... here you have a very easy to use mask capability.

If you want to combine two or more images (be sure that they fit perfectly...), averaging, by SMI or whatever method you like... you have PixelMath.

With a little of imagination (and expertise), you'll be able to create quite complex masks, do the same as Layer Masking, perform unsharp masks, and a lot more.

> I may try some more because I'm sure PixInsight is very powerful.

Be sure of that. If you have an alternative to register (aling) images or create mosaics, you'll find that you don't need nothing more for most of your images. In fact, the only processes I miss in LE, comparing to the current standard edition, are Color Saturation, Deconvolution and Dynamic Alignement. And I have been using exclusively PixInsight for all of my images for more than a year. I use it even with my daytime shots.

Regards,

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