Combining two master light images

[Batch]

Hi,

I am new to the Group and new to PixInsight.  My initial impression is entirely positive…..what a great program, very robust with broad selection of tools. Also the various tutorials from the developers and users have been very helpful in getting comfortable with the program.

I have imaged for a number of years and have used several different processing programs (primarily PS and Maxim) but I am having some challenges learning the ins and outs of PixInsight. One issue that I am currently trying to work out is how to combine two RGB images. These two master lights are from separate imaging runs taken on different nights and at different ISOs, exposure and temperatures (each group has been stacked and calibrated separately). I have registered the two masters and would now like to combine them with one being weighted more than the other (60% / 40%).  I am sure that this is a pretty straight forward process and I am hoping to get a bit of direction on how to do it. Any suggestions would be appreciated….thanks.

Bill

[pfile]

hi... you can do this with pixelmath:

first make sure that "create new image" is checked, and "rescale result" is off (for now, you may want to experiment with that later)

then, with "single expression for RGB" checked, enter this in the RGB/K field:

0.6*Image1 + 0.4*Image2

and apply pixelmath.

this should create a new image which is blended 60/40. of course substitute the identifiers of your two images in the above expression.

hope this helps, rob

[Batch]

Well that was easy....thanks Rob

[kolec]

Well that was easy, but..

1. It´s better linear fit one imagine to another and after this aplly pixelmath

I have question.
Is not better use Image integration tool?( make some copies for three imagines)?
(extract some nois?)

Kolec

[pfile]

fair enough, linear fit might be a good idea to get the statistics of both images into the same ballpark before combination.

i'm not sure if using II makes sense - i understand what you are getting at but you are stuck with the weighting that II gives you and i'm not sure you can really do a sane pixel rejection on just two images.