Hands-On Image Processing with Python

The Canny edge detector with scikit-image

The Canny edge detector is a popular edge detection algorithm, developed by John F. Canny. This algorithm has the following multiple steps:

1. Smoothing/noise reduction: The edge detection operation is sensitive to noise. Hence, at the very outset, a 5 x 5 Gaussian filter is used to remove noise from the image.
2. Computing magnitude and orientation of the gradient: The Sobel horizontal and vertical filters are then applied to the image to compute the edge gradient magnitude and direction for each pixel, as discussed previously. The gradient angle (direction) computed is then rounded to one of four angles representing horizontal, vertical, and two diagonal directions for each pixel.
3. Non-maximum suppression ...