EXTRACT A LUMINANCE |
|
While we are at it I will show you how to use the luminance as a mask to protect the background , then you can just process the signal area's of your image |
|
Of course to extract a luminance we will need a colour image like the one I have opened in fig 1 Below |
|
Click on image to enlarge Fig 1
|
|
To extract a luminance we have to do the hugely complicated action of clicking on the Extract luminance button on the top tool bar and a separate Lum image will appear ( top right in the above ) some people choose to process the luminance separate from the RGB and recombine them later but I personally see no merit in this , but its up to you One of the big advantages of Pixinsight is the use of masks , You can use masks to block of areas of the image you wish not to be affected by process , there are many masks in pixinsight ( see star mask production when I have done it ! ) but one of the simpler to make and use is the luminance mask and being we now have a luminance, lets apply it to the rgb image to protect the background This is very simple to do , just grab the side image identifier ( image name ) while holding down the left mouse key and drag it to the empty space on the side bar on the rgb image and release We will end up with something like Fig2 below |
|
Click on image to enlarge Fig 2 |
|
You will of course notice that the image is now red ( meaning the mask is applied ) you can minimize your lum image at this time but do not close it as it is still being used as a mask. The mask options have become live on the top bar and these being A) Select mask -- you might have multiple mask available B) Remove mask C) Invert mask -- you might want reverse the use of the mask D) Enable / disable mask E) Show mask--You can hide the mask with this while it is still active I do this a lot so you can see the alterations you are making
If you are following the section one basic workflow you need to do the above , so you can do a saturation boost in curves , which is next and of course as the background is masked only unmasked area will have the boost applied too , therefore not increasing the noise in the background
|
|
