This book guides you on how to use OpenCV 3 (Open Computer Vision) library. The library is compatible with C, C++, Java, and Python. This book helps you learn how to use the library with C++, Java, and Python. You are guided on how to read, write, and store images using the OpenCV library. The process of displaying images in a graphical user interface when using the OpenCV is discussed. With OpenCV, you can convert your images from one color code to another. This book helps you learn how to do the conversions. You are also shown how to use the OpenCV and the camera for face detection. There are a number of geometric transformations which can be done on images when using OpenCV. These are explored in this book, thus, you will know how to do them with various programming languages. You are also taught how to analyze videos with OpenCV. The following topics are discussed in this book: - What is OpenCV? - Storing Images - Reading Images - Writing Images - Using Graphical User Interface - Converting Images - OpenCV and the Camera - Geometric Transformations of Images - Video Analysis