34,79 €
Mehr erfahren.
- Herausgeber: Packt Publishing
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Kinect has been a game-changer in the world of motion games and applications since its first release. It has been touted as a controller for Microsoft Xbox but is much more than that. The developer version of Kinect, Kinect for Windows SDK, provides developers with the tools to develop applications that run on Windows. You can use this to develop applications that make interaction with your computer hands-free. This book focuses on developing applications using the Kinect for Windows SDK. It is a complete end to end solution using different features of Kinect for Windows SDK with step by step guidance. The book will also help you develop motion sensitive and speech recognition enabled applications. You will also learn about building application using multiple Kinects.The book begins with explaining the different components of Kinect and then moves into to the setting up the device and getting thedevelopment environment ready. You will be surprised at how quickly the book takes you through the details of Kinect APIs. You will use NUI to use the Kinect for Natural Inputs like skeleton tracking, sensing, speech recognizing. You will capture different types of stream, and images, handle stream event, and capture frame. Kinect device contains a motorized tilt to control sensor angles, you will learn how to adjust it automatically. The last part of the book teaches you how to build application using multiple Kinects and discuss how Kinect can be used to integrate with other devices such as Windows Phone and microcontroller.
Das E-Book können Sie in Legimi-Apps oder einer beliebigen App lesen, die das folgende Format unterstützen:
Seitenzahl: 420
Veröffentlichungsjahr: 2012
Ähnliche
Table of Contents
Kinect for Windows SDK Programming Guide
Kinect for Windows SDK Programming Guide
Copyright © 2012 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.
First published: December 2012
Production Reference: 1191212
Published by Packt Publishing Ltd.
Livery Place
35 Livery Street
Birmingham B3 2PB, UK.
ISBN 978-1-84969-238-0
www.packtpub.com
Cover Image by Sandeep Babu (<[email protected]>)
Credits
Author
Abhijit Jana
Reviewers
Atul Gupta
Anoop Madhusudhanan
Atul Verma
Acquisition Editor
James Keane
Lead Technical Editor
Susmita Panda
Technical Editors
Prasanna Joglekar
Dipesh Panchal
Farhaan Shaikh
Nitee Shetty
Copy Editors
Brandt D'Mello
Insiya Morbiwala
Aditya Nair
Alfida Paiva
Project Coordinator
Yashodhan Dere
Proofreaders
Ting Baker
Matthew Humphries
Indexer
Rekha Nair
Graphics
Valentina D'silva
Aditi Gajjar
Production Coordinator
Nitesh Thakur
Cover Work
Nitesh Thakur
About the Author
Abhijit Jana works at Microsoft as a .NET Consultant, as part of Microsoft Services Global Delivery, India. As a consultant, his job is to help customers design, develop, and deploy enterprise-level secure solutions using Microsoft Technology. Apart from being a former Microsoft MVP, he is a speaker and author as well as an avid technology evangelist. He has delivered sessions at prestigious Microsoft events such as TechEd, Web Camps, Azure Camps, Community Tech Days, Virtual Tech Days, DevDays, and developer conferences. He loves to work with different .NET communities and help them with different opportunities. He is a well-known author and has published many articles on different .NET community sites.
He shares his thoughts on his personal blog at http://abhijitjana.net. You can follow him on Twitter at @abhijitjana. Abhijit lives in Hyderabad, India, with his wife, Ananya and a beautiful little angel Nilova.
Note
Disclaimer
The opinions in this book are purely my personal opinions and do not reflect in any way the opinions of my employers.
Acknowledgement
Writing this book would not have been possible without the help of many people. I had a wonderful time while writing, which was mainly due to the skills, support, dedication, and motivation of the people around me.
First of all I am extremely thankful to Sachin Joshi, Pinal Dave, and Prasant Kraleti for the continuous support and motivation they gave me from the time I started writing this book. They have been awesome with their support at every stage of writing.
I am deeply thankful to the entire team at Packt Publishing, including Prasad, Susmita, Mayur, Prasanna, Dipesh, Farhaan, and Nitee. I would like to extend my thanks to the Project Coordinator, Yashodhan, for his support from the beginning. Thank you all for your effort and dedication.
A sincere thanks to Atul Gupta and Anoop Madhusudanan for their insightful and excellent technical review. They helped me to identify and fill the gaps and improve the overall quality of this book.
