1 Introduction The most profound technologies are those that disap- Copyrighted Materialpear. They – Taylor weave themselves & Francis into the fabric of every- day life until they are indistinguishable from it. —Mark Weiser The seminal work known as SketchPad [Sutherland 63], by Ivan Sutherland has inspired many researchers in the field of Human-Computer Interaction (HCI) and Three-Dimensional User Interface (3DUI). Sutherland created an elegant and sophisticated system, which is considered by some as the birth of computer user interface studies. The invention of the mouse by Douglas Engelbart in 1963 [English et al. 67] and the invention of the Graphical User Interface (GUI) in the Palo Alto Research Center (PARC) gave way to one of the most successful paradigms in HCI: Windows-Icon-Menu-Pointer (WIMP), which has allowed users to interact easily with computers. Today, with the introduction of new input devices, such as multi-touch surface displays, the Nintendo Wii Controller (WiiMote), the Microsoft Kinect, the Leap Motion sensor, and Inertial Navigation Systems (INS), the field of HCI finds itself at an important crossroads that requires solving new challenges. Humans interact with computers, relying on different input-output channels. This may include vision (and visual perception), auditory, tactile (touch), move- ment, speech, and others [Dix et al. 04]. In addition, humans use their (long and short-term) memory, cognition, and problem-solving skills to interact with computer systems [Dix et al. 04]. This computer interaction has a set of challenges that needs to be addressed. This book cover user input interfaces, the input for users when working with computer systems. The areas of HCI and 3DUIs are broad fields, making difficult for most books to cover details in depth about a specific topic. This book concentrates in input technology while other books may focus in other areas. There are some seminal books that covered more general topics, that any developer or researcher must have. Those are The seminal book titled The Psychology of Human Computer 3 4 1. Introduction Interaction [Card et al. 83]; User Interfaces: Theory and Practice1 [Bowman et al. 04]; Human-Computer Interaction [Dix et al. 04]; and Human Computer Interaction: An Empirical Research Perspective [MacKenzie 12]. The challenge for this book to be at par with the ones mention is great, the opportunity is welcome, and the journey is uphill. This book deals with input technologies in the form of user input interfaces (and 3DUI). The book is divided into three parts: theory, advanced topics, and hands- on approach. The book concentrates in concepts; however, whenever possible, complete source code will be made available in the book’s website. Additional material will also be found in the website, which includes the online chapters we have provided with the book. Finally, it is important to note that while the objective is to cover input interfaces, output devices are critical when using input. Therefore, this book will coverCopyrighted basic details Material about output – Taylor interfaces. & Francis The book covers input technology, which in most cases are commodity2 devices. However, it is hard to avoid the topic of Virtual Reality with the introduction of the Oculus Rift or even the Google Cardboard. Many of the topics covered in this book may be use in different types of environments. This book covers basic concepts of Virtual Reality (VR) headset. However, it is important to keep in mind that VR is outside the scope of this book in its current form. This chapters offers a brief introduction to HCI and input technologies. 1.1 The Vision Vannervar Bush was the director of the Office of Scientific Research and Develop- ment [Packer and Jordan 02] when he wrote “As We May Think” [Bush 45]3 which was the inspiration of scientist to come, including Ivan Sutherland. His vision was prophetic for many scientist that have cited him over 4000 times [MacKenzie 12]. Bush envision the personal workstation (which he called Memex) as an essential tool for researchers and every day users. He was ahead of his time saying that “a record if its to be useful to science, must be continuously extended, it must be stored, and above all it must be consulted”(p.37)4. He went on to write that “the human mind does not work that way. It operates by association”(p.43), which is important for 3D input user interfaces. This article has proven an inspiration by many scientist because of the vision that was laid and the remainder that collab- oration and thinking outside of the box is imperative. Ahead of its time, Bush wrote: A touch brings up the code book. Tapping a few keys projects the 1The authors are working in a newer edition. 2Off-the-shelf devices. We prefer affordable devices whenever possible. 3A reprint of this article is found in [Bush 96]. 