PixInsight Forum (historical)

Software Development => PCL and PJSR Development => Topic started by: sdh on 2012 July 07 17:45:55

Title: Problem with MaskedStretch?
Post by: sdh on 2012 July 07 17:45:55

Hi,

I'm trying to use the MaskedStretch script for the first time, and I'm getting strange results.
I wasn't sure where to post a question about this, so I just took a guess here.

It works fine on the M57 .fit file linked to by an older thread. However, on my data, it does
very little stretching of the image, it just increases the background. My histogram remains
almost linear.

I have attached a crop of my data, and a screencap of the parameters I'm using. If anyone
could enlighten me, I would be grateful. MaskedStretch looks very useful.

Thanks,
Steve

Title: Re: Problem with MaskedStretch?
Post by: Andres.Pozo on 2012 July 07 18:23:19

This behavior probably is because your image has a very high background level.
If this is the case, before applying MaskedStretch you should adjust the histogram for removing the unused part at the left. Using HistogramTransformation move the shadows handle to the right to the position where the histogram starts to increase. If you do not change the midtones value the result is still lineal.

Title: Re: Problem with MaskedStretch?
Post by: sdh on 2012 July 07 22:15:12

Thanks Andres, that worked.