I would like to acknowledge the efforts of Atul Verma for his extended support for in-depth technical review, and also for his time in discussing, peer coding, and providing feedback on many topics.
I would like to thank Jebarson Jebamony for his excellent peer review for this book, and also for spending his time and effort in sharing his thoughts and feedback for improving the content. He also helped me to organize content and design many demo applications.
I would like to thank Arka Bhattacharya and Atul Sharma for their offline review of the book and for sharing their feedback. A big thank you to Rajesh R. Nair for helping me on designing sketches and icons, and also Rishabh Verma for capturing and sharing the dismantled sensor images with me.
My sincere thanks to Jag Dua and Sanjoyan Mitra, two true leaders I have worked with. I would like to extend my thanks to Jag for giving me his Kinect sensor when I was overseas and was urgently looking for a Kinect sensor for some experimentation.
I was fortunate enough to be present at many seminars and conferences over the past year, on Kinect. This helped me to interact with many developers and students who are really passionate about programming with Kinect. Thanks to each one of them for spending their time with me and discussing about their problems and questions.
A big thanks to the Kinect for Windows team, the Kinect for Windows Community, and my Community friends, and MSPs who helped me in writing this book. I would like to thank my friends Kunal Chowdhury, Abhishek Sur, Dhananjay Kumar, Suresh Bemagani, Sheo Narayan, and Sharavan Kasagoni for their continuous support and help while writing this book. I am also thankful to the bloggers on the various Kinect topics, and also the researchers who have been working and experimenting day in and day out with Kinect. On many occasions I have been reading their posts and referring to them.
I spent time in writing when I should have been sleeping, spending time with family, or playing with my newborn child. I'd never have been able to write this book without the support of my wife, Ananya. I cannot even express her love and support while I was writing this book. Thank you Ananya.
Being a Community lover and an active blogger, I have been writing blogs for the last couple of years; but this is the first time I am putting something in the form of a book. The credit goes to each one of you who has been connected with me and have been my blog reader and supporter.
I would really appreciate it if you would contact me at <[email protected]> for any kind of clarification.
About the Reviewers
Atul Gupta is currently a Principal Technology Architect at Infosys' Microsoft Technology Center, Infosys Labs. With more than 16 years of experience working on Microsoft technologies, his expertise spans User Interface technologies, and he currently works on touch and gestural interfaces with technologies such as Windows 8 and Kinect. He has prior experience on Windows Presentation Foundation (WPF), Silverlight, Windows 7, Deepzoom, Pivot, PixelSense, and Windows Phone 7.
He has co-authored the book ASP.NET 4 Social Networking, Packt Publishing. Earlier in his career, he has also worked on technologies such as COM, DCOM, C, VC++, ADO.NET, ASP.NET, AJAX, and ASP.NET MVC. He is a regular reviewer for Packt Publishing and has reviewed books on topics such as Silverlight and Generics.
He has authored papers for industry publications and websites, some of which are available on Infosys' Technology Showcase (http://www.infosys.com/microsoft/resource-center/pages/technology-showcase.aspx). Along with his colleagues from Infosys, he is also an active blogger (http://www.infosysblogs.com/microsoft). Being actively involved in professional Microsoft online communities and developer forums, he has received Microsoft's Most Valuable Professional award for multiple years in a row.
Anoop Madhusudanan has been a Microsoft MVP in C# for the last 3 years and has more than 10 years of experience with Microsoft technologies. Presently, he is working as a Solution Architect with the Cloud & Mobile Center of Excellence, Marlabs Inc. He works across multiple Microsoft technologies and platforms including Windows 8, ASP.NET, Windows Azure, and so on, across domains including education, healthcare, and telecom.
He blogs at http://amazedsaint.com and is the developer of various open source frameworks such as BrainNet Neural Network Library, ElasticObject, SilverDraw, MetaCoder, and so on. He is also an active contributor to CodeProject. His Twitter handle is @amazedsaint.
