Book Image

OpenCV 4 Computer Vision Application Programming Cookbook - Fourth Edition

By : David Millán Escrivá, Robert Laganiere
Book Image

OpenCV 4 Computer Vision Application Programming Cookbook - Fourth Edition

By: David Millán Escrivá, Robert Laganiere

Overview of this book

OpenCV is an image and video processing library used for all types of image and video analysis. Throughout the book, you'll work with recipes to implement a variety of tasks. With 70 self-contained tutorials, this book examines common pain points and best practices for computer vision (CV) developers. Each recipe addresses a specific problem and offers a proven, best-practice solution with insights into how it works, so that you can copy the code and configuration files and modify them to suit your needs. This book begins by guiding you through setting up OpenCV, and explaining how to manipulate pixels. You'll understand how you can process images with classes and count pixels with histograms. You'll also learn detecting, describing, and matching interest points. As you advance through the chapters, you'll get to grips with estimating projective relations in images, reconstructing 3D scenes, processing video sequences, and tracking visual motion. In the final chapters, you'll cover deep learning concepts such as face and object detection. By the end of this book, you'll have the skills you need to confidently implement a range of computer vision algorithms to meet the technical requirements of your complex CV projects.
Table of Contents (17 chapters)

Filtering images using a median filter

The first recipe of this chapter introduced the concept of linear filters. Nonlinear filters also exist and can be used advantageously in image processing. One such filter is the median filter that we present in this recipe.

Since median filters are particularly useful in order to combat salt-and-pepper noise (or salt-only noise, in our case), we will use the image we created in the first recipe of Chapter 2, Manipulating the Pixels, and that is reproduced here:

Let's get started with the steps.

How to do it...

The step to take for this recipe is as follows:

  1. The call to the median filtering function is done in a way that is similar to the other filters; we use the medianBlur function...