satprocess 0.1.3

Astronomical image calibration pipeline

Satprocess - A Spectral Alignment Toolbox

A Python package for spatial, wavelength, and intensity calibration of FITS files. This toolbox was specifically built using data from the CHASE satellite, available at https://ssdc.nju.edu.cn/NdchaseSatellite.

Features

• Three-stage calibration pipeline:
  • Spatial alignment using the Hough transform
  • Wavelength calibration via cross-correlation
  • Intensity normalisation to reference spectra
• FITS file support with memory-efficient processing
• H-alpha companion file processing that applies calibrations from Fe files
• Comprehensive logging and shift parameter tracking
• User selected calibration where the reference file is chosen (although the default is the first file in the list)

Installation

  pip install satprocess

Dependencies

• Python 3.7+
• NumPy
• SciPy
• Matplotlib
• Astropy
• scikit-image

Usage/Examples

Basic usage: Calibrates all files in the supplied folder

from satprocess import Calibration
import os

if __name__ == "__main__":
    try:
        folder_path = "TestImages"
        shifts_file = os.path.join(folder_path, "shifts.csv")
        
        # Ensure folder structure exists
        Calibration.ensure_folder_structure(folder_path)
        os.makedirs(os.path.join(folder_path, "plots"), exist_ok=True)
        
        # Load or initialise shifts
        shifts = Calibration.load_shifts(shifts_file)
        
        # Run the calibrations
        spatial_results = Calibration.spatial_calibration(
            folder_path,
            shifts,
        )
        wavelength_results = Calibration.wavelength_calibration(
            folder_path,
            shifts,
        )
        intensity_results = Calibration.intensity_calibration(
            folder_path,
            shifts,
        )
        
        print("Calibration completed successfully")
        
    except Exception as e:
        print(f"Pipeline failed: {str(e)}")

Advanced Features

Calibration calculated on Fe files, then applying the shifts to Ha files. The file used as the target for calibrations is the third file available.

# ... Initialisation code as before

print("=== CALIBRATING FE FILES ===")
spatial_results = Calibration.spatial_calibration(
    folder_path,
    shifts,
    alignment_wavelength=40,
    reference_index=2,
    wide_min_radius=600,
    wide_max_radius=1200,
    mode="fe_only"
)

wavelength_results = Calibration.wavelength_calibration(
    folder_path,
    shifts,
    reference_index=2
    region_size=100,
    percentage=1,
    mode="fe_only"
)

intensity_results = Calibration.intensity_calibration(
    folder_path,
    shifts,
    reference_index=2
    region_size=100,
    percentage=1,
    mode="fe_only"
)

# Second run: Apply calibrations to H-alpha files with plotting
print("=== APPLYING TO H-alpha FILES ===")
ha_results = Calibration.apply_calibrations_to_ha_files(
    folder_path,
    shifts,
    alignment_wavelength=40,
    plot_spectra=True
)

File Structure

The package creates the following directory structure during processing:

input_folder/
├── AlignedImages/
│   ├── Spatial/       # Spatially aligned files
│   ├── Wavelength/    # Wavelength calibrated files
│   ├── Intensity/     # Intensity normalized files
│   └── H_alpha/       # Processed H-alpha files
├── plots/             # Diagnostic plots
└── shifts.csv         # Tracking file for calibration parameters

License

This project is licensed under the BSD 3-Clause License - see the LICENSE file for details.