Session 1 - PixInsight Basics

Introduction to PixInsight

Mehdi Bozzo-Rey: [email protected]

PixInsight ● software made by astronomers for astronomers● growing community● no “painting”● masks are heavily used and you build your masks using the original data● processes highly tunable● the development team will implement function based on research papers if

needed● works almost anywhere● not a good idea to use it for planetary imaging pre-processing / mosaics


By the way … what is that FITS thing ?● FITS: Flexible Image Transport System

○ Open Standard defining a digital file format○ specifically designed for a scientific usage○ most common file format used in astronomy○ the header contains the scientific information


https://en.wikipedia.org/wiki/FITS

https://en.wikipedia.org/wiki/FITS

PixInsight: where to find help ?● Pixinsight online resources page


http://pixinsight.com/resources/

PixInsight: Where to find help ? (2)● PixInsight forum : a lot of information, examples etc ...


http://pixinsight.com/forum/

http://pixinsight.com/forum/

PixInsight: where to find help ? (3)● inline help


UI: main interface


UI: tab: Process Console● All the “system” operations are logged here


UI: tab: View Explorer ● Information about currently available views (any workspace)


UI: tab: Process Explorer ● shortcuts for the processes (i.e. operations available)


UI: tab: File Explorer ● File browser with integrated preview, histogram and info


UI: tab: Script Editor ● a script editor


UI: tab: History Editor ● Allows you to view the process history for a particular view


PixInsight workspaces● There are 4 workspaces available


Working with images: change image identifier● changing the name of the view


Working with images: previews● creating a preview


Working with images: previews (2)● preview properties


Working with images: duplicate an image● left click, drag&drop


Working with images: duplicate an image (2)● End result


readout mode● Pixel location and values per channel


A word about histograms and linear images

● horizontal: left to right = black to white● vertical: number of pixels with the same value● very good introduction here

● A linear image is an image where values of its pixels follow a linear function of the source intensities : needed for enhancement

● non linear transformations are applied at the end


http://pixinsight.com/doc/tools/HistogramTransformation/HistogramTransformation.html

http://pixinsight.com/forum/index.php?topic=457.0

http://www.cambridgeincolour.com/tutorials/histograms1.htm

STF autostretch


STF autostretch● based on the histogram, so you need a clean picture


Dynamic crop● removing parts you don’t want/need


STF autostretch again● using a clean picture this time


Saving processes


Saving processes (2)


reinjecting a process


reinjecting a process (2)


Working with masksExtract Lightness = work on the structure

Invert it and work on the background


mask selection: red is preserved !


mask selection: show (or not) mask


applying process on a masked picture● The process is applied only on certain regions


applying process on a masked picture (2)● in our case we exposed details in the core of the galaxy


not using masks● bad idea: the process is applied on both the structure and background


using masks: background work (1)example: using the inverted lightness mask and Histogram transformation


using masks: background work (2)● trying to remove high intensity pixels from the background


using masks: background work (3)● final result


Commonly used processes● ScreenTransfer Function (AutoStretch)● Dynamic crop● Dynamic Background Extraction● Background neutralisation● Sample format conversion● Histogram Transformation● Channel Extraction● Channel Combination● HDR multiscale transform● curves transtormation

● ACDNR● Color Saturation● ATrousWaveletTransform


Ready to go !


Session 1 - PixInsight Basics

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Transcript of Session 1 - PixInsight Basics