Edge-based Segmentation Transform Hough Edge Tracking Linking - PowerPoint PPT Presentation

Edge-based Marr-Hildreth http://vision.ouc.edu.cn/~zhenghaiyong CVBIOUC ZhaoHaiwei DaiJialun WangRuchen 基于边缘的图像分割 Edge-based Segmentation Transform Hough Edge Tracking Linking Edge Detection Canny Edge Techniques Segmenta- Edge Detection Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion April 28, 2015

Edge-based Steps in Edge Detection Hough Transform Contents 1 Introduction Edge & Boundary Problems Steps in Image Segmentation Linking 2 Edge Detection Edge Detection Techniques Marr-Hildreth Canny Edge Detection 3 Edge Linking Edge Tracking Edge Tracking Edge Segmenta- Detection tion Introduction Edge & Boundary Problems Steps in Edge Steps in Image Detection Segmentation Edge Detection Edge Detection Techniques Marr-Hildreth Canny Edge Hough Transform

Edge-based Edge Detection Transform Hough Edge Tracking Linking Edge Detection Canny Edge Marr-Hildreth Techniques Detection Segmenta- Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion What?

Edge-based Marr-Hildreth The edge of object may be not a boundary, the boundary edge original image Edge & Boundary Transform Hough Edge Tracking Linking Edge Detection Canny Edge Techniques Segmenta- Edge Detection Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion boundary may also be not edge.

Edge-based Canny Edge detection. Noise and background afgect the accurate of edge problems: segmentation methods. However, there also are some Edge detection is a simple and fast technique used in Problems Transform Hough Edge Tracking Linking Edge Detection Marr-Hildreth Segmenta- Techniques Edge Detection Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion Edges are the sign of lack of continuity, and ending.

Edge-based Canny Edge 3 Detection: Find the zero crossing and peak value to the neighborhood of a point. edges, it is essential to determine changes in intensity in 2 Enhancement: In order to facilitate the detection of edge strength. 1 Filtering: Filtering to reduce noise results in a loss of Steps in Edge Detection Transform Hough Edge Tracking Linking Edge Detection Marr-Hildreth Segmenta- Techniques Edge Detection Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion detect edge.

Edge-based Canny Edge detection. Noise and background afgect the accurate of edge problems: segmentation methods. However, there also are some Edge detection is a simple and fast technique used in Problems Transform Hough Edge Tracking Linking Edge Detection Marr-Hildreth Segmenta- Techniques Edge Detection Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion Edges are the sign of lack of continuity , and ending.

Edge-based Edge Detection Transform Hough Edge Tracking Linking Edge Detection Canny Edge Marr-Hildreth Techniques Detection Segmenta- Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion Step in Image Segmentation

Edge-based Marr-Hildreth Ramp edge Step edge Three edge types and defjnitions: Edge Detection Transform Hough Edge Tracking Linking Edge Detection Canny Edge Techniques Segmenta- Edge Detection Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion Roof edge

Edge-based Edge Detection Transform Hough Edge Tracking Linking Edge Detection Canny Edge Marr-Hildreth Techniques Detection Segmenta- Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion Edge Detection

Edge-based Segmenta- 1 Rafael C. Gonzalez et al. , “Digital Image Processing”, Publishing Canny Edge Detection Marr-Hildreth Edge Detection (LoG) Prewitt Edge Detection Sobel Edge Detection Roberts Edge Detection Edge Detection Techniques 1 Transform Hough Edge Tracking Linking Edge Detection Canny Edge Marr-Hildreth Techniques Edge Detection Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion House of Electronics Industry, 2011. . . .

