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

Installation

1. Download the zip file

For windows: http://valerie.desnoux.free.fr/inti/inti.zip
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 issues with the inti.yaml file, please remove it and restart the program. Make sure the directory has write acess mode enabled.

At first launch, it may take time to display the interface.

INTI manual

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

INTI will open a system dialog box for file selection. Can be a unique file or a multiple selection of SER video files.

or

1.Click on "Last" instead of "Open"

If you have processed already one file in your current acquisition directory, click on Last instead of "Open " will process the last file found in the directory. No need to select the name of the last file. But at least process one so INTI can know the directory to look at the last file.

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.

You have also 2 sliders to adjust image thresholds - the top one sets the value below all pixels will be set to zero (black) and the second one sets the value above all pixels will be set to 65535 (white). This is a quick way to adjust contrast and brightness.

Click on the image you want to adjust the display. The settings and image will not be saved as you display, the saved image use the automatic settings to avoid mistake.

Here are the png images saved to the disk

• Raw... the raw disk with no transversallium and geometric corrections - this is proposed for quick check after acquisition to adjust the exposure time / frame per second to have quasi circular disk
• Contrast... a view of the final image with predefined contrast thresholds
• Protus... a view of the final image with thresholds adequate for low intensity protuberances view and black occulting disk
• Clahe... final image with the post-processing 'contrast local adaptation histogram equalization' applied

INTI will create 3 sub directories in your working directory

• BASS2000... it will save the 3 files generated for upload to BASS2000, 2 fits files disk and protus and the thumbnail as jpg
• Clahe... all the clahe processed png files, for quick review
• Complements... the raw, mean and other fits and png files of complementary images

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

Dat file

• .dat profile of line from the _mean.fits image in the Complements directory, can be open with vspec or equivalent

Fits images

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.

You have the capability to shift the 2 doppler images around a constante set in Doppler shift. Instead of having the 2 images at -2 pixels / +2 pixels of the center, if you enter a value for the doppler shift, the 2 doppler images will be computed at doppler_shift - 2 pixels / doppler_shift + 2 pixels

To help you to understand the shape of the line, you can view the line profile with the "Profile" button - If the SER file has never been processed , the Profile button will not display the graph. A filename.dat file contain the 1D profile and is located in the complements. It is computed each time you process a file.

You have also the capability to reverse order of blue - red wings with the option B-R flip

I do this process on one of the best image of my serie of observations, to select the best, I use INTI_Selector

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.

• xx_recon_cont_value of pixel shift.fits
• xx_recon_dp_--value of pixel shift.fits (first doppler image: - pixel shift)
• xx_recon_dp_+value of pixel shift.fits (second doppler image: + pixel shift)

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

Ask INTI to display live the line by line reconstruction of the disk from the scan - this will take longer but you will see real time the disk built with the corresponding spectral video. Very nice to demonstrate the principle Noise reduction mode, average of 3 pixels In some special modes Magnetogram or Free line, you may have a strong deep line net to your line of interest. You can use this deep line to compute the polynome and copy the parameters in the special modes - this option is not saved for security reason Autocrop option, will force centering of the disk image and cropping of the image at consistent values for height and width Force application of Scaling SY/SX and Tilt angle - latest values are saved in the inti;yaml file - if left unchecked, the values are not considered and will be automatically computed by INTI.

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)

You can also watch the dedicated video on youtube Astro-Spectro channel.

Those BASS2000 images will only be generated if you process only 1 serfile at a time.

Grid tool

In the BASS2000 directory a file with _grid.png will be created with an overlay of a stonyhurst grid at proper P and B0 angles computed locally. The sun shall be oriented E-W and N-S properly, use the Gong button to retrieve and display in our browser the image at the date of your file.

Grid parameters are accessible with the "grid" button. 

By default the grid color will be yellow and the latitude angles will be displayed. But you can adjust the parameters as you prefer.

Select the wavelength domain you want the dispersion to be computed
Enter the value of the angström range
Indicates the pixel size and the binning of your camera used for the SER file acquisition
Click on 'Compute' to see the pixel shift requires to offset by the value in angström
Click on 'Exit' or on the top cross to close the tool and get the computed value in Shift of Pixels field

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.

Known limitations

INTI automatisation relies on assumption on the acquired scan. Its novelty algorithms is based on an image mean to initiate all the automatic processings. A paper may be published.

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 of different configurations. We are confident it provides reliable results in most of the case.

Windows 7 incompatibility due to python 3.9 and above beeing not supported by W7

Reference

INTI is an original work part of the Sol'Ex project, if you build on it or be inspired by it, please add a reference to : Sol'Ex - INTI by Christian Buil & Valerie Desnoux

Contributions

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. http://doi.org/10.5281/zenodo.3723294

Magnetogram processings and Sun Corona processings are from Christian Buil

The python code is available at https://github.com/Vdesnoux/Solex_ser_recon