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Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary • Similarity -- region Discontinuity Detection: Point, Line and Edge Mask Operation (Review)

Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

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Page 1: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Segmentation: Dividing into the regions/segments of similar properties

•  Discontinuity -- boundary •  Similarity -- region Discontinuity Detection: Point, Line and Edge Mask Operation (Review)

Page 2: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Edge Detection

Page 3: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Edge Detection

Page 4: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Edge Detection

Page 5: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Edge Detection

Page 6: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Hough Transform Lines

Page 7: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Hough Transform Lines

Page 8: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Hough Transform Lines

Page 9: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Hough Transform Lines

Apply edge operator to image f(x,y), and compute gradient magnitude M(x,y) at each pixel. Build the accumulator array A: for each edge pixel M(x,y) if ( M(x,y) > threshold )

for each quantized value of θ compute: ρ = x cosθ + y sinθ increment: A[ρ][θ]++

Search accumulator array for maxima, corresponding to lines in the image.

Page 10: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Hough Transform Lines

Page 11: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Hough Transform Circles

Page 12: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Hough Transform Circles

Apply edge operator to image f(x,y), and compute gradient magnitude M(x,y) at each pixel. Build the accumulator array A: for each edge pixel M(x,y) if ( M(x,y) > threshold )

for each quantized value of θ compute: xc = x – R * cosθ yc = y – R * sinθ increment: A[xc][yc]++

Search accumulator array for maxima, corresponding to circle centers in the image.

Page 13: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Hough Transform Circles

Page 14: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Thresholding

Page 15: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Thresholding

Page 16: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Thresholding

Page 17: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Thresholding

Page 18: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Image Segmentation

Region Based

Page 19: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Color Image Processing

Page 20: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Color Image Processing

Page 21: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Color Image Processing

Page 22: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Color Image Processing

Page 23: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Color Image Processing

Page 24: Image Segmentation - cse.iitd.ernet.inpkalra/csl783/week-3.pdf · Image Segmentation Segmentation: Dividing into the regions/segments of similar properties • Discontinuity -- boundary

Color Image Processing