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)

Working with kernels

Now, let's learn about kernels. We will learn how to use kernels for signal and image processing operations. Kernels are square numerical matrices. Depending on the size and components of the kernel, if we convolve the kernel with the image, we get blurred or sharpened output. Kernels are used for a variety of image processing operations.

Let's look at an example of a simple kernel used for averaging. It can be represented with the following formula:

By using the preceding formula, an averaging kernel that's 3x3 in size can be expressed as follows:

The value of the number of rows and the number of columns is always odd and always the same. They are all square matrices.

We can use the following NumPy code to create the preceding kernel:

K = np.ones((3, 3), np.uint8)/9

Now, we'll learn how to use the preceding kernel and other kernels to process the sample images from the dataset...