Raspberry Pi 3 Cookbook for Python Programmers - Third Edition

How to do it...

1. Import the necessary packages:

import sys 
import cv2 
import numpy as np 

2. Read the input image:

in_file = sys.argv[1] 
image = cv2.imread(in_file, cv2.IMREAD_GRAYSCALE) 

3. Implement the Sobel edge detection scheme:

horizontal_sobel = cv2.Sobel(image, cv2.CV_64F, 1, 0, ksize=5) 
vertical_sobel = cv2.Sobel(image, cv2.CV_64F, 0, 1, ksize=5) 
laplacian_img = cv2.Laplacian(image, cv2.CV_64F) 
canny_img = cv2.Canny(image, 30, 200) 

4. Display the input image and its corresponding output:

cv2.imshow('Original', image) 
cv2.imshow('horizontal Sobel', horizontal_sobel) 
cv2.imshow('vertical Sobel', vertical_sobel) 
cv2.imshow('Laplacian image', laplacian_img) 
cv2.imshow('Canny image', canny_img) 

5. Wait for the instruction from the operator: ...