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

The Canny edge detector

Effect of Gaussian kernel width

Edge detection by subtraction

Edge detection by subtraction

Edge detection by subtraction

Gaussian - subtraction 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

Summary