solar image processing at sidc - royal observatory of belgium
DESCRIPTION
http:// sidc .be. 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. Necessity & timeliness. - PowerPoint PPT PresentationTRANSCRIPT
Solar Image Processing at SIDC - Royal Observatory of
BelgiumJ.-F. Hochedez, V. Delouille, S. Gissot, E. Robbrecht, B.
Nicula, O. Podladchikova, J. de Patoul, D. Berghmans
http://http://sidcsidc.be.be
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.
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.
Link to Science
However, the scope of SIP goes actually 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.
CACTus Computer Aided CME Tracking
11 N
ovem
ber
2003
θ
t
θV
(km
/s)
500 -
1500 -
Start time, Principal angle, Width and
velocity profile
15h18 15h54 17h06
sidc.be/cactus
Method: Hough transform and clustering Robbrecht and Berghmans A&A ’04 and SoPh ‘05
Result: Real-time extraction of LASCO CMEs + Catalog 1997-2004.
AIA relevance: AIA-coronagraph coordinated studies
B2X flare detector
Just before the flare begins
At flare peak
log(scale)
½ log(μ
(sca
le))
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
EIT waves detectorMethod: 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
Method: Multiscale Local Optical Flow Gissot et Hochedez A&A ’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…
Velociraptor
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.
Image enhancement
Scale mapof a 195
EIT image
NCT of a 195
EIT image
Method: Normalized Contrast Transform (NCT) or Scale maps. Unpublished
Expected result & AIA relevance:Preprocessing and enhance the irreplaceable visual inspection
Loop extraction
Method: Multiscale ridge detection. Unpublished
Expected result & AIA relevance: loop identified and labelled, DEM reconstruction, loop modeling, coronal seismology…
Beauty spotterMethod: Extraction in scale space by Lipschitz coefficientHochedez 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
Network scale analysis
EIT 304 typical quiet sun
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
Synthetic Quiet Sun
123
1 2 3
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
Image and movie compression
Recoded pixel distortion
after decompressio
n
Method: recoding and MPEG4 AVC/H.264Nicula private com + Nicula, Berghmans, Hochedez SoPh ‘05.
Result: x180 compression!
AIA relevance: Save Internet bandwidth!
SWB Solar Weather Browser
This is a
Simple tool for easy visualisation
of important Space Weather data.
sidc.be/SWB
• Near-real-time images• Combine with overlays• Save images with
overlays as PNG• Cycle through images• Dynamical interface• Simple and portable !!
Method: Client-Server architecture. Nicula, Berghmans, Katsiyannis, Lawrence, Baumann
Result & AIA relevance: Visualisation made easy!