Inti... Sol'Ex processing

Inti... Sol'Ex spectroheliography processing

INTI Selector INTI Register Sol'Ex site

INTI process spectroheliographic scans of the sun to automatically produces the reconstructed monochromatic image with only one click... It has been designed for Sol'Ex spectrograph and process video ser files on 16 bits.


1. Download the zip file

For windows:
For Mac: soon to come...

2. Extract the inti directory on your disk or on usb key

Once unzipped you'll have a directory with a lot of files. INTI has been written in Python and to deploy a Python program as an executable the installator includes a lot of files to recreate the python required environment. 

3. Click on INTI_[language].exe to launch the application

The exe file is in the unzipped directory. It may take a dozen af seconds before the user interface appears. Maybe less at second launch
At launch, windows does not recognize the signature so may display a warning to protect your pc from virus and prevent the program to execute. Trust the program and force windows to execute it anyway.

For english language, launch inti_en.exe - for french, launch initi_fr.exe

If you have a previous inti.yaml file, please remove it.

INTI manual

1. Click on open to select one or multiple .ser scan of the sun disk

2. Click on ok

That's it !
Some intermediate results will be displayed in the black cmd windows behind the user interface. They are also logged in a text file name 'yourserfilename_log.txt'.

At the end of the processing, four windows will appear. You can move the mouse over une image to see a small zoom window. This is helpful to check focus during acquisition.

3. Exit INTI

If you process a unique ser file... the 4 images will stay for 1 min - if you want to exit before, make sure one image is selected then enter escape key or enter key
If you process multiple ser file... the 4 images will briefly appears before the next file is processed.

At the end of the processing, once the images are closed, the main window of INTI will stay to allow you to process another file or another batch. To completely exit from INTI click on the Exit buton or the cross on the top right of the INTI window.

4. INTI results

You will find all the results in the directory of your ser file. The name of the files processed always start with underscore "_" then name of the ser file and an extension.

Png Images

Fits images

  • _recon.fits ... final fits image
  • _clahe.fits... final image with the post-processing 'contrast local adaptation histogram equalization' applied
  • _img.fits ...  raw disk reconstructed from the scan
  • _mean.fits ... intermediate result, scan frame average
  • _flat.fits ...  intermediate result, after transversallium and before geometric corrections
  • _tilt.fits ... intermediate result, after transversallium and tilt correction, before scaling

5. DopplerGram and Continuum

To get a composite image made of 2 images with same wavelength shift from central line wavelength aka called a dopplergram image or to get the image from wavelength outside of a line, also called continuum image you have to click on the tab, enter the value in pixels of the respective shifts. Click on Ok to generate the doppler and continuum images.

I do this process on one of the best image of my serie of observations.

At the end of the process, if no errors are encountered you will have 2 additional png images displayed and stored with the extension _doppler.png and _cont.png

Errors can occur if the pixel shift is outside of the image over the length of the slit. Also some pink pxels may appears if the image is saturated. Zoom fonction is not enabled on those images.

Additional 3 fits images will be provided as well.

6. Advanced settings

You can easely from the basic interface ask INTI to build the monochromatic images with a pixel shift (aka wavelength shift) to explore around the central line.  Make sure the pixel shift will still fit the image size all along the spectral line.

If you click on the small arrow next to advanced, additional settings are provided

Database compatibility

If you click on the small arrow next to database compatibility, addtional fields and services are displayed.

This has been designed to be compliant with professional Solar Database as defined by the BASS2000 team as of today. It requires mandatory information and correct orientation of the sun.

Refer to the additional operator manuel for a detailed description of the fields and operations to make the image compatible with the solar database (French - English)

7. Doppler sequence

This tab will allows you to generate a serie of reconstructed disk at all the pixel shift within the range entered.

INTI will generate all the images fits and png with "_dpxx" and a mp4 movie named inti.mp4. (H264 codec) - if you process in the same directory a new mp4 sequence, make sure you change inti.mp4 name or it will be override.

8. Magnetogram

This tab is dedicated to the generation of disk at a very faint wavelength and not the darkest one of your video. This is an assistant for polarization and magnetogram as explained in video from Christian Buil on youtube on astro-spectro channel.

A dedicated section on the sequence of the operations, and how to obtain the parameters to fill the tab will be published soon.

In the results, Inti will generate a b- sequence and a r- sequence to be later combined to create the magnetogram.

9. Free Line

This tab is dedicated to the computation of a sun disk at a specified position of a spectral line. This overrides the automatic function of finding the dark spectral in the image. The detailed process is detailed in the linked pdf file based on Helium image observation. English - French

SER files for the example below can be download here (1.05Go)

Christian Buil – Sol’Ex with TS refractor 80/480mm - Helium D3 line image with INTI

10. INTI.yaml file

The INTI.yaml file contains INTI settings at loading. 

At the end of a session, the current settings will be saved in this file to restore your preferences next time you will run INTI.

You can manually edit the yaml file by any text editor.

If you reinstall INTI and you still have an inti.yaml file, remove it so INTI will recreate one with the appropraite format, otherwise INTI will not work prperly.

Known limitations

INTI automatisation relies on assumption on the acquired scan. Its novelty algorithms will be described in a future paper.
Video images are expected to be 16 bits.
If the scan does not start and end outside of the sun then the tilt and the scaling correction based on limbs detection will fail and a defaut scaling will be applied and recorded in the logs.
If the intensities are too low, then edge detection may fail for the scaling correction.
There is no limitation for H-alpha and H&K Spectral lines, but as the algorithm is finding the minimum intensities in the frames, the targeted spectral lines shall be the darkest one unless you operate manually in free line tab.
For more complex situation, ISIS is the reference and will be able to proceed with the fits file from INTI or process directly the ser files.

INTI has been tested by Christian Buil and myself on a lot different configurations. We are confident it provides reliable results in most of the case.


Python implementation for line extraction acceleration is a code from Doug and Andrew Smiths

Ser files reading is a Python class module developped by Jean-Baptiste Butet, with date decoding from Matt Considine

Ellipse fitting is a python module from Ben Hammel, & Nick Sullivan-Molina. (2020, March 21). bdhammel/least-squares-ellipse-fitting: v2.0.0 (Version v2.0.0). Zenodo.

Magnetogram processings are from Christian Buil