PixelMath with ImageContainer

[Alejandro Tombolini]

Hi,

I have a set of 300 images in a ImageContainer and I would need to apply a PixelMath process that make image1 - image2, image 2 - image3, image n - image n+1
Any help with the formula would be appreciated! 

Thank you
Alejandro.

 

[oldwexi]

Hi Alejandro!
Put in the Image Container
the files which you want to use and
put the expression:
image;&count;&extension;
into "Output template:"
this writes your files to the selected output directory as:
image_00001
image_00002

Yes it creates allso these files as views in your workspace but a
"Close All" removes them all.

In PixelMath put your formula and simply  click "Create new image"
and set the Image id to:            image

This is how it works for me.

Gerald

 

[Alejandro Tombolini]

Hi Gerald!!,

In PixelMath put your formula and simply  click "Create new image"
and set the Image id to:            image
Gerald

Which would be the Pixelmath expresion?

I already have all the images in Image container named form image0001 to image0300. What I want to achieve is to subtract image0002 from image0001, then subtract image0003 from image0002, image0004 form image0003 and so on.

Alejandro.

 

[oldwexi]

Usually i use $T and do calculations with the actual image.

I have no idea how to access the last image for calculations with the actual image.
Will think about it but dont see a big chance.

Your request would need a little script which calls PixelMath with the formula and does the job
with actual image and previous image...

Sorry for havin no solution for your specific question.

Gerald

 

[Alejandro Tombolini]

Don't worry Gerald, thank you anyway!! 

Saludos, Alejandro.

 

[Juan Conejero]

Hi Alejandro,

These tasks can be implemented very easily as scripts. What you are describing is beyond the scope of the PixelMath process.

Here is a small script (34 lines) that does exactly what you want:

#include <pjsr/ImageOp.jsh>
#include <pjsr/UndoFlag.jsh>

function SubtractSuccessiveImages( inputTemplate, outputDir )
{
   let inputFiles = searchDirectory( inputTemplate );
   inputFiles.sort();

   for ( let i = 0; i < inputFiles.length-1; ++i )
   {
      let thisWindow = ImageWindow.open( inputFiles[i] )[0];
      let nextWindow = ImageWindow.open( inputFiles[i+1] )[0];
      let thisView = thisWindow.mainView;
      let nextView = nextWindow.mainView;
      thisView.beginProcess( UndoFlag_NoSwapFile );
      thisView.image.apply( nextView.image, ImageOp_Sub );
      thisView.endProcess();

      let outputFilePath = outputDir + format( "/%03d-%03d.xisf", i+1, i+2 );
      if ( !thisWindow.saveAs( outputFilePath,
                               false/*queryOptions*/,
                               false/*allowMessages*/,
                               true/*strict*/,
                               false/*verifyOverwrite*/ ) )
      {
         console.criticalln( "*** Error: Failure to write output image: ", outputFilePath );
         break;
      }

      thisWindow.forceClose();
   }
}

SubtractSuccessiveImages( "/Users/juan/test/*.xisf", "/Users/juan/test/output" );

The script performs subtractions between successive pairs of images, which it finds on a specified input directory. The results are written to a specified output directory. The script assumes that the order of images corresponds to the list of image file names sorted alphabetically in ascending order. I think the script is quite self-describing; let me know if you need further help to understand how it works.

PixInsight is a scriptable environment precisely to solve this kind of problems.

 

[Alejandro Tombolini]

Excellent Juan!!, it worked perfectly well. Thank you for your help!

Saludos, Alejandro.