Introduction

Computer vision algorithms consume and produce data—they usually take images as an input and generate features of the input, such as contours, points or regions of interest, bounding boxes for objects, or another images. So dealing with the input and output of graphical information is an essential part of any computer vision algorithm. This means not only reading and saving images, but also displaying them with additional information about their features.

In this chapter, we will cover basic OpenCV functionality related to I/O functions. From the recipes, you will learn how to obtain images from different sources (either filesystem or camera), display them, and save images and videos. Also, the chapter covers the topic of working with the OpenCV UI system; for instance, in creating windows and trackbars.