ITK Hough Transform
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Transcript ITK Hough Transform
ITK Hough Transform
指導教授: 張顧耀
學生: 沈仁立
2015/4/13
ITK Hough Transform
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Outline
Hough Transform
◦ Find line
◦ Find circle
ITK Hough Transform(Ch9.5)
◦ itk::HoughTransform2DLinesImageFilter
測試
疑問
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ITK Hough Transform
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Hough Transform
-Find line
b
y
y=mx+b
(2,1)
y=x-1
2 = 3m+b
(3,2)
a
1 = 2m+b
x
影像空間 x-y
參數空間 a-b
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ITK Hough Transform
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Hough Transform
-Find line
影像空間 x-y
參數空間 a-b
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累加器
(Accumulator)
ITK Hough Transform
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Hough Transform
-Find circle
影像空間
參數空間
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ITK Hough Transform
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Hough Transform
-Find circle
http://www.markschulze.net/java/hough/
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ITK Hough Transform
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Hough Transform
-Find circle
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ITK Hough Transform
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ITK Hough Transform
itk::HoughTransform2DLinesImageFilter
◦ Find straight lines in a 2-dimensional image
◦ Step
Load image data
itk::GradientMagnitudeImageFilter
To segment edges
Threshold
Keep only bright values
Only high values will be used
Hough transform
Number of lines
Variance of the accumulator blurring
Radius of the disk to remove from the accumulator
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ITK Hough Transform
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測試
Line:50 var:5 radius:10 Line:50 var:5 radius:5
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ITK Hough Transform
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測試
Line:50 var:5 radius:3
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ITK Hough Transform
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測試
Line:50 var:3 radius:10 Line:50 var:3 radius:5
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ITK Hough Transform
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測試
Line:50 var:3 radius:3
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ITK Hough Transform
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測試
Line:50 var:7 radius:10 Line:50 var:7 radius:5
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ITK Hough Transform
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測試
Line:50 var:7 radius:3
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ITK Hough Transform
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疑問
整張影像 or 部份區域
結果的反推
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