Book Image

Raspberry Pi Computer Vision Programming - Second Edition

By : Ashwin Pajankar
5 (1)
Book Image

Raspberry Pi Computer Vision Programming - Second Edition

5 (1)
By: Ashwin Pajankar

Overview of this book

Raspberry Pi is one of the popular single-board computers of our generation. All the major image processing and computer vision algorithms and operations can be implemented easily with OpenCV on Raspberry Pi. This updated second edition is packed with cutting-edge examples and new topics, and covers the latest versions of key technologies such as Python 3, Raspberry Pi, and OpenCV. This book will equip you with the skills required to successfully design and implement your own OpenCV, Raspberry Pi, and Python-based computer vision projects. At the start, you'll learn the basics of Python 3, and the fundamentals of single-board computers and NumPy. Next, you'll discover how to install OpenCV 4 for Python 3 on Raspberry Pi, before covering major techniques and algorithms in image processing, manipulation, and computer vision. By working through the steps in each chapter, you'll understand essential OpenCV features. Later sections will take you through creating graphical user interface (GUI) apps with GPIO and OpenCV. You'll also learn to use the new computer vision library, Mahotas, to perform various image processing operations. Finally, you'll explore the Jupyter Notebook and how to set up a Windows computer and Ubuntu for computer vision. By the end of this book, you'll be able to confidently build and deploy computer vision apps.
Table of Contents (15 chapters)

Filtering and blurring with OpenCV

OpenCV also has many filtering and convolution functions. These filtering functions are cv2.filter2D(), cv2.boxFilter(), cv2.blur(), cv2.GaussianBlur(), cv2.medianBlur(), cv2.sepFilter2D(), and cv2.BilateralFilter(). In this section, we will explore all these functions in detail.

2D convolution filtering

The cv2.filter2D() function, just like the scipy.signal.convolve2d() function, convolves a kernel with an image, thus applying a linear filter to the image. The advantage of the cv2.filter2D() function is that we can apply it to data that has more than two dimensions. We can apply this to color images, too.

This function accepts the input image, the depth of the output image (-1 means the input and the output have the same depth), and a kernel for the convolution operation as arguments. The following code demonstrates the usage of this function:

import cv2
import numpy as np
from matplotlib import pyplot as plt
img = cv2.imread(&apos...