PixInsight Forum (historical)
PixInsight => Tutorials and Processing Examples => Topic started by: vicent_peris on 2011 September 16 08:36:04
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Hi all,
I've just published a tutorial about processing techniques concerning dynamic range and local contrast. Although it's an advanced tutorial, I think some sections can be easily followed. In this article I describe some techniques that are extremely important for me at this moment. I recommend to take a closer look to the star dynamic range compression section that speaks about the techniques I am using now to restore the Gaussian profile of the stars. Follow the below link to read the article:
http://pixinsight.com/tutorials/NGC7023-HDR/en.html
Hope you like it!
Best regards,
Vicent.
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Vicent,
Thank you for all the work you put into this tutorial. It describes several new techniques for me, and I'm sure that I will find them valuable in the future. I plan to rework one of my old images while following along, to better understand the processes involved.
Thanks again,
Sean
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Hola Vincent, excelente tutorial, muchas gracias.
Tratando de seguirlo noté que mi MaskedStreth tiene 0,2 como valor máximo para Target median (es la misma versión), ¿hay alguna actualización del script?
Saludos. Alejandro.
Hi Vincent, great toturial, many thanks for it.
Trying to follow it I notice that my MaskedStretch has 0.2 as maximun value for Target median (same version), are there any update of the script?
Regards, Alejandro.
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Hi Alejandro,
You're right, the tutorial uses a customized version of the script. Do the following:
- Open the Process Explorer window
- Expand the Scripts > Utilities node
- Right-click the MaskedStretch script item and select "Edit Script"
- On the script editor, go to line number 508. This line has the following text:
setRange (0.001, 0.2);
Replace it with
setRange (0.001, 0.5);
Now save the modified script to any location and run it by pressing F9.
Let me know if this works.
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Yes, it worked perfectly! Thank you.
Saludos.
Alejandro.
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Hello I have this type of error
Why?
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Hi Giorgio,
Because the script is on a subfolder of "C:/Program Files", which is a system folder where you need administrative privileges to write a file.
For now, the solution is writing the modified script to a different folder where you have full access, such as your Documents folder for example, or your Desktop folder.
Later I'll release an update with the modified script for all platforms. Sorry for the inconvenience.
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Hi all,
I've just published a tutorial about processing techniques concerning dynamic range and local contrast. Although it's an advanced tutorial, I think some sections can be easily followed. In this article I describe some techniques that are extremely important for me at this moment. I recommend to take a closer look to the star dynamic range compression section that speaks about the techniques I am using now to restore the Gaussian profile of the stars. Follow the below link to read the article:
http://pixinsight.com/tutorials/NGC7023-HDR/en.html
Hope you like it!
Best regards,
Vicent.
great article and hints but i cant get the mouseovers to work Vicent?
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H0ughy,
I clicked on each of the mouse-over links and waited 'til they downloaded. Then the MO works but the changes might be very subtle.
Charles
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Very interesting turorial Vicent, thanks for sharing :D
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Hi
How do you work out the median , mine says 2.2-- in the statistics bit ::)
Regards Harry
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Hi,
Thank you very much for your comments.
How do you work out the median , mine says 2.2-- in the statistics bit ::)
I'm sorry, Harry, but I don't understand you...
Best regards,
Vicent.
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Hi
Don't worry not many people can >:D
How did you arrive and find the target median ? ( 0.43 you used )
Regards Harry
Hi,
Thank you very much for your comments.
How do you work out the median , mine says 2.2-- in the statistics bit ::)
I'm sorry, Harry, but I don't understand you...
Best regards,
Vicent.
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How did you arrive and find the target median ? ( 0.43 you used )
The goal is to make a similar stretching with MST as the one you have with the histogram-stretched image (this doesn't need to be very precise). Simply read the statistics of the latter image and put this value in the target median parameter of MST.
Regards,
Vicent.
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Hi
Vincent
I have used your star technique , and it works really well :D
http://www.harrysastroshed.com/Image%20html/zoommcocoon2011/cocoonjpeg2011/cocoon20113.html (http://www.harrysastroshed.com/Image%20html/zoommcocoon2011/cocoonjpeg2011/cocoon20113.html)
Many thanks for your work
Harry
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Harry, seems to have an error in the image path code (error to load in FF 7.0.1) Maybe something like this in the flashvars work:
zoomifyImagePath=/Image html/zoommcocoon2011/cocoonjpeg2011/cocoon-full
Regards,
Enzo.
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Hi
Sorry the zoom thing may be causing a problem :o But if you look below the zoom box there is a link to a std high res version
Harry
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That's a great image, Harry. The stars do indeed look very nice and colorful. I'm going to have to try and figure out Vicent's star method.
Steve
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Hi
I am sure a man with more brains than me could script the star bit , seems like a challange to me
Regards Harry
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I have a question about this tutorial. I suppose that Vicent would be the person most likely to be able to clarify this point:
I have been following along with the tutorial, using some M31 data I shot in October. I am having some trouble following the method around Figures 14 and 15. From the looks of Fig. 14, it appears that the PixelMath operation will be applied to an image (`Replace Target Image' is checked).
But which one?
Three images are shown in the PixelMath expression: MS, MS_LS, and HDRWT_LS. Should the PixelMath operation be applied to one of these?
Here's another thing I'm confused about: The tutorial's text gives the impression that the PixelMath expression is being used to modify the HDRWT image. But that's not one of the images in the Expression. Can we (and should we) apply the PixelMath expression to the HDRWT image, if it's not *in* the expression?
Thank you for the clarification,
Marek