Daniel Lelis Baggio 
OpenCV Computer Vision with Java [EPUB ebook] 
Create multiplatform computer vision desktop and web applications using the combination of OpenCV and Java

If you are a Java developer, student, researcher, or hobbyist wanting to create computer vision applications in Java then this book is for you. If you are an experienced C/C++ developer who is used to working with Open CV, you will also find this book very useful for migrating your applications to Java.
All you need is basic knowledge of Java, with no prior understanding of computer vision required, as this book will give you clear explanations and examples of the basics.