Edge Detection

Edge detection

Origin of Edges

Edge detection

Image gradient

The discrete gradient

The Sobel operator

Effects of noise

Solution:  smooth first

Derivative theorem of convolution

Laplacian of Gaussian

2D edge detection filters

The Canny edge detector

The Canny edge detector

The Canny edge detector

Non-maximum suppression

The Canny edge detector

Effect of s (Gaussian kernel size)

Scale space (Witkin 83)

Edge detection by subtraction

Edge detection by subtraction

Edge detection by subtraction

Gaussian - image filter

An edge is not a line...

Finding lines in an image

Finding lines in an image

Finding lines in an image

Hough transform algorithm

Hough transform algorithm

Extensions

Extensions