Multiscale Detection and Characterisation of CMEs
description
Transcript of Multiscale Detection and Characterisation of CMEs
![Page 1: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/1.jpg)
Multiscale Detection and Characterisation of CMEs
J. P. Byrne1, P. T. Gallagher1, C. A. Young2 and
R. T. J. McAteer3
1 Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2, Ireland.2 ADNET Systems Inc., NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
3 Catholic University of America, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
STEREO/Cor1 24-Jan-07
![Page 2: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/2.jpg)
Overview
• CME Models
• Image Processing: Multiscale methods
• CME Morphology & Kinematics
• Application to LASCO and STEREO/SECCHI LASCO/C3 27-Feb-00
![Page 3: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/3.jpg)
CME Models
• Magnetic Flux-Rope:
• Magnetic Break-out:
-Forbes & Priest, 1990-Chen & Krall, 2003
-Antiochos et al. 1999-Lynch et al. 2004
![Page 4: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/4.jpg)
Image Pre-Processing
• Normalisation - exposure time- CCD bias- data dropouts
• Background subtraction
• Median filtering (de-noising)
LASCO/C2 18-Apr-00
![Page 5: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/5.jpg)
Finding the CME Front
Edge Detection:
![Page 6: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/6.jpg)
Our Algorithm
1) Multiscale Decomposition
Vector-Arrow Field
3) Spatio-Temporal Filter
4) Non-Maxima Suppression
5) CME Front Characterisation
Kinematics & Morphology
Image Pre-Processing
2) Gradient Space Information
![Page 7: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/7.jpg)
Our Algorithm
1) Multiscale Decomposition
CME Vector Flow Field
2) Spatio-Temporal Filter
3) Non-Maxima Suppression
4) CME Front Characterisation
Kinematics & Morphology
Image Pre-Processing
![Page 8: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/8.jpg)
Wavelets:
- Scaling / dilation factor (a)- Shifting / translation factor (b)- Suppress noise
€
ψa,b (x) =1
bψ
x − b
a
⎛
⎝ ⎜
⎞
⎠ ⎟
1) Multiscale Decomposition
![Page 9: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/9.jpg)
LASCO/C2 24-Jan-07
Low pass: Approximation
High pass: Detail
Input: f
1) Multiscale Decomposition
€
0
€
0
€
φ
€
∂φ
![Page 10: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/10.jpg)
Vertical Direction:
Horizontal Direction:Scale 1
Scale 1 Scale 3 Scale 5
Scale 3 Scale 5
1) Multiscale Decomposition
€
AN ∗∂yφ
€
AN ∗∂xφ
![Page 11: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/11.jpg)
2) Gradient Space Information
€
DN +1 = AN ∗∂xφ( ), AN ∗∂yφ( )[ ]
Consider the Gradient of an image:(which points in the direction of most rapid change)
We have the Detail at a scale (N+1) resulting from the directional Derivative-of-Gaussian convolved with the Approximation at scale (N):
The gradient specifies:
€
θ =tan−1 ∂f
∂y
∂f
∂x
⎛
⎝ ⎜
⎞
⎠ ⎟2) Direction:
1) Magnitude:
€
∇f =∂f
∂x
⎛
⎝ ⎜
⎞
⎠ ⎟2
+∂f
∂y
⎛
⎝ ⎜
⎞
⎠ ⎟
2
So too can the Magnitude and Direction be taken from the multiscale decomposition as illustrated…
![Page 12: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/12.jpg)
Original: Magnitude:Angle:
€
∇f =∂f
∂x
⎛
⎝ ⎜
⎞
⎠ ⎟2
+∂f
∂y
⎛
⎝ ⎜
⎞
⎠ ⎟
2
€
θ =tan−1 ∂f
∂y
∂f
∂x
⎛
⎝ ⎜
⎞
⎠ ⎟
(McAteer et al. 2007)
2) Gradient Space Information
![Page 13: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/13.jpg)
€
∇fVectors with magnitude:and inclination angle:
€
θ
QuickTime™ and aH.264 decompressor
are needed to see this picture.
2) Gradient Space Information
![Page 14: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/14.jpg)
Our Algorithm
1) Multiscale Decomposition
CME Vector Flow Field
2) Spatio-Temporal Filter
3) Non-Maxima Suppression
4) CME Front Characterisation
Kinematics & Morphology
Image Pre-Processing
![Page 15: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/15.jpg)
2) Spatio-Temporal Analysis
Degrees of Freedom: Scale, Magnitude & Angle … in Space & Time
QuickTime™ and aH.264 decompressor
are needed to see this picture.
![Page 16: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/16.jpg)
Our Algorithm
1) Multiscale Decomposition
CME Vector Flow Field
2) Spatio-Temporal Filter
3) Non-Maxima Suppression
4) CME Front Characterisation
Kinematics & Morphology
Image Pre-Processing
![Page 17: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/17.jpg)
3) Non-Maxima Suppression
1) Nearest-neighbour info.
