Here is where you can download the software used to transform multi-instrument EUV data from STEREO-A/B EUVI 195Å and AIA 193Å into synchronic EUV and coronal hole (CH) maps. The image segmentation code used in the coronal hole detection is made available as a stand-alone module for integration into your own codes/scripts.

EUV2CHM: An all-in-one coronal hole detection example

EUV2CHM is a ready-to-use MATLAB script for taking STEREO-A/B EUVI 195Å and AIA 193Å images, applying the new preprocessing, detecting coronal holes, and then stitching the results into synchronic EUV and CH maps. The script performs the CH detection using our EZSEG image segmentation code modules (see below) accessed through MEX codes.

This download includes all necessary codes (including EZSEG) as well as sample PSF-deconvolved EUV images along with the required preprocessing data for the images. We also include an IDL script ( which converts fits files of EUV image data downloaded using SSW into the correct format for use in EUV2CHM. Click here to view the included README manual which contains details on how to install and run EUV2CHM.

EZSEG: Image segmentation code modules

EZSEG is a dual-threshold variable-connectivity image segmentation algorithm. It seeds locations based on the first threshold and grows them until the second threshold is reached or the connectivity condition fails. A schematic of the algorithm is shown here:

EZSEG is implemented in both FORTRAN with OpenMP and in CUDA-C. The codes are modular such that they can be linked to any calling code/language which has the capability of calling FORTRAN or C external routines. The download below contains the codes as well as example compile scripts to generate the object files ready for linking.

EUV_GEN_PREPROC: EUV pre-processing data generation

MATLAB script package (Advanced)

Here we provide the MATLAB scripts which were used to generate the pre-processing data sets for STEREO-A/B 195Å and AIA 193Å provided on the Data Products page. These are provided for advanced users who wish to generate the limb-brighting and/or inter-instrument transformation factors using alternative data sets (such as EUV images deconvolved with alternative PSFs or for EUV images of alternative intruments/filters). Please consult the README file for notes on how to use the scripts.

© 2015 Predictive Science Inc.