s. mandayam, ece dept., rowan university parametric characterization of psf of split-d core ec...
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S. Mandayam, ECE Dept., Rowan University
Parametric Characterization of Parametric Characterization of PSF of Split-D Core EC ProbesPSF of Split-D Core EC ProbesParametric Characterization of Parametric Characterization of PSF of Split-D Core EC ProbesPSF of Split-D Core EC Probes
Department of Electrical & Computer Engineering
201 Mullica Hill RoadGlassboro, NJ 08028, USA
engineering.rowan.edu
Shreekanth MandayamShreekanth Mandayam
GE John F. Welch Technology CenterBangalore, India
S. Mandayam, ECE Dept., Rowan University
OutlineOutline• Objectives
• Approach– Parametric PSF Model– EC Signature Deconvolution
• Pre-Restoration Filtering
• Results– Simulated Image Template– SC EC Images
• Summary
S. Mandayam, ECE Dept., Rowan University
ObjectivesObjectives
• To design and develop a numerical parametric model for multiple EC probe PSFs
• To validate parametric PSF model by deconvolution of EC signatures for flaw characterization
S. Mandayam, ECE Dept., Rowan University
Experimental Data (GEMTC)Experimental Data (GEMTC)
• SGE638 and SGE596 split-D core EC probes• EC-2000 system at 6-MHz• Copper wire (200-mils diameter) tip sharpened to
3-mil diameter embedded in 1” thick hard polystyrene foam.
• Ferrous tip• 500 x 500 TIFF files with a pixel resolution of 1-
mil x 1-mil
S. Mandayam, ECE Dept., Rowan University
Experimental Data (GEMTC)Experimental Data (GEMTC)
Cu Tip Fe Tip SGE638
S. Mandayam, ECE Dept., Rowan University
Parametric PSF Model (1-DOF)Parametric PSF Model (1-DOF)
2
22
2
)(
),( yx
eyxg
yyxpxyxqyyxgy
xyxgx
yxg ˆ),(ˆ),(ˆ),(ˆ),(),(
S. Mandayam, ECE Dept., Rowan University
Parametric PSF Model (2-DOF)Parametric PSF Model (2-DOF)
2
2
2
2
22),( yx
yx
eeyxg
),(ˆ).,(),( yxgy
yyxgyxp
S. Mandayam, ECE Dept., Rowan University
Parametric PSF Model (2-DOF)Parametric PSF Model (2-DOF) PSF
Size
mils
mils
mils
SGE638 – Cu tip
44 x 42 19.802 11.002
SGE638 – Fe tip
51 x 43 17.852 12.752
SGE596 – Cu tip
121 x 36 12.102 32.672
SGE596 – Fe tip
109 x 31 10.92 32.702
2y2
x
S. Mandayam, ECE Dept., Rowan University
PSF: Fe Tip PSF Model
0
50
02040600
0.5
1
Comparison
0 20 40 600
0.2
0.4
0.6
0.8
1
Experimental
Model
SGE638
S. Mandayam, ECE Dept., Rowan University
PSF: Cu Tip PSF Model
0
50
02040600
0.5
1
Comparison
0 20 40 600
0.2
0.4
0.6
0.8
1
Experimental
Model
SGE638
S. Mandayam, ECE Dept., Rowan University
PSF: Cu Tip, SGE596 PSF Model
0
20
40
0501001500
0.5
1
Comparison
0 50 100 1500
0.2
0.4
0.6
0.8
1
Experimental
Model
SGE596
S. Mandayam, ECE Dept., Rowan University
PSF: Fe Tip, SGE596 PSF Model
020
40
0501001500
0.5
1
Comparison
0 50 100 1500
0.2
0.4
0.6
0.8
1
Experimental
Model
SGE596
S. Mandayam, ECE Dept., Rowan University
EC Signature DeconvolutionEC Signature Deconvolution
: Probe PSF model : Eddy-current inspection signature
: Deconvolved image (defect/flaw profile)
),( yxp ),( vuP
),( yxs ),( vuS
),( yxd ),( vuD
),(),(),(
),(*),(),(
vuPvuDvuS
yxpyxdyxs
S. Mandayam, ECE Dept., Rowan University
Deconvolution MethodsDeconvolution Methods
Lucy-Richardson Algorithm
),(),(),(),(
),(),(1 yxdyxp
yxpyxdyxs
yxd ii
i
Wiener Filter
),(
),(),(),(
),(),(ˆ
2
*vuS
vuSvuSvuP
vuPvuD
ddnn
S. Mandayam, ECE Dept., Rowan University
Simulated Image Template: Simulated Image Template: Effect of Anisotropic PSFEffect of Anisotropic PSF
Slot Template
d(x,y) * p(x,y) = s(x,y)
Wiener Lucy-Rich.
S. Mandayam, ECE Dept., Rowan University
Simulated Image Template: Simulated Image Template: Effect of Isotropic PSFEffect of Isotropic PSF
Slot Template
d(x,y) * p(x,y) = s(x,y)
Wiener Lucy-Rich.
Blurred
Wiener Restored
Lucy-Richardson Restored
S. Mandayam, ECE Dept., Rowan University
Pre-Restoration FilterPre-Restoration Filter
),(),(),( yxpyxdyxs
),(),(),( yxfyxsyxs f
),(),(),( yxhyxfyxp
),(),(),( yxhyxdyxs f
Anisotropic PSF
Pre-restoration filter
Isotropic PSF
Isotropic blur
S. Mandayam, ECE Dept., Rowan University
Results: Simulated ImageResults: Simulated ImageSlot Template PSF Model: Grad(Gaussian)
Blurred
BlurredPre-Restoration Filter Pre-Filtered
Restoration PSFPSF Model: Grad(Gaussian) Pre-Restoration Filter
Lucy-Richardson Restored
d(x,y) * p(x,y) = s(x,y)
s(x,y) * f(x,y) = sf(x,y)
p(x,y) * f(x,y) = h(x,y)
L-C Restored
Anisotropic PSF
Pre-restorationfilter
Isotropic blur
IsotropicPSF
S. Mandayam, ECE Dept., Rowan University
Simulated Image; Simulated Image; Experimental PSFExperimental PSF
Blurred Cu TipPre-Filter Cu Tip Restoration PSF Cu Tip
Lucy-Richardson Restored: Cu Tip
s(x,y) p(x,y) f(x,y) h(x,y)
L-CRestored
PSF: Cu Tip
S. Mandayam, ECE Dept., Rowan University
SC-EC Images on DatabaseSC-EC Images on Databaseiimlgeaenge$ on 'bng1nas02.jfwtc.ge.com‘
DA718_H01_163S/DA718_H01_163S.S.1.030504.1459
EC Signature Binary
Original RestoredEC Signature Binary
S. Mandayam, ECE Dept., Rowan University
SC-EC Images on DatabaseSC-EC Images on Databaseiimlgeaenge$ on 'bng1nas02.jfwtc.ge.com‘
DA718_H01_163S/DA718_H01_163S.S.2.030504.1459
Original Restored
EC Signature Binary
EC Signature Binary
S. Mandayam, ECE Dept., Rowan University
SummarySummary
• Parametric model for PSF of split-D core EC Probe
• Deconvolution algorithm to compensate for anisotropic probe PSF