Book Image

OpenCV 3.x with Python By Example - Second Edition

By : Gabriel Garrido Calvo, Prateek Joshi
Book Image

OpenCV 3.x with Python By Example - Second Edition

By: Gabriel Garrido Calvo, Prateek Joshi

Overview of this book

Computer vision is found everywhere in modern technology. OpenCV for Python enables us to run computer vision algorithms in real time. With the advent of powerful machines, we have more processing power to work with. Using this technology, we can seamlessly integrate our computer vision applications into the cloud. Focusing on OpenCV 3.x and Python 3.6, this book will walk you through all the building blocks needed to build amazing computer vision applications with ease. We start off by manipulating images using simple filtering and geometric transformations. We then discuss affine and projective transformations and see how we can use them to apply cool advanced manipulations to your photos like resizing them while keeping the content intact or smoothly removing undesired elements. We will then cover techniques of object tracking, body part recognition, and object recognition using advanced techniques of machine learning such as artificial neural network. 3D reconstruction and augmented reality techniques are also included. The book covers popular OpenCV libraries with the help of examples. This book is a practical tutorial that covers various examples at different levels, teaching you about the different functions of OpenCV and their actual implementation. By the end of this book, you will have acquired the skills to use OpenCV and Python to develop real-world computer vision applications.
Table of Contents (17 chapters)
Title Page
Copyright and Credits
Packt Upsell

Let's add some movements

Now that we know how to add a virtual pyramid, let's see if we can add some movements. Let's see how we can dynamically change the height of the pyramid. When you start, the pyramid will look like this:

If you wait for some time, the pyramid gets taller and will look like this:

Let's see how to do it in OpenCV Python. Inside the augmented reality code that we just discussed, add the following snippet at the end of the __init__ method in the Tracker class:

self.overlay_vertices = np.float32([[0, 0, 0], [0, 1, 0], [1, 1, 0], [1, 0, 0], [0.5, 0.5, 4]]) 
self.overlay_edges = [(0, 1), (1, 2), (2, 3), (3, 0), 
            (0,4), (1,4), (2,4), (3,4)] 
self.color_base = (0, 255, 0) 
self.color_lines = (0, 0, 0) 
self.graphics_counter = 0 
self.time_counter = 0 

Now that we have the structure, we need to add the code to dynamically change the height. Replace the overlay_graphics() method with the following method:

    def overlay_graphics(self, img, tracked):