Role of image processing in solar coronal research

The wealth of information regarding the structure and distribution of magnetic fields and plasmas embedded in images of the solar corona taken in the visible wavelength range and/or the extreme ultraviolet (EUV), covers several orders of magnitude in brightness, in the radial and azimuthal directions. As such, they present serious visualization challenges. These can only be revealed with the use of image processing tools. This presentation will focus on results from two recently developed approaches: (1) The Adaptive Circular High-pass Filter, ACHF, and the Normalized Radial Gradient Filter, NRGF, which are ideal for limb observations of the corona made in the visible wavelength range during total solar eclipses or with coronagraphs. (2) The Noise Adaptive Fuzzy Equalization (NAFE) and the multi-scale Gaussian normalization process (MGN), suitable for the visualization of fine structures in EUV images. These methods yield artifact-free images and uncover details that are hidden in the original unprocessed images. Such details have led to the discovery of new features that are essential for exploring the dynamics and thermodynamics of structures in the solar corona.