Yes / PICARD is a space-based observatory hosting the Solar Diameter Imager and Surface Mapper (SODISM)
telescope, which has continuously observed the Sun from July 2010 and up to March 2014. In order to study the fine structure
of the solar surface, it is helpful to apply techniques that enhance the images so as to improve the visibility of solar features
such as sunspots or faculae. The objective of this work is to develop an innovative technique to enhance the quality of the
SODISM images in the five wavelengths monitored by the telescope at 215.0 nm, 393.37 nm, 535.7 nm, 607.1 nm and 782.2
nm. An enhancement technique using interpolation of the high-frequency sub-bands obtained by Discrete Wavelet Transforms
(DWT) and the input image is applied to the SODISM images. The input images are decomposed by the DWT as well as
Stationary Wavelet Transform (SWT) into four separate sub-bands in horizontal and vertical directions namely, low-low (LL),
low-high (LH), high-low (HL) and high–high (HH) frequencies. The DWT high frequency sub-bands are interpolated by a
factor 2. The estimated high frequency sub-bands (edges) are enhanced by introducing an intermediate stage using a stationary
Wavelet Transform (SWT), and then all these sub-bands and input image are combined and interpolated with half of the
interpolation factor α/2, used to interpolate the high-frequency sub-bands, in order to reach the required size for IDWT
processing. Quantitative and visual results show the superiority of the proposed technique over a bicubic image resolution
enhancement technique. In addition, filling factors for sunspots are calculated from SODISM images and results are presented
in this work.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/16611 |
| Date | 12 August 2018 |
| Creators | Alasta, Amro F., Algamudi, Abdulrazag, Qahwaji, Rami S.R., Ipson, Stanley S., Hauchecorne, A., Meftah, M |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Article, Accepted manuscript |
| Rights | © 2018 Elsevier. Reproduced in accordance with the publisher's self-archiving policy. This manuscript version is made available under the CC-BY-NC-ND 4.0 license., CC-BY-NC-ND |
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