SLIDE 1 Reporter : Chih-Chieh Lien <cclien@islab.csie.thu.edu.tw> Reporter : Chih-Chieh Lien <cclien@islab.csie.thu.edu.tw>
Blind restoration of atmospherically degraded images by automatic best step-edge detection
Ormi Shacham, Oren Haik, Yitzhak Yitzhaky Ben-Gurion University, Department of Electro-Optics Engineering, Israel Pattern Recognition Letters, Volume 28 , Issue 15 (November 2007) Page 2094-2103
SLIDE 2
Outline
Blind restoration Atmospherically degraded image Proposed method Experimental Result Conclusion
SLIDE 3
Blind restoration
Only available data is the recorded image
itself.
An image restoration process in this case is
called blind restoration.
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Atmospherically degraded images
In horizontal long-distance imaging Degraded due to atmospheric effects
SLIDE 5 Proposed method
Degraded image Edge detection Atmospheric MTF Calculated Wiener filter Restored image
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Edge detection
Canny edge detection used to produce
single-line edge, Provides non-broken edges
Evaluation of edge length and straightness Small-scale evaluation Large-scale evaluation
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Small-scale evaluation
Weighting code given by relationship with
neighbors.
Have one or zero neighbor: 1 Has neighbors angels of 45,90,135,180 will
be assigned 2,3,4, and 5
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Small-scale evaluation
SLIDE 9
Small-scale evaluation
Provide information for Large-scale
evaluation: Locate longer straight edges
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Edge detection: Result
SLIDE 11
Contract and homogeneity of edge sides
Examine which edges has high contrast
and homogeneous regions from both sides (step-edge)
Done by taking a square region
surrounding the center pixel of the edge and observing the histogram of the pixels in that area.
SLIDE 12
Contract and homogeneity of edge sides
SLIDE 13
Contract and homogeneity of edge sides
Small size of the square region will have a
better chance to be the image of a close to an ideal step-edge.
But it should be large enough to include the
whole significant part of the atmospheric blur.
SLIDE 14
Calculation of the atmospheric MTF and image restoration
Using the step-edge obtained to calculate
MTF (Modulation Transfer Function) H(u,v).
Extracted MTF is used for restoring the
atmospherically degraded image.
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Result: synthetically blurred image
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Result: synthetically blurred image
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Result: real degraded image
SLIDE 18
Conclusion
The method in the paper seems works well
in real degraded images.
A good edge detection is very important for
image restoration.
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END