Edge-based Canny Edge g y The direction of the greatest rate of change is: y The magnitude of the gradient is: g y Segmenta- Transform Hough Edge Tracking Linking Edge Detection Gradient Marr-Hildreth tion Boundary Edge & Problems Introduction Steps in Edge Detection Steps in Image Segmentation Edge Detection Edge Detection Techniques The gradient ▽ f of a function is: [ ] B f [ g x ] B x ▽ f = grad ( f ) = = B f B y b M ( x , y ) = mag ( ▽ f ) = g 2 x + g 2 [ g x ] α ( x , y ) = arctan

Edge-based Segmenta- Roberts Edge Detection Edge Detection Techniques Transform Hough Edge Tracking Linking Edge Detection Canny Edge Marr-Hildreth Techniques Edge Detection Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion g x = B f B x = z 9 ´ z 5 g y = B f B y = z 8 ´ z 6

Edge-based Techniques Sobel Edge Detection Edge Detection Techniques Transform Hough Edge Tracking Linking Edge Detection Canny Edge Segmenta- Marr-Hildreth Edge Detection Problems tion Introduction Edge & Detection Boundary Steps in Edge Detection Steps in Image Segmentation Edge Prewitt Edge Detection g x = B f B x = ( z 7 + 2 z 8 + z 9 ) ´ ( z 1 + 2 z 2 + z 3 ) g y = B f B y = ( z 3 + 2 z 6 + z 9 ) ´ ( z 1 + 2 z 4 + z 7 )

Edge-based Laplacian for edge detection. Edge Tracking Hough Transform Marr-Hildreth Edge Detection (LoG) 2 This method combines Gaussian fjltering with the Idea: Edge 1 Gaussian fjler is used to swipe away noise from the image 2 Laplace operator 3 Locate zero crossings 2 Marr D, Hildreth E, “Theory of Edge Detection”, Proc. of the Linking Detection Segmenta- Detection tion Introduction Edge & Boundary Problems Steps in Edge Steps in Image Canny Edge Segmentation Edge Detection Edge Detection Techniques Marr-Hildreth Royal Society of London, 1980.

Edge-based Canny Edge 3 Joun F. Canny, “A Computational Approach To Edge Detection”, 2 Edge points should be well localized 1 Low error rate Idea: Canny is the best edge detection detector. Canny Edge Detection 3 Transform Hough Edge Tracking Linking Edge Detection Marr-Hildreth Segmenta- Techniques Edge Detection Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion PAMI, 1986.

Edge-based Edge Detection Canny Edge Detection Transform Hough Edge Tracking Linking Edge Detection Canny Edge Marr-Hildreth Techniques Detection Segmenta- Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion Canny algorithm:

Edge-based Marr-Hildreth two dimension: one dimension: 1 Gaussian distribution Gauss Filter: Canny Edge Detection Transform Hough Edge Tracking Segmenta- Edge Detection Canny Edge Linking Techniques Problems tion Edge Detection Edge & Boundary Introduction Steps in Edge Detection Steps in Image Segmentation Edge Detection 2 Gaussian kernel 1 2 πσ e ´ x 2 ? G ( x ) = 2 σ 2 1 2 πσ 2 e ´ x 2+ y 2 G ( x , y ) = 2 σ 2

Edge-based Techniques Compute Gradient: Canny Edge Detection Transform Hough Edge Tracking Segmenta- Edge Detection Canny Edge Marr-Hildreth Linking Edge Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion Detection [ ´ 1 ] [ ] 1 1 1 S x = , S y = ´ 1 1 ´ 1 ´ 1

Edge-based Marr-Hildreth Use non-maxima suppression to thin those ridges to ridges around local maxima. Edges generated using gradient typically contain wide Non-maxima Suppression (NMS): Canny Edge Detection Transform Hough Edge Tracking Linking Edge Detection Canny Edge Techniques Segmenta- Edge Detection Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion fjnd thin edges corresponding to local maxima.

Edge-based Edge Detection Transform Hough Edge Tracking Linking Edge Detection Canny Edge Marr-Hildreth Techniques Detection Segmenta- Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion Canny Edge Detection

Edge-based Techniques Problem: The received image may still contain false Double thresholding: Canny Edge Detection Transform Hough Edge Tracking Linking Edge Detection Canny Edge Marr-Hildreth Edge Detection Segmenta- Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion edge points.

Edge-based Marr-Hildreth Dynamic Programming Curve Fitting Hough Transform Edge Tracking Edge Linking Transform Hough Edge Tracking Linking Edge Detection Canny Edge Techniques Segmenta- Edge Detection Detection Edge Segmentation Steps in Image Detection Steps in Edge Problems Boundary Edge & Introduction tion . . .