Solar Image Processing at SIDC - Royal Observatory of Belgium

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Solar Image Processing at SIDC - Royal
Observatory of Belgium

• J.-F. Hochedez, V. Delouille, S. Gissot, E.
  Robbrecht, B. Nicula, O. Podladchikova, J. de
  Patoul, D. Berghmans

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Necessity timeliness

• In modern coronal physics, solar image processing
  (SIP) appears more and more as a needed and
  timely tool.
• SIP is necessary because of
• the large sizes of the current and future
  missions/observatories archives,
• the wish to process solar data automatically in
  order to evidence hidden trends (e.g. solar cycle
  or instrumental effects),
• the need for systematic detection of rare or
  faint events such as EIT waves.

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Benefits

• This quest is even more acute in the context of
  Space Weather forecasting where quasi-real time
  is required. As additional benefits, the
  algorithmic techniques provide reproducibility
  and some level of objectivity. They also
  alleviate the effort of expert forecasters. They
  are sometimes able to reveal information that
  would remain otherwise buried in the noise or in
  the dynamics. Finally, they improve data
  representation and visualization.
• The necessity comes furthermore at a propitious
  time when the available CPU power and the
  underlying mathematics have developed
  considerably.

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Link to Science

• The scope of SIP goes beyond the role of a tool.
  It is an integral part of our science, like
  visual inspection, statistical science or physics
  modeling. Confidence in the outcomes of any
  technique participates to the data analysis. In
  the near future and especially with AIA onboard
  SDO, we expect MHD modeling, SIP, statistics and
  data assimilation schemes to merge in one
  indissociable research for which certitudes
  involve expertise in all fields.

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CACTus Computer Aided CME Tracking
Method Hough transform and clustering Robbrecht
and Berghmans AA 04 and SoPh 05 Result
Real-time extraction of LASCO CMEs Catalog
1997-2004. AIA relevance AIA-coronagraph
coordinated studies
sidc.be/cactus
Start time, Principal angle, Width
and velocity profile
15h54
17h06
15h18
11 November 2003
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B2X flare detector
Method Wavelet spectrum (scale measure) analysis
Hochedez et al 02 Solspa2 Proc., Delouille et
al SoPh 05 Result Small flares automatic
detection Relevance Sympathetic flaring studies
At flare peak
½ log(µ(scale))
Just before the flare begins
log(scale)
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EIT waves detector
Method Histogram skewness and kurtosis Ring
analysis. Podladchikova et Berghmans SoPh
05 Result Wavefront and dimming studies, 90
detection AIA relevance EIT waves automation,
coronal seismology
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Velociraptor
Method Multiscale Local Optical Flow Gissot et
Hochedez AA 06 (in prep.) Result Motion and
brightness variation both estimated and
qualified at each pixel from local similarity
texture AIA relevance Flares, dimmings (CMEs,
EIT waves), loop motions, Dif. Rot., coronal
seismology
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EUV Disc segmentation
Method Fuzzy clustering Barra, Delouille,
Hochedez, Chainais 05 Proc. SPM11 Result 5
regions AR core AR AR aureole QS CH AIA
relevance e.g. Source regions of irradiance,
etc.
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Image enhancement
Method Normalized Contrast Transform (NCT) or
Scale maps. Unpublished Expected result AIA
relevance Preprocessing and enhance the
irreplaceable visual inspection
Scale map of a 195 EIT image
NCT of a 195 EIT image
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Loop extraction
Method Multiscale ridge detection.
Unpublished Expected result AIA relevance loop
identified and labelled, DEM reconstruction, loop
modeling, coronal seismology
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Beauty spotter
Method Extraction in scale space by Lipschitz
coefficient Hochedez et al 2002, Soho11 WS Proc.,
Hochedez et al 2003 Soho13 WS Result BPs,
brightenings and Cosmic Ray Hits
extracted Relevance Oscillations in point-like
structures
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Network scale analysis
Method Wavelet spectrum analysis Delouille et al
SoPh 05, Hochedez et al 02 Solspa2
Proc. Result TR network characteristic scale,
cycle study AIA relevance Continued cycle studies
EIT 304 typical quiet sun
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Synthetic Quiet Sun
Method Infinitely divisible cascades constrained
by EIT histogram and fractal spectrum. in
Prep Result Artificial QS for testing algorithm
(e.g. optical flow). Coronal heating relevance
TBD AIA relevance Better spatial resolution
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Image and movie compression
Method recoding and MPEG4 AVC/H.264 Nicula
private com Nicula, Berghmans, Hochedez SoPh
05. Result x180 compression! AIA relevance
Save Internet bandwidth!
Recoded pixel distortion after decompression
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SWB Solar Weather Browser
Method Client-Server architecture. Nicula,
Berghmans, Katsiyannis, Lawrence, Baumann Result
AIA relevance Visualisation made easy!
sidc.be/SWB
This is a Simple tool for easy visualisation of
important Space Weather data.

• Near-real-time images
• Combine with overlays
• Save images with overlays as PNG
• Cycle through images
• Dynamical interface
• Simple and portable !!