Author Topic: Frame adaption w/o StarAlignment  (Read 3719 times)

Offline fneyer

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Frame adaption w/o StarAlignment
« on: 2012 April 12 03:31:58 »
Hi everyone,

Is there any chanse to apply a linear image adjustement with respect to another image? This would be the same as using the 'Frame Adaption' in the StarAlignment tool.
But what if I don't want to align two (linear) images but adjust there offset and range? Also can the paramater estimation be restricted to some preview areas?

Any help would be greatly appreciated!

Thanks,
Fabian

Offline georg.viehoever

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Re: Frame adaption w/o StarAlignment
« Reply #1 on: 2012 April 12 03:46:37 »
See http://pixinsight.com/forum/index.php?topic=4105.msg28753#msg28753. Beyond that, the PixelMath tool allows to do all kinds of modifications to pixel values.
Georg
Georg (6 inch Newton, unmodified Canon EOS40D+80D, unguided EQ5 mount)

Offline fneyer

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Re: Frame adaption w/o StarAlignment
« Reply #2 on: 2012 April 12 03:59:28 »
Uuupps, didn't see that.. 8)
Thanks for posting the link!
Fabian

Offline vicent_peris

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Re: Frame adaption w/o StarAlignment
« Reply #3 on: 2012 April 12 04:14:51 »
Hi,

If you have two separate and aligned images that form a mosaic and want to fit the pixel values between them, the workflow is the one below:

- Make the same preview in both images and extract them as independent images.

- Apply LinearFit to one of them taking as reference the other preview.

- LinearFit will give you the linear equation to transform the target preview. Apply this equation to the whole image with PixelMath.


Best regards,
Vicent.

Offline fneyer

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Re: Frame adaption w/o StarAlignment
« Reply #4 on: 2012 April 12 04:29:59 »
Hi Vincent,

Yes I was thinking of the same procedure, although it is a bit cumbersome.
Alternatively, would it not be easier to directly but the equation into PixelMath (using the two identical previews for parameter estimation in both images) and apply it to the non-reference image?
Would this be possible?

It would really be handy if one could define the parameter estimation area of the LinearFit...!

Thanks,
Fabian

Offline fneyer

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Re: Frame adaption w/o StarAlignment
« Reply #5 on: 2012 April 12 12:00:26 »
Ok, I tried several things so I have several questions.. :D

- If the LinearFit parameters are applied with PixelMath, the resulting image does not need to be rescaled. Is this correct? (Otherwise - as I understand it - the offset correction would again be removed).

- For the consol window, is there a way to increase the number of digits in output of the parameter estimates?

- In the LinearFit toolbox, you can select an image->Preview as Reference. This however does produce an error. Can this be solved?

Fabian