2) Criteria of angle and magnitude from gradients.
3) Pixels chained along edges.
(Image by C.A.Young)
![Page 18: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/18.jpg)
Our Algorithm
1) Multiscale Decomposition
CME Vector Flow Field
2) Spatio-Temporal Filter
3) Non-Maxima Suppression
4) CME Front Characterisation
Kinematics & Morphology
Image Pre-Processing
![Page 19: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/19.jpg)
• Ellipse fit• Height, Width,
Curvature, Orientation
4) CME Front Characterisation
STEREO/Cor1 24-Jan-07
€
ρ2 =a2b2
a2 + b2
2
⎛
⎝ ⎜
⎞
⎠ ⎟−
a2 − b2
2
⎛
⎝ ⎜
⎞
⎠ ⎟cos(2 ′ θ − 2α )
€
ρ2 cos2 θ
a2+
ρ 2 sin2 θ
b2=1
(H.E. Schrank, 1961)
![Page 20: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/20.jpg)
SOHO/LASCO CMEs
C2 & C3 18-Jan-00
![Page 21: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/21.jpg)
C2 & C3 19-Apr-00
SOHO/LASCO CMEs
![Page 22: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/22.jpg)
C2 & C3 23-Apr-01
SOHO/LASCO CMEs
QuickTime™ and aH.264 decompressor
are needed to see this picture.
![Page 23: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/23.jpg)
STEREO/Cor1 CMEs
SECCHI-A 9-Feb-07
![Page 24: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/24.jpg)
STEREO/Cor1 CMEs
SECCHI-A 24-Jan-07
![Page 25: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/25.jpg)
STEREO/Cor1 CMEs
SECCHI-B & SECCHI-A 24-Jan-07
![Page 26: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/26.jpg)
STEREO/Cor1 CMEs
SECCHI-A 24-Jan-07
QuickTime™ and aH.264 decompressor
are needed to see this picture.
![Page 27: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/27.jpg)
LASCO/C2 24-Jan-07
CME Kinematics
![Page 28: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/28.jpg)
Next Steps…
• More data; distribution of CME kinematics.
• Multiple view points (STEREO); triangulation / projection effects.
• Automated front detection; space weather forecasting.
STEREO illustration
![Page 29: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/29.jpg)
Thank You
NRL:
Angelos Vourlidas, Simon Plunkett.
This work is supported by grants from Science Foundation Ireland & NASA’s Living with a Star Program.
Acknowledgments
![Page 30: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/30.jpg)
C2 & C3 23-Apr-01
SOHO/LASCO CMEs
![Page 31: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/31.jpg)
2) Spatio-Temporal Analysis
Degrees of Freedom: Scale, Magnitude & Angle … in Space & Time
![Page 32: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/32.jpg)
Vector Flow Field
€
∇fVectors with magnitude:and inclination angle:
€
θ
![Page 33: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/33.jpg)
Normalizing Radial Graded Filter
• Radially the coronagraph image intensity drops off steeply.
• The intensity is normalized by subtracting the mean and dividing by the standard deviation.
€
′ I (r,φ) =I(r,φ) − I(r)<φ>
σ (r)<φ>
(Huw et al. 2006)
remove
![Page 34: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/34.jpg)
Scale Chaining / Masks
Degrees of Freedom: Scale, Magnitude & Angle … in Space & Time
=> Spatio-Temporal Image Processing & Thresholding
remove
![Page 35: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/35.jpg)
Image preprocessing
Multiscale decomposition scale chaining (denoising masks)
Spatio-temporal filter (noisy masks)
Combine scale chain & spatiotemp => filter masks
Non-maxima suppression
Ellipse characterization
Gradient space vector field (angle & magnitude)
Method FlowChart
NRGF: radial filter
![Page 36: Multiscale Detection and Characterisation of CMEs](https://reader035.fdocuments.net/reader035/viewer/2022081506/56814513550346895db1d560/html5/thumbnails/36.jpg)
Movie Scripts
• http://www.maths.tcd.ie/~jaydog/Solar/canny_atrous/automation/20000118_arrows_combined_rebin.html
• http://www.maths.tcd.ie/~jaydog/Solar/canny_atrous/automation/20000418_arrows_combined_rebin.html
• http://www.maths.tcd.ie/~jaydog/Solar/canny_atrous/automation/20040401_arrows_combined_rebin.html
• http://www.maths.tcd.ie/~jaydog/Solar/CME_ellipse_movies/24jan07/C2_movie_ell.html
• http://www.maths.tcd.ie/~jaydog/Solar/CME_ellipse_movies/24jan07/C3_movie_ell.html
• www.maths.tcd.ie/~jaydog/Solar/STEREO/pb/24jan07/Graphs_plots.html
Remove