Atul Verma is a Technical Consultant at Microsoft Services Global Delivery and is a graduate from NIT, Hamirpur. He has been developing enterprise-level secure and scalable solutions using agile software methodologies for the past seven years. His technical expertise includes WPF, ASP.NET, WCF, SharePoint, Dynamics CRM, and Kinect for Windows. Apart from this, he also contributes to technical communities, technical seminars, open source projects, and blogs. He is currently studying the essence of Indian culture and loves to spend quality time with his family. You can follow him on Twitter at @verma_atul.
www.PacktPub.com
Support files, eBooks, discount offers and more
You might want to visit www.PacktPub.com for support files and downloads related to your book.
Did you know that Packt offers eBook versions of every book published, with PDF and ePub files available? You can upgrade to the eBook version at www.PacktPub.com and as a print book customer, you are entitled to a discount on the eBook copy. Get in touch with us at <[email protected]> for more details.
At www.PacktPub.com, you can also read a collection of free technical articles, sign up for a range of free newsletters and receive exclusive discounts and offers on Packt books and eBooks.
http://PacktLib.PacktPub.com
Do you need instant solutions to your IT questions? PacktLib is Packt's online digital book library. Here, you can access, read and search across Packt's entire library of books.
Why Subscribe?
Free Access for Packt account holders
If you have an account with Packt at www.PacktPub.com, you can use this to access PacktLib today and view nine entirely free books. Simply use your login credentials for immediate access.
Instant Updates on New Packt Books
Get notified! Find out when new books are published by following @PacktEnterprise on Twitter, or the Packt Enterprise Facebook page.
I dedicate this book to my parents, my lovely wife Ananya and my little angel Nilova.
Preface
Ever since its inception, Kinect has brought about a revolution in the field of NUI and hands-free gaming. There is no wonder that Kinect went on to shatter all records and become the fastest selling electronic device on earth. Although touted as a controller for Xbox console, Kinect applicability is beyond gaming domain and you can think of building applications for diverse domains such as health care, robotics, imaging, education, security, and so on. Thus we have the Kinect for Windows sensor, that enables applications to interacts with users via gestures and voice, and this opens up avenues that developers couldn't even have imagined before.
This book is mainly focussed on the Kinect for Windows SDK with which you can build applications that can leverage the power of the Kinect sensor. This book doesn't require any prior knowledge about the platform from the reader and its strength is the simplicity in which the concepts have been presented using code snippets, a step-by-step process, and detailed descriptions. This book covers:
What this book covers
Chapter 1, Understanding the Kinect Device, introduces Kinect as a hardware device. You will get an insight into the different components that make up Kinect and the technology behind this device, which makes the components work together. This chapter will also give an overview of the difference between Kinect for Xbox and Kinect for Windows sensor. You will also become familiar with different possibilities of domain specific applications that can be developed using the Kinect sensor.
Chapter 2, Getting Started, introduces the Kinect for Windows SDK, its features, and how to start working with the Kinect sensor. In this chapter, you will get to know about the requirements for preparing your development environment. This will also walk you through a step-by-step guide for downloading and installing the SDK. You will delve into the installed components to verify that everything is set up properly. This chapter will also provide you with a quick lap around the different features of the Kinect for Windows SDK as well as introduce the Kinect for Windows Developer Toolkit.
Chapter 3, Starting to Build Kinect Applications, explains the step-by-step process of building your first Kinect-based application. You will understand how applications interact with the Kinect sensor using the SDK libraries. This chapter will give you an in-depth guide on how to start building Kinect applications using the Kinect for Windows SDK and Visual Studio. You will also learn how to deal with applications when there is any change in the device status.
Chapter 4, Getting the Most Out of Kinect Camera, covers the in-depth discussion of the Kinect color camera and how to use it. In this chapter, you will learn about the different types of image streams and different approaches to retrieve them from the Kinect sensor. You will get an understanding of Color camera stream pipeline and its events. You will also explore the different features of the Kinect for Windows SDK that control the color camera and process the color data. This chapter will give you an understanding of processing color images and applying different effects to the captured images and how to save the image frames. You will also learn how you can use the Kinect camera to capture images in low light.
Chapter 5, The Depth Data – Making Things Happen, explores the fundamentals of the Kinect depth sensors and how they produce depth information. This chapter describes how to work with object distances and player indices from the captured depth data. You will also learn about the capturing of data using the near mode and also get a quick view of generating 3D depth data.
Chapter 6, Human Skeleton Tracking, describes how a Kinect sensor tracks the human skeleton and how you can leverage the features of the Kinect for Windows SDK to play around with tracked skeletons and joints. You will also learn how to change the sensor elevation angle based on the player position. This chapter also explores how skeletons can be tracked in a seated mode. You also learn about details of the skeleton joints and bone hierarchy. The sample application in this chapter will help you to understand the APIs for skeleton tracking in better ways such as using Kinect as an intrusion detector. At the end of this chapter, you will be familiar with a few debugging tips and tricks to boost your development speed.
Chapter 7, Using Kinect's Microphone Array, introduces the microphone array that captures and processes the audio signal. You will learn why Kinect uses an array of microphones rather than a single microphone. In this chapter you will get an insight into the Kinect audio processing pipeline that helps Kinect to capture good-quality audio signals and makes Kinect a highly directional audio device. This chapter provides you with information on how to capture and record audio signals using the Kinect microphone array and process the audio data for better quality. You will also learn about different concepts such as Noise Suppression, Automatic Gain Control, Echo Cancellation, and Beam forming.
Chapter 8, Speech Recognition, introduces the building of speech-enabled applications using Kinect. You will explore how speech recognition works and how Kinect's microphone array helps Kinect to recognize human speech. This chapter also shows how you can use Kinect as the default speech recognition device for your PC. You will also learn about the Microsoft Speech API and how it is integrated with Kinect for Windows SDK, which helps us to build speech-enabled applications.
Chapter 9, Building Gesture-controlled Applications, describes how to build applications that can be controlled by human gestures. You will learn different approaches for recognizing gestures and how to apply these approaches in the form of programs to build motion-sensing applications using the Kinect sensor. This chapter will also help you understand how to build some gestured-enabled controls.
Chapter 10, Developing Applications Using Multiple Kinects, explains how multiple Kinect sensors can be placed together and used to build applications. This chapter describes how to set up environments for developing applications using multiple Kinects and walks you through building applications by reading data from multiple devices. You also learn how multiple Kinects work together and different scenarios where multiple Kinects can be used, along with the challenges while developing applications using multiple devices.
Chapter 11, Putting Things Together, introduces us to more advanced developments using Kinect by integrating it with other devices such as Windows Phone, microcontrollers, and so on. This chapter addresses how we can take things up from Kinect to Windows Azure and control the Kinect sensor using Windows Phone via Windows Azure. You will also learn how Kinect can be integrated with the Netduino microcontroller and how you can use a Kinect device for face tracking.
What you need for this book
The basic requirements for this book are as follows:
Please refer Chapter 02, Getting Started , for detailed information on installation of SDK and the development environment setup.
Who this book is for
The purpose of this book is to explain how to develop applications using the Kinect for Windows SDK. If you are a beginner and looking to start developing applications using the Kinect for Windows SDK, and if you want to build motion-sensing, speech-recognizing applications with Kinect, this book is for you.
This book uses C# and WPF (Windows Presentation Foundation) in the examples, so you need to know the basics of C# and WPF. You should be familiar with the Visual Studio IDE as well. You don't have to know anything about the Kinect for Windows SDK.
Conventions
In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.
Code words in text are shown as follows: "Each Kinect device represents an instance of the Microsoft.Kinect.KinectSensor class."
A block of code is set as follows:
When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:
New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "Move to the Listen tab and select the Listen to this device checkbox and click on Apply".
Note
Warnings or important notes appear in a box like this.
Tip
Tips and tricks appear like this.
Reader feedback
Feedback from our readers is always welcome. Let us know what you think about this book—what you liked or may have disliked. Reader feedback is important for us to develop titles that you really get the most out of.
To send us general feedback, simply send an e-mail to <[email protected]>, and mention the book title via the subject of your message.
If there is a topic that you have expertise in and you are interested in either writing or contributing to a book, see our author guide on www.packtpub.com/authors.
Customer support
Now that you are the proud owner of a Packt book, we have a number of things to help you to get the most from your purchase.
Downloading the example code
You can download the example code files for all Packt books you have purchased from your account at http://www.PacktPub.com. If you purchased this book elsewhere, you can visit http://www.PacktPub.com/support and register to have the files e-mailed directly to you.
Errata
Although we have taken every care to ensure the accuracy of our content, mistakes do happen. If you find a mistake in one of our books—maybe a mistake in the text or the code—we would be grateful if you would report this to us. By doing so, you can save other readers from frustration and help us improve subsequent versions of this book. If you find any errata, please report them by visiting http://www.packtpub.com/support, selecting your book, clicking on the errata submission form link, and entering the details of your errata. Once your errata are verified, your submission will be accepted and the errata will be uploaded on our website, or added to any list of existing errata, under the Errata section of that title. Any existing errata can be viewed by selecting your title from http://www.packtpub.com/support.
Piracy
Piracy of copyright material on the Internet is an ongoing problem across all media. At Packt, we take the protection of our copyright and licenses very seriously. If you come across any illegal copies of our works, in any form, on the Internet, please provide us with the location address or website name immediately so that we can pursue a remedy.
Please contact us at <[email protected]> with a link to the suspected pirated material.
We appreciate your help in protecting our authors, and our ability to bring you valuable content.
Questions
You can contact us at <[email protected]> if you are having a problem with any aspect of the book, and we will do our best to address it.
Chapter 1. Understanding the Kinect Device
Welcome to the world of motion computing with Kinect. Kinect was originally known by the code name "Project Natal". It is a motion-sensing device which was originally developed for the Xbox 360 gaming console. One of the distinguishing factors that makes this device stand out among others in this genre is that it is not a hand-controlled device, but rather detects your body position, motion, and voice. Kinect provides a Natural User Interface (NUI) for interaction using body motion and gesture as well as spoken commands. Although this concept seems straight out of a fairytale, it is very much a reality now. The controller that was once the heart of a gaming device finds itself redundant in this Kinect age. You must be wondering where its replacement is. The answer, my friend, is YOU. It's you who is the replacement for the controller, and from now on, you are the controller for your Xbox. Kinect has ushered a new revolution in the gaming world, and it has completely changed the perception of a gaming device. Since its inception it has gone on to shatter several records in the gaming hardware domain. No wonder Kinect holds the Guinness World Record for being the "fastest selling consumer electronics device". One of the key selling points of the Kinect was the idea of "hands-free control", which caught the attention of gamers and tech enthusiasts alike and catapulted the device into instant stardom. This tremendous success has caused the Kinect to shatter all boundaries and venture out as an independent and standalone, gesture-controlled device.
It has now outgrown its Xbox roots and the Kinect sensor is no longer limited to only gaming. Kinect for Windows is a specially designed PC-centric sensor that helps developers to write their own code and develop real-life applications with human gestures and body motions. With the launch of the PC-centric Kinect for Windows devices, interest in motion-sensing software development has scaled a new peak.
As Kinect blazed through the market in such a short span of time, it has also created a necessity of resources that help people learn the technology in an appropriate way. As Kinect is still a relatively new entry into the market, the resources for learning how to develop applications for this device are scant. So how does a developer understand the basics of Kinect right from scratch? Here comes the utility of this book.
This book assumes that you have basic knowledge of C# and a great enthusiasm to program for Kinect devices. This book can be enjoyed by anybody interested in knowing more about the device and learning how to interact with devices using Kinect for Windows Software Development Kit (SDK). This book will also help you explore how to process video depth and audio stream, and build applications that interact with human body motion. The book has deliberately been kept simple and concise, which will aid in the quick grasping of the concepts.
Before delving into the development process, we need a good understanding of the device and, moreover, what the different types of applications are, which we can develop using these devices. In order to develop standard applications using the Kinect for Windows SDK, it is really important for us to understand the components it interacts with.
In this chapter we will cover the following topics:
Components of Kinect for Windows
Kinect is a horizontal device with depth sensors, color camera, and a set of microphones with everything secured inside a small, flat box. The flat box is attached to a small motor working as the base that enables the device to be tilted in a horizontal direction. The Kinect sensor includes the following key components:
Apart from the previously mentioned components, the Kinect device also has a power adapter for external power supply and a USB adapter to connect with a computer. The following figure shows the different components of a Kinect sensor:
Inside the Kinect sensor
From the outside, the Kinect sensor appears to be a plastic case with three cameras visible, but it has very sophisticated components, circuits, and algorithms embedded. If you remove the black plastic cover from the Kinect device, what will you see? The hardware components that make the Kinect sensor work.
The following image shows a front view of a Kinect sensor that's been unwrapped from its black case. Take a look (from left to right) at its IR emitter, color camera, and IR depth sensor:
Let's move further and discuss about component.
The color camera
This color camera is responsible for capturing and streaming the color video data. Its function is to detect the red, blue, and green colors from the source. The stream of data returned by the camera is a succession of still image frames. The Kinect color stream supports a speed of 30 frames per second (FPS) at a resolution of 640 x 480 pixels, and a maximum resolution of 1280 x 960 pixels at up to 12 FPS. The value of frames per second can vary depending on the resolution used for the image frame.
The viewable range for the Kinect cameras is 43 degrees vertical by 57 degrees horizontal. The following figure shows an illustration of the viewable range of the Kinect camera:
The following image shows a color image that was captured using Kinect color sensors with a resolution of 640 x 480 pixels:
IR emitter and IR depth sensor
Kinect depth sensors consist of an IR emitter and an IR depth sensor. Both of them work together to make things happen. The IR emitter may look like a camera from the outside, but it's an IR projector that constantly emits infrared light in a "pseudo-random dot" pattern over everything in front of it. These dots are normally invisible to us, but it is possible to capture their depth information using an IR depth sensor. The dotted light reflects off different objects, and the IR depth sensor reads them from the objects and converts them into depth information by measuring the distance between the sensor and the object from where the IR dot was read. The following figure shows how the overall depth sensing looks:
Note
It is quite fun and entertaining to know that these infrared dots can be seen by you. All we need is a night vision camera or goggles.
The depth data stream supports a resolution of 640 x 480 pixels, 320 x 240 pixels, and 80 x 60 pixels, and the sensor viewable range remains the same as the color camera.
The following image shows depth images that are captured from the depth image stream:
How depth data processing works
The Kinect sensor has the ability to capture a raw, 3D view of the objects in front of it, regardless of the lighting conditions of the room. It uses an infrared (IR) emitter and an IR depth sensor that is a monochrome CMOS (Complimentary Metal-Oxide-Semiconductor) sensor. The backbone behind this technology is from PrimeSense, and the following diagram shows how this works:
The sequence explained in the diagram is as follows:
When there is a need to capture depth data, the PrimeSense chip sends a signal to the infrared emitter to turn on the infrared light (1), and sends another signal to the IR depth sensor to initiate depth data capture from the current viewable range of the sensor (2). The IR emitter meanwhile starts sending an infrared light invisible to human eyes (3) to the objects in front of the device. The IR depth sensor starts reading the inferred data from the object based on the distance of the individual light points of reflection (4) and passes it to the PrimeSense chip (5). The PrimeSense chip then analyzes the captured data, and creates a per-frame depth image and passes it to the output depth stream as a depth image (6).
Note
The IR emitter emits an electromagnetic radiation. The wavelengths of the radiations are longer than the wavelength of the visible light, which makes the sensor's IR lights invisible. The wavelengths need to be consistent to minimize the noise within the captured data. Heat generated by the laser diode when the Kinect sensor is running can impact the wavelength. The Kinect sensor has a small, inbuilt fan to normalize the temperature and ensure that the wavelengths are consistent.
Tilt motor
The base and body part of the sensor are connected by a tiny motor. It is used to change the camera and sensor's angles, to get the correct position of the human skeleton within the room. The following image shows the motor along with three gears that enable the sensor to tilt at a specified range of angles:
The motor can be tilted vertically up to 27 degrees, which means that the Kinect sensor's angles can be shifted upwards or downwards by 27 degrees. The following figure shows an illustration of the angle being changed when the motor is tilted:
Note
Do not physically force the device into a specific angle. The Kinect for Windows SDK has a few specific APIs that can help us control the sensor's motor tilting. Do not tilt the Kinect motor frequently; use this as few times as possible and only when it's required.
Microphone array
The Kinect device exhibits great support for audio with the help of a microphone array. The microphone array consists of four different microphones that are placed in a linear order (three of them are spread on the right side and the other one is placed on the left side, as shown in the following image) at the bottom of the Kinect sensor:
The purpose of the microphone array is not just to let the Kinect device capture the sound but to also locate the direction of the audio wave. The main advantages of having an array of microphones over a single microphone are that capturing and recognizing the voice is done more effectively with enhanced noise suppression, echo cancellation, and beam-forming technology. This enables Kinect to be a highly bidirectional microphone that can identify the source of the sound and recognize the voice irrespective of the noise and echo present in the environment:
LED
An LED is placed in between the camera and the IR projector. It is used for indicating the status of the Kinect device. The green color of the LED indicates that the Kinect device drivers have loaded properly. If you are plugging Kinect into a computer, the LED will start with a green light once your system detects the device; however for full functionality of your device, you need to plug the device into an external power source.
Kinect for Windows versus Kinect for Xbox
Although "Kinect for Windows" and "Kinect for Xbox" are similar in many respects, there are several subtle differences from a developer's point of view. We have to keep in mind that the main purpose of Kinect for Xbox was to enhance the gaming experience of the players. Developing applications was not its primary purpose. In contrast, Kinect for Windows is primarily a developing device and not for gaming purposes.
You can develop applications that use either the Kinect for Windows sensor or the Kinect for Xbox sensor. The Kinect for Xbox sensor was built to track players that are up to 12 feet (4.0 meters) away from the sensor. But it fails to track objects that are very close (80 cm), and we might need to track objects at a very close range for different applications. The Kinect for Windows sensor has new firmware, which enables Near Mode tracking. Using Near Mode, Kinect for Windows supports the tracking of objects as close as 40 cm in front of the device without losing accuracy or precision. In terms of range both the sensors behave the same.
Note
Kinect for Windows SDK exposes APIs that can control the mode of the sensors (Near Mode or Default Mode) using our application, however the core changes for this feature are built within the firmware of the Kinect for Windows sensor.
Both the Kinect for Windows and Kinect for Xbox sensors need additional power for the sensors to work with your PC. This might not be required when connected to the Xbox device as the Xbox port has enough power to operate the device. There is no difference between Xbox Kinect and Kinect for Windows in this respect. However in Kinect for Windows, the USB cable is small and improved to enable more reliability and portability across a wide range of computers.
And finally, the Kinect for Windows sensor is for commercial applications, which means that if you are developing a commercial application, you must use the Kinect for Windows device for production, whereas you can use Kinect for Xbox for general development, learning, and research purposes.
Where can you use Kinect
By now it has already struck you that this is something more than just gaming. The Kinect sensor for Windows and the Kinect for Windows SDK unwrap a new opportunity for the developer to build a wide range of applications. These can include:
With this you can build a number of real-world applications that fall under a different domain. The following are a few examples, which will help you understand the applicability of Kinect sensors:
Well these were just a few specific examples of domains where you can use Kinect, but at the end of the day it's up to your imagination; where and how you want this device to work.
Summary
This chapter gave you an inside look at the different components of the Kinect sensor. You saw that the major components of a Kinect device are its color sensor, IR depth sensors, IR emitter, microphone arrays, and a stepper motor that can be tilted to change the Kinect camera angles. While the color sensor and depth sensors ensure video and depth data input, which is of prime importance for the functioning of the device, the microphone arrays on the other hand ensure that the audio quality is also at par. Also worthwhile is mentioning about how kinect processes the depth data, and the array of microphones, which is a design novelty that helps in clear voice recognition with the use of the noise suppression and echo cancelation mechanisms. Kinect for Windows is also capable of tracking humans at a close range of approximately 40 centimeters using Near Mode. It wouldn't be wrong to say that it is this combination of technological innovations that make Kinect the awe-inspiring device that it is. You have also gone through the different possibilities of applications that can be developed using Kinect. In the next chapter, we will walk you through the step-by-step installation and configuration of the development environment setup along with different troubleshooting tips and tricks that will help you to be sure about everything before beginning with development.
Chapter 2. Getting Started
The Kinect for Windows SDK is a toolkit for developing applications for Kinect devices. Developing applications using Kinect SDK is fairly easy and straightforward. The SDK provides an interface to interact with Kinect via system drivers. The SDK includes drivers for the Kinect sensor, which interact with the device, and the OS and APIs interact with the device through program. Overall, the SDK provides an opportunity to the developers to build an application using either managed code (C# and VB.NET) or unmanaged code (C++) using Visual Studio 2010 or higher versions, running on Windows 7 or Windows 8.