4The quotes were taking from [Bush 96]. For additional comments see [Simpson et al. 96]. 1.2. Human-Computer Interaction 5 head of the trail. A lever runs through it at will, stopping at interesting items, going off on side excursions. It is an interesting trail, pertinent to the discussion. So he sets a reproducer in action, photographs the whole trail out, and passes it to his friends for insertion in his own memex, there to be linked into the more general trail. 1.2 Human-Computer Interaction HCI is the field that studies the exchange of information between computers and their users. The field emerged in the decade of the 1980s, with influences from many other fields, such as Psychology, Computer Science, Human Factors, and others. An alternateCopyrighted definition Material of HCI – is Taylor the communication & Francis between computer systems and computer users. How the communication enables the use of the technology is a central part of the study of HCI. A field closely related to HCI is Human Factors, which is concerned with the capabilities, limitations, and performance by people when using any type of systems5. Also, from the perspective of the system design, Human Factors studies the efficiency, safety, comfortability, and enjoyability when people use a given system. This seems quite close to HCI if you think of systems as computer systems [MacKenzie 12]. The HCI field also draws knowledge from Psychology. Some examples are Cognitive Psychology, Experimental Psychology, and others. This is very useful, as it helps us to understand users, and tests how they interact with different types of computer systems. HCI is a very broad field. In HCI, you can find VR, 3DUI, Affective Computing (which draws as much as from Psychology as it does from Artificial Intelligence (AI)), and others. Major events in the HCI community [MacKenzie 12] started with the vision of Vannevar Bush with “As We May Think,” the development of the Sketchpad by Ivan Sutherland, the development of the computer mouse by Douglas Engelbart, and the launch of the Xerox Star system. Then, the first interest group formed (SIGCHI6) in 1982, followed by the release of the seminal book, The Psychology of Human-Computer Interaction, and the release of the Apple Macintosh, starting a new era for computer systems. 1.2.1 Usability Usability is defined as the user acceptability of a system, where the system satisfies the user’s needs [Nielsen 94]. Furthermore, usability is an engineering process that is used to understand the effects of a given system with the user, in other words, how the system communicates with the user and vice-versa. Usefulness “is the issue of whether the system can be used to achieve some desired goal” [Nielsen 94]. 5It doesn’t have to be a computer system. 6See http://www.sigchi.org. 6 1. Introduction Side Note 1.1: The Mother of All Demos The seminal talk by Engelbert and colleagues became to be known as “The Mother of all Demos”. This presentation set the stage for what was to come. It prepared the way for what later innovations at Xerox Parc (see Figure 1.1), the commercial success of the Macintosh, and Microsoft Windows. It presented collaborated editor, word processing, and video conferencing, among others. Most importantly, it showcased the use of the mouse in conjunction with the keyboard to performed cut, copy, and paste, among other operations. Wendy Hu, reflected about Engelbart’s demo and said: “Engerlbart was not wholly prophetic; his obsession with viewing the human as an informa- tion processor,Copyrighted for example, Material keeps him – even Taylor today & from Francis appreciating the mouse’s value for its easy of use” [Ju 08]. Figure 1.1: Xerox PARC System. With permission This breaks down into utility and usability. Utility addresses the question of the functionality of the system, which means if the system can accomplish what it was intended for [Nielsen 94]. Usability in this case refers to “how well users can use that functionality” [Nielsen 94]. Finally, it is important to understand that usability 1.2. Human-Computer Interaction 7 applies to all aspects of a given system that a user might interact with [Nielsen 94]. The following list briefly describes the five traditional usability attributes (adapted from [Nielsen 94]): • Learnability: The system must have a very small learning curve, where the user can quickly become adapted to the system to perform the work required. • Efficiency: Once the user has learned the system, the productivity level achieved must be high in order to demonstrate a high efficiency. • Memorability: The system is considered to have a high memorability if when the user returns after some time of usage, the interaction is the same or betterCopyrighted than it was the Material first time. – Taylor & Francis • Errors: The system is considered to have a low error rate if the user makes few errors during the interaction.