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)

Disparity maps and depth estimation

Disparity refers to the difference in the location of an object in the images captured by the left and right eyes or cameras. This difference or disparity is caused by parallax. Our brain uses this information regarding disparity to estimate the depth of objects (that is, their distance from us). We can compute the disparity between two images by applying this principle to every pixel in the pair of images captured by a webcam. This disparity information can be used to compute the estimated depth, thus mimicking the functionality of the brains of primates.

In terms of biology, this is known as Stereoscopic Vision, which enables us to see in three dimensions. OpenCV offers a cv2.StereoBM,compute() function that accepts the left image and the right image as an argument and returns a disparity map of the image pair. The StereoBM_create() function initializes the stereo state. It can have a number of disparities and block sizes as arguments. By default...