Segmentation of Coronal Holes Using Active Contours Without Edges

Abstract

An application of active contours without edges is presented as an efficient and effective means of extracting and characterizing coronal holes. Coronal holes are regions of low-density plasma on the Sun with open magnetic field lines. As the source of the fast solar wind, the detection and characterization of these regions is important for both testing theories of their formation and evolution and from a space weather perspective. Coronal holes are detected in full disk extreme ultraviolet (EUV) images of the corona obtained with the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO/AIA). The proposed method detects coronal boundaries without determining any fixed intensity value in the data. Instead, the active contour segmentation employs an energy-minimization in which coronal holes are assumed to have more homogeneous intensities than surrounding active regions and quiet Sun. The segmented coronal holes tend to correspond to unipolar magnetic regions, are consistent with concurrent solar wind observations, and qualitatively match the coronal holes segmented by other methods. The means to identify a coronal hole without specification of a final intensity threshold may allow this algorithm to be more robust across multiple datasets, regardless of data type, resolution, and quality.

References in corpus (8)

• Automated Coronal Hole Detection using Local Intensity Thresholding Techniques
• Solar Magnetic Tracking. I. Software Comparison and Recommended Practices
• Automated Detection of EUV Polar Coronal Holes During Solar Cycle 23
• Synchronic coronal hole mapping using multi-instrument EUV images: Data preparation and detection method
• Real-time solar wind prediction based on SDO/AIA coronal hole data
• Solar Wind Forecasting with Coronal Holes
• Measurements of EUV Coronal Holes and Open Magnetic Flux
• Automated Coronal Hole Detection using He I 1083 nm Spectroheliograms and Photospheric Magnetograms

Cited by in corpus (10)

• The Open Flux Problem
• Statistical Analysis and Catalog of Non-polar Coronal Holes Covering the SDO-era using CATCH
• Automated Coronal Hole Identification via Multi-Thermal Intensity Segmentation
• Estimating Total Open Heliospheric Magnetic Flux
• Characteristics of Low-Latitude Coronal Holes near the Maximum of Solar cycle 24
• Coronal Hole Detection and Open Magnetic Flux
• Quantifying the Consistency and Characterizing the Confidence of Coronal Holes Detected by Active Contours without Edges (ACWE)
• Neural-based Compression Scheme for Solar Image Data
• On the short term stability and tilting motion of a well-observed low-latitude solar coronal hole
• Magnetic Field-Constrained Ensemble Image Segmentation of Coronal Holes in Chromospheric